Optimization of Extrusion Process Parameters for Red Lentil-carrot Pomace Incorporated Ready-to-eat Expanded Product Using Response Surface

Md Shafiq Alam,Sunil Kumar

doi:10.13189/fst.2014.020703

Abstract

For optimization of extrusion process for development of red lentil-carrot pomace incorporated ready- to-eat rice based expanded product, experiments were planned in Box-Behnken design using response surface methodology. The independent process variables for extrusion were feed moisture content (14-20%), die temperature (120-180℃), screw speed (300-500 rpm) and formulation (rice flour: pulse flour; 60-80%: 10-30%) with constant proportion of carrot pomace powder (10%). Second order polynomials were used to model the extruder responses, functional and physical properties as a function of extrusion process variables. The extrusion process was optimized for maximum expansion ratio, water absorption index, overall acceptability and minimum bulk density, water solubility index, specific mechanical energy and hardness with in experimental range. The optimum extrusion process conditions obtained were 80:10:10 (rice flour: pulse flour: carrot pomace powder), 14% feed moisture content, 394 rpm screw speed and 120℃ die temperature. An analysis of variance (ANOVA) revealed that among the process variables, feed moisture content followed by screw speed had the most significant effect on all the responses; screw speed had the significantly higher effect on specific mechanical energy. The proportion of red lentil and carrot pomace in rice based expanded product was observed to have significantly lower effect on the selected responses.

Highlights

Fruit and vegetable wastes are inexpensive, available in large quantities, characterized by a high dietary fibre content resulting with high water binding capacity and relatively low enzyme digestible organic matter (Serena and Knudsen, [33])
A wide variation in all the responses was observed for different experimental combinations i.e. 0.233 to 0.483kg/cm3 for BD, 2.004 to 2.673% for ER, 9.02 to 16.67Wh/kg for SME, 3.65 to 4.78 for Water Absorption Index (WAI), 4.8 to 10.8 for Water Solubility Index (WSI) 59.896 to 194.31N for hardness, and 48.15 to 92.59 for overall acceptability (OA)
The results revealed the higher influence of FMC, SS and DT in comparison to Rice flour proportion, irrespective of the responses

Summary

Introduction

Fruit and vegetable wastes are inexpensive, available in large quantities, characterized by a high dietary fibre content resulting with high water binding capacity and relatively low enzyme digestible organic matter (Serena and Knudsen, [33]). A number of researchers have used fruits and vegetable by-products such as apple, pear, orange, peach, blackcurrant, cherry, artichoke, asparagus, onion, carrot pomace (Nawirska and Kwasnievska, [31]; Grigelmo-Miguel and Martin-Belloso, [20]; Ng et al, [32]) as sources of dietary fibre supplements in refined food. The carrot (Daucus carota) is a root vegetable, usually orange, purple, red, white or yellow in color, with a crisp texture when fresh. It is a rich source of-carotene and contains other vitamins, like thiamine, riboflavin, vitamin B-complex and minerals (Walde et al, [37]). A promising way to store the carrot pomace is in dried form and utilize it in the development of bakery products extrudates, which are becoming more popular than other bakery products in ready to eat food category

Methods

Results

Conclusion