Effect of Extrusion Temperature on the Microstructure, Textural and Functional Attributes of Carrot Pomace-Based Extrudates

Abstract

Textural and functional attributes are the main decisive factor for acceptability and stability of the snack food in the market, whereas microstructural study is considered a powerful tool for understanding the behavior of these attributes. The extrudates prepared under the optimized conditions from rice flour, pulse powder and carrot pomace were evaluated for the thermal kinetics of color, hardness and microstructure; β-carotene; and vitamin C. The extrudates were sealed in metalized polypropylene, and the bags were then stored for 6 months in an incubator at temperature of 30C and 50% relative humidity. The increase in L-value, b-value and decrease in a-value, crispiness, β-carotene and vitamin C in carrot pomace-based rice extrudates was observed with the increase in extrusion temperature. The harder and compact texture in microstructural study of extrudates was observed with the increase in temperature. The decrease in L-value, b-value, crispiness, β-carotene and vitamin C, and increase in a-value and hardness extrudates was observed with the increase in storage period. Practical Applications Fruit and vegetable juices have become important in recent years because of overall increase in natural juice consumption as an alternative to the traditional caffeine-containing beverages such as coffee, tea or carbonated soft drinks. Carrot pomace is a by-product obtained during carrot juice processing. A promising way is to store the carrot pomace in dried form and utilize in the development of various food products specifically extrudates. The conversion of dried pomace by the application of novel and versatile technique of extrusion can be very useful both in terms of economic point of view and health benefits. The microstructural and textural changes in the product during storage are still not known. The effect of extrusion temperature and storage on the product microstructure, texture and functional attributes were evaluated for further applications of extrusion processing. Zero- and first-order models were also planned to study the thermal and degradation kinetics.