品種與抑制褐變處理對截切馬鈴薯片品質影響之研究

Abstract

馬鈴薯截切後切面不到一天便能觀察到褐化現象，是影響截切馬鈴薯品質劣變的主要問題。經截切後馬鈴薯細胞隔室化遭受到破壞，致使多酚氧化酵素與基質接觸開始進行氧化反應而導致切面褐變。此外，截切馬鈴薯組織受傷面積增加、組織液滲漏，導致微生物孳長，影響食品安全與櫥架壽命。目前國內關於截切馬鈴薯產品保鮮技術的資料並不多，因此本論文試驗目的在探討抗褐化劑與改變大氣組成處理技術應用在截切馬鈴薯產品之保鮮及延長櫥架壽命的效益。本試驗針對台灣三品種馬鈴薯‘克尼伯’、‘台農一號’及‘種苗四號’進行冷藏後截切褐變分析，結果顯示‘克尼伯’ 馬鈴薯塊莖對於截切後之切面褐變最輕微，但一天內即失去商品價值。馬鈴薯塊莖冷藏越久，截切褐變發展越快且越嚴重，截切前20°C回溫5天可改善切面品質。截切‘克尼伯’馬鈴薯於5°C進行貯放以抗褐化劑或氣調進行處理，可延長商品價值至兩天;以低氧氣高二氧化碳之氣調進行處理，外觀可維持商品價值約十天，但卻受限於生菌數於五天後超標;截切‘克尼伯’以抗褐化劑搭配減壓包裝，外觀於切後第十五天仍未褐變，但生菌數於切後第十天超標，若於0°C進行貯放，則外觀和生菌數於切後十五天皆具商品價值，而黴菌及酵母菌則各處理組於試驗其間皆可維持法定安全標準;減壓包裝袋內為低氧高二氧化碳之環境，造成截切‘克尼伯’馬鈴薯之無氧呼吸而導致袋內乙醛乙醇累積量上升，但並未達到人類乙醛乙醇感官閥值，不致影響產品品質。

Browning of the fresh-cut potato will occur rapidly less than a day after cutting.Slice discoloration is the most important factor in the deterioration of fresh-cut potato. The damage of cell compartment resulting polyphenol oxidase to contact with the substrate to start the oxidation reaction leading slice to browning after cut. Sap released from the cut surface also renders the produce susceptible to microbial contamination, thus raising concerns about food safety and affecting its shelf life. Rare information is currently available about the postharvest technology of fresh-cut potato in Taiwan. This thesis devotes to investigations on the use of anti-browning agents and atmosphere modification for extending the shelf-life of fresh-cut potato.Analysis the browning after cutting of Taiwan three varieties of potato 'Kenniber', 'Tainong no.1' and 'Chongmiao no.4'. The results showed that 'Kenniber' has minor effect on browning after cutting.But the L value of slices will below 64 and loss the commercial value less than 1 day. The longer potato tubers put in cold storage, the faster and more serious slices trun to brown. Potato preparation with rewarming at 20˚C for 5 days before slicing can improve the appearance of slices. The anti-browning agent and the controlled atmosphere (CA) were used in fresh cut 'Kenniber' in 5°C can extend the commercial value for 2 days. Fresh cut 'Kenniber' can extend the commercial value for 10 days by treated with the CA of low oxygen high carbon dioxide, but the mesophiles will wxcessive after 5 days. 'Kenniber' can inhibit browning on the slice until 15 days after cutting by treat with anti-browning agent and hypobaric package in 5°C, but the mesophiles will wxcessive after 10 days. Also, it can maintain the commercial value, the mesophiles, the yeasts and molds under the limit in 0°C. low oxygen and high carbon dioxide in the fresh cut 'Kenniber' hypobaric package lead to anaerobic respiration induced ethanol and acetaldehyde accumulation rise. However, it will not affect the product quality because the ethanol and acetaldehyde do not reach human sensory level.