加工前處理降低冷藏截切鳳梨生菌數之研究

Abstract

鳳梨為台灣最重要的水果之一，其冷藏截切品的外銷需求量也與日遽增。近日有廠商反映，冷藏截切鳳梨常因生菌數過高遭日本買主退貨，造成農民極大損失。本研究即針對冷藏截切鳳梨生產過程中微生物數量的控制而進行。 本實驗分為兩部分，第一部分鳳梨分別以50ppm二氧化氯溶液處理，搭配傳統浸漬法、超音波震盪浸漬 (40kHz) 與真空浸漬法 (65 cmHg )，分別處理2.5 或5分鐘；第二部分利用0.93或1.11ppm臭氧氣體處理，搭配直接接觸法、多次抽氣法以及真空穿透法分別處理30分鐘後，測定各種處理方式對鳳梨芽眼中生菌抑制情形，以及截切成品於低溫 (5±2℃) 儲藏期間 (0、24、48、72hr) 色澤及質地之變化。 結果顯示，以二氧化氯溶液或臭氧氣體配合真空技術皆可顯著下降生菌數，但二氧化氯溶液或臭氧氣體搭配傳統浸漬法、超音波震盪、直接接觸法和多次抽氣法則無法有效抑制微生物生長。儲藏試驗結果發現，鳳梨經二氧化氯溶液或臭氧氣體真空穿透處理後截切之鳳梨，其截切成品色澤及質地於低溫儲藏期間無顯著劣變。由此可見以二氧化氯溶液或氣態臭氧配合真空穿透技術為核心，將可獲得比目前製程更具微生物清潔度，同時保有良好貯藏品質的冷藏截切鳳梨。

Pineapple is one of the most important fruits grown in Taiwan. The demand for fresh-cut pineapple is growing；However, microbial quality has been limiting its marketability. Thus, this study was aimed to look for methods that reduce the microbial load on fresh-cut pineapple effectively. Chlorine dioxide and ozone were used in this study. In the first part, pineapple was immersed into 50ppm chlorine dioxide solution with ultrasonication and with or without vacuuming for 2.5 or 5 min. In the second part, pineapple was treated with gaseous ozone (0.93 or 1.11 ppm) with or without vacuuming or repeated vacuuming for 30 min. After these treatments, the microbial load was evaluated. The effects of chlorine dioxide and ozone on physical properties of fresh-cut pineapples during storage were also investigated. The results showed that vacuum-penetration with chlorine dioxide solution or gaseous ozone can effectively reduce the microbial load in pineapple. Meanwhile, there is no significant effect on the physical properties of fresh-cut pineapples under refrigerated storage. In conclusion, we propose to use vacuum-penetration with microbicide as a pretreatment in the processing of refrigerated fresh-cut fruit to reduce the microbial load.