Azad M A, Lebenthal E
International Institute for Infant Nutrition and Gastrointestinal Disease, Children's Hospital, Buffalo, New York 14222.
Pediatr Res. 1990 Aug;28(2):166-70. doi: 10.1203/00006450-199008000-00017.
Rice starch is a main source of energy in many lesser developed countries. We studied different chain-lengths of rice glucose polymers (GP) to evaluate their possible use in feeding infants in developing countries. The initial GP of rice (G1 = 4.6, G2 = 4.5, G3 = 15.4, G4 = 7.3, G5 = 17.4, G6-G9 = 9.61 and greater than G9 = 31.3%) was analyzed by HPLC and then separated in a Bio-Gel P-2 column and compared to its short-chain GP of rice (G2 = 22.7, G3 = 28.2, G4 = 14.0, G5 = 16.6, G6 = 11.6, G7-G9 = 6.9%), long-chain GP of rice (greater than G9 = 100%), and D-glucose. Intraduodenal bolus infusion of 10% solution of short-chain rice GP when compared with long-chain rice GP, the initial rice GP, or D-glucose showed significantly higher values at peak absorption time (0 to 30 min) in the portal venous blood glucose response. The portal venous glycemic response of short-chain rice GP compared with D-glucose was as follows: 2.5 +/- 0.1 versus 2.0 +/- 0.2 cm2, area under the portal blood glucose curve at 0-30 min (p less than 0.01). Glucoamylase, the key enzyme for brush-border hydrolysis of short-chain GP, was assessed with a newly modified glucoamylase assay using GP G5-G8 as substrate. Our finding of faster glucose absorption with short-chain rice GP compared with isocaloric D-glucose might have important physiologic implications for carbohydrate absorption. The osmolality of short-chain rice GP is nearly one-fourth that of glucose. This might have important bearing in the design of infant feeding where increased caloric density with low osmolality is desirable.
大米淀粉是许多欠发达国家的主要能量来源。我们研究了大米葡萄糖聚合物（GP）的不同链长，以评估其在发展中国家喂养婴儿方面的潜在用途。通过高效液相色谱法分析大米的初始GP（G1 = 4.6%，G2 = 4.5%，G3 = 15.4%，G4 = 7.3%，G5 = 17.4%，G6 - G9 = 9.61%，大于G9 = 31.3%），然后在Bio - Gel P - 2柱中进行分离，并与大米的短链GP（G2 = 22.7%，G3 = 28.2%，G4 = 14.0%，G5 = 16.6%，G6 = 11.6%，G7 - G9 = 6.9%）、大米的长链GP（大于G9 = 100%）以及D - 葡萄糖进行比较。与长链大米GP、初始大米GP或D - 葡萄糖相比，十二指肠内推注10%的短链大米GP溶液时，门静脉血糖反应在峰值吸收时间（0至30分钟）显示出显著更高的值。短链大米GP与D - 葡萄糖相比的门静脉血糖反应如下：0至30分钟门静脉血糖曲线下面积为2.5±0.1与2.0±0.2平方厘米（p < 0.01）。葡糖淀粉酶是短链GP刷状缘水解的关键酶，使用GP G5 - G8作为底物，通过新改良的葡糖淀粉酶测定法进行评估。我们发现与等热量的D - 葡萄糖相比，短链大米GP的葡萄糖吸收更快，这可能对碳水化合物吸收具有重要的生理意义。短链大米GP的渗透压几乎是葡萄糖的四分之一。这可能对婴儿喂养的设计具有重要影响，因为在婴儿喂养中，期望热量密度增加而渗透压降低。
