Department of Nutritional Sciences, University of Toronto, Toronto, Ontario, Canada M5S 3E2.
Food Funct. 2011 Aug;2(8):438-44. doi: 10.1039/c1fo10042d. Epub 2011 Jul 15.
The purpose of this study was to investigate whether the effects of cooling and reheating on the glycaemic index (GI) of novel potato clones (selections) differed depending on selection and whether cooling altered starch absorption in vivo. We conducted 3 experiments using 4 novel potato clones in healthy subjects. Experiment 1: the GI of 4 selections each prepared in 3 ways (freshly boiled, cooled, or cooled and reheated) was measured in 2 groups of 10 subjects (each group tested 2 selections). Experiment 2 (n=10): two selections from Experiment 1 were re-tested one year later, by a different subject group. Experiment 3 (n=10): two selections from Experiment 1 were tested by subjects from Experiment 2 to assess the rate and extent of starch absorption using the second-meal effect and the breath hydrogen method, respectively. Experiment 1 demonstrated a selection×treatment interaction for GI (p=0.024); cooling reduced the GI of two selections by 40-50% (p<0.05) but reduced GI of the other 2 by only 8-10% (ns). Experiment 2 confirmed the selection×treatment interaction (p=0.018) seen in Experiment 1. Experiment 3: cooling reduced the GI by an average of 37% (p<0.05) but only increased starch malabsorption in vivo from 3% to 5% (p=0.021); there was no significant second-meal effect. It is concluded that the effect of cooling on the GI of potatoes may vary from 0-50% depending on selection. However, the mechanism for the effect is not clear: the 2% increase in starch malabsorption seen upon cooling potatoes was not nearly enough to account for the 37% reduction in GI.
本研究旨在探究冷却和复热对新型土豆克隆（品种）血糖生成指数（GI）的影响是否因品种而不同，以及冷却是否会改变体内淀粉的吸收。我们在健康受试者中使用 4 种新型土豆克隆进行了 3 项实验。实验 1：4 种品种的 3 种制备方式（新鲜煮熟、冷却和冷却后复热）的 GI 在 2 组 10 名受试者（每组测试 2 种品种）中进行了测量。实验 2（n=10）：实验 1 中的两种品种在 1 年后由不同的受试者组进行了重新测试。实验 3（n=10）：实验 1 中的两种品种由实验 2 的受试者使用第二餐效应和呼气氢法分别测试，以评估淀粉吸收的速度和程度。实验 1 表明 GI 存在品种×处理的交互作用（p=0.024）；冷却使两种品种的 GI 降低了 40-50%（p<0.05），但使另外两种品种的 GI 仅降低了 8-10%（无统计学差异）。实验 2 证实了实验 1 中观察到的品种×处理的交互作用（p=0.018）。实验 3：冷却使 GI 平均降低了 37%（p<0.05），但仅使体内淀粉吸收不良增加了 3%至 5%（p=0.021）；没有明显的第二餐效应。结论是，冷却对土豆 GI 的影响可能在 0-50%之间变化，具体取决于品种。然而，作用机制尚不清楚：冷却时观察到的淀粉吸收不良增加 2%远不足以解释 GI 降低 37%。
