To prevent the quality deterioration in freezing and thawing of yellowtail (Seliola quinqueradiata) meat having weak resistance to freezing, the efficiency of dehydration treatment with some polymer sheets on thawing was evaluated by determining several quality of frozen-thawed meats. Results obtained are summarized as follows. 1. All polymer sheets used were effective for maintenance of quality and food sanitation of frozen-thawed meats. The dehydration-sheet thawing at 4°C was suitable for keeping the textural quality and low K value, and that at 10°C for retention of color of red meat. 2. The superior method for keeping the textural quality of frozen-thawed meats was to package under vacuum the fresh meat wrapped with polymer sheet before freezing, and thaw it in flowing water at 4°C. As the vacuum-packed frozen meat was likewise effective when thawed in still air of 4°C in the refregerator, the sheet treatment before freezing was of much practical use. 3. The low-temperature storage after dehydration sheet thawing of the frozen meat seem- ed to be effective slightly on the maintenance of the quality compared with that of ordinary frozen-thawed meat. 4. When the meat was kept in frozen storage for a long period, the maintenance of qual- ity of the thawed meat showed a tendency to be superior to ordinary frozen thawed meat in the sheet treated one.

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On the flavor deterioration of Japanese soup packaged into a pouch, a proper selection of laminated film for food packaging was proposed by showing the influences of oxygen permeability (a : cm/ cm • day • atm), storage period (T; day), the ratio of surface area (S; cm?) to volume (V; cm') of pouch. Samples were stored for 4 weeks at 25°C, which had been packaged into 6 kinds of pouches (9cm x 15cm; 200ml) made of the following laminated films; PET/LLDPE (a = 98 × 10-), PA/LLDPE (a = 28 x 10-4), PVDC-coated PA/LLDPE (a = 45 × 10-*), *PVDC-coated PA/LLDPE (a = 1.5 × 10-), EVOH/LLDPE (a = 0.3 × 10-*), PA/AL/LLDPE (a =0). The flavor of stored sample was sensory-evaluated with 8 panelists, while the changes in the gas chromatograms were traced throughout t h e storage. In order to correlate the flavor deterioration to the amount of oxygen permeated, the following equation was introduced ; a =p-a•T•S/V, where p is a partial pressure of oxygen in atmosphere and a, dimen- sionless number was defined as a specific volume of oxygen permeated. As the result, the flavor of packaged soup significantly deteriorated above a = 34 × 10-* Keywords: Food Packaging, Oxygen permeation, Flavor Deterioration

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This investigation was carried out to know whether polyethylene film (PE) can keep the commercial quality of the 'sordum' plums stored at 30°C. No significant differences of changes in hardness, coloring of peel and flesh, titratable acidity and sugar content were found among fruits packed with three kinds of films, that is high density PE (thickness: 15 um), low density PE (30 um) and low density PE (60 um). But organoleptic evaluations differed among them. The fruit packed with lowdensity PE (60 um) (oxygen permiability: 4,150ml/m'• 4,150ml/m'•24hr-atm) smelled nasty and kept the commercial quality only for 3 days, but the fruit packed with high density PE (15 um) (oxygen permiability: 14,000ml/m? •24hr •atm) kept the commercial quality for 10 days. Shelf life of the fruits was related with oxygen concentration in plastic bags, the oxygen concentration in the bag which kept high commercial quality of the fruit was in the range of 8 and 10%.

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A mathematical method was examined for continuous determination of the respiration of broccoli stored under modified atmospheric conditions. Broccoli (ca. 250g) was packaged in different plastic films (oxygen permeability: 1,560 to 7,640 ml/m' • day •atm at 15°C) and stored for 5 days at 15°C. Gas concentrations in the packaging were periodically analyzed by gas chromatography. Mathematical equations were developed for calculating the void volume of the package at any given time as a function of nitrogen concentration of the in-package atmosphere. The calculated volumes gave a close approximation to the actual volumes. The procedure to calculate the periodical changes in the volume and the oxygen or carbon dioxide concentration was combined with a gas permeation model through films to obtain the respiration rates of broccoli packaged with gas permeable films. The total procedure presented here permits evaluation of the respiration of broccoli without unsealing the packages. The respiration rates and modified atmospheres analyzed by this approach were discussed for optimizing packaging conditions for the produce.

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