• Title, Summary, Keyword: freeze dried

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Application of Fixatives to Freeze Dried Rose Petals

  • Jo, Myung-Hwan;Kim, Tae-Yun;Hong, Jung-Hee
    • Journal of Environmental Science International
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    • v.17 no.11
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    • pp.1227-1233
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    • 2008
  • The effect of freeze drying and fixatives in post-treating freeze drying on the morphological properties of the rose (Rosa hybrida L.) petal were investigated for the production of high quality of freeze dried rose. The morphology including form and color of the dried flowers of cut rose were depended on the drying methods. The drying time was extended due to their density and water content, and was shorter in the freeze drying than that in the natural and hot air drying. Freeze dried process for dried flowers took 2 days in a freeze dryer and did not cause shrinkage or toughening of rose petal being dried, preserving its natural shape and color. The diameter of freeze dried flowers showed little reduction compared to fresh flowers. In Hunter color values of petals of freeze dried flowers, L and a values were high and showed little variations in comparison to fresh petals. Freeze drying led to a noticeable increase in anthocyanin contents in petals, suggesting that anthocyanin contents play an important role in the acquisition of freezing tolerance. Exposure of flowers to freeze drying was accompanied by an increase in the carotenoid content. In the post-treating freeze drying, epoxy resin, a fixative, applied alone or in combination to petals of freeze dried flowers showed efficient coating for the protection from humidity and sunlight. Combined application of epoxy and acetone to freeze dried petals permitted maintenance of natural color and excellent tissue morphology, showing color stability and shiny texture in surface of petals. These findings suggest that application of fixatives to freeze dried rose petals improves the floral preservation and epoxy coating provides good quality in the freeze dried flower product.

Antioxidant Activity and Properties Characteristics of Pound Cakes Prepare using Freeze Dried Maquiberry (Aristotelia chilensis [Mol.]) Powder (냉동 동결 건조 머큐베리 분말 첨가 파운드케이크의 항산화 활성과 품질 특성)

  • Lee, Hye Jeong
    • The Korean Journal of Food And Nutrition
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    • v.27 no.6
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    • pp.1067-1077
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    • 2014
  • A study was undertaken to examine the effect of adding freeze dried maquiberry powder on the quality of pound cakes. Freeze dried maquiberry was added to the flour at a ratio of 0.5, 1, 1.5 and 2.5%. The antioxidant activity was estimated by DPPH free radical scavenging activity, the total phenolic compounds content, and flavonoid content in freeze dried maquiberry powder of pounds cakes. Antioxidative activity was highly correlated with the total phenolic and total flavonoids contents of freeze dried maquiberry powder of pound cakes (r=0.9126, p<0.001, r=0.8366, p<0.001, respectively). The quality characteristics of freeze dried maquiberry powder of poundcakes were estimated. The specific volume decreased significantly with increased substitution level of freeze dried maquiberry powder (p<0.01). The lightness significantly decreased with increased freeze-dried maquiberry powder of pound cake crust and crumb (p<0.01, p<0.01). The hardness and adhesiveness increased, while gumminess tended to reduce with increased maquiberry powder. The consumer acceptability score of 0.5~2.5% freeze dried maquiberry powder of pound cakes ranked significantly (p<0.01) higher than those of the other groups in overall preference. These results showed that freeze dried maquiberry powder is a good ingredient to increase consumer acceptability and health.

Effects of Freeze-Drying Time on Quality of Freeze-Dried Kimchi (동결건조 시간이 동결건조김치의 품질에 미치는 영향)

  • Ko, Young-Tae;Kang, Jung-Hwa
    • Korean Journal of Food Science and Technology
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    • v.34 no.1
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    • pp.91-95
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    • 2002
  • Effects of freeze-drying time on the microbiological, sensory, and other characteristics of freeze-dried kimchi were investigated to optimize freeze-drying time for kimchi. Quality attributes of freeze-dried kimchi, including number of lactic acid bacteria (LAB), pH, sensory properties, brittleness, rehydration property, moisture content, and microstructure of Chinese cabbage were observed for 24, 48 and 72 h, respectively. Number of LAB and pH of the kimchi freeze-dried for 24 h were significantly changed in comparison with those of the kimchi not freeze-dried. However, further freeze-drying did not change markedly number of LAB and pH. Overall acceptability of the sample freeze-dried for 48 of 72 h was better than that of the sample freeze-dried for 24 h. As freeze-drying time increased, brittleness of the dried sample increased, and rehydration property was improved while dried weight and moisture content of the sample decreased. In conclusion, the sample freeze-dried for 48 h was better than the sample freeze-dried for 24 or 72 h, based on sensory properties and other characteristics.

Comparative Analysis of the Physicochemical Properties of Sun-dried and Natural Cyclic Freeze-Thaw Dried Alaska Pollack

  • Kim, Jong-Hwan;Choi, Hee-Sun;Lee, Sang-Hyun;Hong, Jeong-Hwa;Kim, Jae-Cherl
    • Food Science and Biotechnology
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    • v.16 no.4
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    • pp.520-525
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    • 2007
  • The physicochemical properties of sun-dried and cyclic freeze-thaw dried Alaska pollack were analyzed to compare the 2 drying processes. The moisture content and water activity of sun-dried Alaska pollack were higher than cyclic freeze-thaw dried and 1 year-aged cyclic freeze-thaw dried Alaska pollack (hwangtae). The relatively low temperatures used in cyclic freeze-thaw drying retards lipid oxidation compared to sun drying based on the acid and peroxide values, and the levels of thiobarbituric acid-reactive substances (TBARS) in the dried fish. The water holding capacity of cyclic freeze-thaw dried Alaska pollack aged for 1 year (hwangtae) under ambient conditions at the drying location was higher than that of sun-dried Alaska pollack. The swelling of myofibrilar filaments during cyclic freeze-thaw drying may be responsible for the softening of the dried muscle protein. Aging the cyclic freeze-thaw dried Alaska pollack for 1 year contributed to an increased yellowish color of the hwangtae.

Analysis of the Components with Freeze Drying and Steam Drying of Gastrodia elata Blume (건조방법에 따른 천마의 성분 분석)

  • 신창식;박채규;이종원;이재곤;장진규;김용규
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.28 no.5
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    • pp.1058-1063
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    • 1999
  • The purpose of this study was to investigate the differences in proximate composition, free sugars, organic acids, fatty acids, amino acids, mineral components, hunter color values and calory values between freeze dried and steam dried Gastrodia elata Blume. Crude fat and crude fiber decreased during manu facture of steam dried Gastrodia elata Blume. The contents of sugars in steam dried Gastrodia elata Blume decreased during manufacture than that of freeze dried Gastrodia elata Blume. The contents of malic acid, oxalic acid, ketoglutaric acid, malonic acid and succinic acid in freeze dried were similar to those in steam dried Gastrodia elata Blume. Citric acid decreased in steam dried Gastrodia elata Blume. The contents of linoleic acid, palmitic acid and oleic acid in freeze dried were similar to those in steam dried Gastrodia elata Blume. The contents of free amino acids in steam dried Gastrodia elata Blume decreased during manufacture. The mineral component contents of the Gastrodia elata Blume were greater in the order of Mn

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Comparative Evaluation of Physicochemical Properties of Pine Needle Powders Prepared by Different Drying Methods

  • Chung, Ha-Sook;Lee, Jun Ho
    • Preventive Nutrition and Food Science
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    • v.20 no.2
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    • pp.143-147
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    • 2015
  • Systematic study of how different drying methods, namely hot-air drying, vacuum-drying, and freeze-drying, affect color, browning index, degree of rehydration, water solubility, and vitamin C content is critical for utilizing pine needle powders (PNP) as a novel ingredient in functional foods. Samples prepared by vacuum-drying showed a significantly higher $L^*$-value, whereas higher $a^*$- and $b^*$-values were detected in the hot-air dried samples (P<0.05). The browning index was significantly higher in samples prepared by vacuum-drying compared to samples prepared by freeze-drying (P<0.05). Freeze-dried PNP exhibited a significantly higher degree of rehydration than hot-air dried samples (P<0.05). Water solubilities of freeze-dried and hot-air dried samples were significantly higher than that of vacuum-dried sample (P<0.05). Vitamin C was less destroyed during freeze-drying compared to hot-air or vacuum-drying (P<0.05). Freeze-dried samples displayed a clear porous structure and appeared to have a bigger space, whereas hot-air dried samples showed lower porosity than vacuum and freeze-dried samples.

Physicochemical characteristics and sensory evaluation of bracken (Pteridium aquilinum) and Aster scaber dried by different methods (건조방법에 따른 고사리와 취나물의 이화학적 및 관능적 특성)

  • Jiang, Gui-Hun;Na, Mi Og;Eun, Jong-Bang
    • Korean Journal of Food Preservation
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    • v.23 no.6
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    • pp.819-824
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    • 2016
  • The changes in physicochemical characteristics and sensory evaluation of bracken (Pteridium aquilinum) and Aster scaber dried by different methods sun-dried, hot-air-dried and freeze-dried were investigated. The freeze-dried Aster scaber showed the lowest moisture content than those of sun-dried and hot-air-dried. Freeze-dried bracken and Aster scaber showed higher rehydration rate than sun-dried and hot-air-dried. In the color values, the freeze-dried bracken and Aster scaber had the highest $L^*$ value of 29.48 and 32.73, respectively, while freeze-dried Aster scaber showed the lowest $a^*$ value of -6.78. Rehydrated bracken and Aster scaber after freeze-dried were the highest value in $L^*$ and $b^*$, while the lowest in $a^*$ value. In sensory evaluation, freeze-dried bracken and Aster scaber showed the highest in color, appearance, flavor, texture and overall acceptability. There were no significant differences in texture between hot-air-dried bracken and freeze-dried bracken after rehydrating. However, freeze-dried bracken and Aster scaber were the highest in color, appearance, flavor and overall acceptability. In conclusion, freeze-dried bracken and Aster scaber showed the best rehydrated rate, color and sensory properties.

Changes of Strength and Stiffness of Freeze-Dried Bovine Cortical Bone according to Rehydration Time in Electrolyte Solution (동결건조한 소의 치밀골에서 전해질용액의 침지시간에 따른 Strength와 Stiffness의 변화)

  • 김남수;장세웅;김희은;정인성;최성진;최인혁
    • Journal of Veterinary Clinics
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    • v.20 no.4
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    • pp.482-488
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    • 2003
  • Transplanted cortical bone grafts of freeze-dried bones also function as sustaining for defected bones, however, it has less strength and is fragile without rehydration. In this study, strength and stiffness of freeze-dried bone from bovine cortical bones were evaluated by three point bending test according to different time frames such as rehydration times of 0.5, 3, 6, 12 and 24 hrs in electrolyte solution and was compared with those of frozen bones. The strength and stiffness of frozen bone were $264.4\pm36.7$ MPa, $17.0\pm1.5$ GPa, respectively. The strength and stiffness of freeze-dried bone which fat was removed by treatments of chloroform-methanol solutions for 6 days, then was freeze-dried at $-80^{\circ}C$ and sterilized with ethylene oxide gas, were $224.9\pm27.6$ MPa, $19.2\pm2.8$ GPa, respectively. The strength and stiffness of feeze-dried bone were decreased 15.0% and increased 13.2% than these of frozen bone, respectively. The strength and stiffness of freeze-dried bone rehydrated for 6 hrs were restored to 96.0% strength and 99.2% stiffness of frozen bone. The rehydration time of freeze-dried bone which had the highest strength and stiffness was six hours and three hours, respectively. The results of the mathematica program for the variation of the strength and stiffness showed 3 hours and 30 minutes of rehydration time in electrolyte solution for the best condition in the strength and stiffness which was adequate to treat freeze-dried cortical bone.

Quality Characteristics of Functional Dasik Prepared with Mixture of Freeze-dried Mealworm (Tenebrio molitor) Powder and Dried Pollack Powder (밀웜(Tenebrio molitor L.) 분말과 북어 분말을 혼합하여 제조한 기능성 다식의 품질평가)

  • Kang, Mi-Sook;Kim, Min-Ju;Han, Mung-Ryun;Shin, Seung-Mee;Kim, Ae-Jung
    • Journal of the Korean Society of Food Culture
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    • v.33 no.1
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    • pp.48-54
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    • 2018
  • This study was performed to evaluate the quality characteristics of functional Dasik prepared with a mixture of freeze-dried mealworm (Tenebrio molitor) powder and dried pollack powder along with assessment of the general and fatty acid compositions of mealworms. General compositions, except for moisture content of freeze-dried mealworm powder, were higher than those of raw mealworms. The ratios of saturated fatty acids and unsaturated fatty acids of freeze-dried mealworm powder and raw mealworms were 1:3.31 and 1:3.19, respectively. Amounts of oleic acid, which was the most abundant among unsaturated fatty acids, of freeze-dried mealworm powder and raw mealworms were 41.12 and 37.84%, respectively. For color values, greater content of freeze-dried mealworm powder in functional Dasik resulted in lower L and b scores, whereas a value increased. In the case of mechanical properties, greater content of freeze-dried mealworm powder resulted in significant reduction of hardness, chewiness, and gumminess. In the case of sensory evaluation, color, taste, and overall quality of DPMD50, which was prepared with a 1:1 ratio of freeze-dried mealworm powder and dried pollack, were the highest. It was concluded that DPMD50 is a nutritious combination of edible insects and fish for protein fortification for growth and the elderly.

Preservation of Coagulation Efficiency of Moringa oleifera, a Natural Coagulant

  • Katayon, S.;Ng, S.C.;Johari, M.M.N.Megat;Ghani, L.A.Abdul
    • Biotechnology and Bioprocess Engineering:BBE
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    • v.11 no.6
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    • pp.489-495
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    • 2006
  • In recent years, there has been an interest to use Moringa oleifera as the natural coagulant due to cost, associated health and environmental concerns of synthetic organic polymers and inorganic chemicals. However, it is known that M. oleifera as the natural coagulant is highly biodegradable and has a very short shelf life. This research was carried out to investigate the effects of storage temperature, packaging methods, and freeze-drying on the preservation of M. oleifera seeds powders. Non freeze-dried M. oleifera was prepared into different packaging namely open container, closed container and vacuum packing, whilst, freeze-dried M. oleifera was stored in closed container and vacuum packing. Each of the packaging was stored at room temperature ($30\;to\;32^{\circ}C$) and refrigerator ($4^{\circ}C$). The turbidity removal efficiencies of stored M. oleifera were examined using jar test at monthly interval for 12 months. The results indicated that non freeze-dried M. oleifera kept in the refrigerator ($4^{\circ}C$) would preserve its coagulation efficiency. In addition, closed container and vacuum packing were found to be more appropriate for the preservation of non freeze-dried M. oleifera, compared to open container. Freeze-dried M. oleifera retained its high coagulation efficiency regardless the storage temperature and packaging method for up to 11 months. Besides, higher increment in zeta potential values for water coagulated with freeze-dried M. oleifera indicated the higher frequency of charge neutralization and better coagulation efficiency of freeze-dried M. oleifera, compared to non freeze-dried seeds. As a coagulant, M. oleifera did not affect the pH of the water after treatment.