Effect of Cooking on Phenolic Compound Content and In Vitro Bioaccessibility in Sustainable Foods: A Case Study on Black Beans

Legume production and consumption have emerged as meeting sustainability principles. Legumes can help fight climate change, hunger, and obesity. Legumes are also a valuable dietary source of phytochemicals, whose content and composition vary depending on genotype, as well as on growing conditions, geographical origin, storage, and cooking. The health effects of legume consumption are nevertheless related to the bioaccessibility of these molecules, which is deeply affected by the cooking method. The aim of this study was to investigate the content and composition of phenolic compounds and anthocyanins present in black beans grown locally and cooked with three different methods (i.e., regular boiling, pressure-cooking, and microwave-cooking) and determine the in vitro biaccessibility. It emerged that Total Phenolic Content (TPC) and Total Anthocyanin Content (TAC) decreased significantly in all three cooked black beans. TPC loss was lowest (63%) in pressure-cooked beans and highest (77%) in boiled beans. TAC loss ranged between 93 and 98% but was not significantly different among treatments. Caffeic, t-ferulic, and sinapic acids were identified by HPLC. Cyanindin-3- O -glucoside and Peonidin-3- O -glucoside were also detected. The simulation of gastrointestinal digestion showed that phenolic compound bioaccessibility was highest when beans were boiled or pressure-cooked, while anthocyanins were mostly bioaccessible in pressure-cooked black beans.