STUDIES ON SOME DAIRY PRODUCTS SUBSTITUTES By MOHAMED SAAD ABD-ELHAMED ALI B.Sc. Agric. Sci. (Dairy Science), Fac. Agric., Cairo Univ., 2004 THESIS Submitted in Partial Fulfillment of the Requirements for the Degree of MASTER OF SCIENCE In Agricultural Sciences (Dairy Science) Department of Dairy Science Faculty of Agriculture Cairo University EGYPT 2012 SUPERVISION SHEET STUDIES ON SOME DAIRY PRODUCTS SUBSTITUTES M.Sc. Thesis In Agric. Sci. (Dairy Science) By MOHAMED SAAD ABD-ELHAMED ALI B.Sc. Agric. Sci. (Dairy Science), Fac. Agric., Cairo Univ., 2004 SUPERVISION COMMITTEE Dr. FATMA MOHAMED MAHMOUD SALAMA Professor of Dairy Science, Fac. Agric., Cairo University Dr. MOHAMED AHMED ABD EL-KHALEK AZZAM Professor of Dairy Science, Fac. Agric., Cairo University Dr. MAHMOUD ABD ELHFEZZ ABDL-RAHMAN Professor of Animal Physiology, Fac. Vet. Med., Cairo University Name of Candidate: Mohamed Saad Abd El Hamed Ali Degree: M.Sc. Title of Thesis: Studies on Some Dairy Products Substitutes. Supervisors: Dr. Fatima Mahmoud Salama Dr. Mohamed Ahmed Abd El Khalek Azzam Dr . Mahmoud Abd El Hafez Abd El Rahman Department: Dairy Science Approval: 27/8/2012 ABSTRACT The aim of this study was to optimize the best processing techniques for production of oat and barley milks (aqueous oil-in-water emulsions stabilized with oat or barley solids) with acceptable taste and level of anti-nutritional components such as phytic acid, hence can be used whether as substitute to cows' milk in non-dairy beverage flavored with mango juice. The soaking, toasting of soaked oat grains or blanching of soaked barley grains and grinding each with sweet whey at ratio of grains to whey 1:3 were the best techniques for production of reasonable milks with high recoveries of solids and protein. In comparison with cows' milk, oat milk had a significant higher content of total protein, potassium and fibres while barley milk was highest in phosphorus, iron and zinc contents. Nutritionally, consumption of one cup (245g) of oat milk can provide adults with about 10, 17 and 20% of their daily fibre, protein and potassium needs, respectively. While, the same amount of barley milk was able to cover about 51, 58 and 74% of adults daily requirements of iron, zinc and phosphorus, respectively compared to cow milk. Healthily, the diet containing oat milk or barley milk solids showed reasonable blood glucose level reduction in serum blood of the diabetic rats (Reduction was 45.82 and 33.78% respectively) compared with diabetic control rats (547.1 mg/dl). Also, the serum levels of total cholesterol (TC), triglyceride (TG) and LDL-cholesterol decreased being 210 and 217, 126 and 132 , 148 and 156 mg/dl for rats group2 and group 3, respectively, while HDL-cholesterol increased being 36 and 34 mg/dl in the rats fed on high-cholesterol diets containing oat or barley milks solids as compared with the positive control groups (297.89 mg TC/dl, 178.8 mg TG/dl, 231.9 mgLDL-C/dl and 30.24 mg HDL-C/dl). Physically, oat and barley milks had significantly higher viscosity and lower heat stability and specific gravity (2.03 and 1.83cP, 2.53 and 2.46 min, 1.022 and 1.02 respectively) than that of cows' milk (1.37cP, 15.43 min, 1.03 respectively). Practically, oat or barley milk beverages flavored with mango juice had high nutritional value as well as high stability of their organoleptic properties up to10th day under refrigerated storage (5-7°C) compared with mango juice-cow beverage. Key words: Oat, barley, cow milk, juice, beverage, cholesterol, glucose, blood. ACKNOWLEDGEMENT Thanks to Allah Deep thanks are due to Dr. Fatma Mohamed Mahmoud Salama professor of dairy science, faculty of Agriculture, Cairo University for suggesting the problem, supervision, continued assistance and her guidance through the course of study and revision of the manuscript of this thesis. Deep gratitude to Dr. Mohamed Ahmad Abd El Khalek Azzam professor of dairy science faculty of Agriculture, Cairo University for his continuous help, suggestions, reading , revising and supervision this work. Deep thanks are due to Dr. Mahmoud Abd El Hafez Abd El Rahman Professor of Animal Physiology, Fac. Vet. Med., Cairo University for his help , suggestions , kind encouragement and supervision of this thesis. Grateful appreciation is also extended to all staff members of Dairy Science Department, Faculty of Agriculture, Cairo University. Grateful appreciation is also extended to my father, my mother, my brothers, my wife and son for their endless support and their valuable help during the course of this study. CONTENTS Page GENERAL INTRODUCTION…………………………… 1 PART I: Optimization of processing techniques for production of oat and barley milks…………… 5 1. INTRODUCTION................................................................. 5 2. REVIEW OF LITERATURE….…....…............................. 5 3. MATERIALS ……………………………………………… 31 4. METHODS OF ANALYSIS………………………………. 35 5. RESULTS AND DISCUSSION……………………………. 38 PART II: Comparative studies on some properties of oat, barley and cow milks………………….. 55 1. INTRODUCTION............................................................... 55 2. REVIEW OF LITERATURE ….…....….......................... 57 3. MATERIALS…………………………………………….. 65 4. METHODS OF ANALYSIS ……………………………. 68 5. RESULTS AND DISCUSSION …… …………………….. 76 PART III: Utilization of oat and barley milks in manufacturing of beverages flavored with mango juice………………………………. 95 1. INTRODUCTION………………………………………... 95 2. R EVIEW OF LITERATURE ………………………….. 96 3. MATERIALS…………………………………………….. 100 4. METHODS OF ANALYSIS ……………………………. 102 5. RESULTS AND DISCUSSION ………………………… 109 SUMMARY………………………………………………….. 119 CONCLUSION……………………………………………... 127 REFERENCES…………………………………..………….. 128 ARABIC SUMMARY. ………………………………….…. -- General Introduction Cereal grains such as wheat, oat, rice, barley and rye are notified the most common cereal based functional foods and nutraceuticals (Brennan and Cleary, 2005). While cereal grains are important sources of energy, cereals are also a primary provider of protein, biologically active constituents and several vitamins and minerals. Cereal proteins have high nutritional quality and low cost in relation to other protein sources (Kinsella, 1979). Cereal proteins also contribute important functional properties to many foods. The best example of this is wheat, whose gluten proteins have unique viscoelastic properties that enable wheat flour dough to be made into bread and many other unique products (Kinsella, 1979). Biologically active constituents of cereals that promote beneficial physiological effects are dietary fibers, starch and polyphenols (Grausgruber et al., 2004). Dietary fibers include poly- and oligosaccharides, lignin, and associated plant substances. The actions of cereal dietary fibers on the body included reduction of plasma cholesterol and postprandial glycaemic response, which decrease the risk of cancer, heart disease, hypertension and obesity in the long term. Resistant starch resists enzymatic activity in vivo and in vitro, and therefore shows similar physiological effects as dietary fibers. Phenolic compounds are effective antioxidants with the potential therapeutic value to reduce the risk of cardiovascular disease and 1 cancer. Also, cereals can be used as fermentable substrates for the growth of probiotic microorganisms (Mårtensson et al., 2001 and Charalampopoulos et al., 2002). Among the cereals, oat and barley are the best materials used in food industries for providing nutritional and wholesome economic foods. Oat as a healthful and nutritious food, contain high concentrations of well-balanced protein and soluble fibers, energy in the form of carbohydrate, oil, and several vitamins and minerals (Peterson, 1992 and Welch, 1995). In addition to the well-known effects of reducing blood cholesterol and affecting glycaemic response, dietary fibers of oat have been shown to have numerous other physiological effects (Behall et al., 1997). In the large bowel, soluble dietary fiber increases the fermentation activity, especially production of butyric acid, enhances growth and colonization of some probiotic bacterial strains, increases production of microbial mass and thereby aids the removal of nitrogen via feces and also increases wet weight of stools, thereby alleviating constipation (Mälkki and Virtanen, 2001 and Mårtensson et al., 2002). Numerous studies have demonstrated that whole grains that are high in soluble fibers, such as oats and barley, are more effective in lowering blood cholesterol than are grains in which fibers are predominantly insoluble, such as wheat or rice (Mclntosh et al., 1993; Lupton et al., 1994; Onning et al., 1999; and Behall et al., 2004). Also soluble fibers of barley 2 implicated in hypoglycemia, and in reducing incidence of chemically induced colon cancer (Truswell, 2002). Therefore, the concept of consumption of oat and barley milks has been circulated worldwide through the last 2 decades. This circulation has been attributed to the effects of the soluble fibers content of these milks on risk factors for heart and obesity diseases, including cholesterol (Behall et al., 1997), blood glucose (Hallfrisch and Behall, 2003), and insulin (Willett et al., 2002) These milks have no cholesterol or lactose, therefore, can be used as alternatives to bovine milk, especially, for lactose-intolerant humans or some individuals who are allergic to milk protein and may well also be allergic to soy protein or when milk may be either too expensive or unavailable. They may also be used as the basis of or additives in infant formulas (Benward and Benward, 2000); reduced sugar and reduced calorie milks for dietetic and diabetic purposes (Demirag et al., 1999); and non-dairy vegetarian alternatives to dairy and cultured dairy products (Martensson et al., 2000). The preparation of oat and barley milks is usually associated with the presence of anti-nutritional factors in product, such as phytate, which is known to reduce the bioavailability of minerals (Sandström et al., 1987 and Rossander-Hulten et al., 1990). Therefore, the studies which achieved on methods of preparing of oat and barley foods indicated that the hydrolysis of 3 phytate can be obtained by activation of the endogenous phytases during food processes such as soaking, germination, fermentation or by addition of phytase (Turk and Sandberg 1992 ; Svanberg et , al., 1993 and Larsson and Sandberg, 1995). Hence, to obtain a better mineral availability, it seems important to define appropriate conditions for phytate degradation during processing or preparation of oat or barley products. Thus, it was thought considerable to investigate: 1- Some variables that affect oat and barley milks processing to choose the suitable conditions for the manufacturing of palatable and acceptable product. The studied variables were: a) Heat treatments of oat and barley grains after soaking. b) Grinding media (tap water and sweet whey). 2- Some chemical, nutritional and physical properties of oat and barley milks compared with those of cows' milk. 3- Utilization of oat and barley milks in some dairy- like products manufacture. 4