Functional evaluation of wax-based oleogels as solid fat replacers for designing low saturated fat plant-based meat analogues

Abstract

Meat analogues have gained global attention as consumer demand increases for healthier and more sustainable food products. However, research aimed at replacing solid fats in meat analogues to lower saturated fat content remains very limited. Canola oil was structured with three natural waxes (candelilla wax, carnauba wax, and beeswax) and their potentials as solid fat replacers were evaluated for low saturated fat meat analogues. The wax-based oleogels retained solid fat at higher temperatures compared to coconut oil. Candelilla wax oleogels showed the highest hardness at room temperature. Upon melting, carnauba wax oleogels exhibited the highest viscosity and the greatest sensitivity to temperature changes, as evidenced by their highest activation energy. Replacement of coconut oil with wax-based oleogels did not significantly alter the visual appearance of meat analogues. Meat analogues with oleogels had significantly lower cooking loss, especially with carnauba wax oleogels. The hardness of coconut oil and oleogels was correlated to that of the corresponding meat analogues (R² = 0.76). Additionally, oleogel-based analogues had a much healthier fatty acid profile, with lower saturated and higher unsaturated fat content, closely resembling canola oil. Therefore, this study demonstrated that wax-based oleogels were promising solid fat alternatives for developing plant-based meat analogues with enhanced cooking performance and healthier fatty acid composition.

Introduction

Meat analogues have recently attracted the attention of current consumers due to increasing interest in health, sustainability and animal welfare¹. With this trend, the global alternative protein market is expected to grow from USD 15.3 billion in 2023 to USD 26.5 billion by 2030, with plant-based proteins accounting for the largest market volume at 88.9% in 2023². Since protein is the most important nutritional component of meat, the core of meat analogues likewise lies in their protein sources. Traditionally, soy protein has been widely used in meat analogue formulations³, largely due to its low cost and broad availability. In addition, a variety of alternative protein sources, including cereal-based proteins derived from wheat⁴, pea protein⁵ and mushroom-derived proteins⁶ have been explored for the development of meat analogues. Thus, most preceding studies on meat analogues have primarily focused on plant-based proteins to replicate the quality attributes of real meat^7–9. However, although lipids play a critical role in determining the nutritional and sensory quality of meat analogues, most products still rely solely on saturated fat–rich sources such as coconut oil and palm oil. Research exploring diverse alternative lipid sources remains limited, and efforts to reduce saturated fat content in meat analogues are still insufficient¹⁰.

There is a growing interest in replacing traditional solid fats with healthier fat alternatives that can provide the desired structural and sensory characteristics, since solid fats are high in saturated fatty acids, of which excessive intake has been associated with increased risks of cardiovascular diseases and other chronic health conditions¹¹. This trend is no exception in meat analogues. Guo et al.¹² used Spirulina platensis protein-based emulsion gels as fat replacers in meat analogues and reported comparable cooking loss and shrinkage to traditional fats. Furthermore, Lee et al.¹³ demonstrated that the use of O/W emulsions with Tween 80 and medium-chain triglyceride oil as a fat replacer improved the tenderness and juiciness of plant-based meat patties.

Structured lipid systems have attracted considerable interest in recent years as the food industry seeks healthier alternatives to conventional solid fats without compromising product quality¹⁴. These systems are designed to modify the physical organisation of liquid oils, allowing structured lipid systems to mimic the textural and functional properties of solid fats while maintaining a more favourable lipid profile. Among the various approaches, oleogelation technology has emerged as one of the most promising strategies. Oleogelation enables liquid oils to be structured into semi-solid or solid-like networks through the incorporation of oleogelators without requiring hydrogenation or other chemical modifications, offering functionality similar to that of conventional solid fats¹⁵. Among various oleogelators, natural waxes are widely used for oleogel preparation. In particular, carnauba wax, candelilla wax, and beeswax are approved as food additives and are commonly combined with various edible oils to produce oleogels. Carnauba wax may be used at levels up to 200–1200 mg/kg of food¹⁶. For candelilla wax, although an acceptable daily intake has not been established, low absorption, absence of genotoxicity, and sufficient margins of safety have been reported¹⁷. Likewise, the use of beeswax as a food additive—both for its current applications and newly proposed uses—has been deemed to pose no safety concerns¹⁸. Numerous studies have investigated the replacement of solid fats with wax-based oleogels in bakery products such as cakes¹⁹, cookies²⁰ and muffins²¹. Furthermore, oleogels have been widely studied as fat replacers in conventional meat products such as patties²², pâté²³ and sausages²⁴. Although several studies have reported the replacement of animal fat with ethyl cellulose–based oleogels²⁵, to the best of our knowledge, no studies have yet reported the application of wax-based oleogels in meat analogues.

In this study, oleogels were therefore prepared with three different waxes (candelilla wax, carnauba wax, and beeswax) and their physicochemical features were compared with coconut oil, which is typically used in meat analogues. Then, the oleogels were applied to meat analogues by completely replacing coconut oil and their effects on the quality attributes of meat analogues were evaluated.

Results and discussion

Characterisation of wax-based oleogels

The solid fat contents of coconut oil and canola oil oleogels prepared with candelilla wax, carnauba wax, and beeswax were evaluated within the temperature range of 10–90 °C (Fig. 1). Coconut oil exhibited a solid fat content of more than 55% up to 20 °C. However, it then decreased rapidly and completely melted into a liquid state at 30 °C. These results were consistent with the findings of Sonwai et al.²⁶ who reported the solid fat contents of acetone-fractionated coconut oils. In contrast, the oleogels showed a distinctly different trend of solid fat content compared to the coconut oil. Oleogels containing carnauba wax maintained a stable solid fat content up to 40 °C, after which a gradual decrease in solid fat content was observed at higher temperatures. In the case of candelilla wax oleogels, a reduction in solid fat content began at about 30 °C, and the oleogel completely melted at 70 °C. The beeswax oleogel samples exhibited the lowest melting point, with no solid fat content detected beyond 50 °C.

Fig. 1.

Solid fat content of coconut oil and oleogels structured with candelilla wax, carnauba wax, and beeswax.

The hardness of canola oil oleogels prepared with three different waxes was measured at room temperature using a puncture test and compared with that of the coconut oil. As shown in Fig. 2, the oleogel made with candelilla wax exhibited the hardest texture, followed by coconut oil, carnauba wax, and beeswax. With the incorporation of candelilla wax, canola oil appeared to undergo transformation into solid oleogels with a more rigid crystalline network, potentially resulting in the highest hardness. The hardness trend of wax-based oleogels was consistent with the findings reported by Scharfe et al.²⁷ and Dassanayake et al.²⁸.

Fig. 2.

Hardness of coconut oil and oleogels structured with candelilla wax, carnauba wax, and beeswax (Means with different letters on the bars significantly differ at p < 0.05).

The viscosity changes of melted oleogels were investigated in the temperature range of 50 and 90 °C (Fig. 3). Within this temperature range, the coconut oil showed lower viscosity than the oleogel samples. Around the temperature range of 50–70 °C, distinct viscosity differences were detected in carnauba wax and candelilla wax oleogels. The highest viscosity was clearly observed in the carnauba wax oleogel, followed by candelilla wax and beeswax oleogels. These results seemed to be derived from the solid fat contents of the samples, as already mentioned in Fig. 1. Furthermore, the effect of temperature on the viscosity of coconut oil and oleogels was analysed based on the Arrhenius model.

$$\eta =A·e^{\frac{E_{\mathrm{a}}}{RT}}$$ 1

where η is viscosity (Pa·s), A is the pre-exponential factor (Pa·s), $E_{\mathrm{a}}$ is the activation energy ($\mathrm{J}/\mathrm{mol}$), R is the universal gas constant ($8.314\mathrm{J}/\mathrm{mol}·\mathrm{K}$), and T is the absolute temperature (K).

Fig. 3.

Viscosity changes of coconut oil and oleogels prepared with candelilla wax, carnauba wax, and beeswax over temperature.

As shown in Table 1, all samples fit well with the Arrhenius model (R² > 0.95). The carnauba wax oleogel exhibited the highest value of activation energy ($E_{\mathrm{a}}$), followed by candelilla wax, beeswax, and coconut oil. A higher activation energy means that the viscosity changes more significantly with temperature, indicating a greater sensitivity to temperature variations²⁹. Therefore, the carnauba wax oleogel, which had the highest activation energy, exhibited the most temperature-sensitive viscosity change.

Table 1.

Arrhenius parameters of coconut oil and oleogels structured with candelilla wax, carnauba wax, and beeswax (Means with different letters in the same row differ significantly at p < 0.05)

	Coconut oil	Candelilla wax	Carnauba wax	Beeswax
Ea (J/mol)	2.36E + 04 ±0.49E + 03 d	5.52E + 04 ±1.31E + 03b	6.76E + 04 ±1.71E + 03a	2.88E + 04 ±1.93E + 03c
A (Pa s)	2.95E-06 ±3.74E-07a	1.06E-10 ±5.14E-11c	5.64E-12 ±3.74E-12c	6.96E-07 ±5.06E-07b
R2	0.9997	0.9620	0.9522	0.9732

Figure 4 shows the steady-shear viscosity of coconut oil and oleogels at 60 °C as a function of shear rate. As the viscosities of the oleogels were evaluated based on the type of wax used, it was observed that the carnauba wax-based oleogel exhibited the highest viscosity, followed by candelilla wax and beeswax-based oleogel, while coconut oil showed the lowest viscosity. These viscosity trends were in good agreement with the solid fat contents of the coconut oil and oleogels at 60 °C in Fig. 1. It was also noted that the viscosities of oleogels made with carnauba wax and candelilla wax decreased with increasing shear rate, distinctly exhibiting shear-thinning behaviour. However, oleogels prepared with beeswax and coconut oil seemed to display a Newtonian pattern, maintaining a constant viscosity across the range of shear rates applied in this study. As illustrated in Fig. 1, the beeswax oleogel and coconut oil were completely melted at 60 °C, whereas the carnauba wax and candelilla wax oleogels retained a portion of solid fat. Therefore, the rheological behaviour of the coconut oil and oleogels appeared to be significantly influenced by the presence and characteristics of suspended solid fat particles. In Newtonian fluids, shear stress is directly proportional to shear rate. As a result, the viscosity remains constant regardless of the applied shear rate³⁰. This behaviour is typically observed in fluids with low particle concentrations. On the other hand, non-Newtonian fluids exhibit a viscosity that varies with the shear rate. A common non-Newtonian behaviour is shear-thinning, where viscosity decreases as shear rate increases. This shear-thinning behaviour is often observed in fluids containing higher concentrations of particles since the internal structure of these fluids can be oriented or disrupted under shear stress³¹.

Fig. 4.

Steady shear viscosity of coconut oil and oleogels prepared with candelilla wax, carnauba wax, and beeswax at 60 °C.

Application of oleogels into plant-based meat analogues

Global interest in plant-based foods, including meat alternatives, has increased substantially. However, most studies have focused primarily on plant-derived proteins from legumes, mushrooms, and insects^32,33. In contrast, lipids—another primary component determining both nutritional and sensory characteristics—are still commonly supplied by palm oil or coconut oil, which contain high levels of saturated fats. Therefore, oleogels made from the three waxes (candelilla, carnauba, and beeswax) have great potential to serve as new lipid ingredients in meat analogues as they are food-grade and widely available, and their excellent gelation ability and structural stability have been demonstrated in numerous previous studies.

Table 2 shows the visual appearance and colour parameters of coconut oil, oleogels, and their corresponding meat analogues. Coconut oil and beeswax oleogel appeared white in visual appearance, whereas candelilla wax and carnauba wax oleogels exhibited a yellowish colour (Table 2a). The overall pattern of wax-dependent colour variation observed in this study was consistent with the findings of Lim et al.³⁴, although their study reported that carnauba wax oleogels exhibited a more intense yellow colour than those made with candelilla wax. Accordingly, coconut oil and beeswax oleogel showed higher lightness (L) values, while candelilla and carnauba wax oleogels exhibited relatively higher yellowness (b) values. Table 2b illustrates the visual appearance of meat analogues formulated with coconut oil and those in which coconut oil was replaced with oleogels. Overall, no negative differences in appearance were observed before and after cooking as a result of replacing coconut oil with oleogels. Furthermore, the substitution of coconut oil with oleogels did not pose any noticeable processing difficulties during the preparation of meat analogues. Interestingly, the colour of the meat analogues formulated with coconut oil and oleogels before cooking exhibited a pattern different from the inherent colour of the coconut oil and oleogels shown in Table 2a. Whereas the oleogels presented lower L values than coconut oil at room temperature (Table 2a), the patties containing oleogels showed higher L values than those containing coconut oil before cooking. Since the colour measurements were made at room temperature, coconut oil was partially melted, as shown in Fig. 1, while the oleogels remained in a solid state, likely producing a glossier and thus brighter surface appearance. After cooking, the sample with coconut oil and candelilla wax oleogel exhibited lower L values, leading to a darker appearance. These results might be partially explained by their relatively high cooking loss, which could promote more pronounced browning reactions during heating. The total colour difference (ΔE) varied depending on the type of oleogel used. Before cooking, meat analogues containing carnauba wax exhibited a markedly higher ΔE, whereas after cooking, ΔE decreased in all samples regardless of the wax type. The colour changes observed after cooking with oleogel replacement appeared to vary depending on the food matrix, showing increased L values with carnauba and beeswax oleogels in chicken³⁵ and frankfurter sausages³⁶, whereas candelilla wax oleogel decreased the L value in filling cream³⁷.

Table 2.

Visual appearance and colour parameters of (a) coconut oil, oleogels and (b) their corresponding meat analogues (Means with different letters in the same row differ significantly at p < 0.05)

(a)
	Coconut oil	Candelilla wax	Carnauba wax	Beeswax
Visual appearance
L	82.06 ± 0.66a	72.93 ± 0.64c	64.85 ± 0.07 d	76.83 ± 0.26b
a	−2.71 ± 0.16b	−2.22 ± 0.74b	−0.82 ± 0.22a	−4.58 ± 0.03c
b	5.70 ± 0.64c	27.28 ± 0.91a	26.79 ± 0.14a	8.67 ± 0.11b
ΔE	-	24.37 ± 0.57b	28.31 ± 0.08a	7.40 ± 0.25c

(b)
		Control	Candelilla wax	Carnauba wax	Beeswax
Before cooking	Visual appearance
	L	51.31 ± 0.45 d	58.54 ± 0.47b	63.25 ± 1.12a	56.34 ± 0.56c
	a	12.49 ± 0.37bc	12.08 ± 0.72c	13.98 ± 0.63a	13.08 ± 0.57b
	b	18.92 ± 0.47b	15.95 ± 1.60c	22.68 ± 1.06a	17.04 ± 0.88c
	ΔE	-	8.12 ± 0.76b	13.35 ± 1.44a	5.75 ± 0.56c
After cooking	Visual appearance
	L	31.78 ± 0.55b	27.25 ± 0.37c	34.03 ± 0.94a	34.86 ± 0.59a
	a	13.80 ± 0.48a	11.99 ± 0.40c	13.57 ± 0.30b	14.12 ± 0.66ab
	b	17.67 ± 0.90b	16.01 ± 0.32c	19.07 ± 0.50a	18.95 ± 0.45a
	ΔE	-	4.24 ± 0.43a	3.89 ± 0.92a	4.52 ± 0.68a

The effect of coconut oil replacement with oleogels on the cooking loss of meat analogues was presented in Fig. 5. Cooking loss is a critical quality attribute in meat and meat products, defined as the total weight reduction during the thermal processing (cooking), which primarily comprises the loss of moisture (water) and the exudation of fat (oil) from the meat matrix³⁸. In meat patties, it is necessary to minimise cooking loss because it directly affects the important quality attributes of the final products. Overall, meat analogues containing oleogels exhibited lower cooking loss than the control prepared with coconut oil. In particular, the sample prepared with carnauba wax oleogel showed a cooking loss of 12.03%, which was approximately 35% lower than that of the sample made with coconut oil. Although coconut oil and the oleogels largely melted during patty cooking, the patties formulated with carnauba wax oleogel still exhibited the lowest cooking loss. This outcome was likely related to the higher melting point of carnauba wax, which might allow the oleogel to maintain relatively higher viscosity and structural resistance in its liquid state during the heating phase compared to candelilla and beeswax oleogels, as shown in Figs. 3 and 4. The delayed melting and slower viscosity breakdown may help reduce the release of water and oil, thereby lowering total cooking loss. Similarly, Wang et al.³⁹ reported that when steaks were pan-fried using wax–pine seed oil gels as a butter substitute, the use of carnauba wax gel resulted in lower cooking loss values than butter.

Fig. 5.

Effect of coconut oil replacement with oleogels on the cooking loss of meat analogues (Means with different letters on the bars significantly differ at p < 0.05).

Figure 6 presents the texture properties of meat analogues formulated with coconut oil and oleogels at room temperature, which were characterised using TPA. The sample prepared with candelilla wax oleogel exhibited the highest value of hardness (12.7 N), which is defined as the maximum force during the first compression cycle, whereas the one made with beeswax oleogel showed the lowest hardness (7.9 N). It was also noted that the trend in hardness among the meat analogues closely resembled the hardness pattern observed between coconut oil and oleogels in Fig. 2, showing an R² value of 0.7613 (Fig. 6b). It was therefore inferred that the intrinsic hardness of each oleogel contributed to the hardness of the corresponding meat analogues, which may be influenced by cooking-related properties such as cooking loss. Because the oleogels exhibited higher viscosity than coconut oil, their corresponding samples showed greater adhesiveness (the negative force area following the initial compression) compared to the control. Although oleogels have not yet been applied to plant-based meat analogues to our knowledge, previous studies that incorporated oleogels into pâtés as animal fat replacers²³ reported a decrease in hardness when beeswax oleogel was used, whereas hardness increased when ethylcellulose oleogel was incorporated. As shown in Fig. 6a, the samples in which coconut oil was replaced with oleogels generally exhibited lower values in springiness, cohesiveness and chewiness, which represents the ability of the sample to recover its original height, its internal structural integrity based on the ratio of the first and second compression areas, and the energy required to masticate the solid sample to a swallowing state, respectively⁴⁰.

Fig. 6. Textural characterization of meat analogues prepared with coconut oil and oleogels.

a TPA parameters and b Hardness correlation between coconut oil/oleogels and their corresponding meat analogues (Means with different letters on the bars significantly differ at p < 0.05).

The fatty acid compositions of meat analogues formulated with coconut oil and oleogels were investigated before and after cooking (Table 3). The meat analogues formulated with coconut oil showed lauric acid, myristic acid, and palmitic acid as the predominant fatty acids, and caprylic acid and capric acid were also detected. De Marchi et al.⁴¹ similarly reported the presence of caprylic, capric, lauric and myristic acids in plant-based burgers when comparing the fatty acid profiles of plant-based and meat-based burgers. When coconut oil was replaced with wax-based oleogels, oleic acid, linoleic acid and linolenic acid became the major fatty acids, regardless of cooking. This fatty acid profile exhibited a pattern consistent with the inherent fatty acid compositions of coconut oil and canola oil. In addition, similar trends in fatty acid composition have been reported in various products where oleogels were used as fat replacers, such as cookies prepared with candelilla wax–canola oil oleogels instead of shortening⁴², instant noodles fried in soybean oil–carnauba wax oleogels⁴³, and meat patties formulated with HPMC–canola oil oleogels⁴⁴, all of which showed oleic acid, linoleic acid, and linolenic acid as the predominant fatty acids. From the perspective of fatty acid saturation, the meat analogue containing coconut oil consisted of approximately 94% saturated fatty acids and 6% unsaturated fatty acids, irrespective of cooking. In contrast, the oleogel-containing samples exhibited only about 7–16% saturated fatty acids, while more than 84% were unsaturated fatty acids. Consequently, the replacement of coconut oil with oleogels in meat analogues markedly decreased the saturated-to-unsaturated fat ratio from 15.60 to 0.08.

Table 3.

Fatty acid compositions of meat analogues with coconut oil and oleogels before (a) and after cooking (b)

(a)	Meat analogues
	Control	Candelilla wax	Carnauba wax	Beeswax
Caprylic acid	5.25 ± 0.05	-	-	-
Capric acid	5.29 ± 0.04	-	-	-
Lauric acid	49.68 ± 0.25	-	-	-
Myristic acid	19.82 ± 0.07	-	-	-
Palmitic acid	10.27 ± 0.08	5.80 ± 0.11	5.62 ± 0.04	8.21 ± 0.07
Stearic acid	3.57 ± 0.08	1.98 ± 0.06	1.67 ± 0.12	6.03 ± 0.07
Oleic acid	4.59 ± 0.08	58.13 ± 0.80	57.72 ± 0.22	54.89 ± 0.24
Linoleic acid	1.53 ± 0.04	22.58 ± 0.14	23.08 ± 0.14	20.95 ± 0.05
Linolenic acid	-	9.46 ± 0.70	9.72 ± 0.24	8.61 ± 0.08
Arachidic acid	-	0.68 ± 0.01	0.72 ± 0.04	0.76 ± 0.03
Eicosenoic acid	-	1.37 ± 0.06	1.47 ± 0.01	0.55 ± 0.04
Behenic acid	-	-	-	-
Saturated fatty acid (%)	93.89 ± 0.16	8.46 ± 0.13	8.01 ± 0.14	15.01 ± 0.16
Unsaturated fatty acid (%)	6.11 ± 0.16	91.54 ± 0.13	91.99 ± 0.14	84.99 ± 0.16
Saturated/Unsaturated	15.37 ± 0.42	0.09 ± 0.00	0.09 ± 0.00	0.18 ± 0.00

(b)	Meat analogues				Oils
	Control	Candelilla wax	Carnauba wax	Beeswax	Canola oil	Coconut oil
Caprylic acid	5.21 ± 0.38	-	-	-	-	7.65 ± 0.37
Capric acid	5.04 ± 0.25	-	-	-	-	5.36 ± 0.09
Lauric acid	50.05 ± 0.48		-	-	-	43.34 ± 0.18
Myristic acid	19.90 ± 0.20	-	-	-	-	18.56 ± 0.15
Palmitic acid	10.44 ± 0.36	4.66 ± 0.03	5.13 ± 0.06	7.93 ± 0.13	4.74 ± 0.02	10.93 ± 0.10
Stearic acid	3.31 ± 0.15	1.85 ± 0.04	1.96 ± 0.02	7.05 ± 0.20	2.04 ± 0.01	4.68 ± 0.05
Oleic acid	4.61 ± 0.30	60.34 ± 0.89	57.70 ± 0.03	53.26 ± 0.35	61.73 ± 0.19	7.51 ± 0.08
Linoleic acid	1.44 ± 0.09	22.53 ± 0.22	22.33 ± 0.04	20.82 ± 0.08	20.86 ± 0.10	1.97 ± 0.02
Linolenic acid	-	8.84 ± 0.79	10.75 ± 0.07	8.59 ± 0.14	7.74 ± 0.14	-
Arachidic acid	-	0.53 ± 0.03	0.65 ± 0.02	1.04 ± 0.03	0.63 ± 0.01	-
Eicosenoic acid	-	1.25 ± 0.03	1.48 ± 0.05	1.31 ± 0.02	1.91 ± 0.01	-
Behenic acid	-	-		-	0.35 ± 0.01	-
Saturated fatty acid (%)	93.95 ± 0.39	7.04 ± 0.12	7.75 ± 0.05	16.03 ±0.44	7.76 ± 0.03	90.52 ± 0.10
Unsaturated fatty acid (%)	6.05 ± 0.39	92.96 ± 0.12	92.25 ± 0.05	83.97 ±0.44	92.24 ± 0.03	9.48 ± 0.10
Saturated/unsaturated	15.60 ± 1.02	0.08 ± 0.00	0.08 ± 0.00	0.19 ±0.01	0.08 ± 0.00	9.55 ± 0.11

Table 4 presents the Pearson correlation coefficients between the fatty acid composition of meat analogues prepared with coconut oil and oleogels, and their texture properties and cooking loss. Distinct statistical correlations were not observed between fatty acid composition and cooking loss/hardness. However, among the texture parameters, adhesiveness, springiness, cohesiveness, and chewiness showed strong correlations with the levels of saturated and unsaturated fatty acids, although the p-values for adhesiveness and chewiness (approximately 0.05–0.08) were slightly higher than 0.05. In particular, springiness, cohesiveness, and chewiness exhibited positive correlations with saturated fatty acids, whereas negative correlations were observed with unsaturated fatty acids. In contrast, adhesiveness showed negative correlations with saturated fatty acids and positive correlations with unsaturated fatty acids. This trend may be attributed to the higher proportion of double bonds in unsaturated fatty acids, which leads to a more fluid-like and less crystalline structure, thereby resulting in decreased springiness and cohesiveness but increased adhesiveness. These results are comparable to the findings of Kong et al.⁴⁵, who replaced lamb fat with a lecithin/sorbitol monostearate–canola oil oleogel in lamb sausages, resulting in a reduction in saturated fat content to 59% and corresponding decreases in springiness and chewiness.

Table 4.

Relationship between fatty acid composition and quality attributes of meat analogues with coconut oil and oleogels (*indicates p < 0.05)

	Textural properties					Cooking loss
	Hardness	Adhesiveness	Springiness	Cohesiveness	Chewiness
Palmitic acid	−0.63	−0.98*	0.84	0.94	0.69	0.59
Stearic acid	−0.77	−0.30	0.02	0.14	−0.24	0.40
Oleic acid	0.31	0.96*	−0.96*	−1.00*	−0.91	−0.49
Linoleic acid	0.27	0.94	−0.97*	−0.99*	−0.93	−0.51
SFA	−0.28	−0.95	0.97*	0.99*	0.92	0.52
USFA	0.28	0.95	−0.97*	−0.99*	−0.92	−0.52

It has been reported that using wax-based oleogels at high concentrations can create a technical hurdle for food applications due to off-flavours or odours originating from the wax itself⁴⁶. However, food products such as cookies⁴⁷ and sponge cakes⁴⁸ formulated with wax-based oleogels have shown favourable sensory attributes, suggesting that, when used at appropriate concentrations, these oleogels can be incorporated without compromising sensory quality. Further study is therefore required to assess the sensory properties of wax-based oleogels when applied to plant-based meat analogues.

This study evaluated the physicochemical properties of wax-based oleogels and their application as solid fat replacers in plant-based meat analogues. Although all oleogels served as viable alternatives to coconut oil, their functional performance varied distinctly depending on the type of wax incorporated. Carnauba wax oleogel, characterised by its higher solid fat content and melting point, retained water and oil more effectively, resulting in the lowest cooking loss. In contrast, candelilla wax oleogel, exhibiting high intrinsic hardness but a relatively lower melting point and earlier solid fat reduction, produced meat analogues with the greatest hardness values. Thus, the inherent hardness of each oleogel was reflected in the hardness of the corresponding meat analogues. Furthermore, replacement of coconut oil with wax-based oleogels shifted the fatty acid profile from predominantly saturated to mostly unsaturated fatty acids, thereby substantially improving the nutritional quality of the final products. Overall, the findings of this study may provide insights for food manufacturers seeking to develop healthier meat analogues with reduced saturated fat content through the incorporation of oleogels.

Methods

Materials

Canola oil was purchased as a commercial product (Sajo Co., Seoul, Korea). Textured vegetable protein (TVP) and coconut oil were provided by Nongshim Taekyung (Seoul, Korea). Candelilla wax, carnauba wax, and beeswax were obtained from Kahl GmbH & Co. KG (Trittau, Germany), Starlight Co. (Fortaleza, Brazil) and Hooperpharm GmbH (Hamburg, Germany), respectively. Methylcellulose was purchased from a commercial source (Lotte Fine Chemical Co., Seoul, Korea). The other chemical reagents were of analytical grade.

Preparation of oleogels

Wax-based oleogels were prepared based on the procedure of Lim et al.³⁴. Canola oil was blended with each wax sample (candelilla wax, carnauba wax, and beeswax) at a concentration of 10% (w/w), a level that has been widely employed in preceding studies^22,49. The mixtures were then agitated and heated to 90 °C until the waxes were fully melted. After being solidified overnight at −18 °C to promote the development of a uniform and dense crystalline structure, the samples were equilibrated at room temperature for 1 h prior to analysis.

Measurement of solid fat content

The solid fat contents of coconut oil and oleogels were assessed using an Oxford MQC+ nuclear magnetic resonance system (Oxon, UK) across a temperature range from 10 °C to 90 °C. For each measurement, approximately 2–3 g of the sample was transferred into a 10 mm NMR tube and allowed to equilibrate at the designated temperature for 30 min.

Measurement of texture

A puncture test was applied to investigate the hardness of oleogels, which was compared with that of coconut oil. Based on the method of Jang et al.⁴², oleogel (20 g) was placed in a cylindrical container (height 5 cm, diameter 4 cm) on the platform of a texture analyser (TA-XT plus, Stable Micro Systems Ltd., Godalming, UK) at room temperature. A rod probe (5 mm diameter) was then lowered 10 mm into the oleogel sample at a crosshead speed of 100 mm/min at room temperature. The maximum peak force was recorded as hardness from the force-time plots.

Rheological measurement

The viscosity of coconut oil and oleogels was measured using a controlled-stress rheometer (Discovery HR-2, TA Instruments, New Castle, DE, USA) with parallel plates (40 mm diameter), employing two different measurement protocols. First, the viscosity of the melted oleogels was measured as a function of temperature at a constant shear rate of 100 s⁻¹ while the temperature increased from 50 °C to 90 °C at a rate of 2 °C/min. In addition, their steady shear viscosity was measured as a function of shear rate (1–500 s⁻¹) at 60 °C.

Preparation of meat analogues

Based on the preceding study of Lee et al.⁵⁰ with slight modifications, plant-based meat analogues were prepared using the following formulation: 18.59% TVP, 16.88% coconut oil, 2.03% methylcellulose, and 62.50% water. TVP, methylcellulose and water were mixed using a KitchenAid mixer (St. Joseph, MI, USA) for 10 min. Coconut oil was then added and blended for an additional 10 min. The mixture was shaped into patties using a mould (100 mm diameter × 18 mm height) and stored in a freezer at −18 °C. Prior to cooking, the samples were thawed at room temperature for 3 h and pan-fried at 150 °C in a Teflon-coated pan for 7 min, flipping them four times during cooking. The control meat analogue was prepared with coconut oil, and three different oleogels were applied to completely replace coconut oil.

Measurement of colour

The colour of meat analogue samples was measured using a colorimeter (CR-400, Konica Minolta Sensing, Inc.) and expressed as L, a, and b values, which indicate lightness/darkness, redness/greenness, and yellowness/blueness, respectively.

Measurement of cooking loss

The cooking loss of meat analogues was calculated by measuring their weights before and after cooking as follows:

$$\mathrm{C}\mathrm{o}\mathrm{o}\mathrm{k}\mathrm{i}\mathrm{n}\mathrm{g}\mathrm{l}\mathrm{o}\mathrm{s}\mathrm{s}\left(\mathrm{\%}\right)=(\mathrm{u}\mathrm{n}\mathrm{c}\mathrm{o}\mathrm{o}\mathrm{k}\mathrm{e}\mathrm{d}\mathrm{p}\mathrm{a}\mathrm{t}\mathrm{t}\mathrm{y}\mathrm{w}\mathrm{e}\mathrm{i}\mathrm{g}\mathrm{h}\mathrm{t}-\mathrm{c}\mathrm{o}\mathrm{o}\mathrm{k}\mathrm{e}\mathrm{d}\mathrm{p}\mathrm{a}\mathrm{t}\mathrm{t}\mathrm{y}\mathrm{w}\mathrm{e}\mathrm{i}\mathrm{g}\mathrm{h}\mathrm{t})/\left(\mathrm{u}\mathrm{n}\mathrm{c}\mathrm{o}\mathrm{o}\mathrm{k}\mathrm{e}\mathrm{d}\mathrm{p}\mathrm{a}\mathrm{t}\mathrm{t}\mathrm{y}\mathrm{w}\mathrm{e}\mathrm{i}\mathrm{g}\mathrm{h}\mathrm{t}\right)\times 100$$ 2

Measurement of texture after cooking

The textural properties of the meat analogues prepared with coconut oil and oleogels were analysed using a texture analyser (TA-XT plus, Stable Micro Systems Ltd.). After cooking, the samples were cooled at room temperature and then cut into cylindrical shapes (18 mm in height × 20 mm in diameter). Texture profile analysis (TPA) was performed with a 50 mm-diameter cylindrical probe (60% strain and 60 mm/min crosshead speed), and textural parameters (hardness, adhesiveness, springiness, cohesiveness, and chewiness) were obtained from the resulting TPA curves.

Determination of fatty acid composition

The fatty acid compositions of vegetable oils and meat analogues before and after cooking were analysed by gas chromatography (GC) equipped with a flame ionisation detector (7890A, Agilent, Santa Clara, USA). The samples were subjected to the Soxhlet extraction method with diethyl ether to extract oils. Fatty acids were converted into their corresponding methyl esters via derivatization with 14% boron trifluoride in methanol (BF₃/MeOH, Sigma-Aldrich, St. Louis, MO, USA), and the resulting FAMEs were separated on a SP-2560 capillary column (100 m × 0.25 mm i.d., 0.20 μm film thickness; Supelco Inc., Bellefonte, PA, USA). Triundecanoin (C11:0) dissolved in isooctane (1000 mg/L) served as the internal standard, and helium was used as the carrier gas at a flow rate of 0.75 mL/min, with the injector and detector temperatures maintained at 225 °C and 285 °C, respectively.

Statistical analysis

Meat analogue samples were prepared in three independent batches, and all measurements were performed in triplicate. Experimental values were expressed as mean ± standard deviation, and statistical analysis was conducted using analysis of variance (ANOVA) in the R software package (The R Foundation for Statistical Computing, Vienna, Austria) at a 95% confidence level. Duncan’s multiple range test was subsequently used to determine significant differences among the means. In addition, Pearson correlation analysis was performed to evaluate the relationships between fatty acid composition and quality attributes of meat analogues with coconut oil and oleogels.

Author contributions

Y.S.P. conducted formal analyses and study design, interpreted the data, and drafted and edited the manuscript. S.J. interpreted the data, supervised the study, and edited the manuscript. S.L. contributed to conceptualisation, supervised, edited the manuscript and acquired funding.

Data availability

Data will be made available on request.

Competing interests

The authors declare no competing interests.