To investigate the effect of several bactericides and fungicides against fruit & vegetable decay grapefruit seed extract(GFSE) was tested in a dilution solution. GFSE was shown to be effective against decay and rind breakdown and to extend the shelf-life of fruits and vegetables during storage and tiansport. Antimicrobial efficiency of GFSE on a wide spectra of gram + & - bacteria, moulds and yeasts was demonstrated by the measurement of minimal inhibitory concentrations performed (Bacteria 10-500ppm, Fungi:250-1,000ppm, Yeasts:100-250ppm). GFSE was separated and extracted into water-soluble fraction, water-insoluble and non-dialyzed fraction to isolate the antimicrobial substances. The water-soluble fraction showed the most active antimicrobial effect. The antimicrobial substances were isolated by gas chromatography. As the result of the isolation using GC, Peak-D was found to be the antimicrobial compound in GFSE. The identification of the most antimicrobial substance was carried out by using GC-MS.
Soluble solids(Brix), acid content and edible part ratio of Citrus unshiu collected at sorting Places in south Cheju area wee more lowered, and peel thickness was more thickened with increasing fruit size. Compared to early variety of Citurs unshiu(C. unshiu Miyakawa Mar), peel thickness of medium variety of Citurs unshiu(C. unshiu Hayashi Mar) was more thickened, and edible part ratio was more lowered with increasing fruit size. Soluble solids of medium variety of Citurs unshiu were lowered, and acid contents were increased compared to early variety. Processing properties for pressing concentrated juice was good for early variety of Citurs unshiu, especially on fruit diameter of 50-65mm. Soluble solids, acid contents and juice ratio were decreased with increasing peel thickness. The quality properties for fresh fruit with peel thickness had a good correlation on early variety of Citurs unshiu, and these data are supposed to be applied to the quality evaluation of Citurs unshiu produced in Cheju.
This experiment was carried out to select the optimum thickness of polyethylene film for the nonastringency of astringent persimmon fruits during modified atmosphere(MA) storage of Cheongdo Bansi kept at 0. The experimental plots were divided into 5 plots by film thickness(0.08, 0.10, 0.12, 0.14 and 0.16mm). The experimental items were the changes in concentration of CO2 and O2 in film brig, soluble tannin contents, loss of weight firmness and external appearance of fruits. The nonastringency of persimmon fruits can be achieved all groups excepting the 0.08mm film during MA storage. The sweet persimmon in film bag of 0.10 and 0.12mm maintained a high quality and firmness, but following the deastringency the fruits in 0.14 and 0.16mm developed off-color. The increasing of carbon dioxide level and decreasing of oxygen level in film bag created anaerobic condition at earth stage, and then it kept a constant level during stooge. According to film thickness the obvious difference in the change of soluble tannin contents external appearance and firmness were observed. It could be concluded that the optimum thickness of film for the desirable nonastringency on Cheongdo Bansi was 0.10mm.
For the purpose of improving microbiolgical quality of carrot powder, which is being used as minor ingredients of convenience foods, comparative influence of Υ-irradiation and ethylene oxide(E.O) fumigation was investigated with emphasis on sterilizating effect and physicochemical propertied Carrot powder sample was contaminated with thermophiles 4.0103/g, acid tolerant bacteria 3.7103/g and coliforms 1.6102/g, respectively. And thus sanitation process was required. E.O fumigation in commercial practice was not enough to destroy thermophilic bacteria, while Υ-irradiation at below 5 kGy could reduce all microorganisms up to undectected levels. Radiosensitivity(D10) of thermophiles was shown to be 2.25 kGy. The applicable dose of irradiation to the improvement of microbiological quality showed insignificant influences on the physicochemical quality of the sample.
This study was carried out for the establishment of optic harvest date and storage condition of 'Fuji' apple for CA storage. Apples were picked at 10 day intervals from 17 Sept to 27 Oct.. Apples were analyzed for respiration rata, weight flesh firmness, titratable acidity, soluble solid, total sugar, reducing sugar, surface color and thiault value. In 1990, the optimal harvest season could be judged between 17 Oct. and 27 Oct. from the results of respiration rate rise and change of quality properties. Apples harvested on 27 Oct. wert stored at 2 and 90~95% RH in 1%O2 + 3%CO2, 3%O2 + 3%CO2 and air for 9 months. After 9 months of storage, apples kept in CA storages had beater quality than apples kept in refrigeration storage. Especially, apples kept in 1%O2, + 3%CO2 were fumer and more acid than those kept in 3%O2 + 3%CO2 At the sensory evaluations, apples stored in CA were rated higher quality than apples stared refrigeration.
A microcomputer system consisting of 16-bit microcomputer, PCL-711S interface board, censors, and converters have been set up in order to automatically measure temperature, humidity and weight loss which are major variables of storage of apple. This system was operated by PC-LabDAS software. It has been possible to measure continuously the weight loss of Fuji apple stored in CA with the weight converter made by a miniature load cell and a strain amplifier. The temperature was checked by a k-type thermocouple and Pt 100 RTD, and humidity by PQ653JAl humidity sensor. It has been possible to set up a linear equation which showers high correlationship between the estimate of temperature, weight humidity and the output of the converter in that r2 is more than 0.99. Transpiration rate, a significant factor of quality deterioration for CA storage of apple, can be estimated with these values.
Circulation state and changes in quality during ripening of strawberry were investigated. Tissue damage of the fruit happened when it was harvested and selected. Strawberry has been harvested without considering of fruit temperature in the farm. It takes 25 hours from Goreung which is main production area of strawberry to retailer, and seasonal variation in the price was severe. Shelf-life of strawberry from Feb to Mar was 5-6 days, and was 24-30 hours from May to June. Desirable ripening stage was 28-30th day after blooming and 40th day and after this was over ripening stage when the degree of ripening estimated by color "a" value and color saturation. Overall eating quality and vitamin C contents and sugar content were more higher in the fruit of the desirable ripening stage than that of unripening and over ripening stage. The dark redness degree was high in the over ripening stage.
To invedtigate the effect of refrigerate case on the Quality of strawberry during circulation, the temperature changes on the amounts of dry ice and ice cube were examined. And also, the effect of precooling on the changes in temperature and quality of the fruits were studied. Strawberry precooling-treated at 4 for 24hours was prolonged the shelf-life, and Quality was Progressed.150g of dry-ice Per kg of the strawberry was kept quality. It was prolonged more 2 days than present circulation system.