School of Engineering, University of Guelph, Guelph, N1G 2 W1, ON, Canada.
Food Funct. 2019 Feb 20;10(2):616-624. doi: 10.1039/c8fo02266f.
Starch is the major glycemic carbohydrate related to postprandial glycaemia and it naturally exists in the form of partially crystalline starch granules. Interestingly, the microstructural and granular features of banana starch have been reported to be inherently resistant to enzyme digestion. Converse to bread, sugar-snap cookie dough undergoes minimum starch gelatinization during baking. Therefore, the inclusion of banana starch in sugar-snap cookies could have a major role on starch susceptibility to be undigested or digested slowly, which could be especially relevant in gluten-free diets, typically characterized by a lower fiber intake and higher glycemic response. Here, we demonstrate that the starch digestion rate (k) and consumer's acceptance of gluten-free sugar-snap cookies can be simultaneously improved by a 30% replacement of rice flour by native banana starch. Furthermore, the content of resistant starch was increased from 0.1 to 3.6% (g per 100 g cookie), which would allow labeling of cookies as "source of fiber" in some food regulations. We also showed that the inclusion of fully gelatinized banana starch causes an increase of the water fraction that dramatically shifts the texture from brittle to soggy, according to the three-point bending test, that contributed to worsen consumer's acceptance. Classic sugar-snap cookies are composed mainly of a continuous glassy sucrose-water matrix which confers this product its brittle textural properties. Therefore, when selecting novel starches for low/sustained glycemic response, it is paramount to deliberately formulate sugar-snap cookies to begin their shelf-lives in a glassy state that allows a desired crispy texture.
淀粉是与餐后血糖相关的主要血糖碳水化合物，它以部分结晶淀粉颗粒的形式自然存在。有趣的是，香蕉淀粉的微观结构和颗粒特征已被报道为固有地抵抗酶消化。与面包相反，糖酥曲奇面团在烘焙过程中淀粉的糊化程度最小。因此，在糖酥曲奇中添加香蕉淀粉可能会对淀粉的消化速度产生重大影响，使其未被消化或消化缓慢，这在无麸质饮食中尤为重要，无麸质饮食通常的特点是纤维摄入量较低和血糖反应较高。在这里，我们证明通过用天然香蕉淀粉替代 30%的米粉，可以同时提高淀粉消化率（k）和消费者对无麸质糖酥曲奇的接受度。此外，抗性淀粉的含量从 0.1 增加到 3.6%（每 100 克饼干中的克数），这将允许在某些食品法规中将饼干标记为“纤维来源”。我们还表明，完全糊化的香蕉淀粉的加入会增加水分部分，从而根据三点弯曲测试将质地从易碎变为湿软，这导致消费者的接受度下降。经典的糖酥曲奇主要由连续的玻璃状蔗糖-水基质组成，这赋予了该产品易碎的质地特性。因此，在选择用于低/持续血糖反应的新型淀粉时，至关重要的是精心设计糖酥曲奇，使其在玻璃态下开始其保质期，从而获得所需的酥脆质地。
