Effects of Different Cooking Methods on Glycemic Index, Physicochemical Indexes, and Digestive Characteristics of Two Kinds of Rice

Abstract

Diets including rice and rice-cooking methods influence digestive processes and blood glucose control. In this research, the effects of three different treatments (high-temperature and low-pressure plasma cooking, high-temperature cooking at atmospheric pressure (traditional method), and high-temperature cooking at high pressure) on the texture, color, molecular structure, infrared spectrum, microstructure, debranching enzyme activity, amylopectin content, glycemic index (GI), and in vitro starch digestibility of two rice varieties were studied. The results showed that the hardness, elasticity, viscosity, and chewability of rice after the high-temperature and low-pressure plasma treatment had no obvious changes compared with the traditional cooking method. A SEM analysis showed that the physical properties of the hydrophilicity on the surface of the rice increased after the high-temperature and low-pressure plasma treatment; the debranching enzyme activity reached 3.88 U/g (Xiantao rice) and 3.81 U/g (Heyuan rice), respectively, the amylose content of raw rice reached 68.77 mg/mL (Xiantao rice) and 64.92 mg/mL (Heyuan rice), which increased by 43.31 mg/mL and 39.46 mg/mL, respectively, and the GI was within the medium glycemic index of 56–69. The resistant starch in the Heyuan and Xiantao rice varieties amounted to 88.60 ± 3.10% and 89.40 ± 3.58%, respectively, after the high-temperature and low-pressure plasma processing method. The results showed positive effects and application potential for the cooking method in respect of diabetic consumers.

Endosperm structure and Glycemic Index of Japonica Italian rice varieties

“…Several studies revealed a correlation between the consumption of high-GI foods, causing a rapid rise in blood-glucose levels, and Type 2 Diabetes (Livesey et al, 2013;Bhupathiraju et al, 2014;Yao et al, 2023), cardiovascular diseases (Sheu et al, 2011;Ma et al, 2012;Mirrahimi et al, 2012), and cancer (Choi et al, 2012;Turati et al, 2015).…”

“…Many factors, such as cooking method and time, condiments and accompaniments, presence of antioxidant components (phenolic compounds in pigmented varieties), degree of polishing of the grain and industrial treatments, can affect rice GI (Hallfrisch and Behall, 2000;Larsen et al, 2000;Hettiarachchi et al, 2001;Sun et al, 2010;Boers et al, 2015;Dwiningsih and Alkahtani, 2023;Ngo et al, 2023;Srikaeo, 2023;Yao et al, 2023); however, comparing different varieties under the same conditions also reveals the existence of a strong genetic component. A wide study conducted by the International Rice Research Institute (IRRI) and the Commonwealth Scientific and Industrial Research Organisation's (CSIRO) Food Futures Flagship on 235 rice varieties from all over the world, highlighted a great variability in GI, with values between 48 and 92 (average value 64), compared to glucose (100) (Fitzgerald et al, 2011).…”