Effect of sulfur fertilization on the composition, functionality, and protein quality of navy beans (Phaseolus vulgaris)

Background

Soil sulfur deficiency leads to reduced crop yield and quality loss, which is especially critical for pulses as sulfur is a major component of methionine and cysteine. The present research evaluated the influence of sulfur fertilization on two varieties of navy beans grown at soil sulfur levels of 17, 26, 35, and 44 kg/ha by analyzing their composition, functionality, and protein quality.

Results

Increasing the soil application of sulfur did not affect the protein content of the test navy bean flours. Methionine, cysteine, and tryptophan were limiting, and their concentrations were not enhanced by sulfur fertilization nor was protein digestibility. The oil holding capacity and emulsion stability were different among sulfur treatments; however, no clear trend was observed.

Conclusion

Sulfur fertilization had only a minimal effect on the quality attributes of navy beans, possibly due to a combined effect of environmental factors that limited the plant's response to sulfur supply. Despite the limited change, the findings underlined the possible role of the environment (e.g., location, crop year, and other variables) in determining the sulfur fertilization response of navy beans and provided valuable insight for researchers to further investigate the topic and optimize navy bean production and quality.