Jiangsu Key Laboratory of Crop Cultivation and Physiology/Jiangsu Key Laboratory of Crop Genetics and Physiology/Jiangsu Co-Innovation Center for Modern Production Technology of Grain Crops/Key Laboratory of Saline-Alkali Soil Reclamation and Utilization in Coastal Areas, the Ministry of Agriculture and Rural Affairs of China/Research Institute of Rice Industrial Engineering Technology, Yangzhou University, Yangzhou 225009, China.
Jiangsu Key Laboratory of Crop Cultivation and Physiology/Jiangsu Key Laboratory of Crop Genetics and Physiology/Jiangsu Co-Innovation Center for Modern Production Technology of Grain Crops/Key Laboratory of Saline-Alkali Soil Reclamation and Utilization in Coastal Areas, the Ministry of Agriculture and Rural Affairs of China/Research Institute of Rice Industrial Engineering Technology, Yangzhou University, Yangzhou 225009, China.
Food Res Int. 2023 Jul;169:112886. doi: 10.1016/j.foodres.2023.112886. Epub 2023 Apr 29.
The difference in grain yield between superior grains (SG) on the upper part and inferior grains (IG) on the lower part of the same panicle was widely reported. To date, variations in rice taste quality between SG and IG and the related starch physicochemical properties remained poorly understood. Here, rice cultivars with different taste quality (NT, normal taste; GT, good taste) were grown to investigate the mechanism underlying taste difference between SG and IG and the correlation between cooked rice taste and starch properties. In this study, the taste value of GT rice was 32.2% higher than that of NT rice across the cultivars. The GT rice comprised a series of typical taste qualities of larger stickiness, smaller hardness, lower apparent amylose content (AAC), and lower protein content (PC). The taste quality differed among rice grains on the same panicle; SG achieved 21.9% and 17.0% higher taste value than IG in GT rice and NT rice, respectively. The higher taste value in SG was owing to the larger stickiness and lower PC. Meanwhile, SG of GT rice achieved the lowest PC (8.2%) and gluten content (5.6%), which might indicate a better health value. Additionally, larger and smoother granules, more fa (DP < 12), lower crystallinity, and larger 1045/1022 cm ratios were found in SG starch compared to IG starch. These led to a weaker swelling power and lower gelatinization enthalpy in SG starch, while gelatinization temperature and retrogression enthalpy were the opposite. Moreover, SG starch exhibited higher storage modulus, loss modulus, slowly digestible starch contents, and resistant starch contents than IG. Our results revealed a great difference in taste quality between SG and IG in rice. The larger and smoother starch granules and shorter chain length could increase the ordered structure of starch, thus improving swelling power, gelatinization properties, and rheological characteristics and facilitating better taste quality of SG over IG. Besides, the lower PC (especially gluten content), higher slowly digestible starch, and higher resistant starch content indicated a more promising health value of SG in the food industry.
同一稻穗上部分颖壳的优质粒（SG）与下部颖壳的劣质粒（IG）之间的粒重差异已有广泛报道。迄今为止，SG 和 IG 之间的稻米食味品质差异及其相关淀粉理化特性仍知之甚少。本研究选用不同食味品质（NT，正常食味；GT，优质食味）的水稻品种，研究 SG 和 IG 食味差异的形成机制以及蒸煮食味与淀粉特性之间的相关性。本研究中，GT 水稻的食味值比 NT 水稻高 32.2%。GT 水稻具有一系列典型的食味特性，包括较大的粘性、较小的硬度、较低的表观直链淀粉含量（AAC）和较低的蛋白质含量（PC）。同一稻穗上的稻米粒食味也存在差异；GT 水稻和 NT 水稻的 SG 比 IG 的食味值分别高 21.9%和 17.0%。SG 具有较高的食味值是因为其具有较大的粘性和较低的 PC。同时，GT 水稻的 SG 具有最低的 PC（8.2%）和谷朊粉含量（5.6%），这可能表明其具有更好的健康价值。此外，SG 淀粉的颗粒较大且更光滑、更多的短链（DP<12）、较低的结晶度和较大的 1045/1022cm 比值。这些导致 SG 淀粉的膨胀力较弱，糊化焓值较低，而其糊化温度和回生焓值则相反。此外，SG 淀粉具有较高的储能模量、损耗模量、慢消化淀粉含量和抗性淀粉含量。研究结果表明，同一稻穗上 SG 和 IG 的食味品质存在较大差异。较大且更光滑的淀粉颗粒和更短的链长可增加淀粉的有序结构，从而提高 SG 淀粉的膨胀力、糊化特性和流变特性，使其食味品质优于 IG。此外，较低的 PC（尤其是谷朊粉含量）、较高的慢消化淀粉和较高的抗性淀粉含量表明，SG 在食品工业中具有更有前途的健康价值。
