Evaluation of the synergistic impact of milk whey and okaraon cracker biscuits properties

Evaluation of the synergistic impact of milk whey and okaraon cracker biscuits properties

Abdel-Mobdy A. E

*Dairy Science Dept. Fac. Agri. Cairo Univ.

Abstract

Whey (milk by – product) and okara (soybean milk by – product) as various types of natural nutrition ingredients were used as additives into bakery – based products such as biscuits to improve their quality for health promotional products. However, these by – products are frequently added with imported dietary fiber and protein ingredients. The present studies are aimed to develop bakery products incorporated with cow milk whey and okara and to evaluate their influences on physical and chemical properties as well as sensory acceptability. Okara used to substitute wheat flour (0, 25, 50 and 75%) but cow milk and its whey (30 ml / 100 g)used in place of water in biscuits. The effects of cow milk and its whey as well as okara incorporation on the proximate analysis and physical properties, texture profile and sensory evaluation of biscuits were studied. The present results showed that cow milk and its whey as well asokara produced significant increases in protein and fiber contents of biscuits produced. Hardness decreased in parallele with okara levels additions. Biscuits produced containing 25% okara with cow milk or its whey received the better score than the other formulations for all of the sensorial attributes judged. It can be concluded that, biscuits formulated form cow milk whey and okara 25% can use as cracker biscuits more healthy than that of control formulation functional. However, okara and milk whey can potentially be used as alternative ingredient for partial replacement of wheat flour in formulating biscuits for their ability to improve the nutritional quality without jeopardizing sensorial palatability.

Key words: milk – whey – okara – biscuits – sensory – nutrition

Introduction

Cow's milk is a complete food for nutrition. Well – known components of milk are specific protein for growth, easily digestible fat, lactose (as energy source), minerals (for bone formation), vitamins and minor components that protect against infections. Cow's milk is a highly nutritive food for human beings (Hamad et al., 2012).de Wit (2000) reported that milk is a nutritional liquid, not only for humans and animals but also for micro – organisms which may spoil the quality of milk products. The composition of cow's milk is involving water, protein, milk fat, minerals and lactose as main nutrients. Most of these components are also available in whey, except for the caseins and most of the milk fat.

The liquid remaining after removal of the fat and casein from milk by isoelectric point or rennet coagulation of the casein is called whey. Most cheeses are made from full fat or partially skimmed milk and typically about 10% of the fat in such milk is lost in the whey as a result of the formation of free (nonglobular) fat during pasteurization or other manufacturing processes. Traditionally whey was regarded as a waste product and was disposed of by the cheapest possible method – fed to animal, spray irrigated onto land, dumped in water ways, or treated as effluent, which is unacceptable today for environmental reasons. World production of whey is about 160 million tonnes per annum, protein whey contains about 50% of the total solids of milk (Foxet al., 2000). Whey products consider as functional ingredients in food and pharmaceutical applications and as nutrients in diabetic and health food (Souse et al., 2012 and Sukkar and Boeinous, 2004 and El-desauky et al., 2017).Over 25% of the whey production in the European Union and 50% in USA of it is utilized for human consumption and forecasts indicate that human application of whey may surpass its utilization as feed in the near future.

Okara is the by – product generated during tofu or soy milk production processes. Okara contains about 50% dietary fibers,25% protein, 10% lipid and other nutrient. Due to its high fiber content and low production costs, okara is a good raw material and rich source for preparing fiber and could also be used as a dietary supplement to prevent diabetes, obesity and hyperlipidemia a (Li et al., 2012). Large quantities of okara produced annually pose significant disposal problem. Okara contains mainly insoluble fiber and complex carbohydrates, protein, polyunsaturated fatty acids and isoflavones which induce pharmaceutical properties. An important characteristic is that okara flour does not contain gluten, so it is suitable for celiac (Ostermann- Porcel et al., 2017). The high _ quality protein fraction has good water holding and emulsifying qualities and contains a peptide with anti-hypertension effect (Toole, 1999). Agro – industries are focused in the transformation and processing of raw materials from agricultural source (plant and animals) and contribute to the generation of large amounts of organic residues. These are solid (soy – bean okara) and liquid (milk whey) materials, which are not used in the production chain and constituents a serious problem because apparently without valuable application, they are discarded directly into the environment and if not properly treated, can cause pollution in soil, surface water and ground water (Tavares et al., 2016).

The aim of the present studies was to develop cracker biscuits products incorporated with cow milk whey with okara and to evaluate the effects on physic-chemical properties and sensory acceptability relative to cow milk and water incorporations.

Materials and Methods

Cow – milk was obtained from the herd farm of Faculty of Agriculture Cairo University, Giza, Egypt.

Cow milk whey a by – product during the processing of cow milk fat the production of white cheese was obtained Dairy Sciences Department Fac. Agric. Cairo Univ.

Okara as by – product obtained from soy bean factory, Food Technology Research Institute, Agriculture Research Center, Ministry of Agriculture Giza, Egypt. Okara was dried in an oven at 50^°C for 24 hr. and powdered using lab –grinder, then stored at - 4^°C until using.

The other ingredient that composed and formulation of cracker biscuits such as wheat flour, fat, salt, sugar and baking power were purchased from local markets in Giza, Egypt.

The procedure for preparation of the different kind of cracker biscuits were carried out according to Bose and Shams – Ud Din (2010). The wheat flour and okara flour, as well as other ingredients were mixed. Water or cow milk or cow milk whey was added (30 ml / 100 g) to form the dough. The dough was rolled to a thickness of 3 mm. The cracker biscuits were cut with a round cutter of 5.5 cm diameter and baked at 200^°C or 15 min, then cooled at ambient temperature and packed in high density polyethylene bag. The basic formulations of cracker biscuits were 100 g flour, 6 g fat, 2 g salt, 4 g sugar, 2 g baking powder and 30 ml water or 30 ml cow milk or 30 ml cow milk whey. Four formulations were developed: one with wheat flour (without okara) as control and the three other with different proportions of okara: 25%, 50% and 75% in place of wheat flour.

The chemical composition of the ten kinds of cracker biscuits (moisture, crude protein, total lipid, ash and crude fiber but by difference calculated total carbohydrate) were determined according to the A.OA.C. (2000) methods.

In case the physical properties of the present products, color according to Ostermann and Forcell et al., (2017) was measured using Hunter – Lab – Color – Flex – Colorimeter. A chronometer was calibrated with the standard black and white color. The results reported are averages of five measurements in each sample using b* L* (value is the lightness variable from 100 for perfect white to zero for black) a* and b* (values are the chromaticity and values) increased chromaticity produced redness but decreased it produced greenness also increased chromaticity resulted yellowness but decreased values produced blueness respectively (+ redness / - greenness and + yellowness / - blueness for a* and b* respectively).

The hardness of the cracker biscuits was determined with the TA – XT2i Texture Analyzer and the data was expressed in Newtons (N). Water activity (Wa) was determined using the Aqualab apparatus (Aqualab – CX-2) at 30^°C to determine the rupture force of the developed okara biscuits.

The sensory evaluations analysis of the present products was carried out 2 hr. after baking in a uniformly illuminated room by 20 men untrained 20 – 40 years – old, 20 women untrained 20 – 40 years – old, 20 men and women untrained 60 – 65 years – old and 20 children untrained8 – 12 years – old panel member, healthy men, women, elderlies and children were randomly chosen. The sample were coded digit number and presented in randomized order. The attributes estimated on ten – points scale (from 10 = I like very much to 1 = I dislike very much). The sensory attributes evaluated were Odor, Taste, Color and Crispy. Water was provided between samples to cleanse the palate. Then the statistical analysis was performed.

The present results were subjected to the convenient statistical analysis methods, where mean and standard deviation was calculated .Data were analyzed using two way- classification ANOVA followed by Duncans multiple composition tests to find the statistical significant difference between treated groups. (p≤ 0.05) according to Waller and Duncan (1969).

Results and Discussion

The results of the present studies (Table 1) show the proximate analysis of cow milk and its whey as well as okara. Whey, which contains about 50% of the total solids of milk. The three sources raw material contained a good amounts of protein, lipids, ash and carbohydrate but okara only contained crude fibers (19.11%). Milk and whey are well – known sources for adapting infant, dietetic foods and pharmaceutical products. The specific bioactive protein of milk, whey and okara such as lactoferrin, lactoperoxidase and a number of growth factors reveal several beneficial health promoting effects. Milk, whey and okara salts contained also Na, K, Ca, P, Mg and Zn of a good amounts also contained several vitamins such as B complex and D as well as E but vitamins A and C presented in the milk and whey only. Salts, particularly calcium and zinc are presented in a bioavailable form which is important in for example elderly food. The interest in the functional and nutritional efficacy of whey and okara ingredients is still growing and can serve as the raw material for the production of a wide range of food products and ingredients on a commercial scale. Similar results were found by Elreffaei et al., (2014) and Grizotto et al., (2010) for okara and Hamad et al., (2012) for cow milk also Fox (2000), de Wil (2001) and El-Desoky et al., (2017) for caw milk whey.