| Summary: | 碩士 === 臺灣大學 === 園藝學研究所 === 96 === The objective of this study was to evaluate the postharvest applicability of micronized chitosan on fruit and freshly-cutted sliced papaya (Tainung No.2). Two kinds of chitosan, micronized chitosan (MC) and chitosan control (CC), were used in this study. Color of fruit surface and flesh, fruit hardness, soluble solid, and microorganisms were assayed to evaluate the effects of micronized chitosan on the postharvest quality factors.
Our results showed that fruit hardness with 1% (w/v) CC treatment was decreased by 1.5% after 2 weeks storage, and that with 1% MC treatment was decreased by 8.9%, the hardness with both two treatments were significant (P < 0.05) higher than that with the control treatment. Fruit color were evaluated by hue angle value. MC and CC treatments effectively (P < 0.05) inhibited the yellowing of fruits surface. The colony forming unit (CFU) of 1% MC and 1% CC treatments was over 104 CFU/g at the 10th day of storage, but that of the control was over 104 CFU/g at the 4th day. A significantly (P < 0.05) difference in CFU among different treatments was observed.
MC and CC have been used to treat freshly-cutted papaya by soaking and spraying methods. Soaking treatments using 1% MC and 1% CC resulted in a significant (P < 0.05) change in flesh bright value as compared to the control. A similar phenomenon was observed in the spraying treatments using 1% MC and 1% CC. In weight-lose observation, 1% MC, 1% CC, and control treatments resulted in weight reduction by 4.36%, 5.62%, and 6.66%, respectively as compared with, showing that 1% MC treatment showed a significant (P < 0.05) difference to the control. The CFU with 1% MC and 1% CC treatments was over 104 CFU/g at the 4th day of storage, and that of the control was over 104 CFU/g at the second day, suggesting that MC and CC treatments resulted in a significant reduction in the growth of microorganisms. Soaking treatment caused water core injury after two days of storage, while spraying method could avoid this problem.
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