Effect of Dry- Crystallization Method on the Engineering Properties of an Instant Mix for Rice Flake – Milk Pudding

An attempt was made to evaluate the engineering properties of an experimental sample of dry crystallized rice flake-milk pudding convenience mix (prepared using an in-house developed mechanical unit) against a control (prepared with manual stirring). Analysis of the proximate composition of the samples showed marginal differences; fat and sucrose content were slightly higher in control, whereas protein and starch were slightly higher in experimental sample. However, both samples reported identical water activity in the range of 0.410-0.418. Particle size analysis revealed that the average mean diameter of control and experimental sample to be 2.55 and 2.49 mm, respectively. Experimental samples reported slightly higher values of lightness and lower Browning Index, clearly indicated that the control samples were marginally darker than the experimental samples. Flow behaviour indices such as Hausner Ratio and Carr’s Index were found to increase with moisture content, indicative of a marginal reduction in its flowability with moisture content. Porosity was found to be slightly higher in experimental sample (56.80%) than control sample (54.77%). Experimental samples had higher thermal conductivity and specific heat than the control samples and the thermal properties of both the samples were found to be affected by moisture. X-ray diffraction (XRD) graphs yielded sharp peaks for both the samples indicative of the crystalline nature of sugar, whereas the XRD data for the dry gelatinized rice flakes confirmed their amorphous nature