Effects of Enzymatic Liquefaction, Maltodextrin Concentration, and Spray-Dryer Air Inlet Temperature on Pumpkin Powder Characteristics

Abstract

This study was conducted to investigate the effects of three variables namely cellulase (Celluclast, Novozymes, Denmark) concentration (0–1%, v/w (x1)), maltodextrin (MD) concentration (15–30%, w/w (x2)), and spray-dryer air inlet temperature (150–190 °C (x3)) on pumpkin powder characteristics using enzymatically macerated pumpkin with Pectinex® Ultra SP-L (2.5%, v/w). The powder characteristics considered as response variables in response surface methodology were process yield, moisture content, stickiness, water activity, and hygroscopicity. Results indicated that the response surface models were significantly (p ≤ 0.05) fitted for all response variables in the studied independent variables range. The concentration of Celluclast and MD should be considered as critical factors which may increase process yield of pumpkin powder. The effect of Celluclast concentration on pumpkin powder characteristics especially for process yield and stickiness was noticeable. The main effect of MD and quadratic term of Celluclast had the most significant effect on stickiness. Negative interaction value of MD with Celluclast indicated that stickiness decreased when mixture of MD and Celluclast was used and also Celluclast reduced the impact of air inlet temperature on stickiness. The overall optimum region resulted in a desirable powder characteristics was predicted to be obtained by combined level of air inlet temperature 180 °C, Celluclast 0.7% (v/w), and MD 23% (w/w). The theoretical and experimental validation ensuring the adequacy of the response surface models described the changes in physical properties of powder as a function of Celluclast, MD, and air inlet temperature.