EFFECT OF FREEZE-DRYING ON THE SURFACE PROPERTIES OF SOILS AS MEASURED BY THE HEAT OF IMMERSION

1971 ◽  
Vol 51 (2) ◽  
pp. 229-233 ◽  
Author(s):  
FREDERICK BISAL ◽  
W. L. PELTON
Keyword(s):  
Moisture Content ◽  
Soil Properties ◽  
Surface Properties ◽  
Freeze Drying ◽  
Physical Effect ◽  
Dry Process ◽  
Heat Of Immersion ◽  
Freeze Dried ◽  
Integral Heat

The integral heat of immersion was determined for three textural classes of soils which had been freeze-dried, air-dried, oven-dried, alternately frozen and thawed and then freeze-dried, alternately frozen and thawed and then air-dried, alternately frozen and thawed and then oven-dried, and freeze-dried and then oven-dried. There were highly significant differences in the heat of immersion as a result of texture. The significant differences found in the various drying treatments could only be attributed to moisture content at the time of immersion. The physical effect of the freeze-dry process is transient and it does not alter the inherent soil properties with respect to clod formation.

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 Effect of Size and Drying Time on the Rehydration and Sensory Properties of Freeze-Dried Snails (Achatina achatina)

2020 ◽  
Vol 2020 ◽  
pp. 1-5
Author(s):  
Matthew A. Achaglinkame ◽  
Eric Owusu-Mensah ◽  
Abena A. Boakye ◽  
Ibok Oduro
Keyword(s):  
Moisture Content ◽  
Nutritional Value ◽  
Freeze Drying ◽  
Consumer Preference ◽  
Sensory Properties ◽  
Temperature Dependent ◽  
Drying Time ◽  
Standard Methods ◽  
Freeze Dried ◽  
Hedonic Scale

Snails, a delicacy in most tropical communities, are highly perishable and seasonal. Employed preservative methods are highly temperature dependent, adversely affecting their nutritional value and sensory properties. This study was aimed at determining the effect of size and drying time on the rehydration and sensory properties of freeze-dried snails. Snails were sized into three categories with average weights: 7.59 g (quarter-sized), 14.41 g (half-sized), and 30.71 g (whole), and freeze-dried for 15, 20, and 25 h. The moisture content and percent rehydration of the dried samples were determined by standard methods and sensory properties assessed by an in-house panel of 30 using a 5-point hedonic scale. The moisture content of the fresh and freeze-dried samples ranged from 65.80 to 75.20% and 3.25 to 10.24%, respectively. Freeze-dried samples had higher percent rehydration (27 to 102%) than the control; smoked snails (21 to 32%). Size had a significant (P<0.05) effect on the rehydration ability of the samples with the half-sized and freeze-dried for 15 h samples having the highest. The freeze-dried samples generally had higher consumer preference than the control in all attributes assessed. The findings show that freeze-drying snails (approximate weight of 14.4 g) for 15 h could be a consumer-preferred alternative preservative method for extending the shelf life of snails.

scholarly journals Optimised Extraction of Trypsin Inhibitors from Defatted Gac (Momordica cochinchinensis Spreng) Seeds for Production of a Trypsin Inhibitor‐Enriched Freeze Dried Powder

Separations ◽  
2019 ◽  
Vol 6 (1) ◽  
pp. 8 ◽  
Author(s):  
Anh V. Le ◽  
Sophie E. Parks ◽  
Minh H. Nguyen ◽  
Paul D. Roach
Keyword(s):  
Moisture Content ◽  
Freeze Drying ◽  
Trypsin Inhibitors ◽  
Seed Kernel ◽  
Solvent Ratio ◽  
Optimal Conditions ◽  
High Solubility ◽  
High Quality ◽  
Freeze Dried ◽  
Momordica Cochinchinensis

The seeds of the Gac fruit, Momordica cochinchinensis Spreng, are rich in trypsin inhibitors (TIs) but their optimal extraction and the effects of freeze drying are not established. This study aims to (1) compare aqueous solvents (DI water, 0.1 M NaCl, 0.02 M NaOH and ACN)/water/FA, 25:24:1) for extracting TIs from defatted Gac seed kernel powder, (2) to optimise the extraction in terms of solvent, time and material to solvent ratio and (3) to produce a TI-enriched freeze-dried powder (FD-TIP) with good characteristics. Based on the specific TI activity (TIA), the optimal extraction was 1 h using a ratio of 2.0 g of defatted powder in 30 mL of 0.05 M NaCl. The optimisation improved the TIA and specific TIA by 8% and 13%, respectively. The FD-TIP had a high specific TIA (1.57 ± 0.17 mg trypsin/mg protein), although it also contained saponins (43.6 ± 2.3 mg AE/g) and phenolics (10.5 ± 0.3 mg GAE/g). The FD-TIP was likely stable during storage due to its very low moisture content (0.43 ± 0.08%) and water activity (0.18 ± 0.07) and its ability to be easily reconstituted in water due to its high solubility index (92.4 ± 1.5%). Therefore, the optimal conditions for the extraction of TIs from defatted Gac seed kernel powder followed by freeze drying gave a high quality powder in terms of its highly specific TIA and physical properties.

scholarly journals Determination of shelf-life using accelerated shelf-life testing (ASLT) method and characterization of the flavour components of freeze-dried durian (Durio zibethinus) products

Food Research ◽  
2021 ◽  
Vol 5 (S2) ◽  
pp. 98-106
Author(s):  
S. Darniadi ◽  
D.D. Handoko ◽  
S. Sunarmani ◽  
S. Widowati
Keyword(s):  
Moisture Content ◽  
Shelf Life ◽  
Volatile Compounds ◽  
Freeze Drying ◽  
Solid Phase ◽  
Gas Chromatography Mass Spectrometry ◽  
Life Testing ◽  
Tropical Fruit ◽  
Durio Zibethinus ◽  
Freeze Dried

Durian is a unique tropical fruit that has a strong smell and distinctive taste. It is a seasonal fruit and has a few days shelf-life. Freeze drying is known for preserving foods while maintaining its original shape and provide excellent rehydrated products. This study aimed to determine the shelf-life of freeze-dried (FD) durian products using the accelerated shelf-life testing (ASLT) method and to assess the flavour changes in fresh and freeze-dried durian products. The parameters used to determine shelf-life were moisture content and L* a* b* colour values of FD durian products for 28 days of storage at 30, 40, and 50oC. Flavour analysis using Solid Phase Microextraction (SPME) and Gas Chromatography-Mass Spectrometry (GCMS) was carried out on fresh durian pulp, FD durian for 30 hrs, and FD durian for 36 hrs. The estimation of shelf-life of FD durian products at storage temperatures of 25 and 30oC, respectively, were based on the following parameters: (1) moisture content: 41 and 37 days, (2) L*(brightness): 467 and 311 days, (3) a* (redness): 144 and 171 days, and (4) b*(yellowness): 43 and 46 days. A total of twenty-four volatile compounds contributed to the flavour of fresh durian fruit and five of them had concentrations of more than 10 ppm. The losses percentage of these five volatile compounds were in a range of 78-95% (FD durian for 30 hrs) and a range of 0- 100% (FD durian for 36 hrs). Freeze-drying technique on durian was able to extend shelflife and preserve flavour compounds.

scholarly journals Proximate Analysis of Goat Milk Yogurt Powder Produced by Freeze Drying and Vacuum-Oven Drying and in Comparing with Freeze-Dried Yogurt Powder Prepared with Tualang Honey

2021 ◽  
Vol 12 (1S) ◽  
pp. 101-111
Author(s):  
Siti Norhannani Ahmat Azemi ◽  
Norshafiqah Zainul ◽  
Asmaliza Abd. Ghani ◽  
John Tang Yew Huat
Keyword(s):  
Moisture Content ◽  
Protein Content ◽  
Freeze Drying ◽  
Ph Value ◽  
Goat Milk ◽  
Drying Method ◽  
Vacuum Oven ◽  
Oven Drying ◽  
Freeze Dried ◽  
Tualang Honey

This study was carried out to produce powdered yogurt from goat milk with longer shelf life.Two methods of drying process of yogurt were used which are vacuum-oven drying (VD) and freezedrying (FD). Goat milk yogurt powder prepared with added Tualang honey (TH) was produced by freeze-drying method. In this study, four formulations of yogurt were prepared with the addition of commercial yogurt containingas starter culture.Granulated sugar was added about 8% into the yogurt as control sample. While other three yogurts were prepared with 8% of Tualang honey, 6% of Tualang honey with 2% of sugar and 4% of Tualang honey with 4% of sugar. The proximateanalysis was used in order to identify the proximate composition and pH value of the yogurt. The moisture content of goat milk yogurt, VD goat yogurt powder and FD goat yogurt powder were 79.20%, 8.22% and 9.66% respectively. While, the moisture content for FD goat yogurt powder with addition of 4%, 6% and 8% Tualang honey were 15.12%,15.92% and 13.53% respectively.While the value of ash content for FD goat milk yogurt powder with addition of 4%, 6% and 8% Tualang honey were 0.37%, 0.35% and 0.50% respectively. The total protein content for goat milk yogurt was 4.61% whilein VD goat yogurt powder and FD goat yogurt powder were 15.04% and 15.07% respectively. The value of protein content for FD goat milk yogurt powder with addition of 8% of Tualang honey was 15.38%. The pH value ofgoat milk sample and fresh yogurt goat milk were 6.52 and 3.82. The pH values for fresh yogurt with addition of 4%, 6% and 8% of Tualang honey were 4.64, 4.68 and 4.73.Vacuum-oven drying method and freeze-drying method did not show any significant different in moisture, ash and protein content but showed significant different in pH value.

scholarly journals Enhanced Microencapsulation of C-Phycocyanin from Arthrospira by Freeze-Drying with Different Wall Materials

2020 ◽  
Vol 58 (4) ◽  
Author(s):  
Wanida Pan-utai ◽  
Siriluck Iamtham
Keyword(s):  
Thermal Stability ◽  
Antioxidant Activity ◽  
Moisture Content ◽  
Water Activity ◽  
Freeze Drying ◽  
Antioxidant Properties ◽  
Gum Arabic ◽  
Water Soluble ◽  
Freeze Dried ◽  
Wall Materials

Research background. C-phycocyanin (C-PC) as a water-soluble blue pigment was extracted from microalga Arthrospira. C-PC could be a good substitute for synthetic pigments with high antioxidant activity. However, C-PC is unstable due to sensitivity to temperature, light, pH, and oxygen; therefore applications of C-PC in food and other products are limited. Microencapsulation of C-PC using freeze-drying is a solution to this problem and is considered a suitable method for drying heat-sensitive pigment. Experimental approach. C-phycocyanin was extracted from Arthrospira platensis. C-phycocyanin microcapsules were modified by freeze-drying, with different ratios at 0-100 % of maltodextrin (MD) and gum Arabic (GA) used as microencapsulation wall materials. The powders produced were evaluated for physical properties including moisture content and water activity, solubility, hygroscopicity, bulk density, colour appearance, particle morphology and size distribution. Thermal stability and antioxidant activity of freeze-dried C-PC microencapsulated powders were also assessed. Results and conclusions. Freeze-dried C-PC microencapsulated powders with maltodextrin and gum Arabic as wall materials gave high encapsulation efficiency of around 99 %. At higher gum Arabic percentage, moisture content decreased and water activity improved. Maltodextrin gave higher solubility of C-PC powders whereas gum Arabic led to a similar colour of C-PC without microencapsulation. Freeze-dried C-PC microencapsulated powders were composed of different sized microparticles regardless of the combination of wall materials with amorphous glassy shapes. Thermal stability of encapsulated C-PC increased and also showed high antioxidant properties. Novelty and scientific contribution. C-PC microcapsules that maintain colourant stability with high antioxidant levels and resistance to high temperatures can be applied in a wide variety of products and also in the food industry.

scholarly journals Evaluation of freeze-drying conditions on the process kinetics and physicochemical properties of purple shallot

Food Research ◽  
2020 ◽  
Vol 4 (5) ◽  
pp. 1630-1636
Author(s):  
N.M. Thuy ◽  
N.T.M. Tuyen ◽  
N.V. Thanh ◽  
N.V. Tai
Keyword(s):  
Moisture Content ◽  
Freeze Drying ◽  
Chemical Properties ◽  
Sample Pretreatment ◽  
Freezing Temperature ◽  
Moisture Diffusivity ◽  
Freezing Time ◽  
Freeze Dried ◽  
Thin Layer Drying ◽  
Drying Conditions

Purple shallot is an important vegetable crop in Vietnam and throughout the world. Its storage is difficult hence, it is dehydrated for value addition. Freeze drying is one of the options for dehydration of purple shallot. There are two main stages (freezing and drying) in the complete freeze-drying process after sample pretreatment. In this study, the sample was frozen at different temperatures and times (-20 to -60oC and 5 to 9 hrs, respectively). Controlling the selected temperature (from the second stage) and pressure 0.001 mbar, eight thin layer drying models were fitted to the experimental moisture content. The physical and chemical properties and antioxidant capacity of freeze-dried purple shallot were evaluated. The obtained results showed that the TPC values and DPPH% almost increased as the freezing time increased at the same freezing temperature. The best drying conditions were found at a freezing time of 7 hrs, freezing temperature of -60oC, a pressure of 0.001 mbar, and a lyophilization time of 12 hrs. Under these conditions, the moisture content, TPC and DPPH% of the final product were 1.56%, 16.95 mg GAE/g and 65.67%, respectively. Among the models proposed, Page's model gave a better fit for the freeze-drying condition used. In freeze-drying, effective moisture diffusivity was estimated to be 5.68×10-7 m 2 /s within the conditions studied.

scholarly journals Novel Combined Freeze-Drying and Instant Controlled Pressure Drop Drying for Restructured Carrot-Potato Chips: Optimized by Response Surface Method

2018 ◽  
Vol 2018 ◽  
pp. 1-13 ◽  
Author(s):  
Jianyong Yi ◽  
Chunhui Hou ◽  
Jinfeng Bi ◽  
Yuanyuan Zhao ◽  
Jian Peng ◽  
...  
Keyword(s):  
Pressure Drop ◽  
Moisture Content ◽  
Response Surface ◽  
Freeze Drying ◽  
Equilibrium Temperature ◽  
Potato Chips ◽  
Freeze Dried ◽  
High Production Cost ◽  
Quality Of Products ◽  
Instant Controlled Pressure Drop

Combined freeze-drying and instant controlled pressure drop process (FD-DIC) for restructured carrot-potato chips was developed and its processing conditions were optimized using response surface methodology (RSM) with the purpose of improving the quality of products and reducing energy consumption. Three critical variables including the amount of carrot, the moisture content of the partially dried product before DIC treatment, and equilibrium temperature of DIC for the restructured chips were considered. Response parameters such as the final moisture content, color value (L, a, and b), and texture properties of restructured carrot-potato chips were investigated. The results showed that the graphical optimal ranges of FD-DIC drying process were as follows: the amount of carrot was 46–54% w/w, the moisture content of the partially dried product before DIC treatment was 0.20–0.35 g/g, and the equilibrium temperature of DIC was 85–95°C. Furthermore, the numerical optimization suggested that conditions were 47.43% w/w, 0.29 g/g, and 90.57°C, respectively. It could be concluded that the combined drying method of FD-DIC provided the restructured carrot-potato chips with higher quality, as compared to the freeze-dried chips. Considering the relatively high production cost of FD, this novel FD-DIC could be an alternative method for obtaining desirable restructured fruit and vegetable chips.

scholarly journals Production and Physical and Physicochemical Characterization Powder in Natura and Freeze-Dried of Moringa Seeds

2019 ◽  
Vol 11 (9) ◽  
pp. 11
Author(s):  
Semirames do N. Silva ◽  
Francisco de Assis C. Almeida ◽  
Josivanda P. Gomes ◽  
Antônio Jackson R. Barroso ◽  
Polyana B. Silva ◽  
...  
Keyword(s):  
Moisture Content ◽  
Water Activity ◽  
Low Temperatures ◽  
Freeze Drying ◽  
Physicochemical Characterization ◽  
High Solubility ◽  
Solubility In Water ◽  
Compressibility Index ◽  
Freeze Dried ◽  
Freeze Dryer

To apply low temperatures, different of other processes, maintain the structure of products and better preserve the thermosensitive components, the freeze-drying has called attention of various researchers. Aimed with the research to produce and characterize the powder in natura obtained by seeds of moringa, elaborate different pastes with addiction of 20, 30, 40 and 50 mL of distilled water, freeze-dry it, characterize it physical and physicochemical and select the best powder. The freeze-drying was produced through a benchtop freeze dryer. After drying it, from the powder were determined the real density, bulk density, compacted density, porosity, compressibility index, Hausner factor, hygroscopicity, solubility, color, moisture content and water activity, ashes, total acidity, pH, proteins, lipids and carbohydrates. The in natura powder was classified as non-hygroscopic, high solubility in water, low moisture content and water activity, high protein, lipids, carbohydrates and low acidity. Freeze-drying was presented as an appropriate method for the preservation of moringa constituents, with a formula selected with the addition of 50 mL of water.

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