scholarly journals Impact of shelf temperature on freeze-drying process and porosity development

2018 ◽  
Author(s):  
M. M. Camacho ◽  
L. A. Egas-Astudillo ◽  
A. Silva ◽  
M. Uscanga ◽  
N. Martínez-Navarrete
Keyword(s):  
Freeze Drying ◽  
Room Temperature ◽  
Gum Arabic ◽  
Drying Kinetics ◽  
Drying Process ◽  
Drying Time ◽  
Lower Porosity ◽  
The Impact ◽  
Shelf Temperature ◽  
Porosity Development

The freeze-drying kinetics and the superficial porosity development of grapefruit puree. The impact of biopolymers addition (gum Arabic and bamboo fiber) and to apply (40 ºC) or not shelf temperature (room temperature) was considered. To increase the shelves temperature during freeze-drying allowed to an important drying time reduction and doesn’t supposed a lower porosity related to the collapse development of the structure. Biopolymers do not affect the drying kinetics. From this results, biopolymers addition and to heat at least up to 40 ºC during grapefruit freeze-drying should be recommended. Keywords: freeze-drying; shelf temperature; drying kinetics; image analysis; pore size distribution.

scholarly journals Impact of the Freeze-Drying Conditions Applied to Obtain an Orange Snack on Energy Consumption

Foods ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 2756
Author(s):  
Marilú Andrea Silva-Espinoza ◽  
María del Mar Camacho ◽  
Javier Martínez-Monzó ◽  
Nuria Martínez-Navarrete
Keyword(s):  
Energy Consumption ◽  
Freeze Drying ◽  
Gum Arabic ◽  
Economic Cost ◽  
Added Value ◽  
Process Conditions ◽  
Drying Time ◽  
Freeze Dried ◽  
Secondary Drying ◽  
The Impact

Nowadays, the consumer is looking for healthier, more attractive, ready-to-eat, and safer foodstuffs than fresh products. Despite freeze drying being known for providing high added value products, it is a slow process which is conducted at low pressures, so, in terms of energy consumption, it turns out to be quite costly for the food industry. With the purpose of obtaining a freeze-dried orange puree, previously formulated with gum Arabic and bamboo fiber, which can be offered to consumers as a snack at a low economic cost, the impact of the process conditions on energy consumption has been considered. The product temperature evolution and the energy consumption were registered during the drying of frozen samples at different combinations of chamber pressures (5 and 100 Pa) and shelf temperatures (30, 40 and 50 °C). In each case, the time processing was adapted in order to obtain a product with a water content under 5 g water/100 g product. In this study, the secondary drying stage was considered to start when the product reached the shelf temperature and both the pressure and the temperature affected the duration of primary and secondary drying stages. The results obtained led to the conclusion that the shorter duration of the process when working at 50 °C results in significant energy saving. Working at a lower pressure also contributes to a shortening of the drying time, thus reducing the energy consumption: the lower the temperature, the more marked the effect of the pressure.

scholarly journals Studies on the Catalytic Properties of Crude Freeze-Dried Preparations of Yarrowia lipolytica Extracellular Lipases for Geranyl Ester Derivative Synthesis

Biomolecules ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 839
Author(s):  
Karina Jasińska ◽  
Bartłomiej Zieniuk ◽  
Dorota Nowak ◽  
Agata Fabiszewska
Keyword(s):  
Freeze Drying ◽  
Antioxidant Properties ◽  
Antibacterial Properties ◽  
Synthetic Activity ◽  
Drying Process ◽  
Enzyme Preparations ◽  
Ester Derivative ◽  
Freeze Dried ◽  
The Impact ◽  
Geranyl Ester

The study aimed to evaluate the impact of selected factors of the freeze-drying process on the hydrolytic and synthetic activity of the extracellular lipases of Y. lipolytica KKP 379 and to attempt the use of the crude enzyme preparation as a biocatalyst in the synthesis of geranyl 4-hydroxyphenylpropanoate. Antioxidant and antibacterial properties of the geranyl ester derivative were also investigated in order to evaluate their usefulness as a novel food additive. The studies confirmed that freeze-drying was an effective method of dehydrating yeast supernatant and allowed for obtaining lyophilizates with low water activity from 0.055 to 0.160. The type and concentration of the additive (2–6% whey protein hydrolyzate, 0.5% and 1% ammonium sulphate) had a significant effect on the hydrolytic activity of enzyme preparations, while the selected variants of drying temperature during the freeze-drying process were not significant (10 °C and 50 °C). Low yield of geranyl 4-hydroxyphenylopropionate was shown when the lyophilized supernatant was used (5.3%), but the yield of ester synthesis increased when the freeze-dried Y. lipolytica yeast biomass was applied (47.9%). The study confirmed the antioxidant properties of the synthesized ester by the DPPH• and CUPRAC methods, as well as higher antibacterial activity against tested bacteria than its precursor with 0.125 mM MIC (minimal inhibitory concentration) against L. monocytogenes.

Experimental Evaluation and Kinetic Analysis of Direct-Contact Ultrasonic Fabric Drying Process

2020 ◽  
Vol 13 (2) ◽  
Author(s):  
Chang Peng ◽  
Saeed Moghaddam
Keyword(s):  
Direct Contact ◽  
Ultrasonic Transducer ◽  
Gaussian Model ◽  
Weibull Model ◽  
Drying Kinetics ◽  
Energy Prices ◽  
Drying Process ◽  
Liquid Form ◽  
Drying Time ◽  
Kinetics Of

Abstract Over the past two decades, due to the rising energy prices and growing awareness about climate change, significant efforts have been devoted to reducing the energy consumption of various home appliances. However, the energy efficiency of clothes dryers has little improvement. Recent innovations in the direct-contact ultrasonic fabric drying technique offer new opportunities for energy saving. In this technique, high-frequency mechanical vibrations generated by the ultrasonic transducer are utilized to atomize water from a fabric in the liquid form, which demonstrates great potential for reducing energy use and drying time of the fabric drying process. Here, for the first time, fabric drying kinetics under different direct-contact ultrasonic drying conditions were investigated experimentally and analytically. The drying processes of four kinds of fabrics were experimentally tested under different ultrasonic transducer vibration frequency (115, 135, and 155 kHz) and input power (1.2, 2.5, and 4.4 W) conditions. According to the experimental data, five different kinds of models were applied to quantify the drying kinetics of fabrics during direct-contact ultrasonic drying. The models not only incorporated the transducer parameters but also the parameters related to the nature of fabric. Our evaluation results of model prediction performance demonstrated that the two empirical models, i.e., the Weibull model and the Gaussian model, were superior to the three semi-theoretical models for anticipating the drying kinetics of fabrics under direct-contact ultrasonic drying. Furthermore, the Weibull model is more suitable for practical energy-efficient direct-contact ultrasonic fabric drying applications compared with the Gaussian model.

scholarly journals Scientific Analysis and Conservation of Waterlogged Woods Excavated from Suyoeng-ri Site, Hwaseong, Korea

2021 ◽  
Vol 37 (5) ◽  
pp. 579-589
Author(s):  
Kwang-Hee Lee ◽  
Jeong-Eun Oh ◽  
Soo-Chul Kim
Keyword(s):  
Freeze Drying ◽  
Room Temperature ◽  
Manufacturing Processes ◽  
Drying Method ◽  
Manufacturing Method ◽  
Neolithic Age ◽  
Scientific Analysis ◽  
Morus Spp ◽  
The Neolithic Age ◽  
Shelf Temperature

Five waterlogged wood artefacts were excavated from Suyeong-ri site in Hwaseong, South Korea. The aim of the present study was to identify the species and estimate the date of manufacture and the manufacturing method of these artefacts. The study also aimed to conserve the original shapes of waterlogged wood artefacts by using the vacuum freeze drying method. The two large waterlogged woods were identified as Ulmus spp. and Morus spp., whereas one of the three small waterlogged woods was identified as Abies spp. and the other two as hard pine. Radiocarbon dating using wiggle match dated the manufacturing of these wooden artefacts between BCE 8520-8490 or BCE 8470-8290 in the Neolithic age, and a similar period was also confirmed for seed excavated from a place close to the location where the waterlogged wood artefacts were excavated. The surface of waterlogged wood artefacts had several traces of manufacturing processes - traces of tearing and chopping - were observed. Based on these observations, it was confirmed that stone adz was used to make these wooden artefacts. Thereafter, the waterlogged wood samples were conserved by immersing them into PEG#4,000 of concentration in water from 10% to 40% at room temperature(15~25℃) and subjecting them to vacuum freeze drying. However, the internal moisture was not completely removed in some thick parts of waterlogged woods by applying the general schedule such as raising the shelf temperature as the surface temperature rises. Therefore, additional study is required using the schedule-method for vacuum freeze drying of large waterlogged wood.

scholarly journals Study and optimization of freeze-drying cycles of a model probiotic strain

2018 ◽  
Author(s):  
Pierre Verlhac ◽  
Séverine Vessot-Crastes ◽  
Ghania Degobert ◽  
Claudia Cogné ◽  
Julien Andrieu ◽  
...  
Keyword(s):  
Experimental Study ◽  
Survival Rate ◽  
Lactobacillus Casei ◽  
Freeze Drying ◽  
Survival Rates ◽  
Probiotic Strain ◽  
Porous Matrix ◽  
Drying Process ◽  
The Matrix ◽  
The Impact

This work is based on the experimental study of the freeze-drying process to understand the impact of numerous factors on the survival rates of a model probiotic strain of Lactobacillus casei type. With the aim to find out if cell density in the matrix and survival rates are linked, we have studied the location of the cells after freeze drying inside a porous  matrix composed of a lactose basis with a polymer, the polyvinylpyrrolidone (PVP) in various amounts. The best survival rate were obtained at slow freezing rate for a formulation containing 5% (m/V) of lactose and 5% (m/V) of PVP. Keywords: Freeze-Drying; Freezing; Probiotics; L. Casei ATCC 393 

scholarly journals Study of vacuum and freeze drying of bee honey

2020 ◽  
Vol 24 (6 Part B) ◽  
pp. 4241-4251
Author(s):  
Nebojsa Nedic ◽  
Milan Gojak ◽  
Ivan Zlatanovic ◽  
Nedzad Rudonja ◽  
Kristina Lazarevic ◽  
...  
Keyword(s):  
Water Activity ◽  
High Performance ◽  
Freeze Drying ◽  
Soluble Solids ◽  
Diffusivity Coefficient ◽  
Chromatography Method ◽  
Drying Time ◽  
Freeze Dried ◽  
Acacia Honey ◽  
The Impact

The aim of this research is to study the drying kinetics of vacuum-dried and freeze-dried bee honey produced from two different varieties: Sunflower honey (Helianthus Annuus L.) and Acacia honey (Robinia pseudo acacia L.). Vacuum drying treatments were carried out with the honey samples? initial temperatures of +25?C, ?20?C, and ?40?C. Water content, total soluble solids, as well as the water activity of fresh and dried honey samples were determined. Freeze-drying of bee honey with initial sample temperature of ?40?C has resulted in shorter drying time (7-9 hours), moisture content (10%-12%), water activity (0.405-0.427 aW) and effective moisture diffusivity coefficient (8.26?10?7-9.51?10-7 m2/s). The high-performance liquid chromatography method was used when analyzing the impact that drying pre-treatments had on honey quality. The application of pre-treatments has led to an increase in hydroxy-methyl-furfural by 39-71%, and a decrease in diastase activity by 17-36%, all compared to fresh honey samples. The solutions of Verma model proved to be the best fit with the experimental results.

Development of a Compact Vacuum Freeze Drying for Jelly Fish (Schypomedusae)

2012 ◽  
Vol 58 (2) ◽  
Author(s):  
M. Idrus Alhamid ◽  
M. Yulianto ◽  
Nasruddin M. ◽  
Engkos A. Kosasih
Keyword(s):  
Heat Loss ◽  
Freeze Drying ◽  
Moisture Ratio ◽  
Cold Trap ◽  
Chamber Pressure ◽  
Internal Cooling ◽  
Drying Process ◽  
Drying Time ◽  
Chamber Temperature ◽  
Drying Chamber

A new design of a vacuum freeze drying with internal cooling and heater from condenser’s heat loss was built and tested. The dryer was used to dry jelly fish (scyphomedusae) to study the effect of drying parameter such as temperature within the drying chamber on mass losses (evaporation) during freezing stage and moisture ratio at the end of drying process and also the drying rate of vacuum drying process. The cold trap temperature rise in when activated the heating from condenser’s heat loss. The midili thin layer mathematical drying model was used to estimate and predict the moisture ratio curve base on different drying chamber temperature. The result of this experiment show that mass loss during freezing stage decreased with a decrease in drying chamber temperature with constant pressure. Drying time reduced with an increase in drying temperature. Drying chamber temperature decreasing has a result pressure saturation of material lower than drying chamber pressure have an effect mass transfer should not occurs.

scholarly journals Effect of Freeze-Drying on Quality and Grinding Process of Food Produce: A Review

Processes ◽  
2020 ◽  
Vol 8 (3) ◽  
pp. 354 ◽  
Author(s):  
Timilehin Martins Oyinloye ◽  
Won Byong Yoon
Keyword(s):  
Glass Transition ◽  
Freeze Drying ◽  
Structural Changes ◽  
Morphological Changes ◽  
Energy Requirement ◽  
Quality Attributes ◽  
Processing Unit ◽  
Drying Process ◽  
Drying Time ◽  
Freeze Dried

Freeze-drying is an important processing unit operation in food powder production. It offers dehydrated products with extended shelf life and high quality. Unfortunately, food quality attributes and grinding characteristics are affected significantly during the drying process due to the glass transition temperature (during drying operation) and stress generated (during grinding operation) in the food structure. However, it has been successfully applied to several biological materials ranging from animal products to plants products owning to its specific advantages. Recently, the market demands for freeze-dried and ground food products such as spices, vegetables, and fruits are on the increase. In this study, the effect of the freeze-drying process on quality attributes, such as structural changes, the influence of glass transition during grinding, together with the effect on grinding efficiency in terms of energy requirement, grinding yield, and morphological changes in the powder as a result of temperature, drying time were discussed. An overview of models for drying kinetics for freeze-dried food sample, and grinding characteristics developed to optimize the drying processes, and a prediction of the grinding characteristics are also provided. Some limitations of the drying process during grinding are also discussed together with innovative methods to improve the drying and grinding processes.

scholarly journals The preservation of bacteriophage H1 of Corynebacterium ulcerans U 103 by freeze-drying

1969 ◽  
Vol 67 (4) ◽  
pp. 573-583 ◽  
Author(s):  
J. D. Davies ◽  
M. J. Kelly
Keyword(s):  
Freeze Drying ◽  
Room Temperature ◽  
Freezing Damage ◽  
Drying Process ◽  
Initial Sample ◽  
Corynebacterium Ulcerans ◽  
Sucrose Solutions ◽  
Rate Of Cooling ◽  
Logarithmic Relationship ◽  
Marked Drop

SUMMARYThis paper describes an investigation into the successful preservation at room temperature of the bacteriophage H1 of Corynebacterium ulcerans U 103 which was extremely labile when in suspension at 4° C.Cooling at a rate of 1° C./min. showed that the survival decreased logarithmically at temperatures between – 14 and – 45° C. Survival of broth suspensions of the corynebacteriophage were found to increase proportionally with an increase in the rate of cooling though there was a marked drop in survival at rates of approximately 900° C./min. The addition of peptone solutions was found to increase the survival over the range studied, whereas the addition of sucrose solutions had only a slight effect.By avoiding freezing damage by cooling at rates of 450° C./min. in (a) 20% peptone solution, (b) 20% peptone and 10% sucrose, and (c) 20% peptone, 10% sucrose and 2% sodium glutamate, a study was made of the drying stage of the freeze-drying process. On drying at controlled temperatures it was found that there was no damage on rewarming to temperatures below – 21° C. after cooling to – 196° C., but that the survival immediately after drying in the absence of glutamate, showed a logarithmic relationship with the temperature of drying, lower temperatures giving better survival.On storage for a period of 3 months at room temperature in vacuo and darkness, there was no appreciable loss in survival in the mixtures though suspensions in peptone alone showed a slight decrease. At higher temperatures this decrease in survival could be differentiated into two types of damage, each of which could be influenced by the presence of sucrose or glutamate.We are grateful to Professor H. R. Carne for providing the initial sample of bacteriophage H 1 of Corynebacterium ulcerans U 103, and to Professor R. I. N. Greaves for his interest and encouragement during the course of this investigation.

Parameter Optimization of Vacuum Freeze-Drying Processing on Tan Lamb

2014 ◽  
Vol 513-517 ◽  
pp. 4281-4284
Author(s):  
Chen Ji ◽  
Yan Li Fan ◽  
Gui Shan Liu ◽  
Wei Wang ◽  
Rui Ming Luo
Keyword(s):  
Freeze Drying ◽  
Orthogonal Design ◽  
Chamber Pressure ◽  
Drying Process ◽  
Quadratic Regression ◽  
Plate Temperature ◽  
Drying Time ◽  
Material Thickness ◽  
Heating Plate ◽  
Drying Chamber

In this paper, the effects of drying chamber pressure, heating plate temperature and material thickness on the drying time of Tan lamb in vacuum freeze-drying process were studied using quadratic regression orthogonal design. The results showed that the drying time was significantly affected by drying chamber pressure, heating plate temperature and material thickness as well as the interaction of heating plate temperature and material thickness. The optimized parameters were drying chamber pressure 27.9 Pa, heating plate temperature 47.9°C and material thickness 4.3 mm. On these parameters, the drying time was 4.3 h.

Sign in / Sign up

Export Citation Format

Share Document