Abstract Cooked whole pulses are widely accepted as a low glycemic food with potential health benefits of reducing the risk of obesity and type 2 diabetes. However, the structural basis for the variation in digestion rate and extent of different pulses is still unclear. In this study, intact cotyledon cells of four commercial pulses (i.e., pinto bean, garbanzo bean, green-split pea, and black-eyed pea) were isolated under controlled cooking and isolation conditions, as a model for whole foods. We investigated the macrostructure of intact cells and structural features of entrapped starch granules, such as crystallinity and thermal parameters, and diffusion of an amylase-sized FITC dextran probe into intact cells. In vitro digestion kinetic profiles of pulse cells were monitored by a reducing sugar assay with a fixed α-amylase activity, and were fitted into a first order model to obtain the apparent rate coefficient and digestion extent at 180 min. Pearson's correlation analysis suggested that there is no significant correlation between the kinetic parameters and structural features of entrapped starch granules nor the size of the cell particles. It is concluded that the starch digestibility of isolated pulses is controlled by the accessibility of digestive enzymes, which is limited by the rigid cell wall and/or pulse protein matrix, rather than starch structure.

中文翻译：

---

淀粉消化率和程度的变化不是由煮熟的整豆的淀粉结构特征决定的

摘要 煮熟的全豆被广泛接受为一种低血糖食品，具有降低肥胖和 2 型糖尿病风险的潜在健康益处。然而，不同豆类消化率和程度变化的结构基础仍不清楚。在这项研究中，四种商业豆类（即斑豆、鹰嘴豆、绿豌豆和黑眼豆）的完整子叶细胞在受控的烹饪和隔离条件下被分离出来，作为全食物的模型。我们研究了完整细胞的宏观结构和包裹的淀粉颗粒的结构特征，例如结晶度和热参数，以及淀粉酶大小的 FITC 葡聚糖探针在完整细胞中的扩散。通过具有固定α-淀粉酶活性的还原糖测定监测脉冲细胞的体外消化动力学曲线，并拟合到一阶模型中以获得180分钟时的表观速率系数和消化程度。Pearson 相关性分析表明，包埋淀粉颗粒的动力学参数和结构特征以及细胞颗粒的大小之间没有显着相关性。得出的结论是，分离豆类的淀粉消化率受消化酶的可及性控制，消化酶的可及性受刚性细胞壁和/或豆类蛋白质基质而非淀粉结构的限制。