Weerachet Jittanit

Corn, Rice, and Wheat Seed Drying by Two-Stage Concept

Corn, rice, and wheat seeds with an initial moisture content (IMC) of 20–25% wb were dried to moisture content below 18% wb at 40–80°C in a fluidized bed dryer (FBD) and spouted bed dryer (SBD) and the seeds with IMC 18% wb were dried to below 14% wb at air temperatures 18–30°C and relative humidity 60–70% by an in-store dryer (ISD). As a result, it appears that a two-stage drying concept is feasible in drying high-moisture-content seeds due to the high germination rate of dried seeds. Nonetheless, the drying temperature must be carefully selected. A drying temperature of 40°C was clearly safe for all samples, whereas more than 90% of wheat seeds still germinated after drying at 60°C in FBD. Furthermore, drying seeds with IMC 18% wb by ISD was safe under specified drying conditions.

Seed Drying in Fluidized and Spouted Bed Dryers

This study was conducted in order to provide information on drying behavior of seed destined for reproduction of corn, wheat, and rice. Drying experiments were conducted in a fluidized bed dryer (FBD) with corn, rice, and wheat and in spouted bed dryer (SBD) with wheat and rice at temperatures between 40 and 80°C. The experimental data were fitted into four thin-layer drying models by a least squares method. As a result, Pages model and a two-compartment model were the best-fitted models. However, due to the limitation of these models, Pages model and the two-compartment model were modified by adding the drying temperature term. Subsequently, these models could adequately predict the drying curves under a wider range of temperatures with root mean square (RMS) of the difference between model-predicted and experimental values of less than 0.035.

Comparison Between Fluidized Bed and Spouted Bed Drying for Seeds

Fluidized bed dryers (FBDs) and spouted bed dryers (SBDs) are considered efficient dryers for drying seeds from high moisture content (MC; 20–25%wb) to medium MC (≈18%wb). In this work, a number of drying experiments and seed quality tests were conducted using rice and wheat seeds in order to compare the FBD and SBD with regard to drying rate, product quality, and specific energy consumption. It was found that FBD was better in terms of a faster drying rate and SBD was better in terms of specific energy consumption. However, it could not be clearly concluded which dryer provided a better product quality in terms of germination percentage.

Electrical and Thermo-Physical Properties of Meat Ball

Ohmic heating is an interesting method for heating meat ball; however, its effectiveness relies on the electrical and thermo-physical properties of the product. Therefore, this research aimed to determine the electrical conductivities and thermo-physical properties of pork-meat balls. The results showed that electrical conductivities of samples could be well-fitted into the mathematical models as a function of temperature and the ratio of each ingredient due to their high R2 and low RMSE. The addition of salt and sodium tripolyphosphate led to a significant increase in electrical conductivity. The specific heats and thermal conductivities of meat balls were measured, whereas the convective heat transfer coefficients were determined by a lump-heat capacity technique. An equation was developed to estimate the convective heat transfer coefficients as a function of temperature difference between particle and surrounding fluid.

Moisture Sorption Behavior and Drying Kinetics of Pre-Germinated Rough Rice and Pre-Germinated Brown Rice

The equilibrium moisture contents of pre-germinated rough rice (pre-GRR) and pre-germinated brown rice (pre-GBR) were studied at 30°C, 50°C, 60°C, and 80°C using saturated salt solutions for controlling the relative humidity of the atmosphere. Empirical models were developed for the prediction of equilibrium moisture content, and a good fit was obtained with the experimental data. In addition, the pre-germinated samples were dried in an oven at 50°C and in a fluidized bed dryer (FBD) at 80°C, 100°C, 120°C, and 140°C. Pages model was the most accurate model for drying at 50°C, whereas the two-compartment model was an excellent model for drying at 80°C, 100°C, 120°C, and 140°C. Effective moisture diffusivities ranged between 5.01 × 10-10 and 8.19 × 10-9 m2 s-1 for pre-GRR and between 7.19 × 10-10 and 1.23 × 10-8 m2 s-1 for pre-GBR. The temperature dependence of the effective moisture diffusivity followed an Arrhenius relationship, with activation energies of 32.69 and 32.54 kJ mol-1 for pre-GRR and pre-GBR, respectively.

Effects of Drying Methods on the Nutritional and Physical Quality of Pre-Germinated Rice

Pre-germinated rough rice (pre-GRR) and pre-germinated brown rice (pre-GBR) were dried to below 14% wet basis (w.b.) by various drying schemes involving three dryers: hot-air oven (HAO), fluidized-bed dryer (FBD), and solar dryer (SD). The aim of this research was to investigate the effects of drying methods on the γ-aminobutyric acid (GABA) content, antioxidant activity, fissuring, and color of GABA rice produced from pre-GRR and pre-GBR in order to maximize the quality of GABA rice. The HAO was operated at 50°C, while the drying temperatures for FBD were 80°C, 100°C, 120°C, and 140°C. The GABA contents of GABA rice produced from pre-GRR and pre-GBR before drying were 25.4 and 22.1 mg per 100 g dry mass of sample, respectively. The antioxidant activities of GABA rice produced from pre-GRR and pre-GBR were 32.89 and 26.11 mg BHAE (t-butylated hydroxyanisole equivalent) per 100 g sample dry mass, respectively. Both GABA content and antioxidant activity were diminished after drying, especially in the case of single-stage drying at 50°C. The multi-stage drying with intermittent tempering steps significantly reduced the fissured kernels. After drying, the lightness of samples was lowered whereas the redness and yellowness were increased. The results of this study recommend GABA rice to be produced from pre-GRR rather than pre-GBR because of its increased GABA content and antioxidant activity, lower tendency to fissuring, and similarity of color to typical brown rice.

Study of hybrid dryer prototype and its application in pregerminated rough rice drying

ABSTRACT In this study, a hybrid dyer, combining heat pump drying (HPD) with fluidized bed drying (FBD) concepts were designed and fabricated. The pregerminated rough rice (pre-GRR) was dried in multistage using this hybrid dryer to compare with the single-stage drying by hot air dryer. The objectives were to test the application of this hybrid dryer and determine the suitable drying condition for pre-GRR. The result indicated that the punched plate distributor was the most suitable distributor. The pre-GRR should be dried by the three-stage drying method using either FBD or HPD at 45°C in the last stage to obtain higher head rice yield, lower fissure grain, and better color values than their counterparts. The scanning electron micrographs proved that starch gelatinization occurred when applying FBD at temperatures between 100 and 140°C causing the adhesive connections inside the kernels and subsequent decrease in fissures.

Physical and chemical properties of powder produced from spray drying of inulin component extracted from Jerusalem artichoke tuber powder

Abstract In this study, inulin was extracted from Jerusalem artichoke tuber (JAT) powder and then concentrated before spray drying. The aims of this study were to (1) determine the drying condition that provided high powder yield together with superior qualities of JAT inulin powder and (2) investigate the chemical and physical properties of inulin powder. The inulin extracts at different concentrations of 10, 20, and 30 °Brix were spray-dried and then compared. The spray drying experiments were conducted at the inlet/outlet air temperatures of 150/90, 170/90, and 190/90 °C for the chosen concentration of inulin extract. It appeared that spray drying of the 30 °Brix extract at the inlet/outlet drying air temperatures of 190/90 °C resulted in the highest value of powder recovery, bulk density, water solubility and the lowest moisture content and hygroscopicity in comparison with its counterparts. SEM micrographs showed that the powder produced by this condition was more stable and less sticky than others. The sugars, total fructo-oligosaccharides (1-kestose, nystose, and 1F-β-fructofuranosyl nystose) and inulin-type fructans contents of powder were 12.88, 11.12, and 64.36 g/100 g of powder, respectively. The moisture sorption data and models developed in this work could be used for determining the suitable condition of surrounding air for inulin powder storage.

Effect of carbonation of fresh egg white prior to spray drying on physical and functional properties of powder

ABSTRACT The effect of carbonation on physical and functional properties of egg white powder during spray drying and storage under vacuum, air, and CO2 gas was investigated. Carbonation (2,000 mg/kg) of fresh egg white before spray drying was found to improve the foaming properties of the fresh egg white powder. However, the carbonation caused accelerated changes in color, solubility, and foaming properties of the powder during storage. In addition, the results showed greater changes in the color and decreased solubility in the powder samples stored in impermeable hermetically sealed bags under CO2 and vacuum conditions than in normal air.