Physicochemical, structural and thermal properties of oxidized, acetylated and dual-modified common bean (Phaseolus vulgaris L.) starch

Abstract Common beans are rich in protein and complex carbohydrates that are valuable for the human diet. Starch is the most abundant individual component; however, in its native form it has limited applications and modifications are necessary to overcome technological restrictions. The aim of this study was to evaluate the influence of oxidation, acetylation and dual-modification (oxidation-acetylation) on the physicochemical, structural and thermal properties of common bean starch. The degree of substitution of the acetylated starches was compatible with food use. Fourier transform infrared spectra confirmed the acetylation of the bean starch, with a peak at 1,735cm-1. The granules of the bean starch were oval to spherical in shape, with no differences between the native and modified samples. Typical C-type diffraction of legume starches was found. The modified samples showed a reduced relative crystallinity and lower enthalpy change of gelatinization. The oxidized starch showed the highest peak viscosity, hardness, and gel adhesiveness due to the presence of functional groups. An increase in solubility and swelling power was observed, and the oxidized-acetylated starch presented the highest values. The properties of the modified bean starches made them suitable for application in breaded/battered foods, mainly due to improved textural attributes.

摘要：普通菜豆富含对人类膳食极具价值的蛋白质与复合碳水化合物。淀粉是其中含量最丰富的单一成分，但天然状态的淀粉应用范围有限，需通过改性来克服其技术应用限制。本研究旨在探究氧化、乙酰化以及双改性（氧化-乙酰化）处理对普通菜豆淀粉的理化、结构及热学性质的影响。乙酰化淀粉的取代度符合食品级应用要求。傅里叶变换红外光谱（Fourier Transform Infrared Spectra）证实了菜豆淀粉的乙酰化改性，其在1735cm⁻¹处出现特征吸收峰。菜豆淀粉颗粒呈卵圆形至球形，天然淀粉与改性淀粉颗粒形态无明显差异。检测到豆科淀粉典型的C型衍射特征。改性淀粉样品的相对结晶度及糊化焓变均有所降低。由于官能团的引入，氧化改性淀粉表现出最高的峰值黏度、硬度及凝胶黏附性。淀粉的溶解度与膨胀势均有所提升，其中氧化-乙酰化双改性淀粉的这两项指标数值最高。改性菜豆淀粉的各项性质使其适用于裹粉/裹浆类食品的生产应用，这主要得益于其质地属性的优化提升。