In Japan, adzuki bean is cooked with rice. During the cooking, the colour of rice becomes pale red. It is postulated that the red pigment is produced from procyanidins and that the ingestion of red rice causes the production of nitric oxide (•NO) in the stomach by reacting with salivary nitrite. The increase in colour intensity accompanied the decrease in the amounts of procyanidins, suggesting the conversion of procyanidins into the red pigment during the cooking. In addition, the red pigment combined with rice strongly. The red-coloured rice produced •NO by reacting with nitrite in artificial gastric juice, and the amounts were dependent on the contents of procyanidins and the equivalents. It is suggested that although adzuki procyanidins were oxidised during cooking with rice, procyanidins and the equivalents bound to rice still have the ability to produce bioactive •NO in the stomach using nitrite in mixed whole saliva.

• MeSH
• Anthocyanins metabolism   MeSH
• Biflavonoids metabolism   MeSH
• Nitrites metabolism   MeSH
• Catechin metabolism   MeSH
• Ascorbic Acid metabolism   MeSH
• Dehydroascorbic Acid metabolism   MeSH
• Humans MeSH
• Nitric Oxide metabolism   MeSH
• Oxidation-Reduction MeSH
• NIMA-Interacting Peptidylprolyl Isomerase MeSH
• Proanthocyanidins metabolism   MeSH
• Oryza metabolism   MeSH
• Starch MeSH
• Saliva MeSH
• Cooking * MeSH
• Vigna chemistry   MeSH
• Hot Temperature MeSH
• Gastric Juice metabolism   MeSH
• Check Tag
• Humans MeSH
• Publication type
• Journal Article MeSH
• Geographicals
• Japan MeSH

Combining high-carbohydrate food with polyphenol-rich food is a possible way of producing slowly digestible starch with beneficial health properties. In Japan, non-glutinous and glutinous rice are cooked with adzuki bean and the colour of the cooked rice is pale red. In this article, we show that (1) the red colour of rice could be attributed to the oxidation of adzuki bean procyanidins, (2) pancreatin-induced starch digestion of the red-coloured non-glutinous rice was slower than white rice and (3) the digestion of amylose and potato starch but not amylopectin became slower by heating with procyanidin B2. Furthermore, the rate of starch digestion of red-coloured rice was not affected by nitrite treatment under simulated gastric conditions. The above results show that procyanidins could bind to amylose independent of the starch source by heating and could suppress starch digestion by α-amylase in the intestine.

• MeSH
• alpha-Amylases MeSH
• Amylopectin metabolism   MeSH
• Amylose metabolism   MeSH
• Biflavonoids MeSH
• Catechin MeSH
• Humans MeSH
• Pancreatin metabolism   MeSH
• Proanthocyanidins metabolism   MeSH
• Oryza * MeSH
• Digestion * MeSH
• Cooking MeSH
• Vigna * MeSH
• Hot Temperature MeSH
• Check Tag
• Humans MeSH
• Publication type
• Journal Article MeSH
• Geographicals
• Japan MeSH