Quantitative analysis of allantoin and allantoic acid in yam tuber, mucilage, skin and bulbil of the Dioscorea species

Published Date
March 2006, Vol.94(4):541–549, doi:10.1016/j.foodchem.2004.12.006

Title 

Quantitative analysis of allantoin and allantoic acid in yam tuber, mucilage, skin and bulbil of the Dioscorea species

• Author 

• Yi-Chung Fu ^a,,
• Lin-Huei A. Ferng ^b
• Pau-Yau Huang ^a

• aDepartment of Food Science, National Chung Hsing University, 250 Kuokuang Road, Taichung City 40227, Taiwan, ROC
• bDepartment of Food Science, National I-Lan University, No. 1, Sec. 1, Shen-Lung Road, I-Lan 260, Taiwan, ROC

Received 24 April 2004. Revised 19 November 2004. Accepted 6 December 2004. Available online 16 February 2005.

Abstract

Allantoin and allantoic acid in yam tubers of the D. batatas (Hualien no. 3) and D. pseudojaponica Yamamoto (Keelung) were quantitatively analyzed because the compounds were thought to prevent inflammation and ulcers in humans as well as playing an important role in the storage and translocation of nitrogen in higher plants. To expand yam tuber use, yam tuber mucilage can be used as an ingredient in functional foods and as a skin protectant. The objectives of this research are to analyze the contents of allantoin and allantoic acid in D. batatas and D. pseudojaponica Yamamoto and to compare bubble separation and centrifugation for recovering allantoin and allantoic acid from the mucilage. The total amount of allantoin and allantoic acid of the following Dioscorea (yam) in both the pulp and skin, respectively, were (mean ± RSD, mmoles/g solid): tuber of Keelung yam (D. pseudojaponica Y.) 0.370 ± 6.8%, 1.130 ± 3.4%; tuber of Hualien no. 3 yam (D. batata) 0.278 ± 7.8%, 0.714 ± 9.1%; bulbil of Hualien no. 3 yam (D. batata) 0.179 ± 7.9%, 0.297 ± 3.4%. The Keelung yam was much higher in allantoin and allantoic acid content than the Hualien no. 3. The skin of yam tuber is rich in allantoin and allantoic acid. The allantoin and allantoic acid content is 305% (in Keelung yam) and 257% (in Hualien no. 3) higher than that of the pulp. Bubble separation is an appropriate procedure in the practice for maximum recovery of allantoin and allantoic acid in yams. It was found that 80% of allantoin and allantoic acid yield can be recovered from the low starch contents of mucilage of the Keelung yam using bubble separation.

Keywords

• Bubble separation
• Yam
• Mucilage
• Allantoin
• Allantoic acid

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• ⁎ 
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