Unveiling the Differences in GABA Enrichment Capacity and Metabolite Profiles of Two Genotypes of Red Kidney Beans (Phaseolus vulgaris L.) Under Heat and Relative Humidity Treatment

Background and Objectives

Kidney beans can serve as a potential source of γ-aminobutyric acid (GABA), but their enrichment capacity varies across varieties. This study investigated the effects of heat and relative humidity (HRH) treatment on GABA accumulation in two kidney bean varieties (JZY-2 and PJY-4).

Findings

HRH treatment significantly enhanced the GABA contents in both varieties, with JZY-2 showing a greater enrichment capacity. The increase in GABA was associated with the elevated activities of key enzymes (DAO, PAO, and GAD) and reductions in the levels of glutamic acid, asparagine, and aspartic acid. Nontargeted metabolomic profiling revealed significant changes in metabolite composition after HRH treatment, particularly involving the flavonoid biosynthesis pathway based on KEGG analysis.

Conclusions

HRH is an effective strategy to increase GABA content in kidney beans, especially in JZY-2.

Significance and Novelty

This study might provide the reference for the screening of excellent GABA-enriched kidney bean varieties under HRH treatment, which contributed to developing GABA-rich functional foods.