期刊名称：Pertanika Journal of Social Sciences & Humanities
印刷版ISSN：0128-7702
电子版ISSN：2231-8534
出版年度：1987
卷号：10
期号：2
出版社：Universiti Putra Malaysia
摘要：Langsat undergo both enzymic browning during preparation and non-enzymic browning during storage of the canned product. Effects of sodium chloride, ascorbic acid, cysteine HCl and citric acid on browning of the product were studied. Enzymic browning during preparation could be reduced by lowering of pH, but the use of citric acid is not recommended because it increases nonenzymic browning during storage. Ascorbic acid delays enzymic browning but produces intense nonenzymic browning on storage. However, amine-dehydroascorbic acid products are not the major pigments in chemically untreated, canned langsat. Amongst the treatments studied, addition of cysteine HCl was most effective in preventing browning and giving an acceptable product with regards to taste and appearance. However, studies using model systems showed that cysteine HCl has no effect on non-enzymic browning. It probably prevents browning of canned langsat, therefore, by the reduction of the O-quinones, formed as intermediates in enzymic browning prior to canning to stable colourless compounds, thus eliminating their activity as precursors for non-enzymic brown pigment formation. NaCI does not have the same effect on the canned product as cysteine HCL The fairly high concentration of NaCI needed to totally inhibit PPO activity would adversely affect the taste and acceptability oj the canned langsat.
