Effects Of Vacuum Drying Research Articles

Effect of Vacuum Drying on Chemical Quality of Bitter Gourd

Effect of Vacuum Drying on Chemical Quality of Bitter Gourd

Effect of vacuum drying and pulsed vacuum drying on drying kinetics and quality of bitter orange ( Citrus aurantium L.) slices

The effect of vacuum pressure (20.0, 17.5, 15.0, 12.5, and 10.0 kPa) of vacuum drying (VD) and vacuum pressure (20.0, 15.0, and 10.0 kPa), drying temperature (65, 70, and 75 °C), and the ratio of pulsed vacuum (5:10, 5:15 and 5 min:20 min) of pulsed vacuum drying (PVD) on drying kinetics and quality (rehydration rate and color difference L*, a*, b*, ΔE, and BI) of bitter orange slices (4 mm) were investigated experimentally. Drying bitter orange slices by PVD can effectively increase the drying rate and decrease quality degradation. The optimal condition was 75 °C, 10.0 kPa and 5 min:15 min, which decreased 47.6%, 28.3%, and 15.5% of the moisture ratio, ΔE and BI than VD. Compared with APD, the moisture content undergoing PVD for 4 hr decreased 72.9%. The Third-degree polynomial drying model was the most suitable (R2 of 0.99865) for PVD. Novelty impact statement Drying bitter orange slices by pulsed vacuum drying can effectively increase the drying rate and decrease quality degradation, and the optimal operating condition is 75 °C, 10.0 kPa and the ratio of pulsed vacuum of 5 min:15 min. The optional vacuum drying condition for bitter oranges slices (4 mm) is 75 °C, 15 kPa but not 10kPa. The Third-degree polynomial drying model is the most suitable for pulsed vacuum drying.

Effect of vacuum drying on drying kinetics and quality of the aqueous extracts of Callicarpa nudiflora Hook. et Arn.

To explore the feasibility to enhance drying kinetics and keep the active ingredients of the aqueous extracts of Callicarpa nudiflora Hook. et Arn., the effects of vacuum drying under different vacuum pressure (8, 20, 50 kPa), drying temperature (80, 95, 110 °C), and the thickness (4, 8, 12 mm) on the drying kinetics, energy consumption and the contents of verbascoside and galuteolin of the aqueous extracts were evaluated. Boiling heat transfer and low-pressure mass transfer of the aqueous extracts during drying were analyzed. Among different drying conditions, the vacuum pressure of 20 kPa, drying temperature of 110 °C and the thickness of 4 mm were recommended as the most suitable ones for vacuum drying of the aqueous extracts of Callicarpa nudiflora Hook. et Arn. in terms of the moisture ratio and the quality of final product.

Effects of two drying methods on the stability and antioxidant activity of phenolic compounds in mulberry fruits

Mulberry is a health-promoting fruit with abundant phenolic compounds. The effects of vacuum drying (VD) and vacuum freeze-drying (VFD) on oxidation resistance and polyphenols, including extractable and non-extractable phenols, were compared in the present work. The total polyphenols and antioxidant capacity of mulberry fruits treated with VFD were higher than those treated with VD. Thirteen phenolic compounds in fresh and dried mulberry fruits were identified and quantified by UPLC-QqQ/MS. The content of extractable phenol was significantly higher than that of non-extractable phenol. In addition, correlation analysis showed that flavonoids cyanidin-3-O-glucoside and phloretin were closely related to the total polyphenols and antioxidant activity. These results provide the basis for further development of dried mulberry products containing high content of total polyphenols and antioxidant activity.

Effect of Vacuum Drying On Nutrient Retention of Some Commonly Consumed Herbs

Effect of Vacuum Drying On Nutrient Retention of Some Commonly Consumed Herbs

Effect of Vacuum Drying in Target Preparation from Potassium Hydroxide Solution on the Spectra of Rutherford Backscattering Spectroscopy

Abstract In order to measure the amounts of fluorine (F) atoms in the off-gas drain from polymer electrolyte fuel cells (PEFCs) using proton Rutherford Backscattering Spectroscopy (p-RBS), we used an impinger where potassium hydroxide (KOH) solution (0.1 mol/L) was filled and prepared the targets for p-RBS using these samples. In the measured RBS spectrum, however, the peak of fluorine (F) atoms of the decomposition products could not be clearly observed due to the interference by the low energy tail of the potassium (K) atom's peak. We confirmed using SEM, EPMA and XRD that the origin of the low energy tail of the potassium (K) atom's peak was the absorption of carbon dioxide (CO 2 ) in the air by potassium hydroxide (KOH) solution during drying. We also found that the target prepared by vacuum drying was more suitable for measuring the spectra of light elements in p-RBS than that by natural drying.

Antioxidant Activity of Anthocyanins Extracted from Iraqi <i>Iresine herbstii</i> L. Flowers after Drying and Freezing

Any processing method that maintains the level of compounds known for their health benefits will be of interest to the food industries. Therefore, the effects of vacuum drying, storage and freezing on the anthocyanin content and their antioxidant properties of Iresine herbstii L. flowers were investigated. The results showed that fresh samples (AEFF) had the highest amount of total anthosyanin content (8.31 ± 0.23 mg/g dry matter, expressed as cyaniding 3-glucoside equivalents), followed by 7.17 ± 0.12 mg/g solid content, 13.72% loss of vacuum dried samples (AEDF). In comparison with fresh samples, total anthocyanins in stored samples for two weeks at 5°C (AESF) and frozen samples during 1 (AEZF1) and 3 months (AEZF3) of storage were significantly (P I. herbstii L. flowers exhibited a dose-dependent (AEFF > AEDF > AESF > AEZF1 > AEZF3, respectively) antioxidant activity against lipid peroxidation in a linoleic acid model system as well as strong reducing power and ferrous ion chelating abilities. Moreover, the anthocyanins extracted were found to show remarkable scavenging activity on superoxide anion radicals, hydroxyl radicals, hydrogen peroxide, nitric oxide radicals and deoxyribose degradation. Based on the results obtained, we can concluded that the Iresine herbstii L. flowers may be valuable natural antioxidant sources and are potentially applicable in both pharmacy and food industry

Effect of Vacuum Drying on Microstructure of Semi-Solid Cheese

Both theoretical and applied studies on microstructure of cheese immediately after a technological cycle and dry cheese obtained by vacuum drying are described. The aim of the microstructure studies is a more comprehensive evaluation of the product quality. Images of cheese upon highand low-temperature secondary heating at different magnification were studied. The effect of drying on cheese microstructure was investigated. Analysis and identification of various components in the cheese mass using microstructure studies were performed. Calcium phosphate depositions were detected with electron microscopy. Calcium lactate was detected in mature cheese.

Effects of Vacuum Drying on Structural Changes of Banana Slices

The objective of this research was to study the optimum condition for the vacuum drying of banana slices using a vacuum dryer and to find out the appropriate thin layer equation for predicting the drying kinetic of bananas. The experiments were carried out at the drying temperatures of 60, 70, 80 and 90oC and absolute chamber pressure of 30 mmHg. The drying experiments were performed until the samples moisture content was lower than 3.4% (w.b.). Next, the dried products were analyzed for physical quality (in terms of color, shrinkage, and texture) and sensory quality (in terms of color, texture, flavor, crispness and overall acceptability). These data were used in choosing the optimum condition for the vacuum drying of banana slices. From experimental results, the drying time at the highest drying temperature was the shortest. At this condition, the dried banana slices showed the highest degree of yellowness, lower shrinkage, and more crispness compared to lower drying temperatures. From sensory analysis, each drying condition showed significant effect on consumer acceptability with the drying temperature of 70, 80 and 90oC showing the levels of the overall acceptability sensory qualities of dried banana is not significantly different. Consequently, the drying temperature of 90oC was suggested as the best drying condition for sliced bananas. Moreover, three mathematical models (Newton, Logarithmic and Page) describing thin layer drying were investigated. It was found that the thin layer equation providing the highest coefficient of determination (R2) and the lowest chi-square (X2) and root mean square error (RMSE) was the Logarithmic equation.

Commercial baker's yeast stability as affected by intracellular content of trehalose, dehydration procedure and the physical properties of external matrices.

The effects of vacuum-drying and freeze-drying on the cell viability of a commercial baker's yeast, Saccharomyces cerevisiae, strain with different endogenous contents of trehalose were analyzed. An osmotolerant Zygosaccharomyces rouxii strain was used for comparative purposes. Higher viability values were observed in cells after vacuum-drying than after freeze-drying. Internal concentrations of trehalose in the range 10-20% protected cells in both dehydration processes. Endogenous trehalose concentrations did not affect the water sorption isotherm nor the Tg values. The effect of external matrices of trehalose and maltodextrin was also studied. The addition of external trehalose improved the survival of S. cerevisiae cells containing 5% internal trehalose during dehydration. Maltodextrin (1.8 kDa) failed to protect vacuum-dried samples at 40 degrees C. The major reduction in the viability during the freeze-drying process of the sensitive yeast cells studied was attributed to the freezing step. The suggested protective mechanisms for each particular system are vitrification and the specific interactions of trehalose with membranes and/or proteins. The failure of maltodextrins to protect cells was attributed to the fact that none of the suggested mechanisms of protection could operate in these systems.

Effects of Vacuum-Drying on the Viability of Oil Palm Pollen

SUMMARYPollen of the oil palm (Elaeis guineensis) was vacuum dried for various lengths of time and stored under vacuum in ampoules at 28°, 5° and −10°C. Little loss in viability over a period of 12 months was observed in any of the storage treatments when vacuum drying did not exceed one hour. Progenies resulting from crosses with pollen stored three months under vacuum have shown no anamolous seedling development.

Effects of Vacuum-Drying on the Surface Properties of Germanium Transistor

It was investigated how the characteristics of germanium transistors, especially the ground-emitter current-amplification factor, hfe, depend upon the process of vacuum-drying. It was found that the dominant factor was the adsorption and the desorption of water on the Ge surface. The surface contamination due to oil vapor from the mechanical vacuum pump also showed a great effect.