Developing psyllium fibre gel-based foods: Physicochemical, nutritional, optical and mechanical properties

Abstract

Psyllium fibre has known health benefits, which are highly related to its gelling properties, so it is important to know the functional properties and its gelling capacity to its possible incorporation as a new source of DF in foods. Therefore, the purpose of this research was to evaluate these properties of two Psyllium fibres. Physicochemical (particle size distribution, pH, water content, water activity, hygroscopicity and bulk density and porosity), hydration (water holding, water retention and swelling capacity, fat absorption capacity and solubility), and nutritional properties (mineral content, total phenolics compounds and antioxidant capacity) of dietary fibre (DF) samples were recorded. Moreover, physicochemical (water content, pH and colour) and mechanical properties (back extrusion test, rheological measurement and texture profile analysis) of gel samples were performed before and after heat treatment (20 min at 65 °C). The hydration properties of Plantago Husk (PH) were higher than those in Plantago Powder (PP), but in functional terms, high values of phenols and antioxidant activity were found in PP. However, both samples displayed similar gelling properties. As a result of the rheological and textural analysis, both fibres showed good gelling properties at both high (65 °C) and cool (5 °C) temperatures, at concentrations 4%–7%. Moreover, the results indicate that PH and PP have suitable characteristics to be functional ingredients, which can help to avoid possible negative effects on food sensory and structural characteristics.