Dept. of Plant Sciences, North Dakota State Univ., PO Box 6050, Dept# 7670, Fargo, ND 58108-6050, USA.
J Food Sci. 2013 Feb;78(2):C192-8. doi: 10.1111/1750-3841.12037. Epub 2013 Jan 18.
Starch has unique physicochemical characteristics among food carbohydrates. Starch contributes to the physicochemical attributes of food products made from roots, legumes, cereals, and fruits. It occurs naturally as distinct particles, called granules. Most starch granules are a mixture of 2 sugar polymers: a highly branched polysaccharide named amylopectin and a basically linear polysaccharide named amylose. The starch contained in food products undergoes changes during processing, which causes changes in the starch molecular weight and amylose to amylopectin ratio. The objective of this study was to develop a new, simple, 1-step, and accurate method for simultaneous determination of amylose and amylopectin ratio as well as weight-averaged molecular weights of starch in food products. Starch from bread flour, canned peas, corn flake cereal, snack crackers, canned kidney beans, pasta, potato chips, and white bread was extracted by dissolving in KOH, urea, and precipitation with ethanol. Starch samples were solubilized and analyzed on a high-performance size exclusion chromatography (HPSEC) system. To verify the identity of the peaks, fractions were collected and soluble starch and beta-glucan assays were performed additional to gas chromatography analysis. We found that all the fractions contain only glucose and soluble starch assay is correlated to the HPSEC fractionation. This new method can be used to determine amylose amylopectin ratio and weight-averaged molecular weight of starch from various food products using as low as 25 mg dry samples.
淀粉是食物碳水化合物中具有独特物理化学特性的物质。淀粉为以根茎、豆类、谷物和水果为原料的食品产品的物理化学属性做出了贡献。它作为独特的颗粒自然存在，这些颗粒被称为颗粒。大多数淀粉颗粒是 2 种糖聚合物的混合物：一种高度支化的多糖，名为支链淀粉，和一种基本线性的多糖，名为直链淀粉。在加工过程中，食品中所含的淀粉会发生变化，从而导致淀粉分子量和直链淀粉与支链淀粉比例的变化。本研究的目的是开发一种新的、简单的、一步法、准确的方法，用于同时测定食品中淀粉的直链淀粉与支链淀粉比例以及重均分子量。面包粉、罐装豌豆、玉米片、小吃饼干、罐装芸豆、意大利面、薯片和白面包中的淀粉通过在 KOH、尿素中溶解以及用乙醇沉淀的方法进行提取。淀粉样品在高效体积排阻色谱（HPSEC）系统中溶解并进行分析。为了验证峰的特征，收集了馏分，并进行了气相色谱分析以及可溶性淀粉和β-葡聚糖分析。我们发现所有馏分仅含有葡萄糖，且可溶性淀粉分析与 HPSEC 分级相关。这种新方法可以用于测定各种食品中淀粉的直链淀粉与支链淀粉比例和重均分子量，最低只需 25mg 干燥样品。
