scholarly journals Effect of Hot-Water Blanching Pretreatment on Drying Characteristics and Product Qualities for the Novel Integrated Freeze-Drying of Apple Slices

2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Hai-ou Wang ◽  
Qing-quan Fu ◽  
Shou-jiang Chen ◽  
Zhi-chao Hu ◽  
Huan-xiong Xie
Keyword(s):  
Electron Microscopy ◽  
Freeze Drying ◽  
Hot Water ◽  
The Novel ◽  
Rehydration Ratio ◽  
Drying Time ◽  
Drying Characteristics ◽  
Promising Alternative ◽  
Freeze Dried ◽  
Apple Slices

The effect of hot-water blanching (HWB) on drying characteristics and product qualities of dried apple slices with the novel integrated freeze-drying (NIFD) process was investigated by comparing with 3 different FD methods. Compared with the NIFD process without HWB pretreatment (VF-FD), the NIFD process with HWB pretreatment (HWB-VF-FD) resulted in a significantly higher mass loss and more sufficient freezing in vacuum-frozen samples, significantly higher rehydration ratio (RR), higher shrinkage ratio (SR), smaller Vitamin C (VC) content and lower hardness and better apparent shape in freeze-dried samples, and fewer change to the color of the dried or rehydrated samples (p<0.05). Compared with the conventional FD process with HWB pretreatment (HWB-PF-FD), HWB-VF-FD cost significantly less processing time and FD time and obtained significantly higher RR (p<0.05), almost the equivalent SR, VC content, and hardness, and similar appearance in dried samples. The microstructure of apple cell tissues was analyzed by transmission electron microscopy and scanning electron microscopy to interpret the above differences in drying characteristics and product qualities. The results suggested that the NIFD process of apple slices with HWB pretreatment was a promising alternative method to decrease drying time, achieve similar product quality, and simplify the process steps of the conventional FD technology.

scholarly journals ASSESSMENT OF FREEZING PRE-TREATMENTS FOR THE FREEZE DRIED OF APPLE SLICES

2013 ◽  
Vol 17 (2) ◽  
pp. 3-14 ◽  
Author(s):  
Tamás Antal ◽  
László Sikolya ◽  
Benedek Kerekes
Keyword(s):  
Water Activity ◽  
Freeze Drying ◽  
Color Difference ◽  
Freezing Rate ◽  
Slow Freezing ◽  
Drying Process ◽  
Drying Time ◽  
Freeze Dried ◽  
Apple Slices

Abstract The effect of freezing rate on the quality of dried Jonagold and Idared was studied. Apple slices underwent various pre-treatments, i.e. freezing in household freezer (freezing rate: 0,5 °C/min), contact plate freezing (2 °C/min) and vacuum-freezing (3 °C/min). The quality of the freeze dried product was then evaluated in terms of water activity, hardness, color and rehydration. The freezing in household freezer (slow freezing rate) significantly reduces the duration of the freeze drying process and consequently the process costs. The slow freezing rate allows the growth of large ice crystals at the beginning of the freeze-drying process, this fact should consequently lead to larger pores and injured cell walls and thus to shorter freeze drying time. Quality of the freezing in household freezer product was assessed as higher than the quality of the other freezing pre-treated material. Slow freezing rate resulted softer texture and higher rehydration capacity, than that of other pre-treated samples. In all cases, slow freezing lead to lower final moisture content, total color difference and water activity.

scholarly journals Evaluation of freezing pre-treatments for the lyophilisation of apple

2013 ◽  
Vol 5 (1) ◽  
pp. 56-68
Author(s):  
Tamás Antal ◽  
László Sikolya ◽  
Benedek Kerekes
Keyword(s):  
Water Activity ◽  
Freeze Drying ◽  
Ice Crystals ◽  
Freezing Rate ◽  
Slow Freezing ◽  
Drying Process ◽  
Drying Time ◽  
Freeze Dried ◽  
Apple Slices

Abstract The effect of freezing rate on the quality of dried Jonagold and Idared (Malus domestica Borkh.) was studied. Apple slices underwent various pre-treatments, i.e. freezing in household freezer (freezing speed/rate: 0,5◦C/min), contact plate freezing (2◦C/min) and vacuumfreezing (3◦C/min). The quality of the freeze-dried product was then evaluated in terms of water activity (aw), hardness, color and rehydration. The texture and color experiments were carried out with texture analyser and colorimeter. The aw of apple slices was measured by aw apparatus. It was found that drying time was influenced by freezing rate. The freezing in household freezer (slow freezing rate) significantly reduces the duration of the freeze-drying process and consequently the process costs. The slow freezing rate allows the growth of large ice crystals at the beginning of the freeze-drying process; this fact should consequently lead to larger pores and injured cell walls and thus to shorter freeze-drying time. Quality of the freezing in household freezer product was assessed as higher than the quality of the other freezing pre-treated material. Slow freezing rate resulted softer texture and higher rehydration capacity than that of other pre-treated samples. In all cases, slow freezing speed lead to lower final moisture content, total color difference and water activity. Freeze-dried samples prepared with higher freezing rates (3◦C/min) were the most white in color because small pores, originated by sublimation of small ice crystals formed by fast freezing.

Drying characteristics and product quality of whole blueberry pulp in vacuum drying process

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Lijuan Zhao ◽  
Yonghuan Li ◽  
Hui Xie ◽  
Jianliang Zhang ◽  
Zhonghua Wu
Keyword(s):  
Freeze Drying ◽  
Heating Temperature ◽  
Convective Drying ◽  
Vacuum Drying ◽  
Operating Pressure ◽  
Drying Process ◽  
Drying Time ◽  
Drying Characteristics ◽  
Freeze Dried ◽  
Monomeric Anthocyanins

Abstract A pilot-scale vacuum dryer with visualization system was used to study the drying characteristics of the whole blueberry pulp. The heating temperature, operating pressure and initial material thickness had significant effects on the drying characteristics and the retentions of total monomeric anthocyanins and vitamin C in dried blueberry powder (P < 0.05). According the heat transfer mode inside the material, the whole drying process could be divided into three periods: the boiling drying period, the convective drying period, and the conductive drying period. Most of water in the material was evaporated in the boiling and convective drying period. Considering the drying characteristics and dried product quality comprehensively, an optimal drying condition for whole blueberry pulp were: heating temperature 70 °C, operating pressure 1 kPa, and the initial material thickness 5 mm. It further compared the drying time, nutrients retention, hygroscopicity and microstructure of the product obtained by vacuum and vacuum freeze drying. The drying time of vacuum drying (1.2 h) was much shorter than that of vacuum freeze drying (44 h); the retentions of the total monomeric anthocyanins and vitamin C in dried blueberry powder of vacuum drying (67.9, 46.7%) were lower than that of vacuum freeze drying (79.0, 85.8%); while the hygroscopicity of vacuum dried powder was less than that of the freeze-dried product. The SEM images displayed that the surface of the vacuum-dried blueberry powder was porous, and the vacuum freeze-dried product was lamellar.

scholarly journals Effect of different drying techniques on the drying time and energy of blueberry

2021 ◽  
Vol 15 (1) ◽  
pp. 23-30
Author(s):  
Tamás Antal
Keyword(s):  
Freeze Drying ◽  
Optimal Solution ◽  
Physical Property ◽  
Vaccinium Corymbosum ◽  
Drying Methods ◽  
Rehydration Ratio ◽  
Drying Time ◽  
Hot Air ◽  
Freeze Dried ◽  
Time And Energy

Blueberries (Vaccinium corymbosum L.) were dried combining vacuum, infrared, hot-air and freeze drying technologies. In this paper, examined the drying time and energy consumption of dewatering methods. The rehydration as a physical property were evaluated in dried blueberries. Combination of vacuum dried and freeze dried blueberries had higher rehydration ratio, followed by the single freeze drying, combination of hot-air drying and freeze drying, and infrared-freeze drying methods. The performance evaluation indicated that combination drying of blueberries at two-stage infrared-freeze drying with 60°C and 15 min pre-drying reduced the drying time by 53.4%, besides consuming less energy (52.9%) compared to single freeze drying. Based on the results, primarily vacuum pre-drying, infrared pre-drying and freeze finish-drying may be the economical and optimal solution for dehydrating blueberries.

Scanning Electron Microscopy-cuticular Lesions on the Roundworm Ascaris Suum

1970 ◽  
Vol 28 ◽  
pp. 114-115
Author(s):  
P. A. Madden ◽  
W. R. Anderson
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Freeze Drying ◽  
Room Temperature ◽  
Secondary Electron ◽  
Distilled Water ◽  
Freeze Dried ◽  
Silver Paint ◽  
To Come ◽  
Scanning Electron

The intestinal roundworm of swine is pinkish in color and about the diameter of a lead pencil. Adult worms, taken from parasitized swine, frequently were observed with macroscopic lesions on their cuticule. Those possessing such lesions were rinsed in distilled water, and cylindrical segments of the affected areas were removed. Some of the segments were fixed in buffered formalin before freeze-drying; others were freeze-dried immediately. Initially, specimens were quenched in liquid freon followed by immersion in liquid nitrogen. They were then placed in ampuoles in a freezer at −45C and sublimated by vacuum until dry. After the specimens appeared dry, the freezer was allowed to come to room temperature slowly while the vacuum was maintained. The dried specimens were attached to metal pegs with conductive silver paint and placed in a vacuum evaporator on a rotating tilting stage. They were then coated by evaporating an alloy of 20% palladium and 80% gold to a thickness of approximately 300 A°. The specimens were examined by secondary electron emmission in a scanning electron microscope.

scholarly journals The Quality of Red Bell Pepper Subjected to Freeze-Drying Preceded by Traditional and Novel Pretreatment

Foods ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 226
Author(s):  
Katarzyna Rybak ◽  
Artur Wiktor ◽  
Dorota Witrowa-Rajchert ◽  
Oleksii Parniakov ◽  
Małgorzata Nowacka
Keyword(s):  
Freeze Drying ◽  
Bell Pepper ◽  
Total Phenolic ◽  
Thermal Methods ◽  
Drying Time ◽  
Freeze Dried ◽  
Dehydration Processes ◽  
Vacuum Freezing ◽  
Better Than

It has been demonstrated previously in the literature that utilization of PEF or a combination of a pulsed electric field (PEF) and ultrasounds (US) can facilitate dehydration processes and improve the quality of dried products even better than the application of thermal methods such as blanching. The aim of the study was to evaluate the quality of red bell pepper subjected to freeze-drying preceded by blanching or PEF or US treatment applied in a single and combined mode. Furthermore, the freeze-drying was preceded by shock freezing or vacuum freezing performed inside the freeze-dryer as a result of pressure drop during the first stage of freeze-drying. All of the analyzed technological variants enhanced the drying kinetics when compared to the intact material. Freeze-dried bell pepper subjected to non-thermal pretreatment exhibited higher vitamin C, total phenolic and carotenoids content than blanched material despite the fact that blanching reduced drying time the most compared to all other analyzed methods.

Study on a Combination Drying Technique of Shrimp

2012 ◽  
Vol 260-261 ◽  
pp. 804-807
Author(s):  
Ya Xiang Bai ◽  
Yu Cai Hu ◽  
Qiang Huang
Keyword(s):  
Freeze Drying ◽  
Sensory Properties ◽  
Drying Rate ◽  
Rehydration Ratio ◽  
Drying Time ◽  
Air Drying ◽  
Combined Process ◽  
Highly Efficient ◽  
Sensory Qualities

In order to develop a highly efficient drying technique for shrimp, a combination of air drying (AD) and vacuum freeze drying (FD) is examined. The drying rate of combination drying, the shrinkage, rehydration ratio, and sensory properties, such as the color and trimness, of the dried product in the AD–FD method are measured. Compared with FD, the combined process consumes less drying time, compared with AD drying alone. Also the product processed by combined drying displays lower shrinkage, higher rehydration rate and better sensory qualities.

scholarly journals Effects of Assistance of High Frequency Dielectric and Infrared Heating on Vacuum Freeze Drying Characteristics of Food Model

2018 ◽  
Author(s):  
Atsushi Hashimoto ◽  
Ken-ichiro Suehara ◽  
Takaharu Kameoka ◽  
Kazuhiko Kawamura
Keyword(s):  
Electromagnetic Wave ◽  
Sodium Chloride ◽  
High Frequency ◽  
Freeze Drying ◽  
Infrared Heating ◽  
Drying Time ◽  
Drying Characteristics ◽  
Additive Component ◽  
Wave Heating ◽  
Food Model

By combining vacuum freeze drying combined with high-frequency dielectric and/or infrared heating, the drying time for frozen gels containing 1% agar with sucrose or sodium chloride was successfully shorten, and the drying time was influenced by the heating methods and by the additive component to the sample. Additionally, it was experimentally confirmed that the power consumption for freeze drying combined with electromagnetic wave heating could be reduced because of the shortened drying time. Consequently, this study could be a very important step for designing a vacuum freeze drying process optimally combining electromagnetic wave heating for each sample component.Keywords: freeze drying, electromagnetic wave heating, food model, sucrose, sodium chloride

scholarly journals Fortified and freeze-dried kiwi fruit (Actinidia deliciosa): quality and sensory assessment

2020 ◽  
Vol 23 ◽  
Author(s):  
Niladri Chakraborty ◽  
Rajat Chakraborty ◽  
Asit Kumar Saha
Keyword(s):  
Moisture Content ◽  
Freeze Drying ◽  
Raw Materials ◽  
Food Product ◽  
Rice Flour ◽  
Actinidia Deliciosa ◽  
Crude Fibre ◽  
Kiwi Fruit ◽  
Drying Time ◽  
Freeze Dried

Abstract Kiwi fruit (Actinidia deliciosa) (KF) is one of the best fruits available due to its large amount of nutrients. Despite its many health benefits, there are no previous reports on its preparation in other readily ingestible forms. The objective of the present study was to make a new food product from KF. The KF pulp was fortified and blended with several raw materials (such as rice flour and oat flour) using a stepwise short time addition and mixing methodology since this avoids unwanted biochemical and chemical reactions. The blended and reduced moisture KF paste was freeze-dried on a round silver coated steel plate (RSCSP), supplying the heat of sublimation using a newly designed cubic heater. The freeze-drying (FD) time was 4.5 h and the drying kinetics were studied using four established models. The effective moisture diffusivity (Deff) during FD (at 50 °C) was 1.532 x 10-6 m2/s and the activation energy (E) estimated for the FD was 28.35 kJ/mol. The freeze-dried sample was ground and placed under vacuum to reduce the weathering effects. The quality of the stored product was evaluated using the proximate analysis, physicochemical analysis and a sensory evaluation using a hedonic scale. The raw, fresh KF had a moisture content of 85.07% and the final freeze-dried product one of 3%. The carbohydrate, total sugar, protein, fat, total ash, crude fibre and vitamin C contents of the final product increased by 563%, 400%, 355%, 386%, 672%, 106%, and 117% respectively. Of the 66 panelists, the % consumer acceptances for the different attributes were: sweetness (68.18%), sourness (90.91%), saltiness (100%), bitterness (100%), flavour (95.45%), texture (77.27%) and overall acceptability (81.82%). Using conventional freeze-drying (CFD) for blended KF pulp without fortification, with the same RSCSP and the same cubic heater for sublimation, the drying time was found to be 7 h to reach the same final moisture content of 3%.

scholarly journals Examination of physical properties of final product and drying properties of combined (convective pre-drying and freeze finish-drying) dehydration method

2014 ◽  
pp. 5-12
Author(s):  
Tamás Antal
Keyword(s):  
Freeze Drying ◽  
Operating Conditions ◽  
Small Scale ◽  
Case Hardening ◽  
Degree Polynomial ◽  
Hot Air Drying ◽  
Drying Time ◽  
Drying Characteristics ◽  
Hot Air ◽  
Drying Properties

In this study, the effects of freeze drying (FD), hot-air drying (HAD) and combined drying (HAD-FD) on drying characteristics, energy uptake, texture, rehydration and color of carrot were investigated. Results showed that HAD-FD significantly improved the drying time compared with FD under the same operating conditions, and the HAD-FD can reduce the total cost of dehydration. The drying kinetics was described by the Henderson-Pabis and the third degree polynomial models in the case of HAD, FD and HAD-FD. The HAD carrot samples were exhibited shrinkage, case hardening, poor rehydration and brown surface. The FD carrot cubes appeared porous structure, excellent rehydration, soft texture and loose color. The HAD-FD samples were superior to HAD products and was nearer in quality to FD products with respect to appearance, rehydration and surface resistance (texture). Finally, it is concluded that HAD-FD is effective in improving the FD drying rate. However, the combined drying has a small-scale adverse effect on product quality.

Sign in / Sign up

Export Citation Format

Share Document