LAUSR

BACKGROUND Most rheological analyses in yam have been done on starch gels, which requires starch extraction from the tubers. In situ rheology bypasses the need of starch extraction and relies on the original cell structure and complex matrix organization under stress or strain. Dynamic rheological properties of tuber from 16 accessions belonging to four yam species (Dioscorea rotundata, D. alata. D. bulbifera and D. dumetorum) were investigated for potential use as a medium throughput phenotyping screening tool that can indicate the quality of yam food products or their industrial potentials. RESULTS Rheographs of the tubers illustrated differences in the structure of D. bulbifera compared to other yam species. High initial G' of yam parenchyma indicated tubers with strong and rigid structure which does not lose its structural integrity easily on heating. D. rotundata and D. alata varieties exhibited a lower temperature (Tgel ) equivalent to the irreversible transition during starch gelatinization (75.3°C and 79.8°C) and took shorter time (867s and 958s, respectively) to reach the G' max, compared to other species. The stress relaxation test showed that the higher the dry matter of the tubers, the higher the work to rupture its structure. CONCLUSION Rheological characteristics G', G″, swelling capacity and Tgel temperature showed potential as suitable quality indicators for yam products. In situ rheological characterization of yam tubers could be used as an instrumental screening tool to phenotype for quality in yam products. This article is protected by copyright. All rights reserved.