This study aims to reveal the quality properties of yogurt enriched with walnut during cold storage (4°C) for 28 days. Five sets of yogurt types were produced by using walnut at varying rates (A: 0% (control), B: 1%, C: 2.5%, D: 3.5%, E: 5%). Physicochemical, sensory, phenolic contents and antioxidant properties of yogurt samples was investigated during the 1st, 7th, 14th, and 28th days of storage. The study was conducted to optimize the walnut addition level to obtain better quality yogurt as a functional food. It was determined that the walnut enrichment affects the gross chemical component of yogurt samples. Yogurt sample with %5 walnuts (E) had the highest total phenolic and antioxidant activity content (respectively 1027.50 mg GAE/kg, 19.95 mM TE) among the samples. The yogurt sample with the highest sensory attribute score was the one containing 1% walnuts. Therefore, it was concluded that yogurt added with walnut could serve as functional yogurt beneficial for human health.

Yogurt is a natural source of gut-friendly bacteria. It has a considerable body of evidence that supports the significant positive effects of yogurt as probiotics on quail production performance and health. Yogurt containing bacteria can improve quail economic indexes and resistance to pathogens. With this objective, 240 growing Japanese quails were randomly distributed into three groups A1 (control), A2 (Yogurt), and A3 (Protexin) (4 replicates/treatment of 20 birds) to investigate the effect of yogurt as a probiotic source. Birds were allowed to be fed ad libitum with a commercial quail ration. Yogurt and Protexin were mixed at the rate of 5 ml/L (5ml into 1 lt. water) and 1g/L (1gm into 1 lt. water) in A2 and A3, respectively. Six (6) weeks of investigation showed a significantly higher result in yogurt than in the other two groups. Body weight had a significant difference between the control and protexin groups. Body weight gain (g) was significantly heavier in A2 at the finisher phase. No significant effect was observed in feed intake, but FCR (Feed Conversion Ratio) was significantly lower in A2, but no significant effect was noticed between A1 and A3. The mortality percentage was higher in the control group (2.66%) and lowest in yogurt (1.03%). Carcass characteristics were significantly heavier in A2 than A1 and A3. Non-carcass characteristics illustrated significant differences among the three groups, but a non-significant difference was observed in head weight. The gross return per bird was higher in A2 (12.05 BDT), whereas it was 6.55 BDT and 7.08 BDT for A1 and A3. With those observations, it can be concluded that yogurt successfully enhanced overall broiler performance and gross return of Japanese quail.

During conventional fermentation of milk into yogurt and kefir, changes of antioxidant capacities (DPPH radical scavenging, ferrous chelating, reducing power, hydrogen peroxide/ H2O2 scavenging activity) and total phenolic content were investigated. Both products showed greater phenolic content, DPPH radical scavenging, and reducing power activities than was the case of their unfermented milk forms. But they were unable to scavenge H2O2. Chelating ability of milk increased by yogurt fermentation but decreased by kefir fermentation. In general, antioxidative capacity of milk improved throughout conventional yogurt and kefir fermentations and ripening periods (except chelating ability for kefir and H2O2 scavenging). This study is valuable since it evaluates the antioxidant power of yogurt and kefir produced by traditional fermentation with 5 different antioxidative approaches. In face of rapidly rising consumer demand for safe, healthy, functional but natural foods, revealed results might strengthen importance of conventional fermentation process and highlight the antioxidative contributions of mentioned products

In the current study, four different types of yogurt were produced as control samples (no MPP added) and 1, 2, and 3% melon peel powder (MPP1, MPP2, and MPP3). These yogurts were determined by physicochemical, microbiological, sensory, total phenolic, and antioxidant activity weekly for 21 days. While ash, moisture, titratable acidity (TA), viscosity, water holding capacity (WHC), a* and b* values, total phenolic content (TPC), and antioxidant capacity of melon peel powder samples increased, L*, pH, and syneresis values decreased. In concentrations of 1, 2, and 3%, the mean antioxidant activity of powdered yogurt was found to have average values during storage of 30.09%, 32.32%, and 36.26%, respectively. All yogurts continued to contain more than 107 cfu/g of live lactic acid bacteria during fermentation. As the storage time increased, the sample’s pH and syneresis decreased, while titration acidity and texture increased. No yeast or mold (2 log cfu/g) was determined in the samples. The panelists preferred MPP1 and MPP2 samples. According to the findings of the study, melon rind powder, which is a by-product, can be recommended as a functional food additive in yogurts.