Abstract:

Cassava (Manihot esculenta Crantz) roots are rich in starch, and could substitute for corn as the source of energy feed. Cassava roots generally contain a large amount of cyanogenic glucosides, which would limit their application in livestock diets. It is necessary to study the detoxifying technique of cassava. In this paper, four detoxification methods of boiling, drying, microwave heating and ensiling were compared. The results showed that:boiling and drying were better than the others in reducing cyanogenic glucosides of cassava roots. Detoxification rates of either boiling for 25 min or drying for 12 h were up to 81.7%. Detoxification rate of microwave heating for 6 min was 78.8%. While ensiling at 30℃ and 40℃ for 56 d removed over a half of HCN Although the former three methods had high detoxification rate, they consumed a lot of energy, especially for that boiling result in a great loss of nutrients. Boiling for 15 min reduced crude protein by 17%,water soluble carbohydrates by 24.9%,starch by 11.8%,and the losses would further increase with the increased time from 15 to 25 min. Ensiling was a low cost method due to requiring less energy and preserving nutrients well.

Key words: Cassava, Hydrocyanic acid, Ensiling

摘要：

木薯（Manihot esculenta Crantz）块根富含淀粉，可作为代替玉米的能量饲料来源，但其含有剧毒物质氢氰酸（HCN），限制了其在畜禽日粮中的应用。因此，对木薯进行脱毒研究具有重要意义。本文研究了水煮、烘干、微波加热和青贮4种脱毒方法的效果，结果显示：木薯块根经水煮和烘干后其HCN去除率最高，水煮25 min和烘干12 h HCN的去除率均达到81.7%，微波加热6 min去除率为78.8%，而30℃和40℃青贮56 d可去除木薯块根一半以上的HCN。前3种方法去除率虽高，但都消耗大量能量，尤其是水煮还会增加营养损失，水煮15 min，粗蛋白降低17%，可溶性碳水化合物降低24.9%，淀粉降低11.8%，并且随着水煮时间的延长（15~25 min），营养损失增加。青贮对HCN的去除率虽低，但基本不消耗能量，营养保存也好，是一种低成本的处理方法。

关键词: 木薯块根, 氢氰酸, 青贮