Description

Abstract: The water, sugar, chocolate and peanut are used in various confectionery products. Quality control and product standardization of existing confectionery products and development of new products are of obvious significance to the confectionery manufacturing industry. Thus, knowledge of rheological and physical properties of mixtures of the above-mentioned ingredients is of importance.

The purpose of this investigation is to study rheological and physical properties of various mixtures of water, sugar, chocolate and peanut meal in the temperature range of 40 to 60oC.

Four types of mixtures were studied: 1) sugar, chocolate and water; 2) sugar, peanut meal and water; 3) chocolate, peanut meal, and water; and 4) chocolate, peanut meal, sugar and water. The rheological characteristics like static flow properties and linear viscoelasticity were examined using Brookfield viscometer and dynamic mechanical analyzer (DMA) at 40, 50 and 60oC. And the physical characteristics such as glass transition temperature (tg) and melting temperature (mp) were investigated using differential scanning calorimeter (DSC).

All mixtures were in semi-solid state and showed pseudoplastic flow behavior with yield stress. The activation energy for flow ranged from 12.093 to 43.819 KJ/mole.K. The linear viscoelasticity values exhibited a very broad range which were affected largely by the change of peanut meal and chocolate Content. The storage moduli (G’) and loss moduli (G”) of the mixtures were significantly affected by temperature. As the sugar Content increased, tg and mp of the mixtures also increased. But as the chocolate Content increased, tg and mp of the mixtures decreased.

The rheological and physical properties of the mixtures consisting of sugar, chocolate and peanut meal are not only of interest to the confectioners in enrobing and molding, but also to the food process engineers in the design of bulk handling systems such as mixing, homogenization and transfer etc.