山药对发酵羊乳质地、风味和蛋白质羰基化水平的影响

Effect of Chinese Yam on the Texture,Flavor,and Protein Carbonylation of Fermented Goat Milk

为制备一种新型风味发酵羊乳,将山药粉加入凝固型羊酸乳中,研究质量分数0%、0.75%、1.50%、2.25%和3.00%的山药粉添加量对发酵羊乳质地和蛋白质羰基化水平的影响,并评价产品的pH值、可滴定酸度、乳酸菌活菌数和风味物质的组成。结果表明,羊乳原料及其在加工过程中的蛋白质氧化会导致最终发酵羊乳产品质地和保水性显著降低(P<0.05),羊乳原料中添加不同比例的山药粉能有效降低发酵羊乳生产过程中由于蛋白质氧化产生的羰基化合物含量。同时,山药粉的添加改善发酵羊乳的口感、稠度和质地等感官特性,提高产品的酸度和乳酸菌数量。气相色谱质谱分析表明,添加山药粉可提高发酵羊乳中丙酮和乙偶姻等成分的相对含量,使发酵羊乳具有特殊的山药风味。因此,发酵前添加0.75%的山药粉可以降低发酵羊乳中蛋白质羰基化水平,改善产品质地和风味等感官特征,并提高乳酸菌数量。

To develop a novel flavored fermented goat milk,Chinese yam was added to set-type goat yogurt,and the effects of different concentrations of yam powder(0%,0.75%,1.50%,2.25%,and 3.00%)on the tex-ture and protein carbonylation levels of the fermented goat milk were studied.The pH,titratable acidity,lactic acid bacteria count,and composition of flavor compounds were also evaluated.The results showed that protein oxidation in goat milk and during processing significantly reduced the texture and water-holding capacity of the final fermented goat milk product(P<0.05).The addition of different proportions of yam powder effectively re-duced the levels of carbonyl compounds generated by protein oxidation during the production of fermented goat milk.Moreover,the addition of yam powder improved the sensory attributes of the fermented goat milk,includ-ing taste,consistency,and texture,while also increasing the acidity and lactic acid bacteria count.Gas chromatography-mass spectrometry(GC-MS)analysis revealed that the addition of yam powder increased the relative content of components such as acetone and acetoin in fermented goat milk,giving the fermented goat milk a distinctive yam flavor.Therefore,adding 0.75%yam powder before fermentation can reduce protein car-bonylation levels,improve the texture and flavor sensory characteristics,and increase the lactic acid bacteria count in fermented goat milk.