Impact of cooking and germination on phenolic composition and dietary fibre fractions in dark beans (Phaseolus vulgaris L.) and lentils (Lens culinaris L.)

Abstract

The impact of cooking and germination on dietary fibre and phenolic compound composition was studied in beans (Phaseolus vulgaris L.) and lentils (Lens culinaris L.). An investigation on phenolic compounds in dietary fibre fractions was carried out due to the scarce literature on the behaviour of these compounds during legume processing. A general decrease in the concentration of insoluble and soluble fibre fractions were observed in processed bean and lentil flours, although an increase in the content of insoluble and soluble fibre fractions in sprouts and cooked beans, respectively, was found. Hydroxybenzoic and hydroxycinnamic compounds, flavan-3-ols, procyanidins, flavonols and flavones were identified in dietary fibre fractions in cooked and germinated beans and lentils. Phenolic compound constituents of the different dietary fibre fractions accounted from 73% to 97% in insoluble dietary fibre fraction (IDF) flours and from 3% to 25% in soluble dietary fibre fraction (SDF) in raw and processed bean and lentil flours. These processing techniques may produce positive changes in the dietary fibre and phenolic compound composition and its association could improve phytochemical and nutritional quality and maximize the health-promoting properties of legumes.