摘要：发酵乳逐渐成为人们生活中必不可少饮品之一，发酵乳的感官方面是消费者是否能接受的重要指标，本课题主要从色、香、、形四个方面对不同加工工序的发酵乳进行分析和评判，为更进一步地了解以及控制发酵乳的品质提供参考。本课题要是针对于原料、配料、杀菌、发酵、翻缸冷却后、灌装和成品七个步骤的加工工艺对发酵乳的品质进行分析。在颜色方面，主要运用的是色差计在保持环境一定的情况下对奶制品进行色泽上的分析。在香气方面，采用GC-MS以及电子鼻对各种样品奶的风物质成分进行分析；觉方面利用酸碱滴定法，对各种样品奶之间酸度的变化进行观察。在形状方面，利用质构仪以及粘度计对发酵奶、翻缸冷却后奶、灌装奶和成品奶四种样品奶的硬度、脆度、粘度、弹性、凝聚力、粘性、咀嚼性和恢复力几大方面进行判别分析。结果显示，发酵工艺对色泽的影响最大；发酵乳香气的风物质的形成主要是在发酵工艺，而冷却放置会使发酵乳的风更丰富，这是多种风物质相互平衡的结果。觉方面，发酵工艺会使pH值小于4.7，酸度上升60个酸度值左右。在组织状态方面：发酵会使原料乳由于蛋白质等电点时的沉淀形成半固体的状态，冷却工艺会使经破乳的酸乳迅速冷却，此时其粘性也会升高，形成更硬实的组织状态和结构。色、香、、形的仪器分析客观数据可以和人工感官评价数据相互补充，为建立客观可靠长期储存的感官质量控制标准奠定基础。61789

毕业论文关键字：发酵乳；质构；酸度；色泽；香气物质。

 Effect of processing technology on the quality of yoghourt 

Abstract: Yoghourt gradually become essential drinks in daily life, the sensory aspects of Yoghourt is an important indicator of whether the consumer can accept, this project analysed and evaluated different processing step yoghurt mainly from the following four aspects, the color, smell, taste and shape. Therefore we can further understand and control the quality of products to provide reference for the quality control of yoghurt. This project aims at seven steps of processing, which are raw materials, ingredients, sterilization, fermentation, cooling after turning cylinder, filling and finishing to analysis yoghurt. The colorimeter in the case of keeping the environment was mainly used to anlyze the color of certain dairy products. GC-MS and electronic nose were used to analyze the aroma components of various kinds of yoghurt samples. The changes of acidity between different samples were observed by using acid-base titration method. Texture analyzer and viscometer  were used to discriminate the shape analysis on four sample milk, which are fermented milk, after turning cylinder cooling milk, bottling milk and finished milk, from several aspects, such as brittleness, viscosity, elasticity, cohesion, viscosity, chewiness and resilience. The results showed that the fermentation process has greatest impact on color, and flavor compounds of yoghurt aroma mainly form in the fermentation process, the cooling will place richer flavors into yoghurt, which is the result of flavour compounds balancing with each other. As for taste, fermentation process will make the pH value less than 4.7 and acidity to increase by about 60 pH value. In terms of organization status: yoghurt makes the raw milk form a semi-solid because of the precipitate, for example protein, from the isoelectric point and cooling process enable demulsificated yoghurt to cool rapidly, meanwhile the viscosity will increase to form a harder status and organization structure. The objective data of color, smell, taste and shape from instrumental analysis can complement artificial sensory evaluation data to lay the foundation for the establishment of objective and reliable sensory quality control standards in long-term storage.