Composition of Rice Foods Used in Taiwan

Abstract

省產稻米的種類依據直鏈澱粉含量的多寡，可分為秈米（高直鏈澱粉含量，俗稱在來米）、稉米（中直鏈澱粉含量，俗稱蓬來米）與糯米（低直鏈澱粉含量）三種。雖然國人對此三種米均加利用，製成不同的加工品，不過秈米及糯米因分別具有高直鏈澱粉及高枝鏈澱粉含量的特性，較易被利用，而直鏈澱粉含量不高不低的稉米，在加工上的用途則較少。近年來由於米菜加工技術的開發，稉米和糯米則同時成為米果的製造原料。比較米加工品之碘呈色液波長620nm 與520nm 吸光密度比值可初步了解米加工品使用原料米種類。比值愈大時直鏈澱粉所佔比率愈高，屬於秈米類；反之則愈低，屬於稉米或糯米。 市售米加工品分析結果如下：一、不同米粉樣本其粗蛋白質含量相差懸殊，註明添加澱粉的米粉粗蛋白質含量均低於1 % ，而標示純米製之米粉中也有部份粗蛋白質含量過低的情形。二、大部份的米加工品游離糖含量均較白米高，可能是加糖調味及部份米澱粉水解成糖。三、米加工品因添加物種類及含量不同而造成加工品成分的差異；例如鈉鹽，造成灰分及鈉含量顯著增加、添加磷酸鹽增加磷含量等。四、部份米加工品鋁含量較高，推測可能與添加發粉或蒸煮時使用鋁製器皿有關。五、添加油脂調味、焙燒，造成粗脂肪含量劇增。六、添加大量外來物質，造成產品成分與白米成分大不相同，如：米血糕含有大量動物血液，其粗蛋白質、粗脂肪、灰分及大部份礦物質元素（尤其是鐵）含量均較白米高出甚多。 Three main groups of rice in Taiwan are classified according to their amylose content as Tsailai rice (high amylose, indica type), Ponglai rice (medium amylose, japonica type) and waxy rice (extremely low amylose, glut mouse). Though all three groups of rice are used to produce various rice foods, the Tsailai and waxy rice are more widely used due to their high content of amylose and amylopectin, respectively. Recently, due to the development of rice snacks manufacturing technique, both the Ponglai rice and waxy rice become good materials. What group of rice used as rice foods materials can be preliminarily identified by determined the optial density ratio of 620nm and 520nm of rice starch iodine solution. The high ratio attribute to the high amylose group rice, the low ratio attribute to the waxy rice. The analysis results of commercial rice foods are as the following: 1. The difference of crude protein content among various rice nooldle ( Mifen) samples is great. All the rice nooldes labelled starch added are with crude protein content lower than 1%. 2. Most of the rice foods contain more sugar than that of milled rice. It may be caused by addition and partly by the hydrolysis of rice starch. 3. The different composition of rice foods depend on various kinds and content of additives. For examples, addition of salt induce the obvious in crease of ash and sodium content, and addition of phosphate induce the increase of P content. 4. Some rice foods contain high alluminum content. It implied the Al-made container were used in the processing or applied with soda powder. 5. Addition of oil for flavor and baking cause dramatic increase of crude fat content of rice foods, such as rice snacks. 6. The composition of rice foods is widely different from milled rice for large amount of other substance. Such as the rice cake with pig blood had a lot of animal blood which contains protein, fat and minerals (especially Fe) than milled rice