不同品种籼型糙米营养成分、质构及体外消化特性

Nutritional Composition, Textural and In Vitro Digestive Characteristics of Different Indica Brown Rice Varieties

摘要:

为了促进全谷物食品的发展和低血糖指数（Glycemic Index，GI）主食的开发，本研究分析了8个品种糙米的营养成分、质构及体外消化特性，并与精白米进行对比，探讨糙米与精白米之间的差异性，以及分析各指标之间的相关性。不同品种籼型糙米的脂肪、蛋白质和膳食纤维等含量存在显著性差异（P<0.05）。所有糙米品种的γ-氨基丁酸、总游离酚类和总游离黄酮含量均显著高于（P<0.05）精白米，其抗氧化能力也显著高于精白米，其中DPPH和ABTS自由基清除活性最高的糙米品种分别约为精白米的4倍和3倍。不同品种籼型糙米的米饭硬度显著高于（P<0.05）精白米米饭，硬度最低的糙米米饭仍约为精白米的1.5倍。糙米米饭的预估血糖指数（Estimated Glycemic Index，eGI)范围为中等至高GI，其中eGI最低的品种为中早39（eGI=61.48），约为精白米eGI的0.8倍。糙米米饭的eGI值与脂肪、蛋白质和膳食纤维呈极显著负相关（P<0.01）。糙米在提升膳食营养价值和开发功能性低GI食品方面具有较大潜力，研究结果可为糙米食品的加工、配方优化及健康功能评价提供理论依据。

Abstract:

To promote the development of whole grain foods and low glycemic index (GI) staple products, this study systematically compared the nutritional composition, textural properties, and in vitro digestion characteristics of eight indica brown rice varieties with milled rice. Significant differences (P<0.05) were observed in fat, protein, and dietary fiber contents among different brown rice varieties. All brown rice varieties exhibited significantly higher (P<0.05) γ-aminobutyric acid, total free phenolics, and total free flavonoids compared to milled rice, accompanied by superior antioxidant capacities. The maximum DPPH and ABTS radical scavenging activities in brown rice were approximately fourfold and threefold higher than those in milled rice, respectively. The cooked brown rice demonstrated significantly greater hardness (P<0.05), with the softest brown rice variety still showing approximately 1.5 times higher hardness than milled rice. The estimated glycemic index (eGI) of brown rice ranged from medium to high GI levels, with Zhongzao 39 exhibiting the lowest eGI value (61.48), equivalent to 0.8 times that of milled rice. Significant negative correlations (P<0.01) were identified between eGI values and fat, protein, and dietary fiber contents. These findings suggest that brown rice holds substantial potential for enhancing nutritional value and developing functional low-GI foods, while providing theoretical support for processing optimization, formula design, and health function evaluation of brown rice products.