Influence of Wet Processing Techniques (Soaking, Boiling, and Pressure Cooking) on Phytic Acid Reduction, Mineral Retention, and Solubility in Common Beans Phaseolus Vulgaris L, VignaUnguiculata, Vigna Radiata, and Cicer Arietinum L.

Abstract

Introduction: Beans and chickpeas are one of the most important crops in the world because of their nutritional quality. Phytic acid lowers the bioavailability of minerals. Heat treatment significantly improves nutritional quality in pulses by destruction or inactivation of heat-labile anti-nutritional factor phytic acid. Methodology: This study examined four local bean cultivars: Red Kidney beans (Phaseolus Vulgaris L), White beans (Vigna Unguiculata), green mung beans (Vigna Radiata), and Chickpeas (Cicer Arietinum L.).  These beans were subjected to different domestic processing techniques, including soaking for 1 hour, 6 hours, and overnight, and boiling (until tender and until all water was absorbed). They were also cooked under vacuum in a pressure cooker with and without use of bicarbonate soda. The samples were analyzed for their percentage of phytate content in both raw (as control) and cooked forms, and the mineral content, percent phytate degradation, and percent mineral solubility were determined following standard procedures. Results: The effects of domestic processing on the phytic acid content of beans are summarized below. Soaking pulses for 1 hour resulted in varying reductions; mung beans had the highest decrease of 68.3%, followed by white beans at 34.1%, red kidney beans at 22.7%, and chickpeas at only 5.71%. While mung beans significantly decreased from 2.08% to 0.66%, white beans dropped from 1.096% to 0.72%, and red kidney beans from 0.97% to 0.75%. Chickpeas showed minimal change, remaining nearly the same after soaking. After soaking for 6 hours, white beans exhibited the highest reduction at 42.9%, down to 0.63%, while red kidney beans decreased by 33% to 0.65%. Chickpeas had a minimal reduction of 1.43%, remaining nearly unchanged. Mung beans showed an anomalous reduction to -0.02%, warranting further investigation. With 12 hours of soaking, mung beans again showed significant improvement, decreasing to 0.63% (a 69.7% reduction), while white beans reduced to 0.54% (50.7%). Red kidney beans and chickpeas had minimal reductions, suggesting that soaking alone is ineffective for these types. Overall, longer soaking times effectively reduced phytic acid in mung and white beans, while red kidney beans and chickpeas may require additional processing methods for better results. Boiling also resulted in a 59.1% reduction for mung beans, indicating varying effectiveness across different pulses. Conclusion: This research has validated the use of soaking and boiling to reduce the phytate’ concentrations presumably by rearranging phenolic compounds, which are likely to entrap nutrients such as minerals in chickpeas, mung beans, white beans, and red kidney beans.