膜醭毕赤酵母与壳聚糖复合处理对柑橘果实防御酶及防御物质的影响

研究膜醭毕赤酵母与壳聚糖复合处理对柑橘果实防御酶和防御物质的影响。采用损伤接种与无损伤浸泡复合液两种处理方式，分别研究经复合处理后果实防御酶和防御物质在7 d和28 d贮藏期内的变化。结果显示：与对照果实相比，复合液接种处理果实中的苯丙氨酸解氨酶（PAL）、过氧化物酶（POD）、多酚氧化酶（PPO）、几丁质酶、β-1,3葡聚糖酶（GLU）等防御酶在贮藏期内活性增加明显，其中以PAL、POD、GLU 3 种防御酶最为明显，在贮藏第3天时均达到最大值；复合液浸泡处理果实中的PAL、POD、几丁质酶活性和木质素含量的增加较为明显，在贮藏第14天时达到最大值。结果表明，膜醭毕赤酵母与壳聚糖复合处理能够诱导柑橘果实中防御酶活性和防御物质含量的升高，从而起到提高果实抗病性的效果。防御酶在果实贮藏前期发挥较关键的抗病作用，而酚类、木质素等防御类物质则在贮藏后期发挥抗病作用。

Effects of Pichia membranefaciens Combined with Chitosan on Defensive Enzymes and Substances in Citrus Fruits

The aim of this study was to investigate how combined treatment with Pichia membranefaciens and chitosan
could affect defensive enzymes and substances in citrus fruits. The changes of defensive enzymes and substances during 7
and 28 days of storage were examined by inoculating or dipping citrus fruits with Pichia membranefaciens combined with
chitosan respectively. The results were reported as follows: compared with the control group, the activities of the defensive
enzymes phenylalanine ammonialyase (PAL), peroxidase (POD), polyphenoloxidase (PPO), chitinase, and β-1,3 glucanase
in citrus fruits inoculated with Pichia membranefaciens in combination with chitosan were increased significantly during
storage. PAL, POD, and β-1,3 glucanase were most evidently increased and reached the maximum on day 3. On the other
hand, the activities of PAL, POD and chitinase and lignin content were increased significantly and reached the maximum on
day 14 in citrus fruits dipped with Pichia membranefaciens in combination with chitosan. In conclusion, disease resistance in
citrus fruits can be enhanced by Pichia membranefaciens combined with chitosan through inducing an increase in defensive
enzymes and substances such as phenolics and lignin. Defensive enzymes and substances play a major role in disease
resistance in the early and late stages of storage, respectively.