Changes in some quality properties of frozen mare milk during 6 months of storage

The aim of this study was to determine how storage in the frozen state affects the quality of mare milk. Therefore, physicochemical properties such as pH, total dissolved solids (TDS), electrical conductivity (EC), particle size distribution and near-infrared (NIR) spectroscopy, as well as changes in antioxidant activity and the total phenol content were determined during 6 months of storage at -18°C. All of the determined parameters were compared to those in raw mare milk prior to freezing. According to the obtained results, frozen storage caused certain changes in mare milk quality, including increase in pH, electrical conductivity and TDS values, changes in protein structure recorded by NIR spectroscopy and SDS PAGE (Sodium dodecyl sulfate-polyacrylamide gel electrophoresis), as well as changes in particle size distribution. There was also a continuous decrease in the antioxidant activity and the total phenol content of frozen mare milk throughout the 6 months of frozen storage. Thus, after 6 months of frozen storage, a decrease in the DPPH value of approximately 59%, in the FRAP value of approximately 26% and in the TPC of approximately 70% was observed, respectively. In conclusion, freezing and frozen storage affected the quality of mare milk, which might have negative consequences on its therapeutic value

Fortification of Cow Milk with Moringa oleifera Extract: Influence on Physicochemical Characteristics, Antioxidant Capacity and Mineral Content of Yoghurt

Background: Fermented dairy products are known for their many positive effects on human health and are consumed worldwide. The supplementation of food with plant extracts as sources of valuable nutritional compounds has recently gained a lot of attention. Milk and fermented products are deficient in bioactive components such as phenolic compounds and iron. Moringa oleifera leaf extract is rich in vitamins, minerals (iron), polyphenols, flavonoids, tannins and proteins. Its addition to milk before fermentation might represent an excellent way to enrich fermented milk products. Methods: Yoghurts enriched with moringa extract (ME) (1, 3 and 4-%, v/v) were produced and compared to a control yoghurt without ME. In all samples, acidity, microbiological parameters, syneresis and water holding capacity, rheology parameters, total colour difference, mineral content, total phenols and antioxidant capacity (FRAP method) and sensory properties were determined. Results: The addition of ME to milk before fermentation resulted in a shorter fermentation time, lower yoghurt pH, increased growth of yoghurt bacteria, better rheological properties and an increased total phenols content as well as antioxidant capacity of yoghurts. Moreover, yoghurts with ME addition had a higher mineral content and gained a better sensory score when compared to the control sample

Production of Acid and Rennet-Coagulated Cheese Enriched by Olive (<i>Olea europaea</i> L.) Leaf Extract—Determining the Optimal Point of Supplementation and Its Effects on Curd Characteristics

This study investigated the potential of olive leaf extract (OLE), as a functional ingredient, to improve cheese properties, because it is rich in phenols. Milk and dairy products are poor in phenolic compounds. The main objective was to determine the most effective coagulation method and timing of OLE supplementation to maximize retention in the cheese matrix. Experimental cheeses were produced using the rennet and acid coagulation methods, with OLE added either directly to the cheese milk or to the curd phase. Three OLE effective concentrations corresponding to 25%, 50%, and 75% inhibition of DPPH reagent (EFC25, EFC50, and EFC75, respectively) were added, i.e., 11.5 mg GAE L−1, 16.6 mg GAE L−1, and 26.3 mg GAE L−1, respectively. The results showed that OLE significantly increased the concentration of total phenols, total flavonoids, and antioxidant activity in all cheese samples and in the residual whey, especially at higher effective concentrations (EFC 50 and EFC 75). Rennet-coagulated cheese to which OLE was added prior to coagulation (EM 25, EM 50, EM 75) exhibited higher hardness, gumminess, and chewiness but lower elasticity, suggesting alterations in the paracasein matrix. OLE did not adversely affect acidity, water activity, or cheese yield. However, higher EFC resulted in significant colour changes (∆E* > 3.0). In conclusion, the enrichment of cheesemaking milk with OLE and the application of the rennet coagulation method are the most suitable to optimise the production of OLE-enriched cheese. This research shows the potential to improve the nutritional value of cheese while maintaining its desired characteristics