scholarly journals Optimization of microwave-vacuum drying processing parameters on the physical properties of dried Saskatoon berries

2016 ◽  
Vol 1 (1) ◽  
Author(s):  
Venkatesh Meda ◽  
Pranabendu Mitra ◽  
Jong Hyeouk Lee ◽  
Kyu Seob Chang

AbstractThe objective of this study is to optimize the microwave-vacuum drying parameters (microwave power, drying time and fruit load) on the physical properties of dried Saskatoon berries. Response surface methodology combined with central composite rotatable design was used to observe the effect of microwave-vacuum drying processing variables and optimize the drying conditions for the physical properties as response variables (moisture content, rehydration ratio, hardness, L value and total color difference) of the microwave-vacuum dried Saskatoon berries. The response variables were effectively modeled as the function of independent variables for the regression as well as response surface modeling. The regression and response surface modeling indicated that increasing microwave power and drying time and deceasing fruit load decreased moisture content but increased rehydration ratio, hardness, L value and total color difference of the microwave-vacuum dried Saskatoon berries. Also, the numerical combining with graphical optimization indicated that microwave power (5.8 – 6.5 kW), drying time (52-59 min) and fruit load (10-10.25 Kg) were very effective to improve the studied physical properties of the dried Saskatoon berries. The findings are expected to be helpful for the process development of commercial scale microwave-vacuum drying of Saskatoon berries within the experimental range.

2019 ◽  
Vol 2 (22) ◽  
pp. 151-167 ◽  
Author(s):  
Izabela Staniszewska ◽  
Szymon Staszyński ◽  
Magdalena Zielińska

The aim of study was to determine the influence of sonication and freezing on the kinetic of the microwave-vacuum drying, energy consumption and physical properties of whole cranberries as well as evaluate the applicability of sonication instead of freezing in order to change their physical properties and the drying kinetic of whole cranberries. Microwave-vacuum drying of whole cranberries with/without initial treatments took from 12 ± 1 to 14.5 ± 0.5 minutes. All of treatments did not significantly shorten the drying time of cranberries. However, they increased SMER values even by 31%. Despite of cryogenic freezing, all of treatments significantly increased the values of Dew. Sonication combined with drying allowed to obtain dried berries characterized by the lowest cohesiveness (0.19±0.02), springiness (0.62±0.02) and chewiness (3.4±0.8 N), while cryogenic freezing combined with drying allowed to obtain dried fruits characterized by highest springiness (0.75±0.03) and low chewiness (3.3±0.5 N). The highest lightness (32.2±0.7), redness (32.6±0.8), and yellowness (11.1±0.7) were found for fruits subjected to initial convective freezing before drying. The efficiency of sonication in color change was comparable to cryogenic freezing and much lower than convective freezing. All of initial treatments increased such thermal properties of dried cranberries as thermal conductivity and thermal diffusivity.


Author(s):  
Anna Michalska ◽  
Krzysztof Lech ◽  
Adam Figiel ◽  
Grzegorz P. Łysiak

Abstract The aim of the study was to determine the influence of four different growing locations of apples cv. ‘Jonagold’ in Europe on the drying kinetics and the physical properties of dried apple slices. The drying methods applied in the study (freeze-drying, convective drying, microwave-vacuum drying and combined drying) significantly affected the drying time, which was the shortest in the case of microwave vacuum drying. The geographical origin of the apples affected the chemical and physical properties of the raw material used for drying, and, consequently, the drying time. Water activity of dried samples was connected with the final dry matter, regardless of the geographical origin of the apples. Freeze-drying resulted in the lightest in colour products (L*), whereas microwave-vacuum dried products had the highest levels of yellow pigments (b*). The highest chroma and browning index values were noted for microwave-vacuum dried samples and were strongly influenced by the drying temperature. The mechanical properties of the apple slices were more dependent on the drying method and temperature of the process than on the geographical origin when the temperature exceeded 83 °C.


Processes ◽  
2020 ◽  
Vol 8 (11) ◽  
pp. 1430
Author(s):  
Zhiheng Zeng ◽  
Ming Chen ◽  
Xiaoming Wang ◽  
Weibin Wu ◽  
Zefeng Zheng ◽  
...  

To reveal quality change rules and establish the predicting model of konjac vacuum drying, a response surface methodology was adopted to optimize and analyze the vacuum drying process, while an artificial neural network (ANN) was applied to model the drying process and compare with the response surface methodology (RSM) model. The different material thickness (MT) of konjac samples (2, 4 and 6mm) were dehydrated at temperatures (DT) of 50, 60 and 70 °C with vacuum degrees (DV) of 0.04, 0.05 and 0.06 MPa, followed by Box–Behnken design. Dehydrated samples were analyzed for drying time (t), konjac glucomannan content (KGM) and whiteness index (WI). The results showed that the DT and MT should be, respectively, under 60 °C and 4 mm for quality and efficiency purposes. Optimal conditions were found to be: DT of 60.34 °C; DV of 0.06 MPa and MT of 2 mm, and the corresponding responses t, KGM and WI were 5 h, 61.96% and 82, respectively. Moreover, a 3-10-3 ANN model was established to compare with three second order polynomial models established by the RSM, the result showed that the RSM models were superior in predicting capacity (R2 > 0.928; MSE < 1.46; MAE < 1.04; RMSE < 1.21) than the ANN model. The main results may provide some theoretical and technical basis for the konjac vacuum drying and the designing of related equipment.


2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Wanxiu Xu ◽  
Guanyu Zhu ◽  
Chunfang Song ◽  
Shaogang Hu ◽  
Zhenfeng Li

This study was conducted to optimize the drying process of Polygonum cuspidatum slices using an orthogonal experimental design. The combined effects of pretreatment methods, vacuum pressure and temperature of inner material, drying kinetics, color value, and retention of the indicator compounds were investigated. Seven mathematical models on thin-layer drying were used to study and analyze the drying kinetics. Pretreatment method with blanching for 30 s at 100°C increased the intensity of the red color of P. cuspidatum slices compared with other pretreatment methods and fresh P. cuspidatum slices. P. cuspidatum slices dried at 60°C retained more indicator compounds. Furthermore, microwave pretreatment methods, followed by microwave vacuum for 200 mbar at 50°C, resulted in high concentration of indicator compounds, with short drying time and less energy. This optimized condition for microwave vacuum drying and pretreatment methods would be useful for processing P. cuspidatum. The Newton, Page, and Wang and Singh models slightly fitted the microwave vacuum drying system. The logarithmic, Henderson and Pabis, two-term, and Midilli et al. models can be used to scale up the microwave vacuum drying system to a commercial scale. The two-term and Midilli et al. models were the best fitting mathematical models for the no-pretreatment case at 600 mbar and 60°C.


Foods ◽  
2019 ◽  
Vol 8 (6) ◽  
pp. 216 ◽  
Author(s):  
Aslı Aksoy ◽  
Salih Karasu ◽  
Alican Akcicek ◽  
Selma Kayacan

This study aimed to investigate the effect of different drying methods, namely ultrasound-assisted vacuum drying (USV), vacuum drying (VD), and freeze-drying (FD), on the drying kinetics and some quality parameters of dried minced meat. In this study, USV was for the first time applied to the drying of minced meat. The USV and VD methods were conducted at 25 °C, 35 °C, and 45 °C. The different drying methods and temperatures significantly affected the drying time (p < 0.05). The USV method showed lower drying times at all temperatures. The rehydration values of the freeze-dried minced meat samples were higher than those obtained by the USV and VD techniques. The samples prepared using USV showed higher rehydration values than the vacuum dried samples for all temperatures. The effects of the different drying techniques and drying conditions on the microstructural properties of the minced meat samples were investigated using scanning electron microscope (SEM). The USV method resulted in higher porosity and a more open structure than the VD method. Total color differences (ΔE) for VD, USV, and FD were 8.27–20.81, 9.58–16.42, and 9.38, respectively, and were significantly affected by the drying methods and temperatures (p < 0.05). Higher drying temperature increased the ΔE value. Peroxide values (PV) significantly increased after the drying process, and samples treated with USV showed lower PV values than the VD treated samples. This study suggests that USV could be used as an alternative drying method for minced meat drying due to lower drying times and higher quality parameters.


2021 ◽  
pp. 1-12
Author(s):  
T. Chaowattanakul ◽  
V.M. Khieu ◽  
C. Rojviriya ◽  
S. Siriwong ◽  
W. Jittanit ◽  
...  

This study evaluated the effects of three drying techniques, tray drying, roasting and microwave vacuum drying, on the physical properties, secondary structures, in vitro protein digestibility and X-ray tomographic structure of crickets (Acheta domesticus) and mulberry silkworm pupae (Bombyx mori L.). The protein contents of dried crickets and silkworm pupae were 49-54% and 51-53% (dry basis), respectively. Roasting produced a significantly higher browning index than the other two methods for crickets and silkworm pupae. The microwave vacuum-dried crickets exhibited the lowest hardness, with hardness values of approximately half those of the tray-dried and roasted crickets. Tray-drying and microwave vacuum drying silkworm pupae produced similar hardness values, which were lower than that of roasted silkworm pupae. The energy consumption of the tray dryer was the lowest, followed by the roaster and microwave vacuum dryer. No significant changes in the secondary protein structure of dried silkworm pupae were observed. A significant decrease in α-helix and β-turn and increase in β-sheet was observed in roasted crickets. Cricket and silkworm pupae powders produced from all drying techniques could be easily digested (90-95% digestibility). This work presents valuable knowledge for understanding the effects of different drying techniques on the properties of dried edible insects, aiming to support the production of alternative and sustainable protein sources for the growing population to improve food security.


2012 ◽  
Vol 18 (5) ◽  
pp. 477-488 ◽  
Author(s):  
Yuting Tian ◽  
Yi Zhang ◽  
Shaoxiao Zeng ◽  
Yafeng Zheng ◽  
Feng Chen ◽  
...  

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Yuan-Yuan Liu ◽  
Wei-Qiao Lv ◽  
Ruo-Hui Lin ◽  
Dong Li ◽  
Li-Jun Wang

Abstract This study was to investigate the effect of different drying methods on the drying kinetics, physical properties, and bioactivity of Platycodon grandiflorum (PG). Four drying methods were employed to conduct the dehydrated process, namely, hot air drying (AD), vacuum drying (VD), microwave hot airflow rolling-bed drying (MHARD), and pulse-spouted microwave vacuum drying (PSMVD). PSMVD showed the highest drying rate among four drying methods based on the result of fitting first-order reaction model. And PSMVD-dried product showed higher rehydration ratio and better mechanical properties, suggesting a better rehydration characteristic. In addition, considering the content of Platycodin D, PSMVD is a promising drying technology for the dehydration of PG.


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