Laboratory of Food Technology, member of Leuven Food Science and Nutrition Research Center (LFoRCe), Department of Microbial and Molecular Systems (M2S), KU Leuven, Kasteelpark Arenberg 22 box 2457, 3001 Heverlee, Belgium.
Food Funct. 2018 Dec 13;9(12):6544-6554. doi: 10.1039/c8fo01619d.
The presence of cell walls entrapping starch granules in common bean cotyledons, prevailing after thermal processing and mechanical disintegration, has been identified as the main reason for their (s)low in vitro starch digestibility. Nevertheless, it is unknown if the role of cell walls on starch digestion changes as processing conditions (e.g. time) are modified. In this study, it was hypothesised that cell wall permeability would be differently affected depending on thermal process intensity, giving origin to distinct in vitro starch digestion kinetic profiles. Cotyledon cells were isolated from common beans by applying processing conditions normally found at the household level (95 °C and times between 30 and 180 min (palatable range)). Isolated cells were characterised and subsequently subjected to in vitro simulated digestion. Microstructural properties, the starch gelatinisation degree, and the total starch content were similar among samples. In contrast, a higher diffusion of fluorescently labelled pancreatic α-amylase inside the cells was evident as processing time increased. From the kinetic analysis of digestion products, it was determined that longer lag phases and slower reaction rate constants were present in samples with a lower degree of process-induced cell wall permeability. The qualitative analysis of the remaining pellets showed that cellular integrity was maintained throughout in vitro digestion. A mechanism for the in vitro starch digestion of isolated common bean cotyledon cells as well as an alternative kinetic model to describe this process were proposed. Overall, our work demonstrated that the in vitro starch digestion kinetics of common bean cotyledon cells can be modulated by influencing cell wall permeability through thermal processing time.
菜豆子叶细胞的细胞壁中存在淀粉颗粒，这些淀粉颗粒在热加工和机械破碎后被捕获，这是导致其体外淀粉消化率低的主要原因。然而，目前尚不清楚细胞壁在淀粉消化中的作用是否会随着加工条件（例如时间）的改变而发生变化。在这项研究中，假设细胞壁的通透性会因热加工强度的不同而受到不同的影响，从而产生不同的体外淀粉消化动力学特征。通过应用家庭中常见的加工条件（95°C 和 30-180 分钟的时间范围（可食用范围）），从菜豆中分离出子叶细胞。对分离的细胞进行了特征描述，并随后进行了体外模拟消化。结果表明，虽然不同处理时间下的样品之间的微观结构特性、淀粉糊化程度和总淀粉含量相似，但荧光标记的胰腺α-淀粉酶在细胞内的扩散程度随着处理时间的增加而增加。从消化产物的动力学分析中可以看出，在细胞壁通透性较低的样品中，滞后时间较长，反应速率常数较慢。对剩余颗粒的定性分析表明，细胞完整性在整个体外消化过程中得以保持。提出了一种用于分离的菜豆子叶细胞体外淀粉消化的机制以及一种用于描述该过程的替代动力学模型。总之，我们的工作表明，通过影响细胞壁通透性，即通过热加工时间来调节菜豆子叶细胞的体外淀粉消化动力学。
