Effect of encapsulated vitamin E on physical, storage and retention parameters in cookies

Abstract

Microencapsulated α-tocopherol and wheat germ oil (WGO) were incorporated as WGO (5.0 ml) in liquid: WGO-L, encapsulated: WGO-E, encapsulated α-tocopherol as E1, E2 and E3 at 2.0, 3.0 and 4.0 g respectively in cookies and evaluated for physical, sensory and shelf life parameters. Spread ratio was decreased, whereas hardness was increased with encapsulated formulations and observed least in WGO-L (40.52 N) formulated cookies. During storage moisture content was observed increased (2.51–4.78%), vitamin E was retained in all formulations except WGO-L and was found maximum in E3 (4.45 mg/100 g) formulated cookies. Formulations brought the peroxide value to nil, free fatty acid development was very less, better antioxidant activity (41.1% maximum), total plate count was observed least in E3 (25 × 10² cfu/g) and good sensory acceptance of cookies up to 4 months of storage. The study concluded that encapsulated vitamin E elevated the antioxidant activity and consequently shelf life and nutritive value of cookies.

Introduction

There is an increasing interest in food and biomedical industries in the creation of delivery systems to encapsulate, protect and release lipophilic bioactive compounds (McClements 2010). During food fortification protective encapsulation techniques are required to avert vitamins from degradation and these techniques enhance the bioavailability of vitamins in human gastrointestinal system (Ozturk 2017). Among fat soluble vitamins, vitamin E possess two main groups such as tocotrienols and tocopherols. The bioactive compounds γ-tocotrienol and α-tocopherol possess high antioxidant activity that exhibits their anticarcinogenic role. α-tocopherol is widely used in food industry and accepted as the major lipid-soluble antioxidant (Cervantes and Ulatowski 2017). However, α-tocopherol is very unstable because it is slowly oxidised by atmospheric oxygen through a reaction catalysed by light, heat and free radical mediated oxidative reactions. By using microencapsulation technique these obstructions can be partially overcome to safeguard α-tocopherol from adverse environmental conditions and this technique helps it to get solubilized in the aqueous environment (Farias et al. 2007).

Wheat germ oil (WGO) is abundant in vitamin E that is a kind of tocopherol which is composed of a saturated lateral chain of 16 carbons and a chromanol nucleus. Tocopherols are of different forms (α, β, γ, δ) depending upon the location of methyl group and number of methyl groups in the chromanol nucleus (Eisenmenger and Dunford 2008). Among vegetable oils, tocopherol content of WGO is maximum i.e. up to 2500 mg/kg that constitute 60% α-tocopherol (Ghafoor et al. 2017).

Yazicioglu et al. (2015) encapsulated wheat germ oil by ultrasonication using maltodexrin and whey protein concentrate in ratio of 1:3 with coating to core ratio of 8:1 and observed that it can be exploited as a functional food because the prepared formulation had the smallest particle size and highest encapsulation efficiency. Shylaja and Mathew (2016) reported the enhanced stability and slow release property of vitamin E loaded in solid lipid nano particles. Ying and Misran (2017) developed a thermoresponsive gel consisting of carboxymethyl cellulose and iota-carrageenan and lipid nanoparticles as a promising carrier system for α-tocopherol in topical use.Eghbal, and Choudhary (2018) reported that encapsules containing active compounds can be incorporated in food products for modification of texture, color, antimicrobial and antioxidant activities.

Cereal based cookies are products that represent an important energy source in the human nutrition. Cookies are widely consumed and accepted in many countries because they have a broad range of choices to be enjoyed as a snack with low cost and longer shelf life (Ostermann-Porcel et al. 2017). Shelf life of cookies varies between 4 and 5 months and during storage, cookies become rancid due to oxidation of fat present in cookies. No literature is available on shelf life study of any bakery product by incorporating encapsulated α-tochopherol and WGO. The main aim of this study was to determine the effect of incorporation of encapsulated wheat germ oil and α-tocopherol on shelf life and retention parameters of vitamin E in cookies. WGO and α-tocopherol was encapsulated using sodium alginate and pectin in ratio of 1.5:2 by encapsulator. A detailed study on the physical, sensory and storage attributes of cookies were conducted.

Materials and methods

Materials

α-tocopherol, a synthetic source of vitamin E and wheat germ oil, a natural source of vitamin E was procured from the Sigma Chemical Co. (St. Louis, USA). Tween 80, calcium chloride, pectin, sodium alginate were of CDH grade. Wheat flour, sugar, shortening, sodium bi carbonate, salt and aluminium laminate (polyethylene/aluminium foil/polyethylene—150 gauge) were obtained from local super market. Reagents used for analysis of cookies were of analytical grade.

Encapsulation

An in house developed encapsulator was used to prepare microcapsules using air atomization technique (Narsaiah et al. 2014). A schematic representation of the process of microencapsulation and a picture of dried encapsules is depicted in Fig. 1. Optimization of microencapsulation of α-tocopherol was part of this study (Singh et al. 2018).

Fig. 1.

a Method of microencapsulation. b Air dried encapsules

Product formulation

The planned treatments and cookie formulations are mentioned in Table 1. Incorporation of α-tocopherolin liquid state (without encapsulation) was evaluated in cookies for retention of vitamin E upon baking, but no retention was observed. Control sample was compared with encapsulated α-tocopherol and WGO incorporated cookies.

Table 1.

Planned treatments

Treatments	Level of incorporation
Control	–
WGO-L	5.0 ml
WGO-E	5.0 g
E1	2.0 g
E2	3.0 g
E3	4.0 g

WGO-L wheat germ oil liquid, WGO-E wheat germ oil encapsulated, E1 Encapsulated α-tocopherol (16.0 mg vitamin E), E2 Encapsulated α-tocopherol (24.0 mg vitamin E), E3 Encapsulated α-tocopherol (32.0 mg vitamin E)

Baking

For preparation of cookies, standard AACC (2000) procedure was followed. Dried encapsules were incorporated during creaming step for preparation of cookies, a firm dough was made. The dough was then sheeted up to 5 mm thickness, cut into circular cookies (5.5 cm diameter) and baked at 400 °F for 12.5 min. After baking, cookies were cooled to room temperature, packed in aluminium laminates and sealed. All the samples of cookies were stored at room temperature under protection from light.

Quality evaluation

Cooking quality and sensory evaluation

Diameter, thickness and spread ratio were calculated as reported by Sharma et al. (2016). Spread ratio of cookies was calculated by:

$$\text{Spread}\text{ratio}=\frac{\text{Average}\text{diameter}\text{of}6\text{cookies}}{\text{Average}\text{thickness}\text{of}6\text{cookies}}$$

Semi trained panel of judges evaluated the sensory parameters of cookies for top grain, crispness, flavour and overall acceptability using 9-point hedonic scale. The first sensory analysis was carried out 2 h after baking in a uniformly illuminated room by 20 semi trained judges comprising staff and students from department. The attributes were estimated on a 9-point hedonic scale (from 9 = liked extremely to 1 = disliked extremely) with a neutral point at 5 (neither like nor dislike) (Giuberti et al. 2018). Between the samples, crackers were provided to cleanse the palate. The second sensory analysis was done for overall acceptability of stored samples and cookies were evaluated at regular intervals. This test was conducted by > 70 trained and untrained panel members.

Texture analysis

The hardness of cookies was determined through a three point bending test performed by Stable Microsystem Texture Analyser Model (TA-H Di England) as described by (Pareyt et al. 2008).

Storage studies

Cookies were evaluated at normal interval of 15 days for a period of 4 months for change in moisture, free fatty acid development, antioxidant activity, total plate count, retention of vitamin E, peroxide value and overall acceptability. Mean temperatures and relative humidity were observed throughout the storage period.

Moisture, peroxide value and free fatty acids

Standard AOAC procedure (AOAC 2000) was followed for estimation of moisture content, peroxide value and frees fatty acids (% oleic acid) during storage study of cookies.

Determination of total % vitamin E

Vitamin E content of cookies was determined by deploying high performance liquid chromatography (HPLC) method (Arshad et al. 2008).

Estimation of antioxidant activity using DPPH method

The antioxidant activity was determined by radical scavenging ability using stable DPPH radical as described by Akowuah et al. (2005).

Total plate count

The samples were analyzed for total plate count as per standard APHA method (APHA 1980) at regular intervals during storage.

Statistical analysis

Data was analyzed employing SAS software version 9.1 (SAS Institute Inc., NC, USA) using analysis of variance (ANOVA). Duncan’s multiple comparison test was used for comparisons (p ≤ 0.05) to test the significant difference between experimental and control samples. All the results were the average of triplicates.

Results and discussions

Encapsulation of α-tocopherol and wheat germ oil

Lipophilic substances are encapsulated to facilitate their handling, maintain sustainable release and enhance stability. α-tocopherol and wheat germ oil (WGO) were microencapsulated with encapsulator using sodium alginate 1.5% w/v as wall material and pectin 2.0% w/v as filler as shown in Fig. 1b. The microencapsules prepared by sodium alginate to pectin ratio in 1.5:2 showed best parametric studies particularly encapsulation efficiency (55.97%). These microencapsules were obtained in powder form and were incorporated to the fat as depicted in Table 1, during creaming step for preparation of cookies and their effect on shelf life of cookies was observed. Singh et al. (2018) investigated that pectin at 2% and sodium alginate at 1.5% has broad potentiality for development of microspheres of α-tocopherol for food applications.

Effect of various treatments on cookie baking & sensory quality

Developed cookies were assessed for thickness, width, force to rupture, spread ratio and sensory parameters (Table 2). The spread factor is an important parameter for determining the quality of cookies. The thickness and width were found significantly higher in E3 treatment and the spread ratio was found significantly higher in control, similar results were reported by Arshad et al. (2008). Another physical parameter evaluated was force to rupture (hardness), which is an important aspect in cookie quality determination (Skrbic and Cvejanov 2011). Hardness was evaluated by peak force to rupture the cookie. Treatments affected significantly the rupture force of cookies. Table 2 shows that the force required to break cookies was observed least (40.52 N) in WGO-L and maximum in WGO-E, this may be due to liquid state of WGO in WGO-L treatment that decreased the hardness, improved softness and crispness in cookies. Surface attributes of cookies are also an important quality parameter. Treatment with WGO-L and WGO-E enhanced the surface cracks however, α-tocopherol treatment decreased the amount of surface cracks (Fig. 2). Arshad et al. (2008) reported that up to 50% replacement of shortening with WGO was suitable for production of cookies.

Table 2.

Effect of different treatments on physical and sensory quality of cookies

Sample	Thickness (cm)	Width (cm)	Spread ratio (W/T)	Force to rupture (N)	Top grain	Crispness	Flavour	Overall acceptability
Control	0.77 ± 0.01	5.80 ± 0.06	7.43 ± 0.04	57.27 ± 0.30	7.5 ± 0.09	7.7 ± 0.08	7.1 ± 0.08	7.2 ± 0.04
WGO-L	0.80 ± 0.01	5.73 ± 0.05	7.16 ± 0.05	40.52 ± 0.40	7.5 ± 0.12	7.5 ± 0.08	7.3 ± 0.08	7.5 ± 0.08
WGO-E	0.83 ± 0.01	5.75 ± 0.05	6.92 ± 0.07	65.24 ± 0.37	7.8 ± 0.04	7.3 ± 0.08	7.4 ± 0.04	7.5 ± 0.04
E1	0.83 ± 0.01	5.74 ± 0.05	6.91 ± 0.10	61.91 ± 5.00	7.6 ± 0.08	7.5 ± 0.04	7.5 ± 0.08	7.5 ± 0.08
E2	0.85 ± 0.01	5.80 ± 0.03	6.82 ± 0.04	59.84 ± 9.70	8.1 ± 0.04	8.2 ± 0.04	8.15 ± 0.08	8.3 ± 0.08
E3	0.88 ± 0.01	5.83 ± 0.03	6.62 ± 0.05	63.86 ± 9.89	8.5 ± 0.04	8.5 ± 0.08	8.2 ± 0.06	8.5 ± 0.04
LSD (0.05)	0.0448	0.164	0.2495	22.827	0.2294	0.2717	0.2784	0.2516

Means from triplicate experiments ± SD

Fig. 2.

Effect of different treatments on cookie baking quality

The sensory evaluation is very important criteria for quality evaluation of cookies. It is performed towards the end of product development. Trained panel of judges evaluated the cookies for sensory parameters on a 9-point hedonic scale. Analysis of variance depicted significant variation (p ≤ 0.05) regarding various sensory attributes for cookies (Table 2). Consumer acceptability and sensory characteristics of cookies incorporated with encapsulated WGO and α-tocopherol was observed good. It was reported that the taste parameters generally determine the acceptability of a product (Banureka and Mahendran 2011). Rating of the sensory panel exhibited that E3 cookies were preferred for all attributes. Arshad et al. (2008) prepared cookies with wheat germ oil to provide antioxidant properties in the diet. Sensory parameters of cookies containing wheat germ oil up to 50% were found acceptable for preparation of cookies. Therefore, these results suggested that cookies with good physical and sensory properties could be prepared by giving above treatments and were analysed for further storage study.

Shelf life of cookies

Cookies were filled in aluminium laminates, sealed and stored under ambient conditions for shelf life estimation. Cookies were evaluated at normal interval of 15 days for a period of 4 months for change in moisture, peroxide value, free fatty acid development, antioxidant activity, total plate count, retention of vitamin E, peroxide value and overall acceptability.

Effect of storage on moisture content, peroxide value and free fatty acid in cookies

Shelf life and stability of any food item is mainly defined by moisture content. High moisture content is usually linked with the undesirable changes in physico-chemical properties of the food product. During storage, moisture content of the cookies was significantly increased with storage (Table 3). Maximum moisture content was observed in cookies prepared by treating with WGO-L (3.15%) and the significant increase in moisture during storage was also maximum (3.15–4.78%), it may be due to addition of liquid form of WGO. Similar results were reported by Gupta and Singh (2005), they observed an increase in moisture content of biscuits after 60 days of storage at room temperature. Pasha et al. (2002) studied the chemical composition of cookies and reported that during storage, there were significant changes in moisture content of cookies.

Table 3.

Effect of treatments on the moisture content (%), peroxide value (mEq/kg) and free fatty acid (%) during storage studies of cookies

Storage period (days)	Moisture Content (%)						Peroxide value (mEq/kg)	Free fatty acid (%)
	Control	WGO-L	WGO-E	E1	E2	E3	Control	Control	WGO-L	WGO-E	E1	E2	E3
0	2.51 ± 0.04	3.15 ± 0.04	2.57 ± 0.04	2.59 ± 0.05	2.55 ± 0.05	2.56 ± 0.02	0.170	0.121 ± 0.002	0.105 ± 0.002	0.109 ± 0.004	0.104 ± 0.002	0.103 ± 0.001	0.101 ± 0.001
15	2.72 ± 0.03	3.50 ± 0.08	2.75 ± 0.04	2.71 ± 0.02	2.65 ± 0.04	2.67 ± 0.03	0.185	0.129 ± 0.002	0.108 ± 0.002	0.111 ± 0.002	0.106 ± 0.002	0.104 ± 0.001	0.102 ± 0.001
30	2.76 ± 0.02	3.75 ± 0.04	2.78 ± 0.05	2.79 ± 0.03	2.75 ± 0.02	2.77 ± 0.03	0.196	0.140 ± 0.001	0.110 ± 0.002	0.116 ± 0.001	0.109 ± 0.002	0.106 ± 0.001	0.104 ± 0.001
45	2.80 ± 0.04	3.94 ± 0.04	2.88 ± 0.07	2.85 ± 0.02	2.82 ± 0.03	2.83 ± 0.03	0.209	0.143 ± 0.002	0.112 ± 0.002	0.120 ± 0.004	0.113 ± 0.002	0.107 ± 0.001	0.104 ± 0.002
60	2.99 ± 0.04	4.09 ± 0.07	3.03 ± 0.03	2.91 ± 0.03	2.87 ± 0.03	2.88 ± 0.03	0.210	0.159 ± 0.003	0.115 ± 0.001	0.125 ± 0.002	0.114 ± 0.003	0.109 ± 0.002	0.105 ± 0.001
75	3.04 ± 0.02	4.18 ± 0.03	3.09 ± 0.04	2.96 ± 0.05	2.95 ± 0.04	2.94 ± 0.05	0.224	0.171 ± 0.003	0.116 ± 0.001	0.131 ± 0.002	0.116 ± 0.004	0.111 ± 0.002	0.107 ± 0.002
90	3.09 ± 0.04	4.45 ± 0.02	3.13 ± 0.02	3.07 ± 0.04	3.03 ± 0.03	3.05 ± 0.04	0.278	0.180 ± 0.002	0.120 ± 0.002	0.133 ± 0.002	0.118 ± 0.004	0.112 ± 0.001	0.109 ± 0.001
105	3.17 ± 0.07	4.60 ± 0.04	3.20 ± 0.04	3.15 ± 0.03	3.09 ± 0.05	3.11 ± 0.06	0.335	0.190 ± 0.002	0.124 ± 0.002	0.136 ± 0.002	0.120 ± 0.003	0.114 ± 0.001	0.110 ± 0.003
120	3.24 ± 0.05	4.78 ± 0.05	3.27 ± 0.03	3.27 ± 0.03	3.17 ± 0.04	3.20 ± 0.03	0.360	0.192 ± 0.002	0.125 ± 0.002	0.139 ± 0.002	0.121 ± 0.003	0.115 ± 0.001	0.111 ± 0.002
LSD (0.05) Treatments: 0.0515 Storage: 0.063							0.059	Treatments: 0.0029 Storage: 0.0035

Means from triplicate experiments ± SD

Most extensively used indicator of fat oxidation is peroxide value, as it determines the lipid peroxides and hydro peroxides generated during the initial primary stages of oxidation. It is mainly used for the determination of rancidity of the samples containing fat or oil when subjected to oxidation (Mehta et al. 2015). No peroxide formation was observed in cookies prepared with all treatments. Peroxide formation was found only in control sample and the trend in peroxide value was increased with increase in storage (0.170 mEq/kg in freshly prepared to 0.360 mEq/kg in 120 days storage period). There were non-detectable results found in peroxide value in cookies prepared by using various treatments due to inhibition or binding of free radical formation by antioxidant capacity of vitamin E present in WGO and α-tocopherol as given in Table 3. Arshad et al. (2007) monitored the lipid profile of experimental rats fed with cookies containing WGO and observed reduction in lipid per oxidation. Taking into account the non-detectable peroxide value in treated cookies, it can be concluded that WGO and encapsulated α-tocopherol prevent fat oxidation.

Free fatty acids (FFA) are produced on hydrolysis of fats and oils. Generation of FFA’s during storage released secondary oxidation products which are undesirable for the quality of food products as they produces rancid flavor and enhances the rate of development of free radicals. Prepared cookies from various treatments were evaluated for free fatty acid content during storage period but cookies were not evaluated for secondary oxidation products. At ambient temperature, significant difference (p < 0.05) was found in treatments and storage of cookies. The results obtained for free fatty acids from all treatments and control samples are given in Table 3. In control sample, free fatty acid was found increased with increase in storage period (0.121–0.192%). Wheat germ oil when incorporated in liquid and encapsulated form results were obtained in similar pattern i.e. free fatty acid content was observed significantly increased with increase in storage period but the increase was significantly less in liquid state of wheat germ oil (WGO-L 0.105–0.125%) than encapsulated state (WGO-E 0.109–0.139%). In α-tocopherol treated cookies, the development trend of free fatty acids was least. The free fatty acid content was found to be highest in control cookies (0.192%) and the treatment E3 had least free fatty acid (0.111%) up to end day of storage. Ghafoor et al. (2017) reported that the composition of WGO fatty acids may change depending on germ characteristics, wheat variety, storage, separation method and extraction conditions. Polyunsaturated fatty acids in WGO constitute 80% of triglycerides that are responsible for soapy and bitter flavor in foods.

Effect of storage on antioxidant activity, retention of vitamin E, TPC and overall acceptability of cookies

Data on the antioxidant activity, retention of vitamin E, TPC (total plate count) and overall acceptability of cookies is presented in Fig. 3a. Lipid oxidation in bakery products is of paramount importance as it results in loss of nutritive value and development of off flavors unacceptable to consumers (Ruiz et al. 2017).

Fig. 3.

Effect of treatments on a antioxidant activity (% inhibition activity), b retention of vitamin E (mg/100 g), c total plate count (× 10² cfu/g) and d overall acceptability during storage study of cookies

Cookies were evaluated for antioxidant activity during storage period. During storage, it was observed that there was significant decrease in antioxidant activity of control and treated cookies. In control cookies, antioxidant activity was observed decreased but trend was least with increase in storage period (18.7–10.8% inhibition activity). Cookies prepared by treatment with WGO liquid and encapsulated showed similar pattern i.e. antioxidant activity was observed decreased with increase in storage period but the antioxidant activity was more as compared to control (24.2–17.5% inhibition activity). Whereas in cookies with encapsulated α-tocopherol, E3 treatment showed maximum antioxidant capacity and it varied between 41.1% inhibition activity to 30.1% inhibition activity with storage. Akowuah et al. (2005) determined the radical scavenging ability using DPPH radical which evaluates the antioxidants capacity to quench a DPPH stable radical and observed that defatted wheat germ showed DPPH scavenging activities in a concentration dependent manner. The result revealed that defatted wheat germ is a primary antioxidant as well as a free radical inhibitor that reacts with free radicals which may limit their occurrence in human body. Chakrabarty (2003) reported that the presence of tocopherols in WGO is a vital property as it is beneficial for prevention of lipid peroxidation, acts as good source of nutraceuticals development and improves the cellular defence against free radicals.

Results regarding vitamin E retention in cookies are presented in Fig. 3b. No vitamin E content was found in control cookies. Cookies with WGO in liquid form showed maximum vitamin E in freshly prepared state (0.92%) and it was observed decreased with increase in storage and found 0.032% at 90th day of storage period. Vitamin E retention was nil at 105th and 120th day of storage, it may be due to oxidation to vitamin E during storage. In cookies with encapsulated WGO, vitamin E retention was more in fresh state (1.40%) and was found retained up to 4 months of storage period, which may be due to encapsulated state of WGO, which prevented the oxidation of vitamin E. Arshad et al. (2008) reported that the gradual increase of WGO in cookies improved the α-tocopherol content. In cookies with encapsulated α-tocopherol, vitamin E retention was highest as compare to control and WGO treatments. Among encapsulated α-tocopherol treatments, maximum vitamin E retention was found in E3 treatment (8.29%) and it decreased to 4.45% up till 120 days of storage period. Arshad et al. (2008) prepared cookies by adding wheat germ oil at various levels, with the means of providing high antioxidants in diet. They observed the retention of α-tocopherol in cookies with 100% replacement with WGO was highest (633,12 mg/kg fat). Ghafoor et al. (2017) reported that vitamin E at higher amounts acts as stabilizer for cell membrane by protection of unsaturated fatty acids from peroxidase cleavage. An American survey found bakery product particularly bread to be the fourth highest contributor to vitamin E intake for both men and women (Engelhart et al. 2002).

In addition to antioxidant activity and vitamin E retention in cookies, a microbiological evaluation i.e. total plate count, as an objective and widely used test in studying the quality of food, was performed. Prepared cookies were evaluated from total plate count during storage period. The results of total plate count during storage period are summarized in Fig. 3c. Total plate count was found increased with increase in storage period (18 × 10² cfu/g to 46 × 10² cfu/g) in control cookies. During storage studies of cookies, total plate count was significantly increased with time. The values are significantly different for all the treatments along with control. The highest plate count was found in WGO-L cookies (41 × 10² cfu/g). Least trend of increase in TPC was observed in E3 treated cookies, which may be due to antimicrobial property of vitamin E. Huang et al. (2006) reported that wheat germ act as a natural antibacterial agent against certain bacteria that cause infections in humans.

Figure 3d represents the overall acceptability of cookies with various treatments. The acceptance of the cookies was tested according to the 9-point hedonic scale. According to the gross sensory scores, the cookie samples exhibited highly acceptable sensory characteristics up to 4 months of storage period. Results revealed that in consumer preference tests, all samples extended a good acceptability up to end of storage period, however the decline in score was observed with the increase in storage period. To summarize, the present investigation demonstrated that the cookies treated with WGO in liquid and encapsulated state and α-tocopherol in encapsulated state improved the storage quality of cookies. Peroxide value was undetectable, free fatty acid development was less, E3 treatment showed maximum antioxidant activity, less microbial count in treated cookies and retention of vitamin E was maximum in E3 treated cookies.

Conclusion

The treated cookies showed better storage stability as compared to control samples. In fresh samples significant variations were observed for physical and sensory characters of cookies. Hardness was observed least in WGO-L treatment and sensory quality was best in E3 treatment. Storage characters of treated cookies were better than control samples. Least variation was observed in moisture content and peroxide value was non-detectable in treated cookies. However, generation of free fatty acid was very less as compared to control and was found increased with increase in storage period. Retention of vitamin E was observed in all treated cookies except WGO-L and was found maximum in E3 cookies up to 4 months of storage period. In WGO-L treated cookies no retention of vitamin E was observed after 90 days of storage period. Treated cookies showed good antioxidant activity as compared to control but antioxidant activity was found decreased with increase in storage period. Encapsulated WGO treated cookies showed better antioxidant activity as compared to WGO-L treated cookies. Samples remained microbiologically stable during storage and microbial count was least in E3 cookies. Overall acceptability revealed the good acceptance of cookies up to 4 months of storage. It was important to emphasize that our study resulted in a new food that favors the shelf life and improved nutritive value. Further works, exploring the role of encapsulated WGO and α-tocopherol as antioxidant and nutrients in developing various fat based functional foods, are recommended.

Compliance with ethical standards

Conflict of interest

The authors declare that there is no any conflict of interest.