• KOREAN JOURNAL OF CROP SCIENCE
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• v.65 no.4
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• pp.294-302
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• 2020

Studies on the occurrence of rice preharvest sprouting (PHS) have primarily focused on temperature and rainfall duration at the time of PHS induction, but average temperature during grain filling can have a great influence on PHS. This study analyzed the effect of average temperature during grain filling on PHS occurrence and subsequent changes in grain quality after PHS. For two consecutive years, average temperature differences during grain filling were produced by varying the transplanting date. Artificial rainfall was treated under identical accumulated temperatures of 1200℃ after heading. It was confirmed that the occurrence of PHS was higher under high average temperature conditions during grain filling. In addition, the degree of grain quality reduction caused by PHS occurred more severely under high temperature conditions during grain filling. In order to reduce the risk of PHS occurrence and subsequent quality damage, it is important to control the planting date to avoid high-temperature conditions during grain filling.

• Korean Journal of Food Science and Technology
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• v.25 no.2
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• pp.185-190
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• 1993

Tilapia cultured in fresh water were acclimated in sea water with daily increase of $5%_{\circ}$ of salinity and it was completely terminated at the 7th day (0 week). Each three tilapia acclimated were examined weekly based from 0 week to elucidate changes of chloride cells in gill, mineral contents and physical properties in muscle and biochemical characteristics in myofibrils. Chloride cells existed in gills were gradually developed in number and size by acclimation to sea water and became to almost constant state at the third week. Shearing value, compressing strength and content of minerals such as Mg, Na and K in muscle were showed remarkable increase by acclimation to sea water in comparison to those of muscle from tilapia reared in fresh water. Myofibrillar $Mg^{2+}-,\;Ca^{2+}-$ and $K^+(EDTA)-ATPase$ activities of tilapia acclimated in sea water also increased showing significant statistic difference (p<0.01) from those of tilapia reared in fresh water However. thermostability of myofibrils was dropped by acclimation to sea water. The increase of shearing value and compressing strength in the muscle of tilapia by acclimation to sea water would be attributed to the increase of myofibrillar ATPase activities which act to accelerate the decomposition rate of ATP. Therefore, it is suggested that this phenomenon associated with muscle contraction could be brought an improvement of texture of tilapia acclimated in sea water.

• Korean Journal of Food Science and Technology
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• v.24 no.3
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• pp.256-260
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• 1992

This study was conducted to calculate and predict the shelf-life of meat sausage through physicochemical and biological analysis. Judging from physico-chemical components, it can be found out the most effective indicator in meat sausage. And also, the materials used for packaging is cellulose #23 in inner-packaging and CN/HDPE laminating film in outer-packaging. The changes of the most effective indicator were discussed through the method of kinetic analysis. Judging from physico-chemical components, VBN was the most available component in quality judgement of meat sausage and their upper limiting contents were 20 mg%. It is possible to calculate and predict the shelf-life of meat sausage through the regression equation and $Q_{10}$ value. As a result, the shelf-life prediction was $58{\sim}63$ days at $10^{\circ}C$, $47{\sim}51$ days at $20^{\circ}C$ and 26 days at $40^{\circ}C$, respectively, but the difference between two methods showed about $4{\sim}5$ days. $Q_{10}$ value on the changes contents was 1.35 at acceralated temperature $40^{\circ}C$. The reaction rate of VBN contents could be interpreted as a first order reaction that divided into 2 periods with different reaction rate constants. The corresponding Arrhenius activation energies were 2.959 Kcal/mole and 3.632 Kcal/mole, respectively.

• Korean Journal of Food Science and Technology
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• v.41 no.5
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• pp.515-521
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• 2009

The DEFT (direct epifluorescent filter technique)/APC (aerobic plate count) test was utilized to screen powdered Ramen soup samples (RS-1, RS-2) whether or not they have been microbial-decontaminated. The initial microbial loads of commercially-packaged samples were log DEFT 6.46 (RS-1) and 7.05 (RS-2), but the viable bacterial counts were log APC 2.74 (RS-1) and 1.95 (RS-2), respectively; this finding showed that they have been already decontaminated by methods other than irradiation. The same samples were then subjected to gamma irradiation at 0, 5 and 10 kGy in order to evaluate the microbial and physicochemical changes during post-irradiation storage for 6 months under room conditions ($10{\pm}3^{\circ}C$). The DEFT count was constant in irradiated samples even at different doses, but APC decreased with dose increases; this implies that the log DEFT/APC increased in a linear fashion with dose. No coliforms, yeasts and molds were detected in any of the samples, whereas the initially detected aerobic bacteria ($5.49{\times}10^2CFU/g$) were inactivated by 5 kGy or more and no growth was observed during the subsequent storage period. The pH of RS-1 was reduced by irradiation (p<0.01), but increased (p<0.01) with increasing storage time. Irradiation induced a reduction in volatile basic nitrogen (VBN), whereas an increase in thiobarbituric acid (TBA) values was observed. The storage time proved more influential than irradiation up to 10 kGy in terms of changes in the VBN and Hunter’s color values of powdered Ramen soups.

• Korean Journal of Food Science and Technology
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• v.49 no.1
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• pp.50-55
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• 2017

The purpose of this study was to investigate the effect of frying number on oxidative changes in edible oils and fried foods. According to the frying number, the extracted edible oils from pork cutlet and fried potato were used as experimental samples. The Ministry of Food and Drug Safety (MFDS) regulations permit edible oils to have <2.5 mg KOH/g of acid value and <50 meq/kg of peroxide value in food. However, there are no regulations for edible oils used to fry livestock. Animal foods contain protein and fat, and should be held to a different standard than ordinary food. Therefore, we present basic information and suggest the establishment of regulations for livestock frying oil and fried livestock.

• Applied Biological Chemistry
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• v.36 no.3
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• pp.146-153
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• 1993

The changes in water uptake rate, cooking property, color of rice grain, gelatinization property of milled rice during storage were studied. The water uptake rate constant of milled rice during storage at $4{\sim}30^{\circ}C$ for 3 months decreased, which was more pronounced at elevated storage temperatures. The activation energy of water uptake was different below and above $25^{\circ}C$ of storage temperature. The activation energy after storage for 3 months below and above $25^{\circ}C$ was 608 and 1269 cal/mole, respectively. The rice grain became harder and the cooking time was prolonged by $3{\sim}8$ minutes upon storage. The cooking rate constant was linearly decreased as a function of storage time. The activation energy of cooking after 1 month of storage was 235 cal/mole, which was increased by 1.7 times after storage of 1.5 months and thereafter by 1.2 times with the increase of 0.5 month. There were no significant changes in color of milled rice grains during storage at $4^{\circ}C$, but the increase of b value was observed at higher temperatures. The Initial pasting temperature of rice flour remained essentially unchanged during storage, but the peak viscosity consistently increased with the increase of storage time and temperature. The gelatinization temperature of rice flour by differential scanning calorimetry was not changed but enthalpy of gelatinization was decreased during storage.

• Food Science and Preservation
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• v.23 no.3
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• pp.291-300
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• 2016

Kiwifruit (Actinidia chinensis, Hayward) was stored at $25^{\circ}C$ for 0~30 days and investigated to find out the optimum storage time to obtain the best physical and functional properties for consumers' preference. Kiwifruits was stored at different time period (0, 5, 10, 15, 20, and 30 days) for investigating their physiochemical quality, nutritional components, and functional characteristics. Kiwifruits stored for 20~30 days showed the best physiochemical quality such as higher total acidity and proper firmness. They were also more enriched with dietary fibers, free sugar, and organic acid, although no significant changes were observed in crude protein, crude fat, and moisture content. For functional properties, kiwifruits stored for 20 days showed significantly higher contents of total phenolics, flavonoids, and actinidin. In addition, it showed stronger antioxidant activity, whitening effect, and proteolytic activity when compared with other samples. SDS-PAGE analysis showed the presence of actinidin enzyme in kiwifruits. These results indicated that the kiwifruits stored for 15~20 days possessed excellent quality and high concentrations of nutritional and functional compounds, which could be best for both fresh consumption and product processing.

• Journal of the Korean Society of Food Science and Nutrition
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• v.38 no.1
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• pp.89-97
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• 2009

Jujube wine was treated with hydrostatic pressure (500 MPa, 5 min) or freezing ($-20^{\circ}C$, 3 days and thawed $20^{\circ}C$, 4 hr) and their microbial counts, physicochemical properties, and sensory characteristics were investigated during storage at $35^{\circ}C$ for 60 days. Microorganisms in pressure-treated jujube wine were not detected during the whole period and chemical compositions as well as color were slightly changed. Sensory quality was significantly preserved until 20 days without increasing sweet aroma and taste. In freezing-treated wine, bacterial counts were decreased after 10 days and remained below 10 CFU/mL while lactic acid bacteria and yeast were not detected. Changes of chemical composition were smaller than those of the untreated wine but bigger than those of the pressure-treated or heat-treated wine. Instrumental color was changed after $10{\sim}20$ days resulting from the increase of L value and the reduction of a value. Sensory quality was significantly similar with the fresh wine for 10 days, suggesting that pressure treatment would be the most effective sterilization method to improve the shelf life of jujube wine whereas freezing treatment would be insufficient.

• Food Science of Animal Resources
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• v.23 no.1
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• pp.56-62
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• 2003

This study was carried out to evaluate the physicochemical properties of spreadable liver sausage manufactured from ostrich and pork during storage. It was found that the changes in pH of all treatments increased significantly over 7 d, but did not show significant difference in the remaining periods. L-value deceased with liver sausage containing ostrich liver and ostrich meat, but others showed only slight increase during storage periods. Although a-value of liver sausage containing pork meat was higher than that containing ostrich meat over 7 d of storage; after this period the trend of a-value was inverse. However, b-value in all treatments did not show significant difference during storage periods. The initial average TBA-value of all products was below 0.1 mg/kg. However, TBA-value increased to about 0.63 mg/kg, and 0.77 mg/kg at 7 and 21 d, respectively. Hardness of liver sausage containing ostrich meat and pork liver was higher than that containing pork meat and ostrich liver. Cohesiveness and elasticity did not show significant changes during storage periods.

• Korean Journal of Food Science and Technology
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• v.38 no.3
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• pp.325-330
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• 2006

To determine freshness and detect changes in quality of beef and pork during storage, we manufactured a freshness indicator and monitored the surface pH, volatile basic nitrogen (VBN), thiobarbituric acid reacted substance (TBARS), total bacterial counts, electronic nose analysis, and sensory evaluation. Both beef loin and pork belly had a change in the color of the freshness indicator after storage of 6 days at $2^{\circ}C$. VBN and TBARS levels and total bacterial counts reached the decay point at the time of the color change of the freshness indicator attached to the surface of the beef and pork samples. Sensory evaluation also indicated that the samples were unacceptable by an 'off' odor on day 6 of storage. There were significant differences in electronic nose analysis for samples from day 0, day 6, and day 10 of storage. These results suggest that this freshness indicator should be useful in determining the expiration date of beef and pork products during marketing by indicating the microbial safety as well as the physicochemical and sensory changes.