Optimizing Drying Conditions for Vacuum-Assisted Microwave Drying of Green Peas (Pisum sativum L.)

Abstract

Green peas were dried in a vacuum-assisted microwave drying system. The effects of microwave power levels (100–300 W) and system vacuum (50–400 mm Hg) on drying parameters (viz. drying efficiency and drying time) and some quality attributes (viz. linear shrinkage, apparent density, green color, rehydration, and sensory attributes) of dehydrated peas were analyzed by means of response surface methodology. A face-centered central composite design was used to develop models for the responses. Analysis of variance showed that a second-order polynomial model predicted well the experimental data. The system microwave power level strongly affected quality attributes of dehydrated peas and drying parameters. A higher vacuum during drying resulted in a better quality product. Microwave power of 237.31 W and a 360.22 mm Hg vaccum were found to be optimum drying conditions for vacuum-assisted microwave drying of green peas.

Keywords:

• Green peas
• Process optimization
• Rehydration ratio
• Response surface methodology
• Vacuum-assisted microwave drying

Notes

^a Mean values of five replications of center point and three replications of axial and factorial points.

^b Mean linear dimension of fresh pea sample = 10.11 mm.

^c Mean apparent density of fresh pea sample = 0.81 g/cm³.

^d Mean green color (Hunter Lab a*) value of fresh pea sample = − 9.74.

^e Overall acceptability score of fresh pea sample = 8.2.

Significant at **p ≤ 0.01; *p ≤ 0.05.