Natural convection heat transfer in the annulus between horizontal circular cylinders/d朴權鉉 著

박권현 한국과학원 1980 국내석사

RSM을 이용한 숭어 반염건품의 개발 및 녹차 처리에 의한 품질안정성의 개선

박권현 경상대학교 대학원 2011 국내석사

The salted semi-dried fish, such as salted semi-dried brown croaker, salted semi-dried convict grouper, and salted semi-dried longneck croaker, have been esteemed as palatable seafood in Korea because of their specific textures, tastes and nutritional values. For the reasons, three kinds of the fish, such as brown croaker, Miichthys miiuy, convict grouper, Epinephelus septemfasciatus, and longneck croaker, Pseudotolithus typus, represent the largest fishery biomass used for salted semi-dried fish production up to now. However, most the fish are imported from foreign country because of very low catch in off domestic based on consumption demand. Common gray mullet (CGM), Mugil cephalus, is popular fish in Korea as a sliced raw fish because of its specific texture and nutritional value. However, the annual CGM harvest exceeds 40,922 M/T as aquaculture technique expanded, which is excessive amount as a sliced raw fish. In the sense, the distribution amount of CGM as a sliced raw fish should be controlled by using as a source of seafood products, such as salted semi-dried fish. For developing other use, such as salted semi-dried fish, as well as sliced raw fish of CGM, this study attempted to establish the guideline for quality control of high quality salted semi-dried fish based on the quality of commecial salted semi-dried fish, to develop high quality salted semi-dried using response surface methodology and to improve its quality stability by soaking into green tea extracts. For establishment of guideline to control quality of high quality salted semi-dried fish, the study in the chapter Ⅰ attempted to examine standards of various nation organs, such as the KS standards of Korean Agency for Technology, and quality certification of seafoods(S) and fisheries traditional foods of Ministry for Food, Agriculture, Forestry and Fisheries, on salted mackerel, Kwamegi and salted-dried croaker and to analyze sanitary and other food components of commercial salted semi-dried fish, such as commercial salted semi-dried brown croaker, convict grouper and longneck croaker, prior to establish guideline for quality control of high quality salted semi-dried fish based on the data analyzed from commercial salted semi-dried fish and standards. Based on the KS standards of Korean Agency for Technology, and the provisions for quality certification of seafoods(S) and fisheries traditional foods of Ministry for Food, Agriculture, Forestry and Fisheries, on salted mackerel, Kwamegi and salted-dried croaker, items should be existed in raw material, shape, color, separation, process, flavor and foreign material for sensory quality control of high quality salted semi-dried fish and in moisture content, salinity, volatile basic nitrogen (VBN) content, peroxide value (POV), heavy metal, such as total mercury and lead, contents, viable cell counts, E. coli and others for chemical and microbial quality control. According to the application of commercial salted semi-dried fish in the established sensory provisions (suggestion), commercial salted semi-dried brown croaker passed in 3 kinds, such as sample code 9, 12 and 15, however, no all the other commercial salted semi-dried fish passed. The commercial salted semi-dried brown croaker, convict grouper and longneck croaker were ranged from 64.2% to 77.1% (mean 74.7±3.5%), from 64.6% to 76.1% (mean 71.5±4.4%) and from 65.7% to 77.5% (mean 72.8±4.3%), respectively, for moisture content, ranged from 2.1% to 9.5%, from 2.7% to 8.2% and from 1.5% to 4.9%, respectively, for salinity, ranged from 0.001 mg/kg to 0.008 mg/kg, from 0.004 mg/kg to 0.011 mg/kg and from 0.006 mg/kg to 0.054 mg/kg, respectively, for total mercury, not detected for lead, ranged from 14.1 mg/100g to 58.1 mg/100g, from 22.1 mg/100g to 88.2 mg/100g, 13.5 mg/100g to 87.4 mg/100g, respectively, for VBN, ranged from 19.1 meq/kg to 107.2 meq/kg, from 17.2 meq/kg to 195.0 meq/kg, from 28.5 meq/kg to 190.2 meq/kg, respectively, for POV. The viable cell counts of the commercial salted semi-dried brown croaker, convict grouper and longneck croaker were ranged from 4.2 log(CFU/g) to 8.3 log(CFU/g) 〔mean 6.2 log(CFU/g)〕, from 6.1 log(CFU/g) to 8.4 log(CFU/g)〔mean 7.1 log(CFU/g)〕 and from 5.4 log(CFU/g) to 7.2 log(CFU/g) 〔mean 6.4 log(CFU/g)〕, respectively. E. coli of commercial salted semi-dried fish was not detected in the 8 kinds of salted semi-dried brown croaker, such as sample code 5, 6, 9-13 and 21, 6 kinds of salted semi-dried convict grouper, such as sample code 22, 24-27 and 31, and 3 kinds of salted semi-dried longneck croaker. According to the application of commercial salted semi-dried fish in the established chemical, microbial and others provisions (suggestion), there were no commercial salted semi-dried fish passed in the provisions (suggestion). The sensory, chemical, microbial and other results of commercial salted semi-dried fish, such as commercial salted semi-dried brown croaker, convict grouper and longneck croaker suggested that the provisions (suggestion) to control quality of high quality salted semi-dried fish should be established. For development of high quality salted semi-dried CGM, the study of the chapter Ⅱ attempted to screen optimal salting drying methods, and to optimize the processing conditions (salt concentration, soaking time, dry temperature, drying time) for preparing salted semi-dried CGM based on moisture content, salinity and overall acceptance using response surface methodology (RSM). According to the results on moisture content, salinity and overall acceptance of salted semi-dried CGM prepared with different salting methods, such as dry salting, brine salting and modified brine salting, dry salting revealed as optimal salting method for preparing high quality salted semi-dried CGM. Optimal drying method for preparing high quality salted semi-dried CGM based on the drying velocity and sensory color was hot air-blast drying. According to the results of RSM program, the optimal independent variables (X1, salt concentration; X2, soaking time; X3, dry temperature; X4, drying time) based on the dependent variables (Y1, moisture content; Y2, salinity; Y3, overall acceptance) for high quality salted semi-dried CGM were -0.18 for X1, -0.35 for X2, -0.32 for X3 and 0.25 for X4 in coded values and 5.6 % for X1, 2.7 hr for X2, 47.0℃ for X3 and 8.5 hr for X4 in uncoded values. The predicted values of Y1, Y2 and Y3 in salted semi-dried CGM prepared under optimal conditions were 54.4%, 4.2% and 6.3, respectively, their experimental values were 55.2±1.0%, 4.1±0.3% and 6.7±0.8, respectively. No difference was slightly found in the data between the actual and predicted values. For effective use of salted semi-dried CGM prepared under optimal processing conditions, the study of the chapter Ⅲ attempted to investigate its quality characterization and to improve storage stability by soaking pre-treated CGM into green tea extracts, and to compare with those of 14 kinds of commercial salted semi-dried brown croaker. The proximate composition of salted semi-dried CGM prepared under optimal processing conditions were 55.3% moisture, 31.3% crude protein, 5.5% crude lipid and 5.7% ash, which was lower in moisture content than 14 kinds of commercial salted semi-dried brown croaker, was higher in crude protein and crude lipid contents. There was no difference in the ash content between salted semi-dried CGM and sample code 11 of commercial salted semi-dried brown croaker. The salinity of salted semi-dried CGM was 4.1±0.3%, which was ranged in 2.1-9.5%, that of 14 kinds of commercial salted semi-dried brown croaker. VBN content, viable cell count and E. coli of salted semi-dried CGM were 16.7 mg/100 g, 3.4 (logCFU/g)and no detection. These results suggested that the salted semi-dried CGM prepared under optimal processing conditions was more sanitary than those of commercial salted semi-dried brown croaker. POV of the salted semi-dried CGM was 9.9 meq/kg which was lower than 19.1-107.2 meq/kg, those of 14 kinds of commercial salted semi-dried brown croaker. Total amino acid content of the salted semi-dried CGM was 29.48 g/100 g, which was 30-69% higher than that of 14 kinds of commercial salted semi-dried brown croaker. There was no difference in mineral content, such as Ca, P and MG, expected for Fe between the salted semi-dried CGM and commercial salted semi-dried brown croaker. The EPA and DHA compositions was lower than in the salted semi-dried CGM than commercial salted semi-dried brown croaker. According to the results of total phenol content, antimicrobial activity, acid value (AV) and viable cell counts of salted semi-dried CGM prepared under optimal processing conditions during the storage, optimal concentration of green tea extract for extending shelf-life of the salted semi-dried CGM was more than 1.0%. In immediately after the preparation, no differences were found in the proximate composition, salinity, total amino acid, mineral contents and fatty acid compositin between green tea extract-treated and -untreated salted semi-dried CGMs. no differences were found in the changes of moisture content and pH during cold storage between green tea extract-treated and -untreated salted semi-dried CGMs. However, the changes in VBN content, viable cell count, POV, fatty acid composition and Hunter color value, such as L and △E values were lower in the salted semi-dried CGM prepared after soaking into green tea extract than in the salted semi-dried CGM unsoaked in green tea extract.