• Korean Journal of Food Science and Technology
• /
• v.22 no.2
• /
• pp.123-128
• /
• 1990

In order to establish the optimal thawing condition of frozen fork, hot-air thawing and microwave thawing were evaluated at various conditions. In hot-air thawing, the higher the air temperature and the lower the meat surface temperature, the grater the thawing rate was. In microwave thawing, the grater the power and the lower the meat core temperature, the faster the thawing rate was. Comparing the two methods, microwave thawing was found to be significantly faster than hot-air thawing. TBA value and cooking loss were higher in hot-air thawing than that of refrigeration thawing or microwave thawing. Total extractable protein tended to be lower in hot-air thawing than that of the other two thawing methods. WHC decreased with the increase of hot-air and meat surface temperature whereas no significant difference was observed in microwave thawing regardless of the thawing conditions. Total microbial counts of thawed meat by the hot-air or microwave thawing were lower than that of refrigeration thawing.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.44 no.10
• /
• pp.1492-1503
• /
• 2015

This study evaluated the combination effect of various freezing and thawing techniques on the quality and nutritional aspects of onions. Onions were frozen by natural air convection freezing (NCF), air blast freezing (ABF), and liquid nitrogen freezing (LNF). Onions were frozen for 76 min by NCF, 9 min by ABF, and 9 min by LNF. The freezing treatment was stopped when the core temperature reached $-12^{\circ}C$ for NCF and ABF, and $-120^{\circ}C$ for LNF. Frozen samples were thawed through natural air convection thawing, running water thawing, sonication thawing (ST), or microwave thawing. The quality and nutritional aspects of frozen-thawed onions were evaluated by measuring thawing loss, pH, texture, water content, color, and SEM image. ST was found to cause the least loss in onion sample among the tested thawing methods, whereas the freezing methods did not cause any significant loss. In our experiment, thawing is found to be a more critical technique when compared to that of freezing. There were no clear quantifications or trends of pH and water content among different freezing and thawing techniques. The highest total color difference (${\Delta}E$) was observed in the NCF sample. For morphological observation, ABF gave the smallest ice crystal size, as well as minimum cell collapse. Loss of vitamin C, free sugar, and organic acid content was lower in the ABF and ST sample, when compared to other trials. In our study, we found that combination of ABF and ST could preserve the quality and nutritional aspects of frozen-thawed onions better than other methods.

• Food Science of Animal Resources
• /
• v.35 no.1
• /
• pp.27-34
• /
• 2015

The ultrastructure in the beef muscle of the electro-magnetic resonance and air blast freezing during the frozen storage, and the changes in the quality characteristics after thawing were evaluated. The size of ice crystal was small and evenly formed in the initial freezing period, and it showed that the size was increased as the storage period was elapsed (p<0.05). The beef stored by the electro-magnetic resonance freezing showed the size of ice crystal with a lower rate of increase than the air blast freezing during the frozen storage. The thawing loss of beef stored by the electro-magnetic resonance freezing was significantly lower than the air blast freezing during frozen storage (p<0.05), and it showed that the thawing loss of the round was higher than the loin. Water holding capacity decreased as the storage period became longer while the electro-magnetic resonance freezing was higher than the air blast on 8 month (p<0.05). As a result of sensory evaluation, the beef stored by the electro-magnetic resonance freezing did not show the difference until 4 months, and it showed higher acceptability in comparison with the beef stored by the air blast freezing. Thus, it is considered that the freezing method has an effect on the change in the ultrastructure and quality characteristics of the beef.

• Food Science of Animal Resources
• /
• v.42 no.2
• /
• pp.341-349
• /
• 2022

The objective of this study was to examine the effect of temperature abuse prior to cold storage on changes in quality and metabolites of frozen/thawed beef loin. The aerobic packaged samples were assigned to three groups: refrigeration (4℃) (CR); freezing (-18℃ for 6 d) and thawing (20±1℃ for 1 d), followed by refrigeration (4℃) (FT); temperature abuse (20℃ for 6 h) prior to freezing (-18℃ for 6 d) and thawing (20±1℃ for 1 d), followed by refrigeration (4℃) (AFT). FT and AFT resulted in higher volatile basic nitrogen (VBN) values than CR (p<0.05), and these values rapidly increased in the final 15 d. Cooking loss decreased significantly with an increase in the storage period (p<0.05). In addition, cooking loss was lower in the FT and AFT groups than in the CR owing to water loss after storage (p<0.05). A scanning electron microscope (SEM) revealed that frozen/thawed beef samples were influenced by temperature abuse in the structure of the fiber at 15 d. Metabolomic analysis showed differences among CR, FT, and AFT from partial least square discriminant analysis (PLS-DA) based on proton nuclear magnetic resonance (¹H NMR) profiling. The treatments differed slightly, with higher FT than AFT values in several metabolites (phenylalanine, isoleucine, valine, betaine, and tyrosine). Overall, temperature abuse prior to freezing and during thawing of beef loin resulted in accelerated quality changes.

• Journal of the East Asian Society of Dietary Life
• /
• v.22 no.2
• /
• pp.298-304
• /
• 2012

This study was carried out to investigate the effects of various thawing methods on the physical and microbiological properties of frozen pork. The frozen pork was thawed using four methods: refrigerator, cold water, room temperature, and microwave oven. Changes in physicochemical properties of thawed pork were analyzed by measuring color, pH, thawing loss and thiobarbituric acid reactive substances (TBARS) values. Changes in the microbiological properties of thawed pork were analyzed by counting total aerobic bacteria and coliform group. L values of thawed pork were significantly increased by all thawing methods for normal thawing time except the uncooked portion of thawed pork via a microwave. However, the a value decreased in pork thawed by all thawing methods. pH values significantly increased in the pork thawed by microwave and by applying two times the normal thawing time. After thawing, thawing loss was highest in the pork thawed at room temperature for two times the normal thawing time. In addition, TBARS values also increased in the pork thawed in a refrigerator and at room temperature for two times the normal thawing time. The total aerobic bacteria count significantly increased in the case of microwave thawing for normal thawing time and it also increased in the pork thawed in a refrigerator and at room temperature for two times the normal thawing time. These results demonstrate that refrigeration and cold water thawing are the most suitable for frozen pork, and that excess thawing should be avoided.

• Korean Journal of Agricultural Science
• /
• v.21 no.2
• /
• pp.133-141
• /
• 1994

Optimal thawing conditions of frozen model foods containing protein and starch were nvestigated at various thawing conditions such as room temperature, hot air, and microwave heating. Hardness of the frozen model foods was getting higher as the water content increased. Thawing rates at room temperature, hot-air heating at $50^{\circ}C$, and microwave heating were 0.02 Kg/min, 0.08 Kg/min, 0.01 Kg/min, respectively. Final thawing time was as follows; control 60min, 5% sucrose: 50 min, 10% sucrose: 30 min, 5% NaCl: 30 min. Total drip loss was as follows; room temperature thawing: 22.5%, 200W microwave thawing 1.3%, and $50^{\circ}C$ hot air thawing nearly negligible.

• Food Science of Animal Resources
• /
• v.35 no.6
• /
• pp.772-782
• /
• 2015

This study was performed to explore the deterioration of physicochemical quality of beef hind limb during frozen storage at −20℃, affected by repeated freeze-thaw cycles. The effects of three successive freeze-thaw cycles on beef hind limb were investigated comparing with unfrozen beef muscle for 80 d by keeping at −20±1℃. The freeze-thaw cycles were subjected to three thawing methods and carried out to select the best one on the basis of deterioration of physicochemical properties of beef. As the number of repeated freeze-thaw cycles increased, drip loss decreased and water holding capacity (WHC) increased (p<0.05) till two cycles and then decreased. Cooking loss increased in cycle one and three but decreased in cycle two. Moreover, drip loss, WHC and cooking loss affected (p<0.05) by thawing methods within the cycles. However, pH value decreased (p<0.05), but peroxide value (p<0.05), free fatty acids value (p<0.05) and TBARS value increased (p<0.05) significantly as the number of repeated freeze-thaw cycles increased. Moreover, significant (p<0.05) interactive effects were found among the thawing methods and repeated cycles. As a result, freeze-thaw cycles affected the physicochemical quality of beef muscle, causing the degradation of its quality.

• Food Science of Animal Resources
• /
• v.40 no.3
• /
• pp.444-460
• /
• 2020

This study was conducted to investigate the effects of freezing and storage temperature (-18℃, -50℃, and -60℃) on the physicochemical properties of pork neck and chicken leg meat in home-scale deep freezers. Pork neck was cut into a thickness of 3 cm (9×9×3 cm, 150 g), individually packed in air-containing packages, and stored at different temperature (-18℃, -50℃, and -60℃) for 6 months. Chicken leg meats were prepared (10 cm long, weighing 70 g) and packed in the same manner. Frozen samples were thawed at 2℃. Physicochemical properties such as thawing loss, cooking loss, water-holding capacity, color, volatile basic nitrogen (VBN), and thiobarbituric acid reactive substances (TBARS) were evaluated. The samples frozen by deep freezing (-60℃) was favorable with respect to thawing loss, color, and VBN. Samples frozen at -60℃ had lower values of thawing loss and VBN than those frozen at -18℃ for all storage periods (p<0.05). Color parameters were more similar to those of fresh meat than to those of samples frozen at -18℃ for 6 months. The TBARS of all samples were below 0.3 mg malondialdehyde/kg, thereby indicating oxidative stability of lipids. Consequently, deep freezing at -60℃ may be acceptable for maintaining the quality of fresh pork neck and chicken leg meat for 6 months without deterioration.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2001.05a
• /
• pp.1029-1034
• /
• 2001

The effects of binder content and silica sand content on the freezing and thawing resistance of lightweight polymer concrete are examined. As a result, the mass loss and pulse velocity of lightweight polymer concrete decrease with increasing binder content and silica sand content. The relative dynamic modulus and durability factor of lightweight polymer concrete reaches minimum at a silica sand content of 50% and a binder content of 28%, and is inclined to increase with increasing binder content and silica sand content.

• Asian-Australasian Journal of Animal Sciences
• /
• v.23 no.5
• /
• pp.665-671
• /
• 2010

Muscle fiber characteristics and their relationship to water-holding capacity of longissimus dorsi (ld) muscle were studied in Brahman (BRA) and Charolais (CHA) crossbred bulls fattened under practical farm conditions. Thirty-four BRA and 34 CHA bulls were randomly selected and slaughtered at 500, 550 and 600 kg live weight. Parameters of water-holding capacity such as drip, ageing, thawing, cooking and grilling loss were determined. Muscle fiber characteristics were conducted for muscle fiber type percentage and cross-sectional areas of slow- and fast-twitch fiber types, and correlation coefficients to water-holding capacity parameters were calculated. Results showed that CHA meat had a better water-holding capacity (less ageing, thawing and grilling loss) when compared with BRA, whereas slaughter weights had no significant effects on these parameters. Furthermore, there were no significant differences between genotypes and slaughter weights in muscle fiber type percentage and cross-sectional areas of ld muscle. Slow- and fast-twitch fiber types of all experimental groups averaged 24.4 and 75.6%, respectively. Cross-sectional areas of fast-twitch fibers had almost twice the size of slow-twitch fibers (6,721 and 3,713 ${\mu}m^2$, respectively). The correlation between muscle fiber area and water-holding capacity indicated that muscles with larger fiber areas had a lower drip and ageing loss but a higher cooking and grilling loss.