小豆あん粒子形成に関する調理科学的研究 [in Japanese] Studies on the Cooking Science of Ann Particle Formation in Azuki Beans Vigna angularis (Willd.) Ohwi [in Japanese]
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About half of Azuki beans in this country are procesed for Ann, whose fundamental strucutre is Ann particles which consist of the separated cotyledon cells, interacting with seed coat constituents of beans during their boiling. The mechanism of Ann particle formation in these beans is still unknown. So the author set up a hypothesis on the mechanism of Ann particle formation in Azuki beans which consist of the two processes, namely the separation of cotyledon cells, and the interaction with the cells and the seed coat components during their boilling. Comparative studies are conducted on the cooking characters, especially on the hard cooking beans due to the dormant beans and the aged beans, and on the roles of seed coat in Ann particle formation. The author also studied about the pigment constituent, the polyphenolics, the correlation between proanthosyanidin and storage protein, compared with Ann characters having the different color of seed coat with and without beans in order to elucidate the mechanism in Ann particle formation in Azuki beans. Results obtained here can be summarized as follows: 1. The hard cooking beans in Azuki were classified into two kinds of beans from the biological point of view, namely dormant beans and aged ones under unfavorable conditions. The cause of the former was an inhibition of water absorption from storophiola of a bean, and not in a cotyledon, while the one of latter was not in storophiola, but a decline of water absorption in a cotyledon. The result of bean storage at different temperature showed that the hard cooking beans of the long storage was observed at 35℃ for 3 months. 2. The kinds of soils in Azuki bean production in Tokachi area, Hokkaido, are classified into four types in terms of soil materials, namely, brown volcanic soil, black volcanic soil, alluvial soil and peat soil. The Erimoshouzu Azuki was collected from the above four different soils producing in the same year, and was compared with starch and protein contents in bean, water absorption character by bean and was flowed out of polyphenolics from the beans during water soaking. The clear differences on the above items were obtained, and these results showed that the kinds of cultured soil had an influence on the cooking characters of Azuki beans. 3. Compared with the Ann characters procesed from whole beans and dehulled beans of red Azuki, the percentage of Ann processed was lower in the case of the latter than the former due to the damage of Ann particles by over-boiling. Ann particles obtained from whole beans precipitated rather faster than those obtained from dehulled beans, which means that the Ann particles were heavier in the case of former than the latter, since no size difference among the Ann particles was found. 4. The color of dried Ann procesed from whole red Azuki beans was low in lightness, yellowness and hue, and was high in redness, compared with the Ann processed from dehulled beans. Dried Ann processed from whole beans having differentct seed coat showed varietal differences in color, though the differences were smaller in the case of dehulled beans than whole beans. The seed coat had great effect on the color of dried Ann in Azuki beans. 5. Chlorophyll prigment was found in Azuki beans, and there were varietal differences in its content. Anthocyan pigment of red Azuki beans extracted by 1% metanolic hydrochloric acid, and 4 spots were detected by thin layer chromatography. These 4 spots were also detected in black, purple, brown and green Azuki beans. Besides, 3 spots were detected in black and purple Azuki beans. These spots were extracted by 1% metanolic trifluoro acetic acid. 6. Aglicones of Azuki anthocyanin were cyanidin, delphinidin, and unknown one spot, which were common in all different seed coat colors except white Azuki beans. The main aglicone was cyanidin in red, brown and green beans, while it was cyanidin and delphinidin in black and purple beans. 7. As for polyphenolics in seed coat of red Azuki beans, there were 30 spots detected by thin layer chromatography, which included 6 spots of flavonol, 10 spots of flavanol, 2 spots of benzoic acid group in phenol carbonic acid and 12 spots of skimic acid group in phenol carbonic acid. From which the following compounds were idinitified; rutin, D-catechin, epi-catechin, proantocyanidin, skimic acid, chlorogenic acid and caffic acid. 8. As for polyphenolics in cotyledon of red Azuki beans, there were 25 spots detected by the same methods of seed coat, which included 7 spots of flavonol, 3 spots of flavanol, 2spots of benzoic acid group in phenol carbonic acid and 13 spots of skimic acid group in phenol carbonic acid. Quercetin and quinic acid were identified in cotyledon with the same compounds in seed coat. 9. 90% of polyphenolics in whole Azuki beans was contained in seed coat, and there were varietal differences by the seed coat color. Polyphenolics content was lowest at white Azuki beans of all varieties tested 10. More than 96% of proanthocyanidin in whole Azuki beans was contained in seed coat, while the soluble ratio of proanthocyanidin was higher in seed coat than cotyledon. There was a varietal difference in the soluble ratio of proanthocyanidin by seed coat color. Brown and green Azukis were rather higher than purple and black ones. 11. Polyphenolics content in Azuki beans was affected by the kinds of soils produced. It was the highest in black volcanic soils. Proanthocyanidin content in the beans was also affected by the kinds of soils produced. It was high in black volcanic soil and alluvial soils. The flow of polyphenolics during water soaking before boiling began earlier in the beans produced by brown volcanic soils and peat soils. There was a little amount in final flow. As for proanthocyanidin by the same as the above treatment, the reverse relation was found in the flow. 12. Correlation to the color of dried Azuki Ann was low on anthocyan pigments, and was rather high on polyphenolics and proanthocyanidin. 13. Proanthocyanidins were absorbted into the proteins of dried Azuki Ann, whose amount was more in albumin than in glogulin. The same result, were obtained in the case of cow serum proteins. 14. The Ann particle formation was the result of the separated cotyledon cell formation and of the reactions in the cells and some components in seed coat during its boiling. Polyphenolics, especially proanthocyanidins reacting with protein, play an important role in the Ann particle formation in the beans. 15. From the above results, the author concluded that the mechanism of Ann particle formation in Azuki beans can be explained by the use of the hypothesis proposed in these studies.
- The Bulletin of Hakodate Junior College
The Bulletin of Hakodate Junior College (28), 1-73, 2001-10
Hakodate Junior College