酸奶中乙醛和双乙酰含量对其风味的影响

本文分别采用碘滴定法和邻苯二胺比色法测定发酵乳中的乙醛和双乙酰含量,试验显示这两种方法操作简单、稳定性和重复性好。通过在鲜奶中添加不同浓度外源性乙醛和双乙酰,经组织感官评价小组品尝和统计,结果显示乙醛能赋予酸奶清爽的芳香味,双乙酰能带来较重的奶油香味,两者可品尝到的最低阈值均为5mg/L,质量含量超过30mg/L时,会使酸奶产生不愉快的风味。当酸奶中乙醛和双乙酰质量含量比例为2.5:1时,酸奶香气最佳。

Effect of content of acetaldehyde and diacetyl on the flavor of yogurt

In this paper,the content of acetaldehyde and diacetyl were determinated by using iodine titration and the o-phenylenediamine colorimetric in fermented milk.And the test showed that both methods were simple,stable and reproducible.The milk added different concentrations of exogenous acetaldehyde and diacetyl were tasted.The results showed that acetaldehyde was refreshing aroma,diacetyl can bring cream flavor.The thresholds of those were 5mg/L.When the content more than 30mg/L,the yogurt will produce an unpleasant flavor.The yogurt had coordinated flavor when the ratio of aldehyde and diacetyl was 2.5.The study provided a more objective reference for the evaluation of yogurt flavor.