Pectin gels enriched with dietary fibre for the development of healthy confectionery jams

Abstract

The objective of this work is to evaluate the effect of the addition of dietary fibre from different sources (apple, bamboo, psyllium and wheat) and pectin mass fraction (0.4 and 0.5 g/100 g) on the physicochemical properties of pectin gels for the development of a novel, healthy product similar to a fruit confectionery jam. A mass fraction of 3 g/100 g fibre was added to each pectin gel in order to declare the final product as a source of fibre. It was evident that pectin content, type of fibre, and their interaction had a significant effect on the viscoelastic and mechanical properties, and syneresis (water loss) of the gels. Since syneresis of the gel with 0.4 g/100 g pectin was undesirably high, only studies of gels with 0.5 g/100 g pectin followed from this point forward. Fibre addition had a reinforcing effect on the viscoelastic properties of these gels (wheat > psyllium > bamboo > apple). Psyllium-enriched gels did not suffer any syneresis, although they showed an undesirable "gummy" property, caused by low fracturability, high cohesiveness and low hardness. Then, in order to improve the organoleptic properties of the gels, we combined fibre from different sources in pairs (1:1). In general, fibre combination decreased the viscoelastic properties of the gels. However, mixing psyllium with other fibre produced a desirable effect on the mechanical properties of the gels, keeping the syneresis at 0 g/100 g. This indicates that 0.5 g/100 g pectin and 1.5 g/100 g psyllium fibre with 1.5 g/100 g other fibre was the best formulation for the stability and texture of this product.