異硫氰酸丙酸烯酯處理對切絲甘藍（Brassica oleracea L. var. Capitata L.）酵素性褐變之影響

Effects of Allylisothiocyanate Treatment on the Enzymatic Browning Characteristics of Shredded Cabbage (Brassica oleracea L. var. Capitata L.)

秀峰甘藍（Brassica oleracea L.var. Capitata L. cv. Summit）切絲後，以真空浸漬法與燻蒸法添加異硫氨酸丙烯酯（a1lylisothiocyanate，簡稱AITC），於室溫下調查其褐變情形、Polyphenol oxidase（PPO）與phenylalanine ammonialyase（PAL）活性、及酚類化合物含量之變化，以瞭解AITC處理對抑制切絲甘藍酵素性褐變之效果。結果顯示，甘藍切絲後，以真空浸漬法施以AITC 500ppm之處理、於室溫下24小時，可有效抑制其酵素性褐變程度約50%，同時對PPO與PAL活性亦有87%與64%之抑制效果，酚類化合物含量之增加也有相當之抑制。燻蒸法亦可達到抑制之效果，然相較真空浸漬法，則效果較不理想。AITC抑制切絲甘藍褐變之機制，應以抑制PPO活性之增加為主，同時配合抑制PAL活性之增加為輔，以達抑制褐變之效果。

Shredded cabbages (Brassica oleracea L.var. Capitata group cv. Summit) were treated with allylisothiocyanate (AITC) by vacuum infiltration and fumigation. To understand the effect of AITC on the inhibition of enzymatic browning of shredded cabbages, the changes of △E, polyphenol oxidase (PPO) activity, phenylalanine ammonialyase (PAL) activity, and total phenols were measured at room temperature. Results showed that 500ppm AITC treated by vacuum infiltration resulted in 50% decrease of △E, 87% inhibition of PPO activity increase, and 64% inhibition of PAL activity increase of the cabbage 24 hours after shredding. The increase of total phenols was inhibited, too. Fumigation could also inhibit the enzymatic browning of shredded cabbage, however, vacuum infiltration was more efficient than fumigation The mechanism of the inhibition of browning could be that both the increases of PPO activity, and PAL activity of cabbage were inhibited after shredded by AITC treatment. However, the former could be more important than the latter.