Effect of different cooking methods and heating solutions on nutritionally-important starch fractions and flatus oligosaccharides in selected pulses

Background and objectives: Consumption of pulses is recommended by health organizations. Pulses are usually soaked and cooked in water before consumption which alters their nutrient composition and ultimately health benefits. This study investigated the effect of four cooking methods (boiling, pressure, microwave, and slow) and four heating solutions (water, salt, sugar, and citric acid) on composition of nutritionally-important starch fractions and flatus oligosaccharides in faba bean, lentil, and pea. Findings: The three pulses had slowly digestible starch (SDS) as the highest fraction with faba bean and lentil exhibited higher SDS than pea, but pea contained the highest level of resistant starch (RS). Rapidly digestible starch (RDS) was comparable among the three pulses. Stachyose and verbascose were the dominant oligosaccharides in faba bean, lentil, and pea. Regardless of the heating solution, slow cooking was more effective in improving starch nutritional fractions, i.e., producing lowest RDS and highest SDS in the three pulses with some exceptions. The RS fraction increased in the three pulses subject to cooking method and pulse type. Pressure and slow cooking methods were effective in reducing oligosaccharides in the three pulses. Conclusions: The results suggest that slow cooking in water or salt solution has great potential to improve starch nutritional fractions and diminish flatus oligo-sugars. Significance and novelty: This is the first study to demonstrate the effectiveness of slow cooking in enhancing starch nutritional fractions and reducing flatus oligo-sugars in pulses. The method could hold a promise for implementation especially small- and large-volume slow cookers are commercially available.