High methoxyl pectin / apple particles composite gels: effect of particle size and particle concentration on mechanical properties and gel structure.

GENOVESE, DIEGO B.; YE, AIQAIN; SINGH, HARJINDER

JOURNAL OF TEXTURE STUDIES

WILEY-BLACKWELL PUBLISHING, INC

Año: 2010 vol. 41 p. 171 - 189

0022-4901

In order to study the effect of fruit pulp on the structure of fruit jams, they were modeled as composites with a high-methoxyl pectin (HMP) gel matrix filled with apple particles. The effect of particle concentration (0, 1, and 2 wt%) and particle size (small: <125 mm, and large: 125-850 mm) on a pectin gel (0.5 wt% HMP, 65 wt% glucose, pH 3.0, 0.1M citrate buffer) were studied. Rheological measurements showed that increasing concentration of small particles produced a significant increase in the elastic modulus of the composite gels. Penetration tests showed that 1 wt% small particles produced a significant decrease of gel strength, rupture strength, adhesiveness and brittleness. Increasing particle size produced a further decrease of these properties (only significant for gel strength). When concentration of small particles was raised to 2 wt%, these parameters (except brittleness) increased back to the control sample (0% particles) values.