• Journal of the Korean Society of Food Science and Nutrition
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• v.16 no.4
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• pp.294-299
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• 1987

Lipid composition of dried grasshopper which the most significant factor of quality deteriorioration for processing and storage were studied. Also brown pigment formation and its effect of lipid autoxidation were studied. Lipid contents of matured female grasshopper were revealed 5.12% and composed of high content of unsaturated fatty acid. The phospholipid comprised 27.35% of the total lipid. On sun ana hot ai' drying, carbonyl values were greatly increased but peroxide values were not determined. On freeze drying, lipid peroxide and carbonyl compounds in grasshopper lipids were nearly not accumulated. Peroxide values were increased during early stage of storage, but carbonyl values were steadly increased for 98 days. Hydrophilic brown pigments which caused by sugar-amino reaction were higher than that of lipophilic. In the water soluble fraction of the browning products has some autioxidative activity, but in liposoluble fraction has not.

• Microbiology and Biotechnology Letters
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• v.11 no.1
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• pp.67-74
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• 1983

The studies on the color improvement of the Doenjang (two types of fermented soybean paste : soybean Doenjang and modified Doenjang) using various Aspergillus oryzae strains (6 strains : A, B, C, D, E, F) were conducted with the series of experiments of enzymatic activities (pretense, $\alpha$-and $\beta$-amylase), browning color formation (Lovibond color), major chemical components (amino nitrogen, reducing sugar and others) and sensory evaluation (color, taste and odor). Aspergillus oryzae 2157 (C strain) had a high potential for the color improvement of Doenjang products and was identified as non-browning strain during Doenjang fermentation and storage period. And also this strain was appeared to be in good enzyme activities and flavor characteristics.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.53 no.3
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• pp.273-280
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• 2020

Volatile compounds in fermented ascidians Halocynthia roretzi were analyzed to identify key flavor compounds using SPME/GC/MSD (solid phase microextraction/gas chromatography/mass selective detector) after 60 days of fermentation at 5℃. The control was chopped ascidians subject to anti-browning and 4% salt treatment. product A was made from product C by adding an alcohol extract of red peppers and onion peel, 0.1% of glucose, and 0.55% of mixed amino acids (MAA; 0.05% Glu, 0.1% Pro, 0.3% Ala, and 0.1% Gly). After blanching and anti-browning treatment of chopped ascidians, Product B1 was made by adding 3% anchovy sauce and 6% sorbitol. Product B2 was made by adding 0.1% glucose and 0.55% MAA to Product B1. In total, 78 compounds were identified, including 31 alcohols, 15 aldehydes, and 10 ketones. The alcohols included 12 compounds from the C8-C10 series with floral and fruit odors, including octanol, 3-methyloctanol, 2,6-dimethyl-1-heptanol, (E)-5-octen-1-ol, 6-methyloctanol, (E)-3-octen-1-ol, (E)-3-decen-1-ol, (Z)-1,5-octadien-3-ol, and nonanol. These were detected in high amounts in ascidians and all fermented products. Aldehydes (octanal, (E)-2-octenal, 2,4-heptadienal, and nonanal) and ketones (1-oten-3-one and 2-heptanone) with fatty and mushroom odors were detected as major compounds, whereas nine ethyl esters were detected only in product A.

• Journal of Microbiology and Biotechnology
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• v.24 no.10
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• pp.1368-1376
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• 2014

This article focuses on the effects of glycine betaine on preventing caramelization, and increasing DCW and $\small{L}$-lysine production. The additional glycine betaine not only decreased the browning intensity (decreased 4 times), and the concentrations of 5-hydroxymethylfurfural (decreased 7.8 times) and furfural (decreased 12 times), but also increased the availability of glucose (increased 17.5%) for $\small{L}$-lysine production. The DCW and $\small{L}$-lysine production were increased by adding no more than 20 mM glycine betaine, whereas the DCW and $\small{L}$-lysine production were decreased with the reduction of pH values, although pH had a better response to prevent caramelization than did glycine betaine. For $\small{L}$-lysine production, the highest increase (40%) was observed on the media with 20 mM glycine betaine. The crucial enzymes in glycolysis and $\small{L}$-lysine biosynthesis pathway were investigated. The results indicated that additional glycine betaine increases the activity of enzymes in glycolysis, in contrast to the effect of pH. All the results indicated that glycine betaine can be used to prevent caramelization and increase the $\small{L}$-lysine production. By applying this strategy, glucose would not be have to be separated from the culture media during autoclaving so that factories can save production costs and shorten the fermentation period.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.39 no.3
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• pp.283-291
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• 2006

This study examined the development of a low-salt fermented seafood product using an ascidian (Halocynthia roretzi), and the optimum processing conditions and quality characteristics of the low-salt fermented ascidian (LSA). The optimum processing conditions for the LSA were as follows. The ascidian was shelled and its muscle sliced into 5 mm widths. This was soaked in a 10% salt and 1% sodium erythorbate solution for 20 min. The solution was drained and then the muscle was soaked in 0.1% sodium bisulfite solution for 1 min. To this was added a 1:1 mixture of anchovy sauce and rice gruel, and it was fermented at $5^{\circ}C$ for 15 days. The moisture content and salinity of the LSA were 75.0-75.4% and 8.0-8.5%, respectively. During salt-fermentation at $5^{\circ}C$ for 20 days, the amino-N content of the LSA increased, and the texture softened gradually. The viable cell counts in early salt-fermentation were $4.2-4.5{\times}10^4CFU/g$, and this decreased gradually. The ratio of saturated fatty acids tended to increase in early salt-fermentation, while that of polyunsaturated fatty acids decreased slightly. Chemical experiments and sensory evaluation showed that the dipping treatment in 1% sodium erythorbate solution and 0.1% sodium bisulfite solution resulted in a good color and prevented browning of the salt-fermented ascidian meat. Moreover, adding anchovy sauce and rice gruel mixture improved the flavor of the LSA.

• Korean journal of food and cookery science
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• v.31 no.1
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• pp.62-71
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• 2015

The purpose of this study was to evaluate the changes on the characteristics of the oxidative stability of Tenebrio molitor larvae during cold storage at $4^{\circ}C$. Pretreatment for T. molitor larvae was designed into three methods: raw (R), freeze-dried (F.D.), and pan-fried (P.F.). The water content of the raw sample (61.46%) was higher than those of other samples (F.D.: 5.02%, P.F.: 3.67%) and its high water content was expected to facilitate the oxidation of the raw sample. In our results, the peroxide value and the carbonyl value of all of the samples increased and the raw sample, after storage for 18 day, showed the highest value. The pan-fried sample had no significant increase in its lactic acid content, acid value, and thiobarbituric acid value; whereas those values were increased in the raw sample and the freeze-dried sample (p<0.05). The browning reaction was more progressed in the pan-fried sample than other samples at 0 day, but there was no significant change during the storage. The raw sample and the freeze-dried sample had their browning indexes increase with the increasing storage period (p<0.05). The pan-fried sample produced less oxidation products than the freeze-dried sample, indicating that the unheated sample was more susceptible to oxidation than the heated samples. In conclusion, heating treatment and low water content would be effective for improving the safety and stability of T. molitor larvae during cold storage.

• Food Science and Preservation
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• v.10 no.2
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• pp.136-141
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• 2003

This they was conducted to investigate the surface treated effect of Packaged kimchi on the PH, acidity, total microbe, number of lactic acid bacteria, browning and formation of off-flavor during storage at 10$^{\circ}C$. Kimchi was treated with 70% ethanol(1 time spraying) and attachment of polyethylene film(PE) on the surface of packaged kimchi and stored at 10$^{\circ}C$. pH of the control and ethanol treated kimchi stored for 15 days was decreased to 4.0 level but, the pH of PE-treated kimchi maintained over pH 4.0 until 21 days of storage. The aridity was the same tendency as the pH, which showed delaying of fermentation by PE treatment. Total microbe of PE treated kimchi was lower and number of lactic acid bacteria was higher than those of control and ethanol treated products, respectively. Degree of browning and off-flavor of control and ethanol treated kimchi increased from 13 days of storage, but the degrees of the PE-treated kimchi was lower during all storage periods.

• Preventive Nutrition and Food Science
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• v.15 no.4
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• pp.287-296
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• 2010

This study was designed to investigate the influence of the pH and enantiomer on the antioxidant activity of Maillard reaction mixture solution in model systems. The loss of glucose in MRPs did not show different characteristics for the different amino acid enantiomers; however, the concentration of glucose decreased as the pH levels increased. The enolization of sugars was observed in all MRP samples according to increase of pH levels. In addition, D-amino acids were detected in L-amino acid systems and L-amino acids could also be observed in D-amino acid systems. Formation of the isomer was the highest in the Glc/L-Lys system. The browning development increased as pH levels increased; however, browning development did not show different characteristics based on the use of L- versus D-isomers of the same amino acid. The L- and D-isomers show different absorption values in the UV-Vis spectra, but the absorption patterns display a similar shape. The antioxidant activities of MRPs derived from the Glc/Gly, Glc/L-Asn and Glc/D-Asn systems at pH 7.0 were greater compared to those of pH 4.0 and pH 10.0. The antioxidant activities of MRPs derived from the Glc/L-Lys and Glc/D-Lys systems decreased as the pH increased. In addition, the results show that the MRPs derived from the D-isomers have similar antioxidant activities as those from L-isomer. Therefore, the MRPs have the different antioxidant activities on the basis of the pH level, but not on the basis of different amino acid enantiomers.

• Food Science and Preservation
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• v.31 no.2
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• pp.235-244
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• 2024

A nonthermally sterilized raw apple vinegar was manufactured using an ultra-fine filtration process (0.2 ㎛ membrane filter) and its quality was comparable to commercially available vinegar products. First, using apple concentrate as a raw material, it was possible to produce non-thermal sterilized Using a two-stage fermentation process of alcohol and acetic acid fermentations, a non-thermally sterilized raw apple vinegar with pH 2.94 and an acidity of 6.20% was produced from an apple concentrate. The fermentation process increased the browning index significantly. However, the fundamental quality parameters of the non-thermal sterilized raw apple vinegar (A) with sterilized apple vinegar (B) did not differ significantly. The pH (2.92-2.95) of apple vinegar (A and B) was higher than that (pH 2.65-2.70) of commercial vinegar (C and D), and the total acidity, which is in the range of 6.20-6.21% and 6.53-6.90%, respectively, was higher in samples C and D than in samples A and B. However, four kinds of organic acids were detected in non-thermal sterilized raw apple vinegar (A), and its total organic acid content (6,245.00 mg%) was significantly higher than that of other samples (B, C, D) (p<0.05). In particular, malic acid content, as a main organic acid in apples, was very high in sample (A) (244.83 mg%) and sample (B) (210.21 mg%), compared to commercial products C (125.78 mg%) and D (86.90 mg%). The total polyphenol content and antioxidant activity of fermented apple vinegar (A, B) were more than twice as high as those of commercial products (C, D). Vinegar A had higher total polyphenol content than vinegar B. The above results suggest it is possible to manufacture and commercialize non-thermal sterilized raw apple vinegar with higher organic acid content and antioxidant properties using ultra-fine filtration.

• Korean journal of food and cookery science
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• v.10 no.4
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• pp.339-345
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• 1994

Polyphenol oxidase in Yam was partially purified through ammonium sulfate fractionation, DEAE-cellulose column chromatography. The specific activity of purified PPO was 138.22 unit/mg protein. The optimum pH and temperature of purified PPO were respectively 7.0 and 30$^{\circ}C$. The heat treatment at 80$^{\circ}C$ for 6 min, decreased PPO activity to 50%. The enzyme showed high substrate specificity toward catechol. The Km value for catechol was 5 mM. In the Ames test using S. typhimurium TA98 and TA100 catechol-YEBRP, pyrogallol-YEBRP, chlorogenic-YEBRP showed strong antimutagenicity on sodium azide and MECF excepting hydroquinone-YEBRP showed killing effect on both strains.