Volume 16, Issue 93 (November 2019)
Abstract
The consumption of extruded snacks has been increased among children. Due to their high content of fat and low nutritional value extruded snacks are contributing to a range of health problems which related to an unhealthy diet. Therefor they had an appropriate potential for production of functional foods. The objective of the research was to substitute fat used in the production of snacks coating partially by different levels of fat replacer containing native inulin (0-20%) and resistant starch (0-20%) in order to supply low fat flavoring of snacks. Based on mixture design the effect of fat replacers on rheological properties, color and emulsion stability of final products were investigated. Results showed that, addition of resistant starch increased emulsion stability of coating (1.42). The flow behavior index of samples were investigated by Power-law and Bingham model. Power-law was successfully fitted to the description of flow behavior of coating. Meanwhile, based on rheological properties, all of the samples showed shear thinning behavior and the samples containing higher amount of inulin(20%) and lower amount of fat (80%) had the highest consistency coefficient (2.219 Pa.Sn) and the lowest and flow behavior index (0.868). The lightness of product was decreased by increasing fat replacers levels. The lowest amount of lightness belonged to sample containing inulin- resistant starch in 10-10% levels
Volume 17, Issue 103 (September 2020)
Abstract
in this project, study of production of food by products (Spent coffee – wheat bran) in order to producing fiber solid foam using extrusion was carried out. Central composite design was used for evaluation of variables containing spent coffee: wheat bran ratio (75:25, 50:50, 25:75), feed moisture content (14, 17, and 20) and screw speed (120, 160, 200 RPM) on final moisture, water activity, expansion index, hardness and microstructure of extrudates. Results showed that by increasing spent coffee and moisture, water activity and humidity of solid foams were increased significantly. However screw speed had no effects on both properties. Improvement of spent coffee: wheat bran concentration in formulations in order to higher concentration of nonsalable fiber caused an increase in hardness and decrease in expansion index significantly. Increasing feed moisture content (14, 17, and 20) and screw speed simultaneously, showed an increase in expansion index and decrease in hardness. Microstructure Survey of solid foams illusterated that increasing spent coffee: wheat bran ratio leaded porosity reduction and improvement of cell wall size and reducing in air buble diameter. Based on optimization results, in order to production of solid foam with appropriate characteristics such as final moisture content (4.73%), wateractivity (0.29), expansion index (1.23), hardness (68.51 N), the process conditiond were determined at spent coffee: wheat bran ratio (69:31), feed moisture content (14.1) and screw speed (190 RPM)
