Ultrastructure of Individual and Compound Starch Granules in Isolation Preparation from a High-Quality, Low-Amylose Rice, Ilpumbyeo, and Its Mutant, G2, a High-Dietary Fiber, High-Amylose Rice

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• 作者：Kyung-Soo Kim ; Hung-Goo Hwang ; Hee-Jin Kang ; In-Kyeong Hwang ; Young-Tae Lee ; and Hae-Chune Choi
• 刊名：Journal of Agricultural and Food Chemistry
• 出版年：2005
• 出版时间：November 2, 2005
• 年：2005
• 卷：53
• 期：22
• 页码：8745 - 8751
• 全文大小：821K
• 年卷期：v.53,no.22(November 2, 2005)
• ISSN：1520-5118

文摘

The ultrastructures of isolated starch granules from Ilpumbyeo (IP), a low-amylose japonica rice,and its mutant, Goami2 (G2), a high-amylose rice, which have extreme contrasts in physicochemicalproperties, cooking qualities (Kang, H. J.; Hwang, I. K.; Kim, K. S.; Choi, H. C. Comparative structureand physicochemical properties of Ilpumbyeo, a high-quality japonica rice, and its mutant, Suweon464. J. Agric. Food Chem. 2003, 51, 6598-6603. Kim, K. S.; Kang, H. J.; Hwang, I. K.; Hwang, H.G.; Kim, T. Y.; Choi, H. C. Comparative ultrastructure of Ilpumbyeo, a high-quality japonica rice, andits mutant, Suweon 464: Scanning and transmission electron microscopy studies. J. Agric. Food Chem.2004, 52, 3876-3883), and susceptibility to amylolytic enzymes (Kim, K. S.; Kang, H. J.; Hwang, I.K.; Hwang, H. G.; Kim, T. Y.; Choi, H. C. Fibrillar microfilaments associated with a high-amyloserice, Goami2, a mutant of Ilpumbyeo, a high-quality japonica rice. J. Agric. Food Chem. 2005, 53,2600-2608), were compared. In isolated preparation, IP consisted entirely of well-separated individualstarch granules (ISG), whereas G2 consisted of two populations, the large voluminous bodies andthe smaller forms, the ISGs. High-voltage electron microscopy revealed that each of the voluminousbodies consisted of tightly packed smaller subunits, the ISGs, indicating that they represent thecompound starch granules (CSGs) of G2. This suggests that the structural as well as functional unitof G2 involved in food processing is, unlike IP and other ordinary rices, not ISG but is primarily CSG.ISGs located at the periphery of CSGs were fused to each other with adjacent ones forming a thickband or wall encircling the entire circumference. The periphery of ISGs separated from CSGs of G2consisted of thin radially oriented filaments arranged side by side along the entire granule surface,whereas no such filaments occurred in ISG of IP. It appears that the thick band and the peripheralfilaments surrounding CSGs and ISGs, respectively, function as a structural barrier that limits theentrance of water into the granules and subsequent absorption, causing the low swelling power,incomplete gelatinization, and finally poor quality of cooked rice in G2.Keywords: Ultrastructure; starch granules; compound starch granules; high-amylose rice; microfilament; SEM; TEM; high-voltage EM