Chemical and physical evaluation, antioxidant and digestibility profiles of white and pigmented rice from different areas of Indonesia

Abstract Black rice and red rice are often claimed to have more health benefits than white rice. They have been reported to have greater antioxidant activity and lower digestibility than white rice, functional properties which are important to prevent the metabolic disorders related to diseases such as diabetes. However, rice grown in different areas or subjected to different processing has shown different physical, chemical and functional properties. Thus the objectives of this study were to determine the physical properties (hardness, colour and gelatinization profile), chemical properties (proximate composition, total phenolic and flavonoid contents, antioxidant capacity), and the in vitro digestibility of Solok black rice (SBR), Solok red rice (SRR), Tangerang black rice (TBR), Cianjur red rice (CRR) and Cianjur white rice (CWR) cultivated in different areas in Indonesia. The results revealed that rice cultivated in different areas showed different physical characteristics and chemical compositions. The In vitro analysis of the digestibility of the starch with α-amylase showed that pigmented rice was less digestible (56.10% to 83.43%) than white rice (87.35%). A normal cooking method commonly used in society was found to significantly reduce the total phenolic content, flavonoids and antioxidant capacity of the rice.

摘要 黑米与红米常被宣称比白米具备更优异的健康获益。已有研究表明，相较于白米，二者拥有更强的抗氧化活性与更低的消化率，这类功能特性对于预防糖尿病等疾病相关的代谢紊乱具有重要意义。然而，不同种植区域或经不同加工处理的稻米，其物理、化学及功能特性存在差异。因此本研究的目标为测定印度尼西亚不同区域种植的索洛克黑米（Solok black rice, SBR）、索洛克红米（Solok red rice, SRR）、丹格朗黑米（Tangerang black rice, TBR）、加拉横红米（Cianjur red rice, CRR）以及加拉横白米（Cianjur white rice, CWR）的物理特性（硬度、色泽与糊化特性曲线）、化学特性（常规营养组成、总酚类与总黄酮含量、抗氧化能力）以及体外消化率。研究结果显示，不同区域种植的稻米其物理特性与化学组成存在显著差异。采用α-淀粉酶对淀粉进行体外消化率分析的结果表明，有色稻米的消化率（56.10%~83.43%）低于白米（87.35%）。此外，日常普遍使用的常规烹饪方式会显著降低稻米中的总酚类物质、黄酮类物质含量与抗氧化能力。