【作者】 沈妍；

【导师】 叶兴乾；

【作者基本信息】 浙江大学 ， 食品科学， 2013， 博士

【摘要】 柑橘果实营养丰富,是人们膳食的重要组成部分,除维生素C外,还富含类黄酮、酚酸等酚类物质。近年来,众多研究表明这些酚类物质具有抗氧化、抗癌、抗炎、预防心血管疾病等生理功效。柑橘果实采后通常会进行长时间的贮藏,贮藏时间和采后处理可能会对果实的功能成分产生影响。但目前国内外关于柑橘采后酚类物质及抗氧化活性变化的研究很少。本文系统研究了柑橘采后贮藏过程中基本品质指标、抗坏血酸、具体酚类物质(类黄酮和酚酸)及抗氧化活性的变化,探讨了果实品种、采后处理及贮藏条件对这些活性成分的影响,主要研究内容和结论如下：1、研究了温州蜜柑和椪柑采后果肉和果皮中酚类物质和抗氧化活性的变化。结果表明贮藏期间温州蜜柑能较好地保持果实的营养品质及抗氧化活性,而椪柑经过长期贮藏后抗坏血酸和抗氧化活性显著降低。贮藏期间酚类物质相对较稳定,温州蜜柑中类黄酮含量有增加过程,椪柑类黄酮则变化不显著,酚酸含量总体呈增加趋势。两种柑橘果皮中的类黄酮含量贮藏后有不同程度的增加,特别是多甲氧基黄酮。2、研究了涂蜡和套袋对温州蜜柑采后酚类物质和抗氧化活性的影响。涂蜡和套袋处理显著降低了果实失重率并可保持果实基本品质指标,在贮藏前15天维持较高的总酚水平。套袋处理能较好地保持果实贮藏期间类黄酮和酚酸的含量,而涂蜡处理的果实酚类物质含量相对较低,特别是贮藏30天后。抗氧化活性与抗坏血酸和酚类物质的变化有关。3、研究了热水处理(50、52和54℃3min)对温州蜜柑采后酚类物质和抗氧化活性的影响。50℃热水处理不影响果实的基本品质指标且能显著降低果实失重率。贮藏前15天,热处理果实中的黄烷酮糖苷含量显著高于对照,热处理对酚酸的影响很小。50℃处理显著提高了果实处理后总酚含量和和抗氧化活性,并在贮藏期间保持与对照相当的水平,而52和54℃处理的果实抗氧化活性相对较低。4、研究了贮藏温度(4和10℃)和采收期(11和12月)对温州蜜柑采后酚类物质和抗氧化活性的影响。11月份采收的果实黄烷酮糖苷、总酚含量和抗氧化活性都显著高于12月份采收的果实,而抗坏血酸和主要的酚酸阿魏酸和芥子酸含量无显著差异。贮藏温度对酚类物质影响较小,10℃下果实的抗坏血酸含量和抗氧化活性高于4℃贮藏的果实。5、研究了短波紫外线(UV-C)处理(0、0.75、1.5、3.0kJ/m2)对温州蜜柑橘瓣(鲜切加工)贮藏期间酚类物质和抗氧化活性的影响。UV-C处理对橘瓣冷藏期间基本品质、酚酸和抗氧化活性影响较小,而1.5和3.0kJ/m2的UV-C处理显著提高了果实贮藏3天时类黄酮(11.75%-33.25%)和总酚的含量(5.73%和8.13%)。较高剂量的UV-C处理(3.0kJ/m2)不会进一步提高类黄酮的含量,而0.75kJ/m2剂量过低对果实类黄酮基本没有影响。更多还原

【Abstract】 Citrus fruit are an important part of human diet due to their nutritional value. In addition to vitamin C, citrus fruit contain large amounts of phenolic compounds such as flavonoids and phenolic acids. Recently, many researches have reported the beneficial effects of these phenolic compounds to human health, such as antioxidant, anticancer, anti-inflammatory and prevention of cardiovascular diseases. Citrus fruit are often stored for a long time after harvest, and storage time as well as postharvest treatments may affect the content of bioactive compounds. However, studies on changes of phenolic compounds and antioxidant capacity of citrus fruit during storage are limited. Thus, this study aimed at evaluating the changes of standard quality parameters, ascorbic acid, individual phenolic compounds (flavonoids and phenolic acids) and antioxidant capacity of citrus fruit, and to discuss the impacts of fruit cultivars, different postharvest treatments and storage conditions on these bioactive compounds. The main contents and results are as follows:1、The changes of phenolic compounds and antioxidant capacity in the pulp and peel of Satsuma mandarin and Ponkan during storage were studied. The results showed that Satsuma mandarin maintained better nutritional quality and higher antioxidant capacity, while ascorbic acid and antioxidant capacity decreased fast in Ponkan during storage. Phenolic compounds were relatively stable. Flavonoids increased in Satsuma mandarin but changed slowly in Ponkan during storage. Phenolic acids increased after storage. Flavonoids in the peels of both cultivars increased after storage in different levels, especially polymethoxylated flavones.2、The effect of waxing and wrapping on phenolic compounds and antioxidant capacity of Satsuma mandarin was investigated. Waxing and wrapping significantly reduced fruit weight loss, retained fruit standard quality and maintained higher total phenolic content during the first15days of storage. Wrapping retained higher levels of flavonoids and phenolic compounds, while phenolic compounds were lower in waxed fruit, especially after30days. Antioxidant capacity was related to the changes of ascorbic acid and phenolic compounds.3、The effect of hot water dips (50,52and54℃for3min) on phenolic compounds and antioxidant capacity of Satsuma mandarin was investigated.50℃treatment did not influence fruit quality attributes and reduced fruit weight loss significantly. Flavanone glycosides were higher in hot water treated fruit as compared to control during the first15days of storage, and phenolic acids were not affected.50℃treatment increased total phenolic content and antioxidant capacity immediately after treatment and maintained similar levels with control during storage, while52and54℃treatments showed lower levels.4、The influence of storage temperature (4and10℃) and harvest time (November and December) on phenolic compounds and antioxidant capacity of Satsuma mandarin was investigated. Fruit harvested in November showed significant higher flavanone glycosides, total phenol contents and antioxidant capacity than fruit harvested in December, while ascorbic acid and major phenolic acids (ferulic acid and sinapic acid) were similar:Storage temperature exerted little effect on phenolic compounds, and ascorbic acid content and antioxidant capacity were higher in fruit stored at10℃.5、The effect of ultraviolet C (UV-C) treatments (0,0.75,1.5and3.0kJ/m2) on phenolic compounds and antioxidant capacity of Satsuma mandarin segments (minimally processed) was investigated. UV-C treatments had no adverse effects on fruit quality attributes, phenolic acids and antioxidant capacity of mandarin segments. Significant increases of flavonoids (11.75%-33.25%) and total phenolic content (5.73%and8.13%) were found in1.5and3.0kJ/m2UV-C treated fruit at3days of storage. Higer dose of UV-C (3.0kJ/m2) did not further improve the increase of flavonoids, and0.75kJ/m2was too low to have any effects on flavonoids.更多还原