Abstract:

【Objective】 The selection of low glycemic index potato varieties is not only essential for controlling blood glucose, reducing obesity, and maintaining oral health but also constitutes a crucial approach to meeting diverse consumer demands and enhancing potato production efficiency. This process provides a foundation for the breeding of low glycemic index potato varieties and the improvement of biological breeding methods.【Method】 Eight domestically and internationally cultivated potato varieties were employed as experimental materials. The study involved the examination of tuber agronomic traits, analysis of total starch, amylose, rapidly digestible starch, slowly digestible starch, resistant starch, soluble sugars, insoluble dietary fiber, soluble dietary fiber, and soluble protein content in tubers before and after steaming processing. Additionally, the investigation included the evaluation of the retention levels of these components and the post-processing tuber flavor quality and in vitro/vivo glycemic index.【Result】 Among the eight varieties, the yield ranged from 21.50 to 49.90 t·hm^-2, with marketable yield percentages ranging from 60.04% to 90.21% and length-to-width ratios from 1.21 to 2.90. Sensory evaluation scores for flavor ranged from 64 to 73. Texture profile analysis results indicated that hardness ranged from 9.78 N to 19.97 N, adhesiveness from 0.44 mJ to 1.66 mJ, cohesiveness from 0.052 to 0.070, springiness from 0.51 to 1.02 mm, and chewiness from 0.28 to 1.38 mJ. Before and after steaming, the total starch content of eight potato varieties ranged from 67.07% to 76.72% dry weight (DW) and 57.69% to 67.40% DW, respectively. The range of amylose content was 5.36% to 19.23% DW and 5.43% to 6.83% DW, while rapidly digestible starch content varied from 1.18% to 8.23% DW and 14.31% to 28.56% DW. The range of slowly digestible starch content was 3.33% to 7.69% DW and 12.81% to 27.65% DW, and resistant starch content varied from 53.71% to 70.36% DW and 11.80% to 25.80% DW. Soluble sugar content ranged from 25.98 to 56.86 mg·g^-1 DW and 11.38 to 50.24 mg·g^-1 DW, while total dietary fiber content varied from 29.62% to 36.17% DW and 43.67% to 52.55% DW. Insoluble dietary fiber content ranged from 17.69% to 23.70% DW and 30.31% to 44.12% DW, and soluble dietary fiber content ranged from 11.07% to 18.48% DW and 7.37% to 14.09% DW. Soluble protein content varied from 42.26 to 64.14 mg·g^-1 DW and 0.71 to 4.82 mg·g^-1 DW. Following steaming, the total starch content of the eight varieties exhibited a range of -15.49% to -5.97%, with changes in amylose content ranging from -12.39% to 0.56%. The variations in rapidly digestible starch, slowly digestible starch, and resistant starch were in the ranges of 10.44% to 25.86%, 5.12% to 23.09%, and -56.8% to -29.88%, respectively. Soluble sugar content varied from -27.07% to 15.70%, while changes in insoluble dietary fiber and soluble dietary fiber ranged from 11.41% to 25.19% and -4.73% to 0.77%, respectively. Soluble protein content exhibited a range of -60.86% to -39.67%. Correlation analysis revealed a significant positive correlation between the glycemic index and tuber total starch and rapidly digestible starch content, while a significant negative correlation was observed with resistant starch and insoluble dietary fiber content. The glycemic index of the eight varieties ranged from 58.08 to 100.64 in vitro and from 57.80 to 92.47 in vivo【Conclusion】 Under potato breeding program, the in vitro glycemic index can replace the in vivo glycemic index as an alternative evaluation method. The content of tuber total starch, rapidly digestible starch, slowly digestible starch, resistant starch, and insoluble dietary fiber are key agronomic traits be considered in the breeding process of low glycemic index potato varieties. The Lucinda was identified as a low glycemic index potato variety with superior flavor quality after cooking processing.

Key words: potato, glycemic index, agronomic traits, flavor quality, starch components, dietary fiber