Lentil flour formulations to develop new snack-type products by extrusion processing: Phytochemicals and antioxidant capacity

Abstract

The effects of extrusion processing on fibre (soluble and insoluble), total available carbohydrates, tocopherols, organic acids, total phenolics, flavonols, hydroxycinnamic and hydroxybenzoic acids, as well as on the antioxidant capacity of different fibre-enriched lentil flours, were evaluated before and after extrusion process. Total dietary fibre was partially decreased after extrusion, which correlated with a significant increase in the soluble fibre fraction. γ-tocopherol was the major isoform, before and after extrusion. Additionally, a marked decrease of 83–94% in total tocopherols content after extrusion was observed. Conversely, an increase in most polyphenolic fractions was found, probably due to the effect of extrusion in the hydrolysis of polyphenols bound to fibre and proteins, with an increase in antioxidant activity. Only flavonols presented an extensive decrease (62–82%) after treatment. The novel pulse-based flours, enriched with gluten-free soluble and insoluble fibres, provide snack-type products with a balanced nutritional and antioxidants composition.