Drying characteristics of Edamame (Glycine max. L. Merill) during freeze drying

Abstract

Edamame (Glycine max. L. Merill) has been consumed due to its savory taste and high nutrient content. Edamame can be dried and consumed as a crunchy snack through the drying process which is able to retain nutrition loss during it, that is freeze drying. There were still least information about freeze drying of edamame. Therefore, the objective of this study was to investigate the edamame's moisture content and physical quality decreasing kinetics during freeze drying. Fresh edamame with initial water content of 60-70% was steam-blanched to 9 minutes before drying. 1,5 kg capacity freeze dryer was used with freezing temperature was set at-18°C and pressure at-76 cmHg. Its parameters was measured at 0 h, 12 h, 18 h, 24 h, 30 h, and 36 h. The drying rate of edamame freeze drying was 6.9355 g/g db per hour. Edamame shrunk 12.64% during 12 hours drying and shrunk more until 22.0046% to the final time. As it dried, edamame became harden due to crispiness at second phase of drying, or more than 24 hours of drying. There were not a significant change of colour.