Optimization of Microwave-Vacuum Drying Parameters of Saskatoon Berries Using Response Surface Methodology

Abstract

A combined microwave and vacuum system was used to dry the Saskatoon berries (Amelanchier alnifolia). A central composite rotate design and response surface methodology were used to determine the influence of process variables (microwave power, drying time, and fruit load) and arrive at optimal processing conditions to reduce the moisture content and water activity of the berries to a safe level. It is concluded that the yield of moisture content and water activity can be reduced to 20% and 0.50, respectively, for microwave power 5.7–6 kW, drying time 51.5–55 min, and fruit load 10–9.75 kg.

Keywords:

• Microwave-vacuum drying
• Response surface methodology
• Saskatoon berries dehydration

ACKNOWLEDGEMENTS

We gratefully acknowledge NSERC and Agricultural Development Fund (ADF), SK, Canada for financial support; Hamish Tulloch for his help with the drying experiments at Riverbend Plantation; and Grace Whittington, the owner of the Riverbend Plantation, for providing Saskatoon berries and drying facilities.

Notes

X₁ = (P − 6)/0.5, X₂ = (t − 55)/5, X₃ = (W − 10)/0.25.