Ca2+ influxes and transmembrane transport are essential for phytic acid degradation in mung bean sprouts

BACKGROUNDPhytic acid is considered as an antinutrient. Ca2+ addition during germination has been proved to be an effective method for reducing phytic acid content in seeds. In this study, mung bean sprouts were treated with LaCl3 (La), verapamil (VP), ruthenium red (RR), and CaCl2 to explore the effect of Ca2+ influxes on phytic acid degradation. RESULTSCaCl2 (6 mmol L-1) significantly improved extracellular and intracellular calcium precipitates and calcium content, elevated phytase and acid phosphatase activity, and further enhanced phytic acid degradation. Conversely, La, VP, or RR induced the opposite results. Among them, RR exhibited the most significant inhibitory effect. Decreased PA, PAP, MIPP, and ALP gene expression after VP or RR treatment was also observed. Enhanced or weakened extracellular Ca2+ influx or intracellular Ca2+ efflux was detected with increased or decreased calcium precipitates distributed in different compartments. However, CaCl2 addition differentially reversed the inhibitory effects of all channel blockers. CONCLUSIONCaCl2 enhanced Ca2+ influxes and accumulation in cells, which contributed to the regulation of phytic acid degradation. This study demonstrates that calcium channels play an essential role in mediating phytic acid degradation in mung bean sprouts, and both extracellular and intracellular Ca2+-regulation were involved in phytic acid degradation. (c) 2017 Society of Chemical Industry