Fresh buffalo milk was standardized to 1.2 g fat 100 g −1 milk. Low-fat, yogurts were fortified with whey protein concentrates (WPCs) 1 g 100 g −1 , Cacaseinates (Ca-Cns) 1 g 100 g −1 , and spirulina (Spirulina platensis) 1 g 100 g −1 powders and their potential effect on the different quality characteristics were studied. Total solids, ash, and fat contents were high in low-fat yogurt added with spirulina powder, while protein content was high in lowfat yogurt enriched with WPCs. The highest level of antioxidant activity (P < 0.05) corresponded to low-fat yogurt containing spirulina powder, which had high total phenolic compound content. In WPCs-fortified low-fat yogurts, the gel exhibited a various structure with a fine network; and it contained very small pores in size. The highest scores of sensory properties (P < 0.05) were observed in low-fat yogurt enriched with WPCs.

Yogurt is a popular fermented milk product across the world. Structure, taste, and odor characteristics are created by fermenting yogurt with diverse ingredients and lactic acid bacteria (LAB), which contribute the most to the acceptance and quality of yogurt. In this study, low-fat buffalo milk yogurts (LFBY) were produced with the enrichment of 1% (w/w) whey protein concentrate (WPC) and Ca-caseinate (Ca-CN). Yogurts were analyzed based on microstructural, microbiological, organoleptical properties; volatile compounds (solid-phase microextraction method associated with gas chromatography-mass spectrometry) during cold storage for 21 days. Yogurts enriched with WPC and Ca-CN had higher total solids, total protein contents, and pH values. A total of 36 volatile components were identified in all produced yogurts. Acetic acid, butanoic acid, acetaldehyde, acetoin, 2,3-butanedione, ethanol, and 1-heptanol were found in significant amounts and mainly contributed to organoleptical properties. Interestingly, the focused volatile compounds that improve taste and odor were higher in LFBY+WPC yogurt than in plain LFBY or LFBY+Ca-CN yogurt. The Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus viable counts were higher in LFBY+WPC yogurt than plain LFBY or/and LFBY+Ca-CN. Conclusively, yogurt enriched with 1% WPC exhibited the best organoleptical properties and volatile component concentrations. The microstructure of the LFBY with WPC was less compact and dense, and regular, with tiny pores and long and individualized casein filaments than the other treatments. The microstructure of the Ca-CN samples caused a compact structure and coarse than in the control yogurt.

The present study examines the impacts of supplementing yogurt with 1% whey protein concentrate (WPC), Ca-caseinate (Ca-CN) and Spirulina platensis on the physiological performance of V-line rabbits receiving diets containing yogurt (at a dose of 5 g/kg body weight/day) and the different meat quality aspects. The results show that fat content was highest (p < 0.05) in yogurt fortified with Spirulina powder, but protein (%) was highest in yogurt enriched with WPC. Yogurt containing Spirulina powder showed a significant (p < 0.05) increase in total antioxidant activity. The final live body weight for G1 was higher than the other groups. However, additives affected the saddle, hind legs, liver and neck percentages significantly (p < 0.05). There were not significant differences for all groups in the forelegs, lung and heart percentages. LDL-cholesterol, total protein, globulin, albumin, creatinine and immunoglobulin M values were lowest (p < 0.05) in the WPC group. Significant improvements appeared in the small intestinal wall, microbiology, growth performance, serum biochemistry, organ histology and meat quality of the group receiving enriched yogurt. Yogurts enriched with WPC, Ca-CN and Spirulina platensis can be used as functional foods.

Frozen yogurt is known as ice cream with some properties of yogurt. Frozen yogurts are a rich source of sucrose levels between 15% and 28% of total ingredients. Consumers suffering from lactose intolerance and metabolic syndrome are looking for sugar-free products. The current study investigates the sugar replacements by using sweeteners (stevia, sucralose and sorbitol) on physicochemical, microbiological, microstructural and sensory characteristics of probiotic-frozen yogurt. Four different treatments of probiotic-frozen yogurts were studied (control probiotic-frozen yogurt with sucrose (F1), probiotic-frozen yogurt with stevia (F2), probiotic-frozen yogurt with sucralose (F3) and probiotic-frozen yogurt with sorbitol (F4)). The chemical properties were not significantly present p > 0.05) during storage in all treatments. In the F1 treatment, sucrose value was higher (14.87%) and not detected in the F2, F3 and F4 treatments. The highest values of overrun, hardness and viscosity (p < 0.05) were detected in the F2, F3 and F3 samples, but the lowest value was detected in the F1 treatment. Total Str. thermophilus and Lb. delbrueckii ssp. bulgaricus counts were gradually decreased (p < 0.05) during storage periods. At 1 day, the Bifidobacteria counts ranged from 7.56 to 7.60 log10 CFU g−1 in all groups and gradually decreased during storage, but these bacterial counts remained viable (>6.00 log10 CFU g−1) during storage periods up to 60 d. During storage periods, the highest scores of total acceptability were detected in the F3, F4 and F2 treatments. Scanning electron microscopy (SEM) micrographs of all probiotic-frozen yogurt treatments illustrated that the microstructures showed a difference with a fine network, size pores and structure between the frozen yogurt with sweeteners (F2, F3 and F3) and control frozen yogurt (F1).

IN THIS STUDY, sweet whey was obtained from manufacturing Ras cheese. Lactose was hydrolyzed by lactase (β-D-galactosidase) at pH 6.6. Hydrolyzed whey beverages were produced by mixing sugar (10%), fruit juice, or/and herbs extract to hydrolyzed whey. The whey beverages were carbonated by injecting CO 2 . The carbonated hydrolyzed whey beverages were evaluated for their amino acids, vitamin C, total antioxidant, total phenol compounds, and minerals. Higher hydrolysis in whey sugar was obtained at pH 6.6 with a β-D-galactosidase level of 0.4% after incubation for 300 min at 37°C (P<0.05). The content of leucine was the highest followed by lysine and threonine in all beverage treatments (P<0.05). Results indicated that carbonated whey beverages containing lemon (S4) had the highest ascorbic acid content, total antioxidant activity, and total phenolic compounds content. The level of calcium was the biggest (P<0.05) in carbonated whey beverages. Generally, carbonated whey fortified with lemon juice, green tea extract, and/or peppermint extract had high contents of major bioactive compounds compared with control samples (S1 and S2).