Unité des Maladies Métaboliques et Micronutriments, U3M, INRA, Centre de Recherche de Clermont-Ferrand/Theix, 63122 Saint-Genès-Champanelle, France.
Nutr Res Rev. 2006 Jun;19(1):18-25. doi: 10.1079/NRR2006118.
Bread is one of the most widely consumed staple foods worldwide. White-wheat bread, largely consumed in France, is made from highly refined flour, which leads to a low nutrient density. Due to a highly porous structure and gelatinised starch, it is easily broken down during digestion, leading to a rapid increase of glucose released into the bloodstream. Low glycaemic responses are considered favourable to health, especially against a background of diabetes. Literature reports show that selection of raw material is an essential factor in decreasing the glycaemic index (GI) of white bread. There are two means of decreasing the rate of starch degradation: either (i) slowing gastric emptying rate and/or glucose diffusion-absorption through the intestinal mucosa, which can be achieved by incorporating soluble fibre or organic acid in bread, or (ii) limiting starch accessibility to alpha-amylase by using high-amylose cereal varieties and/or incorporating intact cereal grains. Studies on cereal products show that preservation of the food structure during digestion seems to be a more important GI-reducing factor than the degree of starch crystallinity or the presence of soluble fibre. Thus, we should look to produce bread with a more compact food structure or higher density, which is the case in leavened wholewheat bread or bread with intact cereal grains. The baking process should also be improved to achieve this goal, by using, for example, a reduced kneading time or less yeast than usual.
面包是全球范围内最广泛食用的主食之一。在法国大量消费的白小麦面包是由高度精制的面粉制成的，这导致其营养密度较低。由于其具有高度多孔的结构和糊化的淀粉，因此在消化过程中很容易被分解，导致进入血液的葡萄糖迅速增加。低血糖反应被认为对健康有利，尤其是在糖尿病背景下。文献报道表明，选择原料是降低白面包血糖指数（GI）的一个重要因素。有两种方法可以降低淀粉降解的速度：一种是（i）通过在面包中加入可溶性纤维或有机酸来减缓胃排空速度和/或葡萄糖通过肠黏膜的扩散吸收，或者（ii）通过使用高直链淀粉谷物品种和/或加入完整的谷物来限制淀粉对α-淀粉酶的可及性。关于谷物产品的研究表明，在消化过程中保持食物结构似乎比淀粉结晶度或可溶性纤维的存在更能降低 GI。因此，我们应该生产具有更紧凑的食物结构或更高密度的面包，这在发酵全麦面包或含有完整谷物的面包中就是如此。通过例如减少揉面时间或使用比通常更少的酵母，可以改进烘焙过程来实现这一目标。
