Surface Hydrophobicity and Protein Cross-Linking in Rice Subjected to Varying Drying and Tempering Conditions

摘要

Rough rice was subjected to 25℃ or 60℃ drying with or without 3 h of tempering at 16.9% relative humidity to obtain rice flours. Proteins extracted from these flours were evaluated for surface hydrophobicity, molecular size, and protein cross-linking via lysine-carbohydrate interaction and formation of S―S bond. Drying at 60℃ significantly increased glutelin surface hydrophobicity (P < 0.05), but did not affect moisture, protein, glutelin components and their molecular sizes, and cystine and available lysine contents in comparison with drying at 25℃. Therefore, drying at 60℃ is considered ineffective to cause protein cross-linking and glutelin changes in molecular size.