輕度加工處理對截切洋蔥之品質與保存時間之影響

Abstract

輕度加工蔬果(Minimally processed vegetables and fruits)在截切後，因蔬果本身組織仍具活性，細胞生理代謝、酵素系統與生化反應仍持續進行而易導致品質劣變，因此常需利用一些處理來降低微生物含量，抑制部分或全部酵素作用，以達到產品符合衛生安全、品質新鮮，並能延長產品之櫥架壽命。 本研究之目的在探討使用不同溶液及處理條件對維持不同截切洋蔥的品質及延長儲架壽命的影響。截切洋蔥以3%檸檬酸溶液、6%氯化鈉溶液、2%幾丁聚醣醋酸溶液及0.3mg/L臭氧溶液等四種溶液處理後，以0.3mg/L臭氧溶液、6%氯化鈉溶液和2%幾丁聚醣溶液處理可有效降低截切洋蔥的初始帶菌數，檸檬酸溶液處理，對截切洋蔥降低總生菌數並無顯著效果。 截切洋蔥以處理組四種溶液處理後貯藏於5±1℃十天，可溶性固形物含量與pH值呈緩慢上升而可滴定酸度則下降，變化趨勢均與對照組相似。 使用2%幾丁聚醣醋酸溶液及0.3mg/L臭氧處理後之樣品對於延長貯架壽命效果較佳，貯藏壽命可分別延長至第6天及第7天，然而，以幾丁聚醣醋酸溶液處理之樣品因幾丁聚醣醋酸溶液呈淡黃色，因此處理後樣品之色澤呈微淡黃色。臭氧處理洋蔥鱗片色澤較白並可有效減少微生物的初始菌數。

After cutting the tissue of minimally processed fruits and vegetables, are still active. The enzyme system and biochemistry reactions are still proceeding which causes the changes of quality. So techniques of lowering the microorganism count and inhibit enzyme system are commonly used. The objectives of this research are providing safety and fresh products, and extending product’s shelf-life. This research adopts different solution treatments on onion. The objective of this study is to investigate the effect of solution pretreatment on the quality of minimally processed fresh-cut onion and shelf-life of the processed products respectively. We discuss the quality changes of fresh-cut onion storage at 5±1℃and treated with NaCl solution 6%, Citric acid solution 3%, Chitosan-acetic acid solution 2% or ozone solution 0.3ppm to improve the quality. The result of this study showes that 0.3ppm Ozone solution , 6% NaCl solution or 2% Chitosan-acetic acid solution treatment effectively decrease the initial microbial in fresh-cut onion. Treated with 3% Citric acid solution can’t decrease the total plate count. The content of soluble solid and pH increase while titratable acid decreases during storage at 5±1℃of each treatment. Treatment with 2% Chitosan-acetic acid solution and 0.3ppm Ozone solution are better than others, The shelf-life extends to 5 days and 6 days. Color change was observed on the onion bulbs because the color of Chitosan-acetic acid solution is yellow The Ozone treatment can bleach, lower Hunter’s b value and Hunter’ a value is closer to fresh wedges. Besides, it can also decrease the total plate count and extending shelf life.