Development and Techno-functional Characterization of Beyaz Cheese Fortified with Walnut (Juglans regia L.) Leaf Powder and Lactobacillus acidophilus LA-5.

This study aimed to produce a new functional Beyaz cheese variety with the addition of different ratios (0.5% and 1%) of walnut leaf powder (WLP) and probiotic bacteria (Lactobacillus acidophilus LA-5.). The probiotic shelf-life and techno-functional properties of Beyaz cheeses were investigated at 30-day intervals during ripening in brine (120 days at + 4 °C). The highest acidity, ash, salt, Fe, Cu, Mn, a*, b*, H°, and C* values were found in the WLP-supplemented cheeses compared with those in the control without probiotic (C) and probiotic control (PC) cheeses (p < 0.01). The count of L. acidophilus LA-5 in probiotic cheeses decreased to less than 10 colony-forming units (CFU)/g after the 60th day of storage. Compared with PC (77.52%), WLP increased the viability rate (82.04-86.52%) over the 60-day shelf-life period. The total phenolic content (TPC), total flavonoid content (TFC), chlorophyll a and chlorophyll b contents, and total antioxidant activity (DPPH•, CUPRAC, and FRAP assays) of the cheeses significantly increased with the addition of 0.5 and 1% WLP (p < 0.01). The addition of WLP increased proteolysis (WSN, pH 4.6‒SN, TCA‒SN and PTA-SN) and lipolysis (p < 0.01). The general acceptability of cheese samples was PC > C > PWL > PWL. Consequently, a new variety of functional Beyaz cheese with a probiotic shelf life of 60 days that is rich in bioactive compounds and microminerals (Fe, Cu and Mn) and natural for healthy nutrition can be produced with the addition of L. acidophilus LA-5 and 0.5% WLP.