Nutritional and qualitative characteristics of beef patties incorporated with hydrated coffee cherry pulp powder

Abstract

The development of more sustainable and healthful meat products is urgently needed. The purpose of the present investigation was to evaluate the impact of utilizing different levels of CCPP as a fat substitute on the nutritional, quality, and sensory attributes of burger samples. The chemical composition, functional characteristics, total phenolics, total flavonoids, anthocyanin, and antioxidant activity of CCPP were assessed. The proximate composition, cholesterol content, cooking qualities, and sensory aspects of produced burgers were investigated. CCPP is a nutrient-rich by-product that contains a crude fiber content of 36.66%, alongside significant levels of ash (6.97%), protein (10.16%), and carbohydrates (44.4%). CCPP exhibits several functional properties that enhance its application in food applications. Its water absorption capacity (WAC), oil absorption capacity (OAC), emulsifying activity, and foaming capacity are significant, with values of 3.25 ml H₂O/g, 2.80 mL oil/g, 43.5%, and 21.50%, respectively. TPC of CCPP was reported to be 24.70 mg GAE/g, with significant phenolic components which contribute to antioxidant activity of the CCPP. Incorporating CCPP into burger enhanced nutritional profiles by increasing fiber, protein, and ash content while significantly reducing fat levels. The 50% and 75% CCPP substitutions received over all acceptability scores of 8.25 and 8.22, respectively, suggesting strong consumer preference for these formulations.

Introduction

The transition towards meat substitutes is increasingly recognized as a vital strategy for enhancing sustainability in food systems¹. Various alternatives, including plant-based, insect, fungi, and single-cell proteins, present promising solutions to mitigate environmental impacts^1,2. However, the success of these substitutes hinges on understanding their nutritional profiles, technological feasibility, and consumer acceptance, which are critical for market penetration and dietary shifts³. In this regard, coffee cherry consists of several components, each contributing to its overall quality and potential applications. The skin, or pericarp, changes color from green to red as it ripens, indicating optimal harvest time and correlating with sugar accumulation, particularly sucrose, which is crucial for coffee quality⁴. Beneath the skin lies the sweet pulp, which is rich in bioactive compounds, making coffee cherry extracts valuable as superfoods with antioxidant and anti-inflammatory properties⁵. The mucilage layer, primarily composed of pectin, plays a role in the processing of coffee cherries⁶. The parchment and silverskin layers, often considered by-products, contain significant nutritional value and can be utilized in various industries, including food and pharmaceuticals⁶. Finally, the coffee bean, the endosperm, is the primary product, with its flavor profile influenced by the ripening process and metabolic changes⁷.

The processing of coffee cherries into beans generates significant waste, primarily through wet and dry methods. In the dry process, cherries are sun-dried, leading to the removal of skin, pulp, mucilage, parchment, and silverskin during de-hulling. This waste can be managed and repurpose effectively⁸. The dry processing method produces various residues, including husk, pulp, and parchment, which are rich in carbohydrates and bioactive compounds⁹.

Coffee Cherry Pulp powder (Cascara powder), a by-product of coffee production, presents both environmental challenges and opportunities for value-added applications. With over 430 g of pulp generated per kg of coffee cherries, the disposal of this waste can lead to significant environmental issues due to its high content of caffeine, polyphenols, and tannins^8,10. However, innovative uses have emerged, such as the production of coffee vinegar through fermentation, which optimizes the pulp’s nutrient content¹¹. Additionally, extraction methods utilizing natural deep eutectic solvents have been developed to recover valuable compounds like caffeine and chlorogenic acid from the pulp¹². Furthermore, coffee pulp can be transformed into non-wood paper, demonstrating its potential as a sustainable resource¹³. These applications highlight the dual nature of coffee cherry pulp as both a waste product and a valuable resource, suggesting a need for further exploration of its benefits and uses in various industries. Coffee pulp (CP), a significant byproduct of coffee processing, constitutes about 28% of the dry weight of coffee cherries, generating approximately two tons of CP for every ton of coffee produced^7,14. This waste, often overlooked, holds potential economic value through various applications¹⁴. Pleissner et al.¹⁵, found that coffee cheery pulp contains substantial quantities of protein (9–11%), lipids (2–17%), cellulose (13–27%), tannin (4.5%), pectin (6.5%), reducing sugar (12.4%), as well as non-nitrogenous extract (57–63%). CP can be processed into cascara tea, a functional drink rich in antioxidants, caffeine, and phenolic compounds¹⁶.

Coffee pulp contains high levels of carbohydrates, hemicellulose, and antioxidants, making it suitable for energy food products and functional drinks like cascara tea¹⁷. Spent coffee ground (SCG) is rich in dietary fibers and polyphenols, which enhance the nutritional value of baked goods, such as cookies, while extending their shelf life¹⁸. In this scenario, Pérez Calvo et al.¹⁷ combined coffee pulp with bars to generate functional bars with valuable nutritional qualities.

The growing consumer interest in safe and health-enhancing foods has led to a significant trend in product reformulation within the food industry. This strategy focuses on replacing traditional ingredients with healthier alternatives, which has been shown to positively impact consumer health and acceptance^19,20. Research indicates that consumers appreciate both ingredient reduction (e.g., fat and sodium) and nutrient addition (e.g., omega-3) in processed meats²¹. Successful reformulation can enhance product appeal without compromising sensory qualities, as demonstrated in studies involving various food product²².

The partial substitution of meat with plant-based products is increasingly recognized as a viable strategy to reduce meat consumption while maintaining desirable attributes of meat. This approach is gaining traction among consumers as it allows for dietary adjustments without complete elimination of meat, thus promoting acceptance and adherence. Below are key aspects of this strategy^23,24. Studies indicate that substituting animal meat with plant-based meat analogues can enhance satiety and improve diet quality, with increases in dietary fiber and reductions in saturated fat^25,26. The reformulation of burgers to reduce saturated fat content is a significant area of research, driven by health concerns associated with high animal fat intake. Various studies have explored alternative ingredients that can replace animal fats while maintaining sensory and physicochemical properties. This transition not only aims to enhance the nutritional profile of burgers but also to cater to consumer preferences for healthier options^27–29. In this regard, replacing 25% to 50% of animal fat with pijuayo flour improved tenderness and flavor, with a notable preference for the 25% reduction among consumers³⁰. Fenugreek Seed Gum demonstrated effective fat-like properties, allowing for a 57% reduction in cooking shrinkage and improved texture in low-fat burgers³¹. The use of oat meal and chia powder not only replaced 50% of animal fat but also enhanced water retention and cooking yield, leading to better overall quality^32,33.

The potential of using hydrated CCPP as a fat replacer in beef burgers or processed meat is promising, given its nutritional profile and functional benefits. Although no direct research has been conducted on its application in meat products. Therefore, the current investigation aimed to investigate the impact of adding varying quantities of CCPP as fat replacer on the nutritional and quality properties of beef burger.

Results and discussions

Total viable count, proximate composition, techno-functional properties, phenolic content, flavonoids content, anthocyanin content and antioxidant activity (%) of CCPP

To assess the safety of CCPP (cascara powder), the total viable count (TVC) was measured (Table 1). The total viable count (TVC) of CCPP (cascara powder) was 1.2 × 10³ CFU/g, indicating that it is safe for consumption (Table 1). This level is generally considered acceptable for food products, indicating minimal microbial contamination. The European Food Safety Authority³⁴. has deemed dried coffee husk (cascara) safe under specified conditions, with no significant toxicological concerns noted³⁴. The TVC of 1.2 × 10³ CFU/g falls well below the thresholds typically associated with foodborne illness, reinforcing its safety for consumption³⁵.

Table 1.

Total viable count, proximate composition, TVC, and some functional properties, Phenolic content (mg GAE/g)), flavonoids content (mg of catechin equivalents (CE) per g DW), anthocyanin content (mg/100 g) and antioxidant activity (%) of Coffee Cherry Pulp powder (Cascara powder)

Total Viable Count		Functional properties
Total Viable Count (CFU/g)	1.2 × 103	Water absorption capacity (mL of H2O/g of sample)	3.25 ± 0.50
Proximate composition		Oil absorption capacity (mL of oil/g of sample)	2.80 ± 0.11
Moisture (%)	8.33 ± 0.68	Emulsifying activity (%)	43.5 ± 1.40
Protein (%)	10.16 ± 0.82	Foaming capacity (%)	21.50 ± 0.50
Fat (%)	1.72 ± 0.13	Phenolic fractionation (HPLC), mg/g DM
Ash (%)	6.97 ± 0.40	Chlorogenic acid	2.61
Crude fiber (%)	36.66 ± 0.72	Caffeine	11.30
Carbohydratesa (%)	44.49 ± 1.92	Caffeic acid	0.32
Energy (kCal/100 g)	234.08 ± 0.96	p-Coumaric acid	0.11
Parameter		Ferulic acid	0.13
Total phenolic content (mg GAE/g)	24.70 ± 0.13	Protocatechuic acid	0.04
Total flavonoids (mg CE per g DW)	9.82 ± 0.11
Total anthocyanin content (mg/100 g)	16.68 ± 0.17
DPPH radical scavenging activity (%)	78.50 ± 1.50

Data are expressed as the mean ± standard deviation (n = 5).

^aby differences DM dry matter, GAE gallic acid equivalents, CE catechin equivalents.

Table 1 shows also the Proximate composition and techno-functional properties of CCPP. The moisture content of CCPP, measured at 8.33%, plays a crucial role in enhancing the shelf life of dried products. Low moisture levels inhibit microbial growth and enzymatic reactions, which are primary factors in food spoilage. This characteristic is particularly beneficial for products derived from CCPP, as it allows for extended storage and usability in various applications. Low moisture content significantly reduces the risk of spoilage, allowing products like Cascara to remain stable over time³⁶. Maintaining low moisture helps preserve the antioxidant properties of cascara, which are beneficial for health³⁷. The protein content of CCPP, was 10.16%, this value of protein content plays a significant role in enhancing the functional properties of food products that incorporate cascara powder. This protein content not only contributes to the nutritional profile but also supports various health benefits and functional applications in food formulations. Coffee by-products, including cascara, are recognized as alternative plant-based protein sources, providing essential amino acids and bioactive peptides³⁸. CCPP contains 10.16% protein, slightly lower than the 10.63% reported for coffee pulp³⁹. This indicates that CCPP may serve as a valuable source of protein, contributing to its potential applications in food and health sectors. The low-fat content of CCPP (1.72%) contributes positively to the stability of food products, enhancing their quality and shelf life. This characteristic allows for the incorporation of CCPP in various food applications, leading to improved nutritional profiles and functional properties. The low-fat content helps maintain a lower calorie count in products, making them more appealing to health-conscious consumers⁴⁰. Reducing fat content is linked to lower risks of obesity and related health issues, reinforcing the appeal of low-fat products⁴¹. CCPP had a high ash content of 6.97%, indicating the availability of mineral content that might improve the nutritional profile of food items. These characteristic positions cascara powder as a valuable ingredient in various food formulations, contributing to improved health benefits. The ash content reflects the presence of essential minerals such as calcium, magnesium, potassium, and trace elements like iron and zinc, which are crucial for various bodily functions⁴². Other coffee by-products, such as silverskin and defective beans, also exhibit high ash contents of 16.31% and 8.47% dw, respectively⁶. The crude fiber content of CCPP, was 36.66%. This high level of fibers contributes significantly in improving the functional properties of produced items. The incorporation of cascara powder increases dietary fiber content, which is beneficial for digestive health⁴³. In this regard, Eleora Setiawan et al.⁴⁴, reported that CCPP is rich in dietary fiber, which aids in digestion and can help prevent obesity by promoting satiety. The addition of CCPP in gluten-free bread formulations resulted in higher dietary fiber and protein content, enhancing the nutritional value of the bread⁴⁵. The total carbohydrate content of CCPP was 44.49%. This level of carbohydrates highlights the nutritional potential of CCPP, which is often overlooked as a by-product of coffee processing. Utilizing coffee by-products like cascara contributes to reducing waste in the coffee industry, promoting environmental sustainability⁴³. The energy value of CCPP at 234.08 Kcal per 100 g is relatively low compared to other food sources. However, this low caloric content can be contextualized within its nutritional benefits and potential applications in food products. The incorporation of CCPP into functional foods, such as energy bars, can enhance their nutritional profile while maintaining a reasonable caloric content¹⁷. CCPP can serve as a partial flour substitute in bakery products, allowing for a reduction in caloric intake while still providing essential nutrients⁴⁶. Our findings are consistent with those obtained by Machado et al.⁶, who assessed the chemical and bioactive potential of coffee by-products generated throughout the coffee processing chain. CCPP presents a compelling alternative as a fat replacer or food additive compared to wheat flour, brans, and vegetables due to its unique nutritional profile. With a crude fiber content of 36.66%, alongside notable levels of protein (10.16%), ash (6.97%), and carbohydrates (44.4%), CCPP offers distinct advantages in food formulations. CCPP’s 36.66% crude fiber can enhance satiety and improve digestive health, making it a beneficial ingredient in weight management products⁴⁷. At 10.16%, the protein content in CCPP can serve as a functional ingredient in various food applications⁴⁸. CCPP can effectively replace fats in baked products, similar to other fiber-based ingredients that reduce caloric content and improve texture⁴³.

The water absorption capacity (WAC) of CCPP was 3.25 ml of H₂O/g of sample (Table 1), this WAC value significantly enhances its functional properties in various applications. This high absorption capacity contributes to the development of innovative food products and absorbent materials. CCPP’s water-binding properties affect dough rheology, leading to stiffer dough and reduced bread volume when incorporated into recipes⁴⁷. CCPP increases dietary fiber and protein content in baked products, improving their health benefits⁴³. The high WAC of CCPP is significantly influenced by its rich dietary fiber and protein content (36.66 and 10.16%, respectively) (Table 1). This characteristic is essential for various food applications, enhancing texture and moisture retention in products. The fiber’s water-binding properties contribute to increased WAC, allowing it to absorb more water compared to other ingredients⁴⁹. CCPP also has a notable protein content of around 9.2%, which aids in moisture retention and contributes to the overall texture of food products⁵⁰. The water absorption capacity (WAC) of CCPP can be quantitatively compared with other food ingredients such as wheat bran, oat flour, and cocoa husk, which also exhibit significant water absorption properties. Wheat Bran has a WAC ranging from 2.5 to 3.0 ml of H2O/g. Its high fiber content contributes to its ability to retain moisture, making it a common ingredient in baked goods⁴⁷. Cocoa Husk shows a WAC of about 2.0 to 3.0 ml of H2O/g. Its fibrous nature allows it to absorb moisture, which can improve the mouthfeel of chocolate products⁴⁶. Oat Flour exhibits a WAC of approximately 2.0 to 3.5 ml of H2O/g. The soluble fiber in oat flour enhances its water retention, which is beneficial for texture in various formulations⁴⁷.

The oil absorption capacity (OAC) of CCPP was 2.80 ml of oil/g of sample, which is significantly influenced by its fiber and protein content. CCPP contains a high level of crude fiber, 36.66%, which contributes to its ability to absorb oil effectively (Table 1). This high OAC enhances the functional properties of food products, making CCPP a valuable ingredient in various applications. CCPP contains a high level of dietary fiber, approximately 51.2%, which contributes to its ability to absorb oil effectively⁵⁰. The protein content in CCPP, also aids in oil absorption, as proteins can interact with lipids, forming emulsions that stabilize oil in food matrices⁵⁰. This interaction can enhance the sensory attributes of food products, such as flavor and mouthfeel, making them more appealing to consumers⁴³. CCPP exhibits significant water and oil absorption capacities due to its unique composition and structural properties. This ability makes it a valuable ingredient in various food and cosmetic applications, as it can enhance texture and stability. CCPP is rich in dietary fibers, which are known to absorb and retain moisture and oils effectively. This characteristic is crucial for maintaining the desired consistency in food products⁴⁶. The presence of phenolic compounds and flavonoids contributes to its functional properties, enhancing its ability to hold water and oil while also providing antioxidant benefits⁵¹. The microstructure of cascara powder allows for increased surface area, facilitating better absorption of liquids compared to other ingredients⁵². The emulsifying activity of CCPP was 43.5%, indicates its potential as a functional ingredient in food applications. This property is significant due to the increasing interest in natural emulsifiers that can enhance food texture and stability. CCPP is rich in dietary fiber, protein, and bioactive compounds, making it a valuable addition to food products⁶. CCPP can serve as a natural emulsifier in various food products, potentially replacing synthetic additives⁵³. In this regard, Rosas-Sánchez et al.⁴⁷ noted that the fiber content of CCPP can enhance the dough’s rheological characteristics, which in turn affects baked product’ texture and volume. Foaming capacity (%) of CCPP was 21.5%, which highlights its potential as a functional ingredient in food products. This capacity is significant, as it suggests that CCPP can enhance the texture and mouthfeel of various beverages and food items.

The techno-functional properties of CCPP, such as high-water absorption capacity (WAC), OAC, emulsifying activity, and foaming capacity, significantly enhance the quality of beef burgers. These properties contribute to improved texture, moisture retention, and overall sensory experience in the final product. CCPP’s high WAC allows for better moisture retention during cooking, reducing shrinkage and improving juiciness in beef burgers⁵⁴. This property can lead to a more satisfying mouthfeel and prevent the burger from becoming dry. The OAC of CCPP aids in flavor retention, allowing the burger to maintain its taste profile even after cooking⁵⁵. This characteristic is crucial for enhancing the overall palatability of the beef burger.

Phenolic content (mg GAE/g)), flavonoids content (mg of catechin equivalents (CE) per g DW), anthocyanin content (mg/100 g) and antioxidant activity (%) of Coffee Cherry Pulp powder (Cascara powder)

The total phenolic content (TPC) of CCPP was recorded to be 24.70 mg GAE/g (Table 1), this value significantly enhances its antioxidant properties. This high TPC is crucial as phenolic compounds are known for their ability to scavenge free radicals, thereby providing protective effects against oxidative stress⁵⁶. High TPC correlates with increased scavenging activity against free radicals, demonstrating potent antioxidant effects¹⁰. Cascara extracts have shown significant inhibition of lipid peroxidation, further supporting their antioxidant potential¹⁰. The antioxidant properties of phenolic compounds in Cascara contribute to anti-aging effects by protecting skin cells from oxidative damage^10,57. This finding aligns with those obtained by Machado et al.⁶, who reported that TPC of coffee pulp was 2.37 g GAE/ 100 g). A study using an aqueous two-phase system (ATPS) for extracting polyphenols from coffee pulp reported a TPC of 434.63 mg GAE/g, which is significantly higher than the TPC of CCPP⁵⁸. Another research found that coffee pulp had a TPC of 40.6 mg GAE/g, which is also higher than that of CCPP⁵⁰. While CCPP has a lower TPC compared to some other coffee by-products, it still represents a valuable source of phenolic compounds. The differences in TPC can be attributed to the extraction methods and the specific coffee by-product analyzed. The extraction method significantly impacts the TPC, with techniques like ATPS and optimized solvent extraction yielding higher phenolic contents⁵⁸. The variety of coffee and the specific part of the coffee plant used (e.g., pulp, mucilage) also contribute to variations in TPC⁵⁹.

The total flavonoid content (TFC) of CCPP, was recorded at 9.82 mg CE per g DW, highlighting its potential as a source of bioactive compounds. This value reflects the significant antioxidant properties attributed to cascara, which can be harnessed for various applications. The presence of various phytochemicals, including flavonoids, contributes to its antioxidant properties, making it a valuable ingredient in functional foods⁶⁰. The TFC of coffee pulp, reported by Machado et al.⁶ as 1.23 g CE per 100 g, highlights the nutritional potential of this by-product. In this regard, CCPP’s flavonoid content is higher than that of other coffee by-products, such as silverskin and parchment, which have lower concentrations of bioactive compounds⁶. Different extraction methods yield varying flavonoid levels, for instance, Soxhlet extraction of coffee cherry pulp resulted in a significantly higher TFC of 296.8 mg QE/g extract¹⁰. The high flavonoid content positions CCPP as a valuable ingredient for food, cosmetic, and pharmaceutical industries, promoting sustainability in coffee processing⁶¹.

The total anthocyanin content of CCPP, has been recorded at 16.68 mg/100 g. This finding aligns with research indicating that coffee pulp is a significant source of anthocyanins, particularly cyanidin-3-rutinoside, which is the predominant pigment identified in various studies. Anthocyanins from coffee pulp exhibit various biological activities, including antioxidant properties and enzyme inhibition, which could be beneficial in food formulations⁶². The potential for using CCPP as a natural colorant in food products is supported by its anthocyanin content⁶³. The DPPH radical scavenging activity of CCPP, has been reported to be 78.50%. This high level of antioxidant activity indicates the potential of CCPP as a functional ingredient in food applications. Studies indicate that cascara from different coffee varieties, such as arabica and robusta, exhibits strong DPPH inhibition, with values ranging from 53 to 78%^37,64, Cascara is rich in phenolic compounds, which contribute to its antioxidant properties. For instance, TPC in cascara can reach up to 80 mg GAE/100 g³⁷. The presence of flavonoids and other phytometabolites further enhances its antioxidant potential, with specific extracts showing IC50 values as low as 9.59 mg/L⁵⁷. The DPPH radical scavenging activity of CCPP at 78.50% positions it favorably among various natural and synthetic antioxidants. The ethyl acetate fraction of Coffee arabica leaves exhibited an IC50 of 28.2 µg/ml, indicating a stronger antioxidant activity than CCPP⁶⁵.

The high content of phenolic compounds, flavonoids, and anthocyanins in CCPP extracts significantly enhances their antioxidant properties, making them appealing to health-conscious consumers. These compounds exhibit strong free radical scavenging activity, as evidenced by DPPH assays, which measure the ability to neutralize free radicals, thus contributing to the health benefits of the final product.

Table 1 shows the quantification of phenolic components in the ethanolic extract of CCPP. The quantification reveals significant bioactive compounds, with caffeine being the most abundant. This aligns with recent findings that emphasize the health benefits and applications of coffee by-products.

The most commonly found phenolic components (mg/g) in of the ethanolic extract of CCPP were caffeine (11.30 mg/g), known for its stimulant properties, caffeine also exhibits antioxidant effects, contributing to the overall health benefits of coffee cherry pulp⁵⁷, chlorogenic acid (2.61 mg/g) this compound is recognized for its antioxidant and anti-inflammatory properties, making it a valuable ingredient in functional foods and cosmetics⁶⁶, caffeic acid (0.32 mg/g), this acid is linked to various health benefits, including anti-cancer properties⁵, p-coumaric acid (0.11 mg/g), Ferulic acid (0.13 mg/g), both acids are noted for their antioxidant capabilities, enhancing the protective effects of the extract⁵. as well as protocatechuic acid (0.04 mg/g), this compound has been associated with anti-inflammatory and antioxidant activities⁶⁷. The presence of these phenolic compounds suggests that CCPP can be utilized in the food and pharmaceutical industries as a natural source of antioxidants. Their bioactive properties support the development of functional foods and cosmetic products aimed at promoting health and wellness⁶⁶. These findings are consistent with the findings of Machado et al.⁶, who identified the phenolic content of. In this regard, Coffee pulp is rich in phenolic compounds, including chlorogenic, caffeic, ferulic, and coumaric acids, which are beneficial for health and can be extracted using sustainable methods⁶⁷.

Proximate composition and cholesterol content (mg/100 g) of uncooked and cooked beef burger incorporated with different quantities of CCPP) as fat replacer

The incorporation of CCPP as a fat replacer in uncooked beef burgers significantly enhances moisture content, with levels observed between 60.46 and 63.89% (Table 2). Statistically, the formulation with 20% CCPP achieved the highest moisture content of 63.89% (P ≤ 0.05), supporting results from other studies that demonstrate fat replacers’ effectiveness in improving moisture retention and overall quality in low-fat beef products⁶⁸. Other non-meat adjuncts have been shown to improve water-holding capacity (WHC) in low-fat formulations, suggesting a broader trend in fat replacement strategies⁶⁹. The fiber content in CCPP can enhance the nutritional value of food products, making them healthier options for consumers⁴⁷. CCPP exhibits significant water absorption and gelling properties, which can improve the texture of food items⁴⁷. In this regard, Papageorgiou et al.¹⁸, reported that the incorporation of CCPP into formulations can lead to increased dough stiffness and improved shelf life of products, as observed in studies on bakery items. The cooking process of beef burger samples results in moisture loss, which affects the nutritional profile and overall quality. Table 2 indicates that the incorporation of CCPP as a fat replacer in burgers significantly reduces moisture loss during cooking, enhancing both moisture retention and nutritional content. Specifically, burgers with 100% CCPP exhibited a moisture loss of only 6.22%, compared to 10.28% in control samples. This reduction not only preserves moisture but also increases the concentration of protein and fat, thereby improving the nutritional profile of the burgers⁵⁴.

Table 2.

Proximate composition and cholesterol content (mg/100 g) of uncooked and cooked beef burger incorporated with different quantities of coffee cherry pulp (CCPP) as fat replacer

Trait	Coffee cherry pulp powder (replacement % as fat replacer)
	0	25	50	75	100
Uncooked
Moisture content (%)	60.46a ± 2.54	61.38b ± 1.65	62.27c ± 2.23	63.14 d ± 2.54	63.89e ± 1.98
Protein	17.54a ± 1.11	18.12ab ± 1.08	18.59bc ± 1.02	19.11c ± 1.82	19.64 cd ± 1.32
Fat (%)	19.37e ± 1.03	14.47 d ± 1.23	9.45c ± 0.98	4.73b ± 0.89	0.37a ± 0.03
Ash	1.75a ± 0.09	2.12ab ± 0.09	2.47b ± 0.32	2.84c ± 0.43	3.18 cd ± 0.49
Crude fiber (%)	0.18a ± 0.04	2.46b ± 0.06	2.71c ± 0.37	3.00 d ± 0.56	3.25e ± 0.49
fCarbohydrates (%)	0.70a ± 0.03	1.45b ± 0.04	4.51c ± 0.29	7.18 d ± 0.76	9.67e ± 0.45
Energy (kCal/100 g)	247.29e	208.51 d	159.41c	147.73b	120.57a
Cholesterol content (mg/100 g)	90.80d ± 2.77	83.20cd±3.86	80.77c± 3.56	73.83b ± 2.55	69.41a ± 2.16
Cooked
Moisture content	54.27a ± 1.23	55.00ab ± 1.32	57.54b ± 2.43	58.95c ± 2.61	59.91 d ± 234
Protein	22.59a ± 0.85	22.67a ± 0.98	23.28b ± 1.48	23.89c ± 2.32	24.57 d ± 1.29
Fat	18.54e ± 0.84	15.06 d ± 0.56	10.62c ± 1.32	6.07b ± 1.43	0.49a ± 0.03
Ash	2.37a ± 0.33	2.60ab ± 0.13	3.06b ± 0.32	3.48c ± 0.34	3.88 cd ± 0.42
Crude fiber	0.24a ± 0.03	2.60b ± 0.34	2.88bc ± 0.11	3.20c ± 0.45	3.44 d ± 0.65
fCarbohydrates (%)	1.99a ± 0.07	2.07b ± 0.24	2.62bc ± 0.23	4.41c ± 0.76	7.71 d ± 0.98
Energy (kCal/100 g)	265.18e	234.5 d	199.18c	167.83b	133.53a
Cholesterol content (mg/100 g)	111.23 d ± 3.44	104.93 cd ± 4.66	101.05c ± 3.56	94.22b ± 2.43	87.77a ± 2.54

Values are means ± SD of five determinations. Values are Mean ± standard deviation of five replicates. Means in the same row with different letters are significantly different (p ≤ 0.05). Values with different superscript letters in the same row differ significantly (p ≤ 0.05).

^fy difference. ND means not detected.

The incorporation of CCPP into beef burgers significantly enhances their protein content, with levels rising from 17.54 to 19.64% as CCPP inclusion increases (Table 2). This trend highlights the nutritional benefits of utilizing coffee by-products in meat formulations, promoting sustainability in the food industry. Beef burgers with CCPP exhibited higher protein levels compared to control samples without CCPP. The highest protein content (19.64%) was recorded in samples with 20% CCPP, indicating a direct correlation between CCPP levels and protein enhancement (Table 2). Coffee by-products, including CCPP, are recognized as potential sources of alternative proteins, essential amino acids, and bioactive peptides³⁸. The cooking process significantly increases protein content in burger samples, owing to moisture reduction process. Additionally, burgers incorporated with CCPP possessed greater protein contents than control samples. This phenomenon can be attributed to the unique properties of CCPP and its nutritional benefits. In this regard, Ariz et al.⁷⁰, reported that cooking process reduces moisture and concentrates protein levels in burgers. Plant-based burgers, including those with coffee by-products, have been found to have a protein profile similar to that of beef burgers, while also being richer in minerals and polyunsaturated fatty acids⁷¹. The incorporation of CCPP into beef burgers significantly reduces fat content, demonstrating its potential as a fat replacer. Specifically, burgers with 20% and 15% CCPP exhibited fat levels 52.35 and 4.09 times lower than a control burger with 20% beef fat, respectively. Hydrated CCPP serves as an effective natural fat replacer, enhancing moisture and fiber content while significantly lowering fat levels in food products. This dual functionality not only improves the nutritional profile but also maintains desirable sensory attributes in various formulations. Similar studies have shown that other plant-based ingredients, like pijuayo pulp, can also effectively lower fat levels in burgers by replacing animal fat without compromising sensory qualities^30,72. Other fat replacers, such as inulin, have demonstrated similar benefits, reducing fat content while maintaining desirable textural properties⁷³. The incorporation of CCPP into burger formulations significantly mitigates fat loss during cooking, attributed to the fiber content of CCPP that enhances fat retention. CCPP contains soluble and insoluble fibers that can absorb and retain fat during cooking, reducing the amount of fat lost compared to burgers without CCPP. Similar studies have shown that other high-fiber ingredients, such as pea fiber and oat flour, also improve fat retention in meat products, indicating a broader trend in utilizing fibers for fat reduction^33,74. Reducing fat content in burgers can lead to healthier products, potentially lowering risks associated with high saturated fat intake, such as heart disease^30,33.

The ash content in beef burger samples is a significant indicator of mineral content, with uncooked samples showing a range from 1.75 to 3.18% (Table 2). statistically, the addition of CCPP significantly increased the ash content, with the highest level of 3.18% achieved at a 20% CCPP supplementation. This enhancement is attributed to CCPP’s rich mineral profile, which contributes to the overall nutritional value of the burgers. This trend is echoed in research on non-conventional food plants (NCFPs), which also contribute to increased ash content and overall nutritional value in beef burgers⁷⁵. The ash content of burgers supplemented with 5%, 10%, 15%, and 20% CCPP was found to be 1.21, 1.41, 1.62, and 1.81 times higher than that of control samples without CCP, indicating a clear trend of enhanced mineral content due to the addition of CCPP. These findings indicate that the addition of CCPP contributes to higher ash content, which is indicative of increased minerals in the burgers.

The incorporation of CCPP into beef burgers significantly enhances their fiber content (Table 2), aligning with the trend of improving the nutritional profile of meat products. The observed increases in fiber content 13.66, 15.05, 16.66, and 18.05 times higher than control samples at 5%, 10%, 15%, and 20% incorporation demonstrate the potential of CCPP dietary fibers to address nutritional deficiencies in traditional meat formulations. Increased dietary fiber intake is significantly associated with reduced cardiovascular disease (CVD) risks and enhanced gut health. This relationship is primarily mediated through the modulation of gut microbiota, which can lower harmful metabolites such as trimethylamine-N-oxide (TMAO)⁷⁶. The cooking process significantly caused significant increases in crude fiber of cooked beef burger. The carbohydrate content in beef burger samples ranged from 0.70 to 9.67%. Significantly, the incorporation of CCPP as a fat replacer has been shown to enhance carbohydrate levels, achieving a maximum of 9.67% when 20% CCPP was added (Table 2). This finding highlights the potential of CCPP in improving the nutritional profile of beef burgers. CCPP serves as a functional ingredient that not only increases carbohydrates but may also contribute to other nutritional benefits.

Energy values of beef burger samples under investigation ranged from 120.57 to 247.29 K cal/100 g samples. The incorporation of CCPP into beef burgers significantly reduces their energy values compared to traditional burgers with 20% beef fat. The relationship between the percentage of CCPP and the caloric content of beef burgers indicates a significant reduction in energy values as the CCPP percentage increases. This trend is supported by various studies that explore the incorporation of different fat replacers in low-fat beef burgers, demonstrating that flavor can be maintained while achieving lower caloric content⁷⁷. As CCPP increases from 5 to 20%, caloric content decreases by 1.18 to 2.05 times, respectively (Table 2).

The findings of the current study suggest that it is feasible to develop a low-calorie burger that satisfies the needs of consumers for essential nutrients alongside lowering fat and saturated fat through incorporating and implementing novel ingredients such as using CCPP as a fat alternative.

Cholesterol content of burger samples under investigation ranged from 69.41 to 90.80 mg/100 g, dry weight basis. The results showed that incorporating CCPP as a fat replacer significantly reduces cholesterol levels compared to traditional beef fat. Table 2 indicates that as the percentage of CCPP increases, cholesterol content decreases, demonstrating a potential health benefit of using plant-based fat replacers in meat products. Incorporating CCPP into beef burger samples has demonstrated significant reductions in cholesterol levels, with varying effectiveness based on the incorporation levels. This aligns with broader research indicating that alternative ingredients can effectively lower cholesterol and fat content in meat products resulted in cholesterol reductions by factors of 1.09, 1.12, 1.22, and 1.31 at 5%, 10%, 15%, and 20% incorporation, respectively. Vegetable fibers, such as oat and chia flour, have been shown to effectively reduce fat and cholesterol in burgers³³. Pijuayo pulp not only reduced fat content but also improved sensory attributes, indicating that plant-based ingredients can enhance both health and palatability³⁰. The cooking process significantly affects the cholesterol content of beef burgers, primarily due to moisture loss during cooking.

Effect of adding different quantities of CCPP as fat replacer on cooking yield, moisture retention, fat retention and reduction in diameter %

Table 3 shows the effect of adding different quantities of CCPP as fat replacer on cooking yield, moisture retention, fat retention and reduction in diameter %. Burger samples under investigation exhibited cooking yields ranging from 77.45 to 85.19%. The incorporation of CCPP as a fat replacer into burger formulations shows significant improvements in cooking yields compared to control samples without CCPP. The highest cooking yield recorded was 85.19% for burgers with 20% CCPP, followed closely by 15% CCPP at 84.89%. This finding suggests that CCPP not only serves as a fat substitute but also contributes positively to the overall cooking performance of the burgers. Moisture retention values of beef burgher samples under investigation ranged from 69.52 to 79.88%. The evaluation of moisture retention values of beef burger samples under investigation reveals that incorporating CCPP as a fat replacer significantly enhances moisture retention compared to traditional beef fat (Table 3). The highest moisture retention (79.88%) was recorded for burgers with 20% CCPP, indicating the effectiveness of CCPP fibers in moisture adsorption during cooking. Control samples with 20% beef fat exhibited lower moisture retention, highlighting the potential of CCPP as a healthier alternative (Table 3).CCPP fibers possess high WHC, which contributes to increased moisture retention in meat products⁴⁹. The ability of CCPP to retain moisture is comparable to other carbohydrate-lipid composites (CLCs), which also improve moisture and cooking yield in low-fat beef patties⁷⁸ (Garzón et al.). The incorporation of CCPP as a fat replacer in beef burgers has shown remarkable improvements in fat retention values, significantly surpassing traditional beef fat samples. This innovative approach not only enhances the nutritional profile of the burgers but also aligns with the growing consumer demand for healthier meat products. The fat retention values for beef burgers with CCPP ranged from 90.99 to 92.09%, indicating a substantial improvement over the control sample, which contained 20% beef fat, with value of 74.13%. The enhancements in burger quality attributed to CCPP stem from its unique ability to retain fat and moisture during cooking, which significantly improves sensory characteristics (Table 1). CCPP effectively retains moisture and fat, leading to juicier burgers with enhanced mouthfeel and flavor. Other fat replacers, such as CLCs and vegetable fibers, also demonstrate improved fat retention and sensory properties in low-fat beef patties^33,78 (Garzón et al., For instance, cocoa shell powder not only increases fiber content but also reduces weight loss during cooking, enhancing the overall quality of meat products⁷⁹. The incorporation of CCPP as a fat replacer into beef burgers significantly mitigates diameter reduction during cooking, with reductions ranging from 6.74 to 27.20%. The highest reduction was observed in control samples with 20% beef fat, highlighting the potential of CCPP to enhance the structural integrity of the burgers by retaining fat and moisture. CCPP’s ability to hold fat and water contributes to reduced cooking losses and maintains burger size (Table 1). Similar studies have shown that other fat replacers, such as peach palm pulp, also reduce diameter loss and improve texture⁷².

Table 3.

Effect of adding different quantities of CCPP as fat replacer on cooking yield, moisture retention, fat retention, and reduction in diameter %

Treatments	Cooking Yield	Moisture Retention	Fat Retention	Reduction in diameter %
Control	77.45a ± 1.23	69.52a ± 2.50	74.13a ± 1.43	27.20e ± 1.61
T1*	80.84b ± 2.43	72.44b ± 1.65	84.14b ± 2.61	22.18 d ± 1.23
T2*	83.34bc ± 2.67	77.01c ± 2.51	93.66c ± 3.11	16.24c ± 1.02
T3*	84.89c ± 3.11	79.26 d ± 2.81	90.99c ± 2.52	11.93b ± 0.99
T3*	85.19 d ± 3.02	79.88 d ± 1.59	92.09c ± 3.01	6.74a ± 0.96

Values are means ± SD of five determinations. Values are Mean ± standard deviation of five replicates. Means in the same column with different letters are significantly different (p ≤ 0.05). For treatments T1, T2, T3, T4 and T5 the beef fat was replaced with hydrated coffee cherry pulp powder at levels of 25, 50,75, and 100% respectively.

The incorporation of CCPP into beef burgers significantly enhances their techno-functional properties, leading to improved cooking yield, moisture retention, and fat retention, while also minimizing diameter reduction. This is particularly relevant for formulations that utilize alternative fat sources or additives, which can modify the physical and chemical characteristics of the burgers.

Sensory properties of beef burger incorporated with different quantities of CCPP as fat replacer

The sensory properties of burgers significantly influence consumer acceptability, particularly for newly developed products. Sensory evaluation encompasses various attributes such as taste, texture, aroma, and appearance, which are critical in determining a product’s market success. Understanding these properties allows food developers to create products that align with consumer preferences⁶⁸. Visual appeal can significantly impact first impressions and overall acceptability. A well-presented product is more likely to attract consumers²⁰. The incorporation of CCPP as a fat replacer in burger formulations significantly impacts their sensory attributes, particularly appearance. Optimal results are achieved at a 10% substitution level, where the highest appearance score of 8.20 is recorded. Beyond this threshold, a decline in appearance values indicates the necessity for careful moderation in fat replacement to maintain sensory quality. Similar studies on other fat replacers, such as pijuayo pulp and peel flours, indicate that a 25% fat reduction can improve sensory attributes like tenderness and flavor, while higher substitutions may detract from overall liking^30,72. The use of vegetable fibers, such as oat and chia flour, also demonstrated improved technological characteristics, suggesting that the type and amount of fat replacer are critical for product quality³³. The color of food significantly influences its quality and consumer acceptability, particularly in products like burgers. In the case of burgers with varying levels of CCPP, the color values ranged from 7.5 to 8.35, with the highest scores observed at 50% substitution. However, increasing the CCPP substitution to 75% and 100% resulted in a significant decline in color values. This trend highlights the critical relationship between ingredient composition and color perception in food products (Table 4). 50% CCPP led to the highest color score of 8.35, indicating a favorable balance between fat reduction and color retention. Higher substitutions (75% and 100%) caused significant decreases in color values, suggesting that excessive replacement may negatively affect visual appeal. Finally, while the incorporation of CCPP can enhance nutritional profiles and reduce fat content, it is crucial to balance these benefits with the potential adverse effects on color, which may impact consumer acceptance. The incorporation of CCPP into burger formulations positively influences the texture properties of produced burgers. As the percentage of CCPP substitution increased, the texture scores of burger samples also improved, indicating enhanced consumer acceptability. This effect can be attributed to the unique properties of CCPP, which contribute to the overall texture and sensory experience of the burgers enhances the hardness and chewiness of burgers, leading to a more favorable texture profile. The addition of CCPP results in reduced weight and volume loss during cooking, which is crucial for maintaining texture (Table 4). Improved texture correlates with higher sensory acceptance, as texture is a significant factor influencing consumer preferences^33,68. Similar to CCPP, the addition of textured soy protein and collagen has been shown to enhance the texture and sensory properties of beef burgers⁵⁴. While the positive effects of CCPP on burger texture are evident, it is essential to consider that consumer preferences can vary widely. Some consumers may prioritize flavor over texture, suggesting that a balanced approach to ingredient formulation is necessary for optimal product acceptance. In this regard, products like biscuits made with cascara exhibit improved texture and consumer acceptance, attributed to the protein and fiber content⁴³. The incorporation of CCPP as a fat replacer in burger formulations significantly enhances juiciness. Table 4 shows that higher percentages of CCPP correlate with increased juiciness scores. For instance, burgers with 100% CCPP achieved a juiciness value of 8.65, compared to 6.70 for those control without CCPP. This improvement is attributed to the functional properties of CCPP, which contribute to moisture retention and texture enhancement. CCPP helps retain moisture in burgers, leading to a juicier product. The fibrous nature of CCPP enhances the mouthfeel, making the burger more palatable. (Table 1). Similar studies show that pijuayo flour also improves juiciness and tenderness in low-fat burgers, suggesting that various fruit pulps can serve as effective fat replacers³⁰. The flavor quality of burger products is significantly influenced by the incorporation of (CCPP) as fat replacer. Table 4 shows that burger samples with 75% CCPP as a fat replacer achieved the highest flavor score of 8.35, while increasing the substitution to 100% resulted in a significant decline in flavor quality. This trend highlights the delicate balance between fat content and flavor perception in meat products. The highest flavor scores were observed at 75% CCPP, suggesting that moderate fat replacement can enhance flavor without compromising sensory quality. The presence of specific flavor-enhancing compounds in CCPP may contribute to improved sensory attributes, aligning with findings that certain fruit pulps can enhance meat flavor³⁰. A shift to 100% CCPP led to a significant reduction in flavor scores, indicating that excessive fat replacement can detract from the overall sensory experience⁴⁶. Similar trends have been noted in other studies where higher levels of fruit or vegetable additions resulted in decreased meat flavor intensity⁶⁸. Conversely, while CCPP shows promise as a fat replacer, it is essential to consider consumer preferences and the potential for off-flavors when substituting fats in meat products. Balancing health benefits with sensory quality remains a challenge in product formulation. The overall acceptability of beef burger samples, particularly those incorporating CCPP as a fat replacer, demonstrates promising sensory attributes. The highest scores of 8.25 and 8.22 were noted for burgers with 50% and 75% CCPP substitution, respectively, indicating a favorable consumer response. Burgers with CCPP showed high overall acceptability, exceeding a score of 7.80, which signifies consumer preference. Similar studies have indicated that fat reduction can enhance sensory characteristics, such as tenderness and flavor, particularly at lower replacement levels³⁰. Other vegetable sources, like oat and chia flour, have also been shown to enhance the quality of low-fat burgers, suggesting a trend towards healthier formulations³³. The growing interest in healthier, lower-fat meat alternatives reflects a shift in consumer preferences towards products that maintain sensory quality while offering nutritional benefits²⁰.

Table 4.

Sensory properties of beef burger incorporated with different quantities of coffee cherry pulp (CCPP) as fat replacer

Treatments	Appearance	Color	Texture	Juiciness	Flavor	Overall acceptability
Control	7.50c ± 0.27	8.00b ± 0.65	8.00b ± 0.67	6.70 d ± 0.43	7.50c ± 0.98	7.54b ± 0.55
T1*	7.65c ± 0.56	8.15ab ± 0.78	8.10b ± 0.86	7.50c ± 0.38	7.60c ± 0.65	7.80b ± 0.92
T2*	8.20a ± 0.78	8.35a ± 0.59	8.35ab ± 0.54	8.20b ± 0.89	8.15ab ± 0.68	8.25a ± 0.52
T3*	8.00b ± 0.63	7.80bc ± 0.98	8.45a ± 0.98	8.50ab ± 0.87	8.35a ± 0.37	8.22a ± 0.51
T4*	8.00b ± 0.70	7.50c ± 0.85	8.50a ± 0.79	8.65a ± 0.32	8.10b±0.39	8.15ab ± 0.42

Values are Mean ± standard deviation of five replicates. Means in the same column with different letters are significantly different (p ≤ 0.05).

For treatments T1, T2, T3, T4 and T5 the beef fat was replaced with hydrated coffee cherry pulp powder at levels of 25, 50,75, and 100% respectively.

The results of the current study concluded that the incorporation of CCPP into beef burgers significantly enhances their nutritional profile by increasing protein content, reducing fat, and improving fiber levels. This innovative approach not only addresses health concerns associated with traditional beef burgers but also aligns with dietary trends favoring lower fat and higher fiber foods. CCPP inclusion raises protein content from 17.54% to 19.64% as the percentage of CCPP increases. Burgers with 20% and 15% CCPP show fat levels 52.35 and 4.09 times lower than a control burger with 20% beef fat, respectively. This reduction positions CCPP as an effective fat replacer, contributing to lower calorie intake and healthier fat profiles. CCPP significantly boosts fiber content, with increases of 13.66 to 18.05 times higher than control samples at varying CCPP levels. The ash content also rises to 3.18% at 20% CCPP, attributed to its rich mineral profile, enhancing the overall nutritional value. The energy values of CCPP-enriched burgers are lower compared to traditional beef burgers. Cholesterol levels decrease by factors of 1.09 to 1.31 with increasing CCPP incorporation, promoting heart health. Consumer acceptability scores for formulations with 50% and 75% CCPP were notably high, at 8.25 and 8.22, respectively, indicating a strong preference for these healthier alternatives.

Methods

Coffee Cherry Pulp powder (Cascara powder) (CCPP) was purchased from privet coffee producer, in Jizan, Saudi Arabia. Lean beef and beef fat were was purchased from the fresh meat section of Al Tamimi store in Buraidah, Qassim, Saudi Arabia. The reagents and chemical substances used in the present investigation have been ordered from Sigma Aldrich Chemical Co. (St. Louis, MO, USA). All chemicals and solvents were categorized as analytical.

Hydrated coffee cherry pulp powder

To prepare hydrolyzed CCPP, a series of systematic actions must be undertaken to ensure quality and efficacy. The process begins with washing the CCPP to eliminate contaminants, followed by draining excess water. Hydration is achieved by combining three parts distilled water with one-part CCPP for 24 h at room temperature (25 °C), after which any remaining water is drained before use⁸⁰. Once hydrated, the CCPP is used immediately in preparing meat burgers,

Processing of beef burger samples containing hydrated CCPP

The burger samples were made using standard techniques⁶⁸. The lean meat and beef fat were ground using an 8 mm plate by a kitchen mincer (Panasonic Meat Grinder 1700 W, MK-GX1710KTZ, Japan). The meat and fat mixture were subsequently combined with other ingredients (Table 5). The fat appropriate for each formulation was added. All burger samples were made with 65% lean beef. Consequently, the control burger was made with 65% lean meat and 20% beef fat.

Table 5.

Beef patties formulated with different levels of Hydrated CCPP (Cascara powder) (CCPP)

Treatments	Lean beef (g)	Beef Kidney fat (g)	Hydrated CCPP(g)	Ice flakes (g)	Spices mixtureb
Control	65	20.0	0.00	10	5
T1a	65	15.0	5.00	10	5
T2a	65	10.0	10.0	10	5
T3a	65	5.00	15.0	10	5
T4a	65	0.00	20.0	10	5

^aFor treatments T1, T2, T3, T4, and T5 the beef fat was replaced with hydrated CCPP at levels of 25, 50,75, and 100% respectively. The specified amounts of hydrated CCPP 5, 10, 15 and 20 grams—equal 1.25, 2.5, 3.75, and 5 g of dry powder, respectively.

^bThe mixture of spices contains 2 g salt, 0.5 g garlic powder, 0.5 onion powder, 0.5 meg nut powder, 1 g sugar, 0.2 g tripolyphosphate, 0.3 g ascorbic acid.

The study aimed to substitute the kidney fat of the developed beef burger (20%) with four different levels of hydrated CCPP as follow:

T1) 75% beef fat (15 g), 25% (5 g) CCPP

T2) 50%beef fat (10 g), 50% (10 g) CCPP.

T3), 25%beef fat (5 g), 75% (15 g) CCPP

T4) 0% beef fat − 100% (20 g) CCPP.

The performed mixture was hand-blended, processed in a meat grinder with a 0.5 cm plate, and molded into 100 g beef patties (10 mm thickness, 10 cm diameter). Beef patty samples were then placed on foam plates, covered in 10-micron polyethylene film, and frozen at −25 °C for later assessment. Each burger trial utilized 0.5 kg of beef meat. All trials were conducted using the identical batches of beef meat and fat. Chemical analysis was performed on five duplicates of each beef burger recipe.

Beef burger samples were grilled on an electric grill (Philips Contact Grill 5000 Series-2200W) at 180 °C for 5 min, until the core temperature reached 73 °C (Fig. 1). Finally, the samples were cooled and kept at −18 °C before being analyzed.

Fig. 1.

Cooked beef patties with different levels of hydrated coffee cherry pulp powder.

Analytical methods

The total viable count (TVC) of CCPP was measured according to the procedures described by Watson et al.³⁵.

Proximate analysis which includes moisture, ash, fat, protein, crude fiber and carbohydrate contents. Were conducted using standard procedure of AOAC⁸¹, AOAC 925.09B, AOAC method no. 930.22, AOAC 950.36, AOAC method no. 950.36, AOAC method no. 950.37).

The Association of Official Analytical Chemists⁸¹ procedures were implemented to determine the proximate parameters (carbohydrate, lipids, protein, and ash) of samples. The micro-Kjeldahl technique is utilized to measure nitrogen content, which is then converted to crude protein by multiplying the nitrogen value by 6.25 (OAC method no. 950.36). Moisture content was determined using weight difference methods, typically involving drying samples to a constant weight (AOAC 925.09B). Ash content was similarly assessed through incineration, allowing for the quantification of inorganic residues (AOAC method no. 930.22). Crude fat is extracted using petroleum ether, following AOAC protocols, which ensures effective lipid recovery AOAC 950.36. Crude fiber content was determined using a digestion technique (AOAC method no. 950.37), Carbohydrate content is calculated by difference, subtracting the sum of other proximate components from 100%⁸².

$$\%\mathrm{Total\; Carbohydrate}=[100-\%(\mathrm{Protein}+\mathrm{Fat}+\mathrm{Moisture}+\mathrm{Ash}+\mathrm{Fiber}\left)\right]$$

Energy values (kcal/100 g) were estimated using the Atwater conversion factor²⁰

$$\mathrm{Energy}\left(\mathrm{kcal}\mathrm{per}100\mathrm{g}\right)=\left[9\times \mathrm{lipids}\%+4\times \mathrm{proteins}\%+4\times \mathrm{carbohydrates}\%\right]$$

Functional properties of coffee cherry pulp powder

The method described by Xing et al.⁸³ involves a straightforward approach to measure WHC. 0.5 g of CCPP was immersed in 10 mL distilled water for 1 h at room temperature. The sample was centrifuged at 2000 × g for ten minutes, and the supernatant was collected. The precipitate was weighed correctly. The WHC was calculated as follows:

$$\mathrm{WHC\; g}/\mathrm{g}=\mathrm{W}2-\mathrm{W}1/\mathrm{W}3$$

where: W1 is the weight of the centrifuge tube, W2 is the weight after removing the supernatant, and W3 is the initial weight of the CCPP sample.

The method described by Li et al.⁸⁴ provides a systematic approach to quantify OHC. A 0.5 g sample is mixed with 10 mL of sunflower oil for one hour, followed by centrifugation at 1000 × g for 30 min, the supernatant and excess oil were collected. The sample weight was recorded, and the OHC was computed as follows: The OHC is calculated using the formula:

$$\mathrm{OHC}\left(\mathrm{g}/\mathrm{g}\right)=\left(\mathrm{W}2-\mathrm{W}1\right)/\mathrm{W}3$$

W1 represents the weight of the centrifuge tube, W2 is the weight of the precipitate after centrifugation, and W3 is the initial weight of the CCPP sample.

Foam capacity (FC %) The technique provided by Li et al.⁸⁴ was utilized to estimate the foam capacity (%) of CCPP.

0.5 g of CCPP was mixed with 50 mL of deionized water, and measured the starting liquid height. The foam height was measured every 15 min by stirring at 12,000 r/min for two minutes using a high-speed disperser. Foamability (FC) was measured by comparing the volume of the foam solution after shearing to its initial volume.

Emulsification capacity, measured in milliliters of oil per gram of CCPP was determined as described by El-Adawy et al.⁸⁰.

Determination of total phenolic content (TPC), total flavonoid content (TFC), Anthocyanin, DPPH radical scavenging activity

Dried samples (5 g) of CCPP were combined with 100 mL of 70% ethanol and 1% HCl for 72 h at room temperature 25 °C. The mixture was filtered using Whatman No. 1 filter paper to separate the liquid extract from solid residues. The resulting ethanolic extract was stored in capped vials at −25 °C to maintain its integrity for subsequent analyses

The Folin-C Assay was used to evaluate TPC, following earlier protocols described by Kupina et al.⁸⁵. The TPC was expressed as mg of gallic acid equivalent per gram of dry weight.

TFC was estimated using the aluminum chloride calorimetric technique based on the approach provided by Alsayari et al.^86,87. TFC is measured in mg of catechin equivalents (CE) per g DW.

The assessment of anthocyanins concentration was conducted in accordance with the method described by Alshammai et al.⁵⁶, involves calculating their content as cyanidin 3-glucoside equivalents. The anthocyanin content was determined using an ethanolic HCl solution, which facilitates the extraction of anthocyanins from samples. The absorbance was measured at 530 nm.

The Alsayari et al.⁸⁶ method for free radical scavenging of stable 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals was used to quantitatively assess the extracts’ antioxidant activity.

Ahmed and Ali’s⁷⁸ method were used to analyze phenolic components in an ethanolic extract of CCPP. HPLC analysis was performed using a Prodigy ODS-2 column (250 mm × 3.2 mm, Phenomenex, Cheshire, UK) with a G1315A diode array detector.

Determination of cholesterol

Cholesterol concentration was determined using previously published techniques by ref. ⁶⁸. Five grams of fat substances from beef burger samples were extracted with petroleum ether. The petroleum ether was removed by evaporation at 50 °C. The extracted fat was weighed and saponified with aqueous ethanolic KOH solution. The mixture was allowed to cool at room temperature before adding 10 mL of petroleum ether. The mixture was shaken vigorously for one minute. After the layers had separated, the ether layer was transferred to a clean test tube and the solvent was evaporated at 50 °C. To generate a chromophore for colorimetric analysis, acetic acid, ferrous sulfate and concentrated sulfuric acid (H₂SO₄₎ were added. The absorbance was measured at 490 nm compared to the reagent blank.

Cooking properties

The cooking yield, moisture retention, fat retention, reduction in diameter % as well as shrinkage % of beef patties were estimated by measuring the differences before and after cooking⁸⁸ and using the formulas listed below.

$$\mathrm{Cooking}\mathrm{yield}\left(\%\right)=\left(\mathrm{weight}\mathrm{of}\mathrm{cooked}\mathrm{burger}\right)/\left(\right)\mathrm{weight}\mathrm{of}\mathrm{raw}\left(\mathrm{Uncooked}\mathrm{burger}\right)\times 100$$ 1

$$\mathrm{Moisture\; Retention}=\mathrm{yield}\times (\mathrm{moisture\; of\; cooked}/\mathrm{moisture\; of\; raw})\times 100$$ 2

$$\mathrm{Fat\; Retention}=\mathrm{yield}\times (\mathrm{fat\; of\; cooked}/\mathrm{fat\; of\; raw})\times 100$$ 3

$$\mathrm{Reduction}\mathrm{in}\mathrm{diameter}\%=\left(\mathrm{diameter}\mathrm{of}\mathrm{raw}\mathrm{patty}-\mathrm{diameter}\mathrm{of}\mathrm{cooked}\mathrm{patty}\right)/\mathrm{diameter}\mathrm{of}\mathrm{raw}\mathrm{patty}\times 100$$ 4

Sensory evaluation

Qassin University Ethics Committee authorized the sensory evaluation procedures. Prior to the sensory assessment, panelists were given guidelines to ensure the reliability of their results. All panelists received information about the components in the beef burger samples. Before the study started, the panelists provided informed, written consent. Panelists were asked to participate in a sensory evaluation training session for Check-All-That-Apply (CATA) items. In accordance with ElAnany and Ali⁶⁸, 50 of healthy judges (20 females and 30 men, aged 25–40 years) were randomly selected from an independent company (producer for burger products) in Qassim, Saudi Arabia, accomplished a sensory evaluation, which is consistent with methodology in sensory analysis. The beef burger samples were a cooked and then cut into equal-sized portions to ensure uniformity in the samples presented to each panelist. Three cut of each formulated beef burger samples were served to the panelist.at 50 °C. Cooked burger samples were placed on white labeled plates with code numbers. Sensory properties of patties were evaluated in terms of appearance, color, texture, juiciness, flavor, and general acceptability (1: not like, 9: extremely like). To mitigate residual flavor effects during sensory evaluations, panelists were provided with plain water between samples, adhering to ISO standards in a controlled environment (ISO-DP ISO 6658:2017). Sensory evaluations were carried out in separate booths under controlled settings (white fluorescent lighting and a room temperature of 22 °C).

Statistical analysis

A one-way ANOVA test (Analysis of variance) was applied for data from five replicates (n = 5), (except sensory results (n = 50), using SPSS software version 21.0 (Chicago, IL, USA). Duncan multiple range tests were performed at the 0.05 level, as described by Gomez and Gomez⁸⁹.

Author contributions

conceptualization, methodology, software, validation, for-mal analysis, investigation, resources and data curation, writing—original draft preparation, Rehab F. M. Ali and Ayman M. ElAnany; writing—review and editing, Rehab F. M. Ali and Ayman M. ElAnany, supervision and project administration and funding acquisition, Rehab F. M. Ali. all authors haveread and agreed to the published version of the manuscript.

Data availability

The original contributions presented in the study are included in the article, further inquiries can be directed to the corresponding author.

Competing interests

The authors declare no competing interests.