Fluidized Bed Drying of Pumpkin (Cucurbita sp.) Seeds

Abstract

Pumpkin seeds are a major agricultural waste from the fresh-cut produce industry. The objective of this study was to investigate the drying behavior of untreated, whole pumpkin seeds in a fluidized bed dryer at 50–80 °C (2.87 m/s), with a view to producing a high-quality pumpkin powder from dried seeds. Seeds were dried at 50–80 °C to an average equilibrium moisture value of 0.035 to 0.006 g H2O/g DM (3.4 to 0.6% wb). Drying occurred in the falling rate period only and drying rate constants ranged from 0.0226 to 0.0900 1/min with corresponding diffusivity values for the first falling-rate period ranging from 4.68 to 18.63 × 10−10 m2/s. The activation energy (Ea)—for the first falling rate period was determined to be 43.9 kJ/mol. Of the nineteen thin layer models tested, the Alibas model could be successfully used as a general model to predict the Moisture Ratio (MR) data for all temperatures investigated. After drying, seeds were blended to produce powders, which were found to be high in fat, crude protein and fiber.

Functionality and Palatability of Yogurt Produced Using Beetroot Pomace Flour Granulated with Lactic Acid Bacteria

“…Fluidized bed granulation is often a method of choice for drying heat-sensitive compounds, including microbial cultures. Advantages, such as good temperature control, equal temperature distribution, high drying capacity, short drying time, low maintenance costs, and large-scale production, are noticeable [15][16][17][18]. To minimize the damage caused by drying and to achieve increased bacterial viability in storage time, fluidized bed immobilization of LAB is mainly performed in the presence of protective carbohydrates [15].…”

Vibro-Fluidized Bed Drying of Pumpkin Seeds: Assessment of Mathematical and Artificial Neural Network Models for Drying Kinetics

“…In most of the drying experiments, empirical models validate the exceptional fitting of data but overlook the basics of the drying processes. While theoretical models justify diffusion mechanism or heat and mass transfer mechanism [15], there are several investigations on mathematical modeling of pumpkin seeds drying kinetics for natural and forced convection solar dryer [6], solar tunnel dryer [16], tray drying [17], fluidized bed drying [17][18][19][20], and infrared dryer [21]. However, no study was found for pumpkin seed drying using a vibro-fluidized bed dryer.…”

Determination of the kinetics of the process of pumpkin seeds vibrational convective drying

“…In [3], the drying process in the moving layer is considered, where the suspended state of the seed material is ensured by blowing the drying agent at speeds of 2.39-2.87 m/s. This method does not guarantee uniform heating of the seed and causes additional energy consumption to provide the required speed of the drying agent.…”