Multi-environment evaluation of raffinose-family oligosaccharide content in diverse dry bean varieties and their reduction upon canning.

BACKGROUND: The substantial amount of raffinose family oligosaccharide (RFO) in dry beans causes flatulence and digestive discomfort, limiting the appeal of dry bean food products. Substantial variation exists in RFO content among dry bean varieties, and various food processing steps such as soaking and canning are known to reduce RFO levels. However, little information exists concerning environmental effects upon RFO accumulation in field-grown dry beans, or varietal differences in RFO reduction upon downstream processing of whole seeds. RESULTS: This study surveyed a multi-environment trial of diverse dry bean varieties grown under irrigation to investigate sources of RFO variation. Controlled heat treatment experiments were conducted to evaluate the effect of moderate heat stress on seed RFO accumulation. These experiments revealed a substantial 1.7-fold variation in dry bean RFO levels due to both genetic and environmental factors and a significant increase in RFO content when plants encounter abiotic stress events during seed fill. Dry bean RFO content was positively correlated with sucrose levels but was uncorrelated with starch levels. When samples from the multi-environment trial were subjected to canning, large varietal differences were discovered in the extent of RFO reduction in canned beans due to leaching, varying from 30% to 69% reductions from starting levels. CONCLUSION: This study clarifies the impact of environmental factors on RFO levels and identifies particular genotypes and market classes with low RFO levels. However, to predict dry bean crops that will contain lower RFO content in finished food products, variation in RFO leaching must also be considered. © 2025 His Majesty the King in Right of Canada. Journal of the Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. Reproduced with the permission of the Minister of Agriculture and Agri-Food.