Effect of Acid Whey Protein Concentrate on the Rheological Properties, Antioxidant Capacities, and Biological Activities of Bioaccessible Fractions in Fermented Camel Milk

The production of set-type camel milk yogurt is challenging due to its unique physicochemical properties, which differ from those of other milk species. The present study aimed to evaluate the effects of camel milk supplementation with different levels (0, 3, and 6%) of whey protein concentrate (WPC) on the texture, rheological properties, antioxidant capacity, and biological activity of camel milk yogurt compared to bovine milk (BM) yogurt. These characteristics were evaluated before and after in vitro digestion of yogurt samples after 1 and 15 days of storage at 4°C. The results show that using WPC, particularly at 6% (WPCA6), significantly affected the characteristics of yogurt. The water-holding capacity increased by increasing the level of WPC and showed higher values than BM yogurt. Furthermore, the adhesiveness in yogurt samples containing 6% of WPC was significantly higher than other treatments, representing 6.3 and 6.1 mJ after 1 and 15 days, respectively. The apparent viscosity of WPCA6 was also higher than other yogurt treatments at different shear rates throughout storage, indicating a thicker and more viscous yogurt. Camel milk yogurt showed higher DPPH values, representing 74.1, 71.6, and 78.1% for WPCA0, WPCA3, and WPCA6, respectively, compared to BM yogurt (22.9%). The biological activities, including α-amylase, α-glucosidase, and angiotensin-converting enzyme inhibitions, increased after in vitro digestion of yogurt samples. Principal component analysis underscored the distinct bioactive profile of WPCA6, distinguishing it from other yogurt treatments and highlighting its superior properties.

骆驼乳酸奶的批量生产颇具挑战，其独特的物理化学性质与其它乳种存在显著差异。本研究旨在评估不同水平（0%、3%和6%）的乳清蛋白浓缩物（WPC）对骆驼乳酸奶质地、流变学特性、抗氧化能力和生物活性的影响，并与牛乳（BM）酸奶进行对比。这些特性在酸奶样品在4°C储存1天和15天后，经过体外消化前后进行了评估。结果显示，使用WPC，尤其是6%（WPCA6）的浓度，显著影响了酸奶的特性。随着WPC水平的增加，其保水能力也随之提高，并显示出高于BM酸奶的数值。此外，含有6% WPC的酸奶样品的粘附性在1天和15天后分别显著高于其他处理，分别为6.3和6.1毫焦耳。WPCA6在不同剪切速率下的表观粘度也高于其他酸奶处理，表明其酸奶质地更厚、粘度更高。骆驼乳酸奶的DPPH值较高，WPCA0、WPCA3和WPCA6分别达到74.1%、71.6%和78.1%，相较于BM酸奶的22.9%。经过体外消化后，酸奶样品的生物活性，包括α-淀粉酶、α-葡萄糖苷酶和血管紧张素转化酶的抑制作用均有所增加。主成分分析突显了WPCA6独特的生物活性谱，将其与其他酸奶处理区分开来，并凸显其优越的特性。