【作者】 陈影；

【导师】 赵征；

【作者基本信息】 天津科技大学 ， 食品科学， 2004， 硕士

【摘要】 本课题的研究目的是通过对解脂假丝酵母脂肪酶对乳脂肪水解时间的控制，得到风味增强的奶香型调味剂。研究的主要内容为：确定解脂假丝酵母脂肪酶水解乳脂肪的工艺条件；分析鉴定产物主要挥发性物质；水解产物喷雾干燥法微胶囊化的研究；喷雾干燥后产品的品质评定。 在单因素实验基础上，通过响应面分析法对解脂假丝酵母脂肪酶水解乳脂肪的工艺条件进行优化，得出最佳工艺条件为：底物浓度50.7％；反应pH值7.5；加酶量317.3U／g乳脂肪；反应温度40℃；摇床转速180r／min。 结合仪器分析及感官评定的结果，确定最佳水解条件下水解6hr的水解产物具有最大可接受性。对水解时间6hr产品同步蒸馏法收集的挥发性物质采用气质联用技术主要鉴定出了下列几种风味物质及其相对含量3-羟基-2-丁酮6.23％，2-壬酮2.98％，5-十二醇0.92％，乙酸1.29％，2-十一酮1.13％，丁酸7.52％，2-十三酮0.56％；已酸17.01％。 通过单因素实验、正交实验确定微胶囊化乳液壁材明胶：麦芽糊精1：4；乳化剂单甘酯、蔗糖酯比例1：3，添加量2％；心壁比1：1，乳化温度60℃，加水量50％。在喷雾干燥条件：进风温度180～190℃，出风温度80～90℃，进料速度30ml／min下所得产品包埋率为92.06％。 喷雾干燥前后产品风味物质组分总量的保留率91.02％。采用差示扫描量热仪分析包埋后产品与乳脂相比热力学性质的变化，产品熔融峰从包埋后乳脂的118℃降到了95℃。采用环境扫描电镜观察到微胶囊化产品外壁组织结构较好。产品的水分含量2.82％，脂肪含量46.55％，容重255ml／100g，在60℃水中溶解性良好，流散性40°。对产品与商业样品进行应用对比，成对比较检验法结果表明，在5％显著水平，两者无显著差异。更多还原

【Abstract】 An investigation was conducted on the hydrolysis of milkfat catalyzed by Candida lipalytica lipase and the microencapsulation of the hydrolysate.On the basis of single factor experiments, response surface analysis was applied to determine the optimal conditions of hydrolysis. The optimal conditions included milkfat concentration 50.7%; pH 15; lipase 317.3U/g; temperature 40 C; shaker rotation 180r/min.The results of instrumental analysis and sensory evaluation indicated the highest acceptance was found for the product which was hydrolyzed 6hr under the optimal conditions. The method of simultaneous distillation-extraction was employed to extract the volatile components of the hydrolysate. The compounds of the characteristic milk flavor of the extract were isolated and identified by GC-MS. The chemical components included: 3-hydroxy-2-Butanone 6.23%, 2-Nonanone 2.98%, 5- Dodecanol 0.92%, Acetic acid 1.29%, 2-Undecanone 1.13%, Butyric acid 7.52%, 2-tridecanone 0.56%, Hexanoic acid 17.01%.The microencapsulated hydrolysate was produced by spray-drying with gelatin and maltodextrin as wall material. The ratio of gelatin to maltodextrin was 1:4. The optimal conditions of emulsion were determined by single factor experiments and orthogonal design: gelatin :maltodextrin 1:4; emulsifier 2% which was comprised of mono-glyceride and sucrose ester 1:3; core/wall 1:1; the temperature of emulsion 60 C; the quantity of added water 50%. Efficiency of encapsulation was 92.06% under the condition of spray-drying: inlet temperature 180~190 C, outlet temperature 80~90 C, feeding rate 1.81/hr.The retention of total volatiles collected by SDE was 91.02%. Compared with the melting peak of microencapsulated milkfat, 180 C, that of microencapsulated hydrolysate was decreased to 95 C as a result of DSC analysis. Environment Scanning Electron Microscopy (ESEM) was applied to view the microstructure of microencapsulated product. Good results were obtained. Moisture of the powder was 2.82%, fat content 46.55%, bulk density 255ml/g, full reconstitution in 60 C water, powder flowability 40. No significant flavor difference (P>0.05) was showed between experimental and market samples.更多还原