Effects of oxidized konjac glucomannan on physicochemical and sensory properties of set-style yoghurt

Abstract

This study explored effects of adding oxidized konjac glucomannan (OKGM) at various concentrations (0.5, 1.0, 1.5, 2.0%) to low-fat set-style yoghurt on its physicochemical and sensory properties. The findings indicated that effects of OKGM on yoghurt were contingent on the quantity added. Lower concentrations (0.5 and 1.0%) of OKGM enhanced the yoghurt's texture, including hardness, elasticity, gumminess, and chewiness. Results showed an increase in the yoghurt's apparent viscosity, viscoelasticity, and thixotropy. Microstructural analysis showed that low concentrations of OKGM decreased yoghurt particle size and gel pore space. However, at OKGM concentrations of 1.5% or higher, the yoghurt's gel structure was disrupted. Throughout storage, OKGM slowed environmental acidification, as indicated by a steady pH drop and slight increase in acidity. Additionally, OKGM improved the yoghurt's water-holding capacity and reduced its L∗ value. Consumer acceptance was higher for yoghurt with OKGM compared to the control, offering a reference for creating healthy set-style yoghurt.