預冷方式及除花萼處理，對甜豌豆貯藏品質之影響

The Effects of Precooling Method and Calyx-removing on the Storage Quality of Sugar Snap Pea

豌豆呼吸率高不易貯藏，本研究以目前外銷主力甜豌豆(Pisum sativum L. var. macrocarpon)‘台中13號’為標的，評估不同預冷方式(真空、壓差及室冷)及去花萼處理對其採後品質之影響。結果顯示果莢在1oC儲藏下20-25天品質開始下降，頂吸式壓差預冷處理至5˚C可減輕劣化程度，且真空預冷相比預冷後失重率僅0.73%，且在貯藏30天後硬度較高，總可溶性醣類含量較多，粗纖維和澱粉含量較低，果莢色差儀CIELAB測值之L*(亮度)、a*(綠紅值)及b*(藍黃值)則無明顯差異，後續於5˚C、3天回溫後之褐化及軟化率亦較低，可售率達93.3%，其次為真空預冷83.3%，室內風冷果莢僅有75.5%；從處理量體10 kg之預冷降溫曲線來看，壓差7/8預冷時間為14 mins，真空預冷操作則延長至25 mins，故建議壓差為甜豌豆合適之預冷方式。另未預冷果莢除花萼處理呼吸率可明顯從183.2 CO2 ml‧kg-1‧h-1降低150.1 CO2 ml‧kg-1‧h-1，對已壓差預冷果莢則無顯著影響，但有較佳的成分品質如維生素C、粗纖維及總可溶性糖含量，褐化和軟化率分別減少3.8%及3.3%，且未觀察到發霉果莢，可售率提升7.6%。本研究建議甜豌豆應以除花萼果莢並配合壓差預冷，以提升內外銷儲運品質。

"Pea is a perishable vegetable due to its high respiration rate. Sugar snap pea (Pisum sativum L. var. macrocarpon)‘Taichung No. 13’, the current exported produce, was used in the present study to evaluate the effect of precooling method and calyx-removing treatment on its postharvest quality. The results showed that the pod’s quality began to decrease after 1oC storage for about 20-25 days, as top-suction forced-air precooling to 5oC could mitigate the degree of deterioration. Compared to vacuum, it only led to the lower weight loss percentage (0.73%), the higher hardness and total soluble sugar (TSS) but also the lower crude fiber (CF) and starch content. Pod color, CIELAB value L*, a*, and b*, measured by colorimeter was not distinctly different. The subsequent browning and softening rate were relatively low after recovering at 5oC for 3 days. The highest marketable rate (93.3%) was reached in forced-air cooling, followed by vacuum (83.3%) and room cooling (75.5%). Besides, the 7/8 cooling time of forced-air was 14 mins which was prolonged to 25 mins by vacuum according to the cooling curve conducted with 10 kg pod. Therefore, forced-air is suggested as a suitable precooling method for sugar snap pea. Additionally, removing calyx could decrease respiration rate from 183.2 CO2 ml‧kg-1‧h-1 to 150.1 CO2 ml‧kg-1‧h-1 in non-precooled pods but showed no significant effect in precooled condition. However, it still led to better quality including vit. C, CF, and TSS content and then it was declined to 3.8% browning and 3.3% softening rate, respectively. There was no moldy pod observed and the marketable rate improved 7.6% consequently. In conclusion, calyx-removing at harvest followed forced-air cooling were suggested for sugar snap pea to improve either domestic or exporting quality."