不同稻米品種之食用品質與化學性質之關係

The study on the Relationship of Eating Quality and Chemical Quality of different Non-waxy Rice Species

劉慧瑛(H. I. Liu) ； 林禮輝(L. F. Lin) ； 宋勳(S. Song) ； 洪梅珠(M. C. Hong)

《臺中區農業改良場特刊》 13號 (1988/11) Pp. 76-90

摘要

國人口味偏好低直鏈澱粉稻米品種，而長粒型秈米（臺中秈3號）雖然與稉米同為低直鏈澱粉品種，但其粗蛋白質、胺基酸組成、單位蛋白質含硫量、水溶性醣、游離糖含量均類似高直鏈澱粉秈米；不過其米粉浸水後膨脹體積及蒸煮液碘呈色比（O.D. 620/520）則與稉米相近。越光為稉米品種，食味較秈米佳，但其蛋白質含量甚高，近似秈米；分析其單位蛋白質含硫量則低於秈米及長秈米，可見蛋白質組成亦可能為影響食味之因子。又越光與其他稉米相同，含有較多量的水溶性醣、游離糖及水溶性蛋白質；浸水膨脹體積大而蒸煮液碘呈色比小， 即蒸煮液之溶出物中含有較多的黏膠性澱粉（amylopectin）。就同一品種米而言，蛋白質、脂肪、礦物質含量較低而水溶性醣及直鏈澱粉量較高者食味較佳。再碾白及水洗可減少蛋白質、脂肪、礦物質量有助於提高食味，但營養價值減低。水溶性蛋白質量與黏膠性澱粉量有密切關係。蛋白質及直鏈澱粉似不隨貯藏期而變化，不過倉儲期增長游離糖量減少，水溶性蛋白質、灰分、磷、鉀、鎂、錳量及蒸煮液碘呈色比增加，顯示米澱粉及蛋白質構造在貯藏中發生改變。

並列摘要

The people living in Taiwan prefer to low amylose content nonwaxy soft rice. Long grain indica type rice (Taichungsen 3) contained low amylose like other japonica type rice grown in Taiwan, had high protein, high total sulfur per unit protein, low hot water soluble polysaccharides, low sugar content and same amino acid composition as other indica type rice. But, the expansion volume of milled rice powder immersed in cold water and the starch of extracted w/hot water after cooking were the same as that of the japonica type rice. Yuekuang (in japanese named Koshihikari) is an japonica rice. It had better taste than indica rice though contained high protein as indica rice. For the sulfur content per unit protein was lower than high and low amylose contents indica rice, We suppose the protein quality were one of the factors affecting on rice quality. Like other japonica rice, koshihikari and higher water soluble polysaccharides, sugar, hot water soluble protein, larger expansion volume in cold water and more amylopectin ratio in the cooking solution. For the same species, lower crude protein, lipid, minerals and higher water soluble polysaccharides, amylose content means better eating quality. Overmilling and washing could increase the taste, but decrease the nutrition. Water soluble protein content had relaton to amylopectin. Crude protein and amylose content didn't change in stroage, but sugar decreased, water soluble protein, ash, P, K, Mg, Mn content and the ratio of amylose in the cooking soltuion increased. The structure of starch particle and protein changed in storage.