Drying Characteristics of Purslane (Portulaca oleraceae L.)

Abstract

Thin layer drying rates of purslane were determined experimentally as a function of temperature with air velocity kept constant at 1.1 m/s and relative humidity below 5%. Thin layer drying data were obtained for purslane at four drying air temperatures (35, 70, 95, and 120°C). Five thin layer-drying models (Henderson and Pabis, exponential, Page, two-term exponential, and Thompson models) were fitted to the drying data. The color of purslane was determined after drying using a spectro-colorimeter (Hunter Lab) in terms of Hunter L, a, and b values. The Page model was found to be most suitable in describing the drying characteristics of purslane. New parameters developed for the model resulted in a good fit at different temperatures. Color measurement indicated that greenness decreased with an increase in drying air temperature. Typical drying times were 88.41, 138.53, 416.38, and 1371.85 min at 120, 95, 70, and 35°C, respectively.

Keywords:

• Color
• Drying rate
• Equilibrium moisture content
• Hunter Lab
• Modeling
• Moisture content
• Moisture ratio
• Portulaca
• Thin-layer drying

Acknowledgments

The authors would like to acknowledge the technical support given by Mr. Bill Crerar and Dr. Karim Sharifat in the experimental setup. The authors would like to acknowledge the funding support of the University of Saskatchewan and Agriculture Development Fund of Saskatchewan Agriculture, Food and Rural Revitalization. The authors also would like to acknowledge the Agri-Food Innovation Fund for the renovation of the Bio processing Research lab. We also acknowledge Elsie Belcheff, Founder and President of Natural Plantation Inc. of Margo, SK for providing the samples.