| 摘要： 本研究是針對高雄縣燕巢地區所栽種的 ‘珍珠拔’及‘水晶拔’ 番石榴果實為材料，探討番石榴利用不同包裝方式有裸果、PE袋密封、PE袋內附乙烯吸收劑、打孔PE袋、舒果套外加PE袋旋口、舒果套外加PE袋密封、舒果套加乙烯吸收劑外加PE袋密封；不同厚度(0.03mm、0.05mm)PE袋襯裡包裝處理、貯藏前熱處理(46℃、48℃處理8、12秒及46℃處理16秒)來進行對果實採後生理、貯藏壽命及品質之研究，並探討PE(pectinesterase)及PG(polygalacturonase)酵素在果實軟化中變化情形等。結果顯示，‘珍珠拔’及‘水晶拔’番石榴果實，在不同貯藏溫度(0-25℃)下，均無出現明顯的呼吸峰和乙烯峰。 ‘珍珠拔’及‘水晶拔’ 番石榴果實利用不同包裝於不同貯藏溫度下，皆以裸果處理失重率最為嚴重，其次為打孔PE袋處理，而利用不同PE袋包裝處理失重率則最低。隨著貯藏溫度之降低，果實失重率會逐漸下降，所以番石榴利用低溫貯藏搭配PE袋包裝可有效降低果實失重情形。然而番石榴在低溫下果實容易出現果皮凹陷、褐化等之寒害症狀(‘珍珠拔’，0℃10天及5℃20天；‘水晶拔’，0℃4天及5℃6天)，但利用舒果套外加PE袋密封及舒果套加乙烯吸收劑外加PE袋密封包裝，能延緩及減輕果實在低溫下所造成之低溫傷害，而兩品種中以‘珍珠拔’寒害發生率較‘水晶拔’低，且出現寒害時間較晚。在番石榴果實之貯運上，貯藏溫度以5℃為佳。另外，不同包裝處理也會影響果實的貯藏壽命，‘珍珠拔’利用舒果套外加PE袋密封包裝或舒果套加乙烯吸收劑外加PE袋密封包裝處理並搭配適合的貯藏溫度(5℃)，可達最佳的貯藏壽命約33-34天之間；‘水晶拔’約為20天左右。 ‘珍珠拔’及‘水晶拔’ 番石榴果實在裝箱時，利用不同厚度PE袋襯裡包裝處理，不論是0.03mm或0.05mm PE袋襯裡，於常溫貯藏(25℃)下，利用PE袋襯裡且抽氣密封包裝之果實，會加速果實腐敗並產生異味；但於5℃低溫貯藏下，利用PE袋襯裡且抽氣密封包裝之果實則有最長之貯藏壽命(‘珍珠拔’約33天及‘水晶拔’約25-26天)。而在品質方面，無論PE袋襯裡厚薄或抽氣密封與否，均對果實品質無顯著影響。 貯藏前番石榴果實利用不同熱處理後分別於5、10℃貯藏，2品種果實之呼吸率皆比對照組呈緩慢增加之趨勢，而以10℃貯藏者之呼吸率較5℃貯藏者增加更為明顯；‘水晶拔’果實以熱水48℃處理12秒(5℃)及熱水46℃處理12秒(10℃)處理者，果實之乙烯產生率呈明顯偏低。在品質方面，熱處理可維持果實硬度及脆度，可滴定酸、可溶性固形物含量、果肉pH值及維生素C含量則皆不受影響，色澤方面也可延遲果皮顏色轉黃。經熱處理的果實均能延長貯藏壽命，在果實寒害及腐敗發生方面，也能延緩果實寒害症狀及腐敗發生，且寒害、腐敗發生率較低且症狀輕微。 ‘珍珠拔’及‘水晶拔’兩品種番石榴果實在貯藏期間，果實PE及PG酵素活性，以常溫(25℃)裸果之酵素活性較高，而以低溫(5℃，10℃)貯藏者之活性較低。但包裝與否，以PE袋扭轉或打孔PE袋包裝與裸果不包裝者相較，果實PE及PG酵素活性，雖在貯藏期間均呈增加趨勢，但包裝對酵素活性有稍微降低之影響，惟不若對失重及硬度之影響來的明顯。A series of studies were conducted to elucidate the physico-chemical changes during postharvest packagings : unpackage, sealed in polyethylene (PE) bag, sealed in PE bag containing ethylene absorbents, perforated PE bag, torsional PE bag containing polystyrene net sleeve (PNS), sealed in PE bag containing PNS, sealed in PE bag containing PNS and ethylene absorbents. Different thickness (0.03、0.05mm) of PE bag lining packaging treatments, heat treatments (8、12 and 16sec. at 46℃ and 8、12sec. at 48℃), PE (pectinesterase) and PG (polygalacturonase) activity of two cultivars of guava fruits (Psidium guajava L.), named ‘Jen-Ju Bar’ and ‘Shui-Jing Bar’ during storage were also investigated. Results showed that the ‘Jen-Ju Bar’ and ‘Shui-Jung Bar’ fruits were stored at different temperatures (0-25℃) , there were not appeared clearly climacteric respiration and ethylene peak. After stored at 0-25℃, the weight loss of unpackaged fruits were significantly higher than other package, secondly were perforated PE bag packaged fruits, and the fruits packed with PE bags were significantly lower. The weight loss were reduced with the lowering the storage temperature. However, guava fruits storing at low temperatures exhibited surface pitting and browning symptoms of chilling injury (‘Jen-Ju Bar’ , 0℃10 days and 5℃20 days ; ‘Shui-Jing Bar’ , 0℃4 days and 5℃6 days). Fruits packed with sealed in PE bag containing PNS and sealed in PE bag containing PNS and ethylene absorbents would delay and alleviate the development of chilling injury. The rate of chilling injury of ‘Jen-Ju Bar’ fruits were lower than ‘Shui-Jing Bar’ fruits, and the time of chilling injury symptom appeared of ‘Jen-Ju Bar’ was also late. Therefore, guava fruits should be stored at 5℃during storage and transportation. In addition, different packaging methods affected storage life of fruits. The fruits of ‘Jen-Ju Bar’ packed with sealed PE bag containing PNS and sealed in PE bag containing PNS and ethylene absorbents at 5℃were significantly extended the storage life to 33-34 days；‘Shui-Jing Bar’ fruits were 20 days. Using different thickness of PE bag lining in carton of ‘Jen-Ju Bar’ and ‘Shui-Jung Bar’ fruits, regardless of 0.03mm or 0.05mm of PE bag linings, fruits stored at 25℃with vacuum sealed in PE bag lining produced off-flavor and decay. But fruits stored at 5℃with vacuum sealed in PE bag lining had the longest storage life (‘Jen-Ju Bar’, 33 days and ‘Shui-Jing Bar’, 25-26days). Fruits quality among those of fruits, with it used regardless of thickness of PE bag lining or vacuum sealed treatments, were no significantly different. Prestorage heat treatments of ‘Jen-Ju Bar’ and ‘Shui-Jung Bar’ fruits stored at 5、10℃, the respiration rate of two cultivars fruits were increased slowly compared to untreatment fruit, the respiration rate of fruits stored at 10℃ was higher than stored at 5℃. The lower ethylene production rate of ‘Shui-Jing Bar’ fruits with heat treatments (12sec. at 48℃) stored at 5℃ and (12sec. at 46℃) stored at 10℃. On the quality of guava fruits, the fruit firmness and crispness retained after heat treatments, and did not affect total soluble solids, titratable acidity, pH value and Vit. C of the fruits, and delay yellowing of peel color. Moreover, could extend their storage life and delayed and alleviated chilling injury and decay incidence. Two cultivars of guava fruits ‘Jen-Ju Bar’ and ‘Shui-Jing Bar’ during storage, the enzyme activity of PE and PG were higher at 25℃than those of fruits stored at 5℃and 10℃. Regardless of package, PE and PG activity of fruits increased during storage and the effect of packagings on both enzymes activity were smaller than its effects on weight loss and firmness. |
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