Bitterness and toxicity in wild yam (Dioscorea spp.) tubers of nepal
Bitterness and toxicity in wild yam (Dioscorea spp.) tubers of nepal
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DOI：
10.1007/s11130-005-6841-1
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发表时间：
2005-09-01
影响因子：
4
通讯作者：
Kawabata, J
中科院分区：
文献类型：
--
作者：
Bhandari, MR;Kawabata, J
野生山药对尼泊尔部落人民的饮食做出了重大贡献。然而，这些野生块茎味道不好，味道苦，会产生炎症，并且偶尔会出现毒性。对尼泊尔原住民经过初步处理后食用的四种野生山药进行了苦味和有毒成分的分析。苦味成分被鉴定为呋喃类去甲二萜（diosbulbins A 和 B）。 Diosbulbins A和B的含量分别为0.023-0.046和0.151-0.442 g kg(-1)。结果表明，与异球菌素A（0.037 g·kg(-1)）相比，异球菌素B是主要的苦味化合物，其平均值为0.314 g·kg(-1)。这些块茎中未检测到有毒生物碱、薯蓣碱和组胺（一种过敏原），而氰（相当于 HCN）含量为 3.2 至 6.0 ppm。我们的结果显示，尼泊尔野生山药块茎不是有毒品种，因为它们不含有毒的薯蓣碱或组胺，氰含量也完全低于安全限度。观察到的炎症和偶尔的毒性可能是由于这些块茎中存在高水平的草酸盐。人们发现，家庭烹饪方法可以非常有效地去除苦味，从而使苦山药变得可口。
Wild yams make a significant contribution to diets of tribal people in Nepal. However, these wild tubers are unpalatable, taste bitter, produce inflammation and show occasional toxicity. Four wild yam species, which are eaten after primary treatment by Nepali aborigines, were analyzed for bitter and toxic principles. Bitter components were identified as furanoid norditerpenes (diosbulbins A and B). Diosbulbins A and B were found in the range of 0.023-0.046 and 0.151-0.442 g kg(-1), respectively. Results demonstrated that diosbulbin B, with an average value of 0.314 g kg(-1), was the principal bitter compound as compared to diosbulbin A (0.037 g kg(-1)). The toxic alkaloid, dioscorine and histamine (an allergen) were not detected in these tubers, whereas cyanogens (as HCN equivalent) content were found ranging from 3.2 to 6.0 ppm. Our results revealed that Nepali wild yam tubers are not toxic varieties, as they do not contain either toxic dioscorine or histamine and cyanogens contents were satisfactorily below the safety limits. The inflammation and occasional toxicity observed could possibly be due to the presence of high level of oxalate in these tubers. Domestic cooking methods were found to be very efficient in removing bitterness, thus making the bitter yams palatable.