• Resources Recycling
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• v.25 no.6
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• pp.98-104
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• 2016

The purpose of this study is to obtain an optimum condition of the concentrate by floatation using Australian low grade copper ore of suitable particle size by crushing, grinding and sizing. The effect of the dosage of collector, activator, depressant and change of acidity on the floatation was investigated. The floatation conditions comprising of pH 9.0 acidity, 500g/t $CuSO_4{\cdot}5H_2O$ activator, 500g/t K.E.X. collector, 1500g/t $Na_2SO_3$ depressant and 25wt.% plup density were optimized. Grade and recovery of copper in the concentrate obtained by froth floatation under optimum conditions were 4wt.% and 65wt.% respectively.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2011.10a
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• pp.255-269
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• 2011

The purpose of study has to analyze with non destructive method for researching the tool that could be measured with the status of record written on Hanji speedily. Because the original record should be destructed for analyzing with previous method in the case of the paper record, it was to develop the tool based on non destructive method for overcoming such limit. The study was used with FT NIR (Fourier transform NIR) for analyzing the Hanji for being written and preserved. The FT NIR spectrometer that of NIR spectrometer has the better performance of precision and accuracy than dispersive NIR spectrometer was used. Also the wavelength of FT-NIR was measured with 12,500 to 4,000 $cm^{-1}$, and the integrating sphere as diffuse reflectance type was used for analyzing Hanji. The moisture and acidity (pH) of chemical factors as quality evaluated factor of Hanji was studied for the correlation of NIR spectrum. And then The NIR spectrum was pretreated for showing the coefficients of optimum correlation. MSC and First derivative of Savitzky - Golay was used as pretreated method, and the coefficients of optimum correlation were shown by PLSR(Partial least square regression). And the coefficients of optimum correlation were calculated by PLSR(Partial least square regression). The correlation coefficients of acidity had 0.92 on NIR spectra without pretreatment. Also the SEP of acidity was 0.24. And then The NIR spectra with pretreatment would have more good correlation coefficients ($R^2=0.98$) and more good SEP(=019) on acidity. Therefore the data of correlation coefficients ($R^2$) and SEP with pretreatment was shown to be superior. And NIR spectra data of first derivative had best linearity on the correlation coefficients ($R^2=0.99$) and also SEP(=0.45) was superior. Therefore the correlation coefficients and SEP of first derivative had better than those of NIR spectra of no pretreatment. As such result, it was possible to evaluate the record status of Hanji speedily with integrated sphere and NIR analyzer as non destructive method.

• Korean journal of food and cookery science
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• v.10 no.4
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• pp.315-321
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• 1994

The addition of green tea to kimchi making for extanding the optimum edible period was studied. The equality and sensory characteristics of green tea added kimchi were evaluated. The acidity, lactic acid and acetic acid contents of green tea added kimchi showed lower than that of control kimchi but reducing sugar and vitamin C contents was higher. The duration of optimum edible periods of green tea added kimchi lasted two more weeks. While the optimum pH of kimchi for eating lasted, the sensory pannel score for sour taste of green tea added kimchi was lower than that of control but the scores for overall quality and hardness were higher. Especially, the sour taste score between two groups were significantly different(p<0.05). There was no differences in texture determined by Penetrometer between green tea added kimchi and control kimchi until the fermentation reached the optimal condition for eating. After that period, the degree of degradation of texture was much delayed in green tea added kimchi.

• Food Science and Biotechnology
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• v.16 no.4
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• pp.526-530
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• 2007

The objective of this study was to establish the optimum alcohol fermenting conditions for the processing of kiwi wine and vinegar products. Six yeast strains were examined for their alcohol production from kiwi at $30^{\circ}C$ for 72 hr with continuous shaking at 100 rpm. Under these conditions, Saccharomyces kluyveri DJ97 produced the highest alcohol content of 10.2%. As the fermentation time extended to 96 hr, the alcohol content reached a maximum of 12.75%. The optimum alcohol fermenting conditions for kiwi fruit were accomplished when kiwi was added to an equal amount of water, inoculated with S. kluyveri DJ97 and fermented at $30^{\circ}C$ for 96 hr with continuous shaking. The content of soluble solids decreased as the alcohol concentration increased, whereas little change was observed in the pH and titratable acidity during the low temperature aging process. Other alcoholic compounds, such as methanol, isopropanol, n-propanol, isobutanol, and isoamylalcohol, tended to increase as fermentation progressed.

• Journal of Sericultural and Entomological Science
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• v.15 no.2
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• pp.45-53
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• 1973

1. The sericin solubility increased rapidly as the increase of water M-alkalinity. 2. The acidity of the treated water was nutralized at the over 25ppm of M-alkalinity. 3. The more M-alkalinity of the sample water is, the more M-alkalinity was found after cocoon treat. 4. The total hardness of sample water seemed to be droped as M-alkalinity increased. 5. The sericin solubility also seemed to be droped as the increase of water acidity. 6. In case of treat finish with cocoon, the acidity and total hardness seemed to increase as the acidity of the water increased, but M-alkalinity was nutralized at 20~40 ppm of water acidity or the M-alkalinity could not be found in case over 40ppm of acidity. 7. In case increase of iron component with sample water, sericin solubility seemed to drop down, and mangan component showed the same nature but dull drop. 8. After cocoon was treated with water, acidity, M-alkalinity and total hardness were increased by the extraction from cocoon shell because of pH and treating temperature but not because of iron componnent. Mangan component, however, affected as to increase of acidity and total hardness but to decrease for M-alkalinity. 9. In case change of M-alkalinity and total hardness, sericin solubility has increased also. 10. In case constant pH and total hardness, the more M-alkalinity is, the more sericin solubility was found. 11. In case constant pH, total hardness, and M-alkalinity, the more acidity is, the less sericin solubility was found. 12. In case constant pH(6.8) and M-alkalinity, the more total hardness is, the less sericin solubility was found. 13. Though the combination of water, high solubility water, medium solubility water and low solubility water were prepared. The high solubility water desolved sericin 2.2% more than low solubility water. And the medium solubility water desolved sericin as much as 2.4~2.9%. 14. It was found that the most important factors for filature water are pH, M-alkalinity, acidity and total hardness which may need more words for optimum filature water development. 15. In case of repeat use of water, the buffer action of water has increased so that the sericin solubility to be decreased.

• Food Quality and Culture
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• v.1 no.1
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• pp.27-33
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• 2007

In this study, we examined the effects of different concentrations of red pepper seed (0%, 1%, 3%, 5%, and 7%) on pH, total acidity, color, reducing sugar content, total microbes, lactic acid bacteria, and sensory quality, in terms of prolonging the shelf-life of kimchi. The additions of red pepper seed resulted in higher pH levels, while total acidity was lower than that of the control. The kimchi with red pepper seed had higher reducing sugar contents than the control. Furthermore, the kimchi with red pepper seed showed higher b-values than the control. During fermentation, the amounts of lactic acid bacteria and total microbes were higher in the kimchi with red pepper seed than in the control, and the higher ratios resulted in higher quality kimchi. The additions of red pepper seed also resulted in changes of color, flavor, taste, and texture, having a large influence on overall product quality. In conclusion, in terms of preservation and consumption, the 3% and 5% red pepper seed concentrations offered enhanced shelf-life and better quality kimchi products.

• Food Science and Biotechnology
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• v.18 no.4
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• pp.939-947
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• 2009

In order to produce vinegar using onions, 12 acetic acid bacteria were screened from the juice of fallen peaches, and a strain showing the highest acetic acid productivity among them was selected and identified as Acetobacter tropicalis No. 22. The culture broth containing 2.5%(w/v) of initial sugar concentration showed maximum acetic production after 10 days of cultivation, and the acetic acid was produced at the highest rate and reached the maximum acidity after 2 to 6 days of cultivation when the residual sugar and the ethanol concentration were in the range of 1.6 to 2%(w/v) and 0.6 to 1.8%(v/v), respectively. Also optimum conditions for acetic acid production by response surface method using the fractional factorial design with 3 variables and 5 levels were involved with initial ethanol content of 4.67%(v/v), initial acidity of 0.03%, and initial glucose concentration of 2.35%(w/v) and predicted level of acetic acid production at these conditions was 3.77%.

• Journal of the Korean Society of Food Science and Nutrition
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• v.28 no.2
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• pp.365-370
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• 1999

To investigate the effect of natural plants on the prolongation of optimal fermentation time of kakdugi, various kakdugies, added with hot water extract from 105 kinds of natural plants(68 medicinal plants and 37 vegetables), were fermented at 20oC until optimal fermentation time. In case of control without addition, the time required to reach the optimum acidity(0.6% lactic acid) was 60 hr. Among 105 kinds tested, 48 plant(42 medicinal plants and 6vegetables) extracts decreased the acidity after 60 hr fermentation to less than 50% of control. In addition, these extracts extended the optimal fermen tation time(>120 hr) by more than 2 folds. Moreover, among the above 48 kinds, 12 sorts of extracts raised the hardness of kakdugi, by more than 30%, compared to control. And the number of lactic acid bacteria in kakdugi added with the above 12 kinds was not smaller than that of control. In sensory test, 8 kinds of medicinal plants(including Phyllostachys edulis) were found to be acceptable. Based on these results, it is suggested that kakdugi added with 8 kinds of medicinal plants was adequate in the prolongation of optimal fermentation time of kakdugi.

• Food Science and Preservation
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• v.10 no.4
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• pp.470-475
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• 2003

The response surface methodology was performed by central composite design for moisture content, titratable acidity, hunter's color value and organoleptic properties based on drying temperature and time of Citrus, to apply basic data to preparation of dried Citrus. Moisture content, b value and organoleptic color were affected by drying temperature ; That decreased with increase of drying temperature. Titratable acidity was affected by drying time. Organoleptic flavor and taste were affected by drying temperature and time. The optimum drying conditons for organoleptic taste were 67.56$^{\circ}C$ in drying temperature and 8.06 hr in drying time.

• Journal of the Korean Society of Food Science and Nutrition
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• v.38 no.1
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• pp.116-120
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• 2009

Response surface methodology (RSM) was applied to optimize alcohol fermentation of concentrated grape juice. Sugar concentration ($X_1$), agitation rate ($X_2$) and fermentation time ($X_3$) were chosen as the independent variables of the central composite design (CCD). Dependent variables were alcohol content ($Y_1$) and total acidity ($Y_2$). To optimize two dependent variables, desirability function was defined as $Y_1$=10.0% and $Y_2$=minimum. The optimum conditions for alcohol fermentation were $19.98^{\circ}Bx$ (sugar concentration), 104.1 rpm (agitation rate) and 89.67 hr (fermentation time). The predicted responses were 10.0% in alcohol content and 0.86% in total acidity. The coefficients of determination ($R^2$) were 0.948 and 0.958, which indicate that the model fit was highly significant (p<0.001). The experimental values were 10.1% for alcohol content and 0.88% for total acidity. These values were similar to the predicted values from RSM.