红富士苹果采后色泽变化机理及其调控技术途径-果树学专业论文.docxVIP

红富士苹果采后色泽变化机理及其 调控技术途径 摘要 红富士是中国苹果市场上最主要的品种之一，但红富士苹果在贮藏期间色泽很容 易变暗。本试验以套袋和未套袋的红富士苹果(MalusDomestica cvFuji)为试材，研究 了在室温和低温贮藏期间果皮中花青苷、可溶性酚含量、pH值以及多酚氧化酶(PPO) 变化的生理与分子机制，探讨了红富士苹果采后色泽变化机理及其控制技术。并研究 了一种酮糖(Ascopyrone P，简称APP)和曲酸对其多酚氧化酶和果汁褐变的抑制效 果，试验结果如下： 1随着贮藏时间的延长。果皮颜色交睹，花膏苷含量逐渐降低。室温和低温条件 下贮藏的套袋、不套袋苹果的色差和花青菅都呈极显著正相关关系。 2红富士苹果果皮花青苷的颜色依赖于介质的pH，高pH导致花青营褪色和变 色，可见光吸收光谱发生改变。在贮藏过程中红富士苹果果皮中的pH值持续上升， 其中，不套袋果高于套袋果，室温贮藏的高于低温贮藏的。室温贮藏条件下果皮的 pH值与花青苷、色差呈显著或极显著负相关关系。但低温贮藏条件下果皮的pH值 与花青苷和色差不存在显著相关关系。 3套袋果果皮的可溶性酚含量明显低予不套袋果，低温贮藏降低了果皮中可溶性 酚的含量，从而延迟了褐变。在贮藏期间低温和室温贮藏的果皮中可溶性酚含量都呈 下降趋势。 4在贮藏期间低温和室温贮藏果果皮中PPO活性都有一活性高峰，低温延迟了这 一高峰的到来，也延迟了褐变。低温贮藏果的PPO活性较室温的高。套袋降低了PPO 的活性。 铂  5 Northem杂交结果表明，低温贮藏两周内苹果PPO基因有较明显表达，以后 表达量很少；CHS基因在采收时有表达，贮藏前两周表达量很少，但第3周后表达 量有所上升。 6 APP和曲酸都能抑制果实中PPO活性，并且能够抑制果肉和果汁变褐，在 100mg．Lt-500mg．L。浓度范围内，随着浓度的增加，抑制作用增强。 关键词： 果实色泽； 花青苷； pH值； APP； 曲酸  Mechanism of changes in apple fruit color and its control technique in postharvest Abstract “Red Fuji”apples(Malus Domestica CV Fuji)is the central cultivar in commercial at industry in China．Its skin discolors easily during storage．In present paper bagged and non—bagged Red Fuji mature fruit were used to study the changes in skin color, anthocyanin and soluble phenol content，pH and PPO during storage and the effects of a ketose—Ascopyrone P(APP)and kojic acid treatments on fruit juice browning．The main results are as follows 1 The color quitted and content of anthocyanin in fruit skin decreased during storage The total chromatism had significant or very significant positive correlation with anthocyanin content of bagged and non-bagged fruit stored in both room temperature and low temperature 2 The color of anthocyanin in frnit skin depended on the pH，anthocyanin color was fading in high pH buffer．pH in fruit skin juice went up continuously during storage．pH in bagged fruit was lower than that ofnon-bagged fruit and pH during the fruit stored in low temperature was lower than that stored in room temperature．The total chromatism and anthocya