Department of Food Science and Technology, University of Georgia, Athens, GA 30602, USA.
Department of Food Science and Technology, University of Georgia, Athens, GA 30602, USA.
Food Res Int. 2023 Oct;172:113212. doi: 10.1016/j.foodres.2023.113212. Epub 2023 Jun 30.
Cold plasma processing is a non-thermal food processing technique that has been shown to improve the gelling properties of plant proteins by altering their structure through oxidation and crosslinking. This study aimed to investigate the effects of cold plasma treatment on the rheological properties of skim milk under different conditions, focusing on the impact of feed gas and treatment time on skim milk's sulfhydryl content, flow properties, and acid gelling behavior. Results showed that free sulfhydryl content decreased with treatment time, with a notable reduction observed after 2 min of N-O plasma treatment. Skim milk treated with N plasma experienced a more gradual decrease in free SH content. Cold plasma increased skim milk viscosity over time. N-O plasma treatment significantly affected G' and G' storage moduli, with an increase observed after 2 min of exposure but no change beyond that time. Acid gels' greenness (a* value) decreased with increasing treatment time compared to the control. Acid gel firmness of milk treated with N-O plasma for 1 min significantly increased from 1.804 N to 1.912 N, and further to 2.072 N after 2 min of treatment. However, longer exposure times led to lower firmness in gels. N plasma treatment also significantly impacted acid gel firmness. Syneresis in acid gels decreased from 63.4 % to 57.7 % and 58.7 % after 1 and 2 min of N-O plasma treatment, respectively, but increased to about 70 % after 4 min. Acid gels made from milk treated with N plasma experienced considerably less syneresis. The cold plasma treatment under different conditions significantly affected the properties of skim milk, with various impacts on sulfhydryl content, flow properties, and acid gelling behavior. These findings demonstrate the potential applications of cold plasma processing in the food industry to improve product properties.
冷等离子体处理是一种非热食品加工技术，已被证明通过氧化和交联改变植物蛋白的结构来改善其凝胶性能。本研究旨在研究不同条件下冷等离子体处理对脱脂乳流变特性的影响，重点研究进料气体和处理时间对脱脂乳巯基含量、流动性能和酸凝胶行为的影响。结果表明，游离巯基含量随处理时间的增加而减少，在 N-O 等离子体处理 2 分钟后观察到明显减少。用 N 等离子体处理的脱脂乳游离 SH 含量逐渐减少。冷等离子体随时间的推移增加脱脂乳的粘度。N-O 等离子体处理显著影响 G'和 G'储存模量，暴露 2 分钟后观察到增加，但此后没有变化。与对照相比，酸凝胶的绿色值（a*值）随处理时间的增加而降低。用 N-O 等离子体处理 1 分钟的牛奶的酸凝胶硬度从 1.804 N 显著增加到 1.912 N，处理 2 分钟后进一步增加到 2.072 N。然而，更长的暴露时间会导致凝胶硬度降低。N 等离子体处理也显著影响酸凝胶硬度。酸凝胶的析水率从 N-O 等离子体处理 1 和 2 分钟后分别从 63.4%降至 57.7%和 58.7%，但处理 4 分钟后增加到约 70%。用 N 等离子体处理的牛奶制成的酸凝胶析水率显著降低。不同条件下的冷等离子体处理显著影响脱脂乳的性质，对巯基含量、流动性能和酸凝胶行为有不同的影响。这些发现表明冷等离子体处理在食品工业中的潜在应用可以改善产品性质。
