KU Leuven, Department of Microbial and Molecular Systerm (M(2)S), Laboratory of Food Technology, Kasteelpark Arenberg 22, Box 2457, 3001 Leuven, Belgium.
Food Res Int. 2022 Jun;156:111315. doi: 10.1016/j.foodres.2022.111315. Epub 2022 Apr 30.
In this study, two chemical bean seed hardening methods were used to investigate the changes in cooking behavior associated with Ca transport and phytate hydrolysis to better understand their role in the pectin-cation-phytate hypothesis. The texture evolution of fresh and hardened red kidney beans was evaluated, hardening being induced by soaking or in a CaCl solution (0.01 M, 0.05 M, 0.1 M) or sodium acetate buffer (0.1 M, pH 4.4, 41 °C). The beans soaked in a CaCl solution at higher concentrations or in sodium acetate buffer for a longer time exhibited a delayed cooking behavior. This study also explored the bio-chemical changes (calcium content in different bean substructures, phytate content and the pectin degree of methylesterification (DM) in the cotyledons) occurring in the beans during chemical hardening and cooking. The Ca concentrations in the whole beans and cotyledons of beans soaked and cooked in CaCl solutions significantly increased while inositol hexaphosphate IP content showed no significant changes. This indicates that the delayed texture drop in this case results from the influx of exogenous Ca in the cotyledons and seed coats during cooking while the IP was not hydrolyzed and did not release endogenous Ca. For beans soaked in sodium acetate buffer, phytate profiling showed increased hydrolysis of IP with longer soaking time, suggesting the migration of endogenous Ca released from phytate hydrolysis contributing to the delayed cooking of these beans. These results indicate that both an exogenous Ca influx during soaking and cooking and an endogenous Ca replacement resulting from phytate hydrolysis can play an important role in the hardening of beans. In neither of the cases, a significant change in pectin DM was observed during chemical hardening, therefore limiting the delayed cooking to the role of Ca transport. The outcome of both cases is inline with the basic principles of the pectin-cation-phytate hypothesis whereby pectin DM changes are hardly involved and different mechanisms of release/transport are involved.
在这项研究中，使用了两种化学豆种硬化方法来研究与 Ca 转运和植酸水解相关的烹饪行为变化，以更好地理解它们在果胶-阳离子-植酸假说中的作用。评估了新鲜和硬化的红芸豆的质地演变，通过浸泡或在 CaCl 溶液（0.01 M、0.05 M、0.1 M）或乙酸钠缓冲液（0.1 M、pH 4.4、41°C）中硬化。在较高浓度的 CaCl 溶液或在乙酸钠缓冲液中浸泡时间较长的豆子表现出延迟的烹饪行为。本研究还探讨了在化学硬化和烹饪过程中豆子中发生的生物化学变化（不同豆亚结构中的钙含量、植酸含量和子叶中的果胶甲酯化程度（DM））。浸泡和在 CaCl 溶液中煮熟的豆子的整个豆子和子叶中的 Ca 浓度显著增加，而肌醇六磷酸（IP）含量没有显著变化。这表明在这种情况下，质地下降的延迟是由于在烹饪过程中子叶和种皮中外源 Ca 的流入，而 IP 没有水解且没有释放内源 Ca。对于浸泡在乙酸钠缓冲液中的豆子，植酸分析表明，随着浸泡时间的延长，IP 的水解增加，表明植酸水解释放的内源 Ca 的迁移有助于这些豆子的延迟烹饪。这些结果表明，浸泡和烹饪过程中外源 Ca 的流入以及植酸水解导致的内源 Ca 替代都可以在豆子的硬化中发挥重要作用。在这两种情况下，在化学硬化过程中都没有观察到果胶 DM 的显著变化，因此将延迟烹饪仅限于 Ca 转运的作用。两种情况的结果都符合果胶-阳离子-植酸假说的基本原则，其中果胶 DM 变化几乎不涉及，涉及不同的释放/转运机制。
