Abstract
The process for cooking the beans affects the yield and quality of Azuki paste. The effects of the pretreatment used before cooking on the quality of unsweetened and sweetened paste were examined. The seed coat of the beans was broken in a shorter cooking time after they had been soaked in water before cooking, and it was more facilitated by freezing after this soaking. The optimum cooking at 99.5 °C for unsweetened Azuki paste was judged as follows : 90 min with no pretreatment, 45 min with soaking, and 30 min with freezing after soaking. The moisture content of the paste was highest after soaking and freezing. The a-value and b-value, which were measured by a color differential meter, of unsweetened paste after the soaking treatment were lower than those with no treatment, and the paste from soaked and frozen beans was light purple in color. Azuki paste granules obtained with the soaking and freezing treatment were found to have a damaged cell membrane under optical microscopic observation. Sweetened paste made from unsweetened paste made from beans after the soaking and freezing treatment thickened with the shortest stirring time, and presented the characteristic and graceful purple color. The results of the sensory evaluation showed that this sweetened paste was significantly smoother than that with no pretreatment.
