Improving the Functional and Sensory Properties of Cookies by Ultrasonic Treatment of Whey Proteins

Department of Nutrition and Food Technology, Jordan University of Science and Technology, P.O. Box 3030, Irbid 22110, Jordan Department of Chemical Engineering, Jordan University of Science and Technology, P.O. Box 3030, Irbid 22110, Jordan Department of Physical Sciences, Jordan University of Science and Technology, P.O. Box 3030, Irbid 22110, Jordan Jadara University, Faculty of Law, P.O. Box 733, Irbid 21110, Jordan College of Applied Medical Sciences, King Saud University, Riyadh, Saudi Arabia Faculty of Business and Technologies, Utena University of Applied Sciences, Utena, Lithuania


Introduction
Recently, the demand for consuming nutritionally rich products has been increasing among consumers, and these products are ready to eat, have a long shelf life, and are categorized as high and good quality protein contents [1]. Cookies are one of the interesting food products that add a new functional ingredient, because they are easy to prepare, have a long shelf life, and have good acceptance by the population [2], and they are considered as the largest category of snacks around the world [3]. e manufacturing process of cookies was investigated by the authors in [3], and they said that the process was easy and took only 30 min.
First, fat and sugar were being creamed to a smooth consistency, then, eggs and milk were added and mixed, and after that, dry ingredients such as flour, baking powder, and salt were mixed together, followed by adding cream, vanilla extract, and nutmeg and then mixing to form dough. e dough was then placed in greased pans, and eggs were washed; finally, the cookies were baked at 150°C/20 min. In addition, eggs are used instead of water for proper dough formation [1] and milk is added due to its content of protein which contributes to structural properties of products such as emulsion, foaming, and gel properties [4]. Whey is a collective term referring to the serum of watery portion that separates from curd during conventional cheese making [5].
Main proteins present in milk are whey and casein, and also, milk is rich in calcium, phosphorus, essential amino acids, and water-soluble vitamins, which makes whey a highly nutritious product [6]. Whey protein concentrates (WPCs) have been found to be used in biscuits, cookies, cakes, sponges, icings, and glazes to improve texture, flavor, and appearance [7]. Also, whey can be used to produce refreshing beverages [8]. Guimaraes [9] showed that beverages based on whey with at least 51% (m./m.) of content are typically made from ingredients that consist of dairy compounds (liquid or powdered milk and whey). Furthermore, whey is characterized by excellent nutritional and functional properties and low cost of production [10,11]; however, its nutritional and functional properties can be enhanced by incorporating other ingredients such as fruit pulp and prebiotics [9]. Also, Lagrange [12] showed that in the last decades, the demand for high protein dairy powders increased like a whey protein isolate. Guralnick [13] explained that these powders provide a high-quality protein source and have a wide range of functional properties desired during processing and in finished product applications.
Tirloni [14] explained that whey proteins are also used in sports beverages, due to special functionality and high nutritional values. Wheat flour is considered to be the basic ingredient for bakery products such as chapatis, rotis, paratha, bread, buns, cookies, cakes, patties, and pancakes [15]. e chemical composition of whole-wheat flour is as follows: moisture (9.38-10.43%), ash (1.32-1.85%), crude protein (10.13-14.74%), crude fat (1.96-2.52%), crude fiber (2.31-2.99%), nitrogen-free extract (78.71-85.37%), wet gluten (23.53-38.71%), and dry gluten (7.51-13.52%) among different wheat [16]. On the other hand, ultrasound (US) is defined as waves of a mechanical nature that require an elastic medium to propagate, US waves propagate at frequencies greater than 20 kHz (upper limit of audibility for the human ear), and US has been applied to food technologies due to its mechanical and/or chemical effects on improving the processes of homogenization, mixing, filtration, crystallization, dehydration, and others [17]. Frequency, processing time, and power of ultrasound are factors which have significant effects on food [18]. Ultrasound treatment is one of the nonthermal technologies that are studied regarding microbial inactivation and microstructural changes, so this technology is important in dairy products, which represents one of the most important sectors of the food industry and has a wide range of products developed from various processes [19]. Ultrasound frequency range is divided into two types: low and high frequencies. Low frequencies use intensities below 1 W/cm2 and higher than 100 kHz. High frequencies use intensities higher than 1 W/m2 and between 20 and 500 kHz [20]. Results showed that high pressure and US vibrations significantly affect the physical and structural properties of proteins, When whey protein concentrate was treated with ultrasound, a reduction in molecular size was observed.
is indicates that ultrasound increased the particle size and decreased the range for particle size distribution.
is resulted in the formation of molecule aggregates [21].

Materials and Methods
Soft wheat flour, sugar, and shortening was procured from the local market of Jordan and kept at room temperature for further use. All chemicals used were of analytical grade.

Sample Preparation of Cookies.
ree levels of whey protein concentrate (WPC) were used to prepare cookies along with wheat flour. Dough was prepared for 30 min and sheeted manually to a thickness of 5 mm by means of a rolling pin. After that, the cookies were cut by using a 50 mm diameter cookie cutter. en, they were baked at 220°C for 10 min in an oven and cooled at room temperature for one hour and packed in sealed polythene bags for further analysis.

Proximate Analysis of Cookies.
e approximate composition of samples including moisture content, ash content, crude protein, crude fat, and crude fiber based on the dry weight were measured according to the American Association of Cereal Chemists (2000).

Spread Factor.
e AACC Method 10-50D (1983) was used to evaluate the cookie width, thickness, and spread factor. e cookie width (W) was measured by placing six cookies edge to edge to get the average width in mm. e cookie thickness (T) was measured by stacking six cookies on top of each other and restacking in different order and remeasuring them to get the average in mm. e spread factor (SF) was determined from width and thickness as shown in the following equation: C.F is the correction factor for adjusting W/T (as is) to constant atmospheric pressure. For this work, C.F was taken to be 1.0.

Consumer Test.
e consumer sample population was selected from the database of consumers in Jordan University of Science and Technology, who were 18-60 years of age and of various socioeconomic backgrounds. Consumers responded to an e-mail survey questionnaire including demographics as well as the consumption frequency of biscuits. Only those who consumed biscuits at least once per week were selected to participate in the assessment, with a target of 60 participants (36 males and 24 females).
Consumer testing was conducted at the Jordan University of Science and Technology Sensory Analysis Laboratories. Respondents were provided with ID cards in the order in which they arrive at the test site and directed to individual test booths with written instructions and balloting. A blind basis method of analysis was used, where samples were coded with randomly selected 3 digit numbers and balanced ordered testing.
Each consumer was provided with a tray containing 6 pieces of biscuit treatments (for each of sample) in 50 mL plastic sample containers. To eliminate carry over factors, consumers were also provided with unsalted crackers and room temperature water for mouth cleansing between samples. e consumers were asked to record their acceptance and intensity scores for overall impression, overall flavor, overall texture, and overall color (9 point scale with 9 � "like extremely" and 1 � "dislike extremely"); crust and crumb (just about the right scale with 1 � much too rough walls and no pores, 2 � too rough walls and no pores, 3 � just about right, 4 � too soft walls and pores, and 5 � much too soft walls and pores); hardness (just about the right scale with 1 � "much too soft" and 5 � "much too hard"); adhesiveness (just about the right scale with 1 � much too nonadhesive, 2 � too non-adhesive, 3 � just about right, 4 � too adhesive, and 5 � much too adhesive).

Quantitative Descriptive Analysis.
e quantitative descriptive analysis was carried out with a panel of trained tasters, which included 15 tasters with previous experience in the sensory evaluation of cookies [22]. e descriptor set was generated according to the standards of sensory analysis. Descriptors and references to an anchor scale are listed in Table 1. e procedures for selection and training of the judges were in accordance with standard international norms [22]. e trained panel generated the cookie set sensory descriptors, scales, and references to evaluate the sensory profile according to the standard norms [22].  Table 2 (chemical composition before processing), the moisture content of cookies decreased from 12.50 to 10.55%. Control registered the highest moisture content (12.50%), while the lowest moisture content of 10.55% was found for WPCSH (10%). Our results are in good agreement with the findings of the authors in [23] regarding ash, protein, and fat contents where the proximate composition of samples differed slightly from that of the control sample. Gallagher [24] expressed that an increase in moisture content with the increasing WPC supplementation level may be due to more bound water in the system. Our result is not in good agreement with those of the authors in [25] who expressed that biscuits with WPC are higher in moisture content than those with the control sample. Protein content in cookies increased from 12.71 to 18.57%. e highest value for  (5) Milk flavor Intensity of the olfactory-gustatory sensation perceived during mastication associated with raw milk at room temperature Absence (0) Full fat milk (10) Strange flavor No typical aromas related to fresh cheese Absence (0) Intense (10) After taste Intensity of the olfactory-gustatory sensation perceived after mastication and swallowing the sample Absence (0) Intense (10) Persistency Duration of the olfactory-gustatory sensation perceived after the bolus leaves of the mouth ≤10 s ≥60 s (10) protein content (18.57%) was in WPCSH10%, while the lowest value of 12.71% was in the control sample. e results showed that the protein content of all samples differed greatly. Our results agreed with those of the authors in [7] for WPC-enriched biscuits. Also, fat content of cookies slightly increased from 0.91 to 1.09%. e highest value of fat (1.09%) was observed in WPCSH10%, while the lowest value (0.91%) was observed in control samples. Singh and Mohamed [26] results showed the same variations in fat content of soy-fortified cookies. Finally, ash content of cookies increased from 0.48 to 0.72%. e highest value of ash content (0.72%) was reported in WPC 10%, while the lowest value for ash content (0.48%) was observed in control samples. is result agreed with that of the authors in [25], and they found that ash content in biscuits enriched with the WPC and casein increase. On the other hand, Table 3 (chemical composition after processing) shows the moisture content of cookies increased from 4.12 to 4.93%, where the highest moisture content (4.93%) was observed in WPCSH10%, while the lowest moisture content of 4.12% was found in control samples. Also, protein content in cookies increased from 15.83 to 21.89%, and this could be linked with increased protein denaturation due to a cavitation effect between myofibrils and thus an increase in protein content [27]. However, the highest value of protein content (21.89%) was observed in WPCSH10%, while the lowest value of (15.83%) was reported in control samples. Moreover, fat content of cookies increased from 1.62 to 1.98%. e highest value of fat (1.98%) was observed in WPCSH10%, while the lowest value (1.62%) was observed in the control sample. e authors in [28] reported that sonication leads to an increase in fat concentration, which was demonstrated by the larger surface area of fat globules after ultrasonication treatment, which resulted in an increase in light scattering. Ash content of cookies increased from 1.43 to 1.59%. e highest value of ash content (1.59%) was reported in WPCSH 10%, while the lowest value of ash content (1.43%) was observed in control samples. Table 4 shows physical characteristics of different levels of replacement, which shows that the thickness of (i) WPC (5%) whey protein concentrate + 95% flour, (ii) WPCSL (5%) with sonication low, (iii) WPCSL (5%) with sonication high, (iv) WPCSL (10%) with sonication low and 10% WPC, and (v) * means ± SD in the same column with the same letters are not significantly different (P ≤ 0.05). (i) WPC (5%) whey protein concentrate + 95% flour, (ii) WPCSL (5%) with sonication low, (iii) WPCSL (5%) with sonication high, (iv) WPCSL (10%) with sonication low and 10% WPC, and (v) * means ± SD in the same column with the same letters are not significantly different (P ≤ 0.05). (i) WPC (5%) whey protein concentrate + 95% flour, (ii) WPCSL (5%) with sonication low, (iii) WPCSL (5%) with sonication high, (iv) WPCSL (10%) with sonication low and 10% WPC, and (v) * means ± SD in the same column with the same letters are not significantly different (P ≤ 0.05).  Journal of Food Quality cookies increases with an increase in the WPC supplementation level in wheat flour. However, the findings of the authors in [25] agreed with our results. Significant difference in thickness was observed for samples WPC, WPCSL, and WPCSH, and the obtained results are similar to those found by the authors in [29]who stated that the thickness of WPC-fortified biscuits was greater than that of control biscuits. As biscuits shrunk (diameter decreasing), the decrease in diameter was compensated by the expansion of the thickness, which was the cause of the increased thickness. On the other hand, each decrease in weight of cookies showed an increase in the level of WPC supplementation, and there were significant differences in weight in WPC, WPCSL, and WPCSH, which can be related to the addition of excess water in the formulation of WPC-fortified dough than control biscuit dough [29]. Mishra and Chandra [30] reported that there was a decrease in the diameter in rice bran and soy-fortified biscuits. ere was an increase in the spread factor in WPC-supplemented cookies, and a significant difference in weight was observed for samples WPC, WPCSL, and WPCSH and width of cookies with an increase in the level of WPC supplementation. A significant difference in width was also observed for samples WPC, WPCSL, and WPCSH. ere is a significant difference in the spread ratio for all cookies, and our results are in compliance with those of the authors in [31] who reported that there was a significant increase observed (P ≤ 0.05) as the levels of whey protein concentrates increased. Maybe the increase in the rate of prevalence in the definition files is complementary because of the link for WPC significant reduction in the thickness of the complementary profile link for WPC. Similar results were observed in the rate of prevalence by the authors in [32] in the definition of complementary file link powder islands. Also, the author in [33] noticed an increase in the value of the factor in the spread of complementary millet flour biscuits.

Effect of WPC Sensory Perception of Cookies.
e study of consumers' perception can be of major worth to industrial community since it helps in identifying the negative and positive factors that guide the consumer behavior and purchase habits [34].
e results for the sensory evaluation of cookies are given in Table 5 (sensory consumer analysis), and the overall mean score increased from 6.95 to 7.45. e highest score (7.45) was observed in WPCSH 10%, while the lowest mean score (6.95) was observed in control, and flavor increased from 6.15 to 6.37. e highest score (6.37) was observed in WPC 10%, while the lowest mean score (6.15) was observed in control. e mean score of texture increased from 6.54 to 6.85 with the increasing level of WPC supplementation. e highest score of 6.85 was noticed in WPCSH10%, while the lowest mean score (6.54) was noticed in control. e mean score of color increased from 6.11 to 6.31. e highest score (6.31) was observed in WPCSH 10%, while the lowest mean score (6.11) was observed in control. e crust (JAR) mean score increased from 2.11 to 2.18. e highest score (2.18) was observed in WPCSH 5%, while the lowest mean score (2.11) was observed in control. e crumb (JAR) mean score increased from 1.81 to 2.18. e highest score (2.18) was observed in WPCSH 10%, while the lowest mean score (1.81) was observed in control. e mean score of hardness decreased from 3.47 to 3.12 with the increasing level of WPC supplementation. e lowest score of 3.12 was noticed in WPCSH10%, while the highest mean score (3.47) was noticed in control. e color (JAR) mean score decreased from 2.44 to 2.25. e lowest score (2.25) was observed in WPCSH 10%, while the highest mean score (2.44) was observed in control, and the adhesiveness mean score increased from 3.21 to 3.68. e highest score (3.68) was observed in WPCSH 10%, while the lowest mean score (3.21) was observed in control. e findings obtained from the current work agree well with those of Singh et al. [35]who found the overall acceptability score of sensory evaluation in soy flour-fortified biscuits. Ahmed and Ashraf [31] found that the significant difference in sensory evaluation between samples (5% and 10%) and results regarding color could be related to the Maillard reaction between reducing sugars and proteins.

Conclusion
From the present study, it can be concluded that 5% WPC-supplemented cookie samples are nutritionally rich. Sensory evaluation results revealed that 5% WPCsupplemented cookie samples scored highest in most of the attributes. Diameter, thickness, and weight of the cookie samples decreased with an increase in the WPC level. e textural characteristics of cookie samples indicated that control and WPC-supplemented cookies did not show significant differences.
is study concluded that the supplementation level of 5% WPC results in acceptable sensory, textural, and physiochemical characteristics.
Data Availability e data are available upon request from the corresponding author.

Conflicts of Interest
e authors declare that they have no conflicts of interest.