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速溶红茶加工过程中香气的变化及保香措施的研究
Changes of Aroma Constituents of Instant Black Tea during Processing and the Research of Aroma Retention Measures
【作者】 李真;
【作者基本信息】 安徽农业大学 , 营养与食品卫生学, 2015, 硕士
【摘要】 近年来,速溶茶已经成为当下国内外颇为流行的一种饮料,其中尤以速溶红茶的产销居多,但是速溶茶香气匮乏的问题至今没有寻找到较好的解决办法。本文跟踪速溶红茶加工过程,研究每一阶段过程中的香气变化,旨在探索速溶红茶加工中香气的变化规律,找出其香气损失的关键点,并从这些关键点下手,寻求速溶红茶香气的保留措施,为高香速溶红茶的研究提供借鉴。本文利用同时蒸馏萃取法(SDE)和顶空吸附法(HAS)两种不同的香精油提取方式提取茶叶香气,结合气相色谱-质谱联用技术(GC-MS)检测香气成分,对比不同提取方式提取茶叶香气的效果,选取较合适的香气检测方法。然后对速溶红茶生产中香气组分的变化进行全面跟踪,探索香气损失的规律。还探讨了速溶红茶与其加工原料——红茶的香气特征之间的正相关性,对比不同产地、不同等级的红茶的香气特征,为速溶茶加工原料的选择提供建议。同时研究了提取时间和干燥方式对茶香气的影响,分析速溶茶生产过程中常用的转溶这一加工步骤对速溶茶成品的香气造成的损失,提出速溶红茶加工工艺优化的建议。从这几个方面入手,争取更多地保留茶叶原有的香气,生产出香气较高的速溶红茶,为速溶红茶的市场开发提供技术支持。主要研究结果如下:1、SDE法比HAS法提取香气得到的香气组分更为丰富,相对能够较为全面的反应红茶及速溶红茶的香气特征,因而最终选取SDE作为香精油提取方式,统一运用SDE法结合GC-MS技术作为文中后续试验的香气检测分析方法。2、红茶原料的香气在速溶红茶的加工过程中逐渐损失,加工工艺对速溶红茶的香气影响明显。其中在提取和浓缩阶段香气的损失最为严重,最终生产出的速溶红茶香气物质的种类和含量都与红茶原料中相差甚远。同时,不同类型的香气成分损失程度也有很大的不同,其中以碳氢类香气物质的损失最为明显,酯类化合物的损失相对最少。3、红茶原料香气越高,生产出的速溶红茶香气也就越高,斯里兰卡BOP、印尼BOPF和印度阿萨姆BOPSM三种红茶香气特征较好,另外建议选择等级较高的红茶作为速溶红茶加工原料。为了更多的保留原茶香气,加工过程中建议在得率满足要求的条件下提取时间80 min以内、干燥方式选择冷冻干燥,另外建议不采取碱转溶的加工方式。
【Abstract】 In recent years,instant tea has become a kind of popular drink at home and abroad,meanwhile,production and marketing of instant black tea got the most.However,the lack of instant tea aroma has not find a better solution.In order to explore the change rule of aroma in instant tea processing,and find out the key points of aroma loss,this paper track the processing of instant black tea to study the change of aroma in each stage.And then take measures from the key points to seek instant black tea aroma retention methods,provide reference for the research of high aroma instant black tea.By using different two kinds of pretreatment methods--simultaneous distillated extraction method(SDE)and headspace adsorb method(HAS)to extract tea aroma,and combining the technique of gas chromatography-mass spectrometry(GC-MS)to detect aroma composition,it contrasted the effect of different pretreatment method,selected a better detection method.Then track the change of aroma in instant black tea processing to explore the change rule of aroma loss.The positive correlations of aroma characteristics between instant black tea and its processing raw materials are discussed in this article.In addition,it contrasted aroma characteristics of black tea from different regions and different grades to provide suggestions for the selection of instant tea processing raw materials.The influence of extracting time and drying methods on tea aroma were studied,it also analyzed the loss of aroma in decreaming--the commonly used processing step in the production of instant tea.Moreover,instant black tea processing technology optimization suggestions were put forward,too.From this a few aspects,strive for retain the original aroma of tea as possible,and produce high aroma instant black tea,provide technical support for instant black tea market development.The main results were as follows:1.SDE method is better as it can extract more rich aroma components than HAS,relatively,it can comprehensively reflect the features of the aroma of black tea and instant black tea.So it finally selected SDE as the aroma pretreatment way,unified SDE with GC-MS technology as the fragrance detection and analysis method in the follow-up test.2.The aroma of black tea raw materials gradually lost in the process of instant black tea processing,effect of processing technology on instant black tea aroma is obvious.Aroma loss in the extraction and concentration is most serious,the types and content of aroma components in instant black tea are far from that of black tea raw materials.At the same time,loss rate of different types of aroma components is also very different,of whichhydrocarbon compounds loss the most,while ester compounds loss it least relatively.3.The higher the raw black tea aroma is,the higher its instant black tea aroma be.Sri Lanka BOP,Indonesia BOPF and India Assam BOPSM got good aroma characteristics,choose a higher grade black tea as raw materials for the instant black tea processing is more beneficial.In order to retain the original tea aroma as much as possible,in the manufacturing process,extracting time 80 minutes,freeze drying be suggested under the condition of yield meet the requirements,additionally,it is better to not take alkali decreaming processing way.
【Key words】 black tea; instant tea; processing; aroma constituents; gas chromatography-mass spectrometry(GC-MS);