薰衣草油不同添加时期对烤烟致香成分和感官质量的影响

【目的】为了改善初烤烟叶香气质量。【方法】以K326中部烟叶为材料,研究了烘烤过程中不同时期添加薰衣草油对烤后烟叶致香成分和感官质量的影响。【结果】在烟叶烘烤干筋期之前添加薰衣草油有利于新植二烯的形成与积累,烤后烟叶致香物质总量高于对照,其中在变黄中期添加薰衣草油烤后烟叶新植二烯含量和致香物质总量相对最高,其次为变黄初期;此外在烘烤过程不同时期添加薰衣草油均有利于类胡萝卜素类降解产物的积累和形成,但对苯丙氨酸类致香物质、美拉德反应产物、西柏烷类降解产物和类酯类降解产物的形成与积累无明显促进作用。从感官评吸结果看,在烘烤过程不同时期添加薰衣草油烤后烟叶感官评吸质量均有提高,在变黄中期添加薰衣草油烤后烟叶感官评吸质量最好。【结论】综合来看,在烟叶烘烤的变黄中期添加薰衣草油烤后烟叶新植二烯含量和致香物质总量较高,烟叶吸食品质最佳。

发酵营养剂NutrienFast添加时期对葡萄酒发酵的影响

在含糖量高、酵母可同化氮不足的葡萄汁中,研究不同发酵时期添加安琪发酵营养剂NutrienFast对葡萄酒发酵的影响。结果表明,在发酵第3天(糖消耗36.26%)、第4天(糖消耗到达44.18%)时添加发酵营养剂NutrienFast对葡萄酒发酵的影响最大,此时CO_(2)累积质量损失最高,分别为129.62 g/L和128.82 g/L;葡萄汁中的酵母干物质含量达到最高值,分别为3.57 g/L、3.62 g/L;葡萄酒相对密度、残糖含量最低;酒精度最高,分别为16.5%vol、16.4%vol,酒精发酵完全(残糖<4 g/L),可有效解决或者预防葡萄酒的发酵停止或停滞问题。

An Additive Hazards Model for Clustered Recurrent Gap Times

In this article, clustered recurrent gap time is investigated. A marginal additive haz- ards model is proposed without specifying the association of the individuals within the same cluster. The relationship among the gap times for the same individual is also left unspecified. An estimating equation-based inference procedure is developed for the model parameters, and the asymptotic proper- ties of the resulting estimators are established. In addition, a lack-of-fit test is presented to assess the adequacy of the model. The finite sample behavior of the proposed estimators is evaluated through simulation studies, and an application to a clinic study on chronic granulomatous disease （CGD） is illustrated.