【作者】 黄媛媛；

【导师】 胡秋辉；

【作者基本信息】 南京农业大学 ， 食品科学， 2006， 硕士

【摘要】 茶叶尤其是名优绿茶在贮运过程中品质极易陈化劣变，降低绿叶的商品价值和经济价值。本研究在绿茶栽培、加工、贮运过程中采用生物制剂、微波杀青、纳米保鲜包装材料等多种技术提高绿茶保鲜品质。主要研究结果如下： 1．绿茶栽培过程中采用生物制剂，经茶树吸收转化，加工而成的商品茶叶具有持久保鲜效果，可一直保持新茶品质的特性；经过喷施浓度为150g ha^-1的硒肥，富硒绿茶维生素C含量为5.26±0.11g kg^-1而普通绿茶为4.46±0.06g kg^-1，富硒绿茶硒含量为5.025±1.303mg kg^-1而普通绿茶为0.048±0.002mg kg^-1，茶多酚、叶绿素、汤色无显著差异；经过4个月的贮藏维生素C保存量比普通绿茶显著提高，叶绿素、汤色有显著差异，茶多酚无明显差异。富硒茶叶的香气、甜味要显著高于普通茶叶，而苦味则显著低于普通茶叶。富硒茶叶的感官品质在贮藏期间更稳定。 2．优化微波杀青关键技术参数，获得最佳的微波杀青参数为投叶量为750克，传送速度为450r min^-1，微波功率为7×850w。采用微波杀青处理的绿茶不论是秋茶还是春茶维生素C含量要显著高于锅炒杀青的绿茶，汤色则低于锅炒杀青绿茶，茶多酚、叶绿素没有差异。经过贮藏，微波杀青绿茶维生素C、叶绿素含量、汤色要显著高于锅炒杀青绿茶，茶多酚并没有显著差异。香气、甜味在贮藏过程中都呈下降趋势，而采用微波杀青技术加工的绿茶下降缓慢和锅炒杀青绿茶有显著性差异，使绿茶具有良好的香气和甜味；微波杀青绿茶的苦味几乎没有变化。采用微波杀青技术不仅提高了绿茶的品质还可以延长绿茶的货架期。 3．以纳米粉体、塑料、腊、聚乙烯等为主要材料制备而成的包装，用于绿茶的包装可显著提高绿茶的贮藏稳定性。透氧量降低2.1％，透湿量降低28.1％，拉伸强度增强24％。纳米包装材料包装的绿茶，维生素C、叶绿素等要明显高于采用普通包装材料的绿茶。纳米包装材料包装的绿茶在常温条件下贮藏240天维生素C、茶多酚、叶绿素含量比普通包装分别高44％、14％、16％。更多还原

【Abstract】 Quality of tea especially high-grade green tea deteriorated easily during storage and transportation, which will lower merchandise and economy value of the tea. The paper put an emphasis on the key technology to improve the preservation quality of green tea including applying of biology preparation, enzyme inactivation by microwave, nano-packing material. The main research results are as follows:1.Commercial green tea processed from application of biology preparation during green tea cultivation had longer preservation quality. Significantly higher Se content of 5.025 ± 1.303 mg kg^-1 was determined in green tea with the application of fermented Se-enriched fertilizer 150 g ha^-1 on the foliar compared with regular green tea of 0.048 ± 0.002 mg kg^-1. Se-enriched green tea had a significantly higher vitamin C content of 5.26 ± 0.11 g kg^-1 than regular green tea of 4.46 ± 0.06 g kg^-1. However, no significant differences of tea polyphenol, chlorophyll and tea color were found between Se-enriched green tea and regular green tea. After 4 months’ storage, more vitamin C was preserved in Se-enriched green tea and there were significant differences in tea color and chlorophyll content. Besides, Se-enriched green tea had more stable sensation quality during storage as it was higher in aroma and sweetness but lower in bitterness. All these results indicated that application of Se-enriched fertilizer would significantly improve the preservation and sensation quality of green tea.更多还原