• Korean journal of food and cookery science
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• v.26 no.3
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• pp.323-329
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• 2010

Studies on the tenderizing effect of fruits has been limited even though fig, kiwifruit, pear, and pineapple cultivated in Korea are utilized commonly during cooking for their proteolytic properties. Therefore, the characteristics of these fruits were investigated by treating beef with their crude protease extracts. The protease effects of crude protease extract from the fruits on casein and myofibrilar protein were in the following order : pineapple > kiwifruit > fig > pear. Electrophoretic analysis results found that pineapple, kiwifruit, and fig cleaved myosin heavy chain into smaller fragments. The myofibrilar fragmentation ratio of crude protease extracts was the highest for pineapple whileas the lowest for pear. Ground fruits (5% and 10%) increased amounts of soluble nitrogen and decreased shear force of beef. Pineapple was the most effective while pear was the least effective. Decrease in springiness and gumminess was observed by texture profile analysis of beef treated with fruits, especially pineapple and kiwifruit. Among the 5% treatments, pineapple and kiwifruit produced the highest tenderness. Additionally, 10% treatment was less preferable than the 5% treatment.

• Korean Journal of Agricultural Science
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• v.47 no.3
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• pp.459-470
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• 2020

This study investigated the effects of the proteolytic hydrolysates of α-lactalbumin (LA), β-lactoglobulin (LG) and bovine serum albumin (BSA) by alcalase on inflammatory cytokines. The proteolytic hydrolysates were separated into two fraction of peptides, ≤ 10,000 Da and > 10,000 Da, respectively, because various low molecular weight peptides were generated during the hydrolysis reaction time. Among the hydrolysate peptides, BSA (all types), β-LG (> 10,000 Da), and α-LA (> 10,000 Da) showed an inhibitory activity against thymic stromal lymphopoietin (TSLP) mRNA expression in lipopolysaccharide-induced RAW264.7 murine macrophages. α-LA (> 10,000 Da), β-LG (hydrolysates), and BSA (> 10,000 Da) showed an inhibitory activity against tumor necrosis factor (TNF)-α expression. α-LA (all types), β-LG (hydrolysates, > 10,000 Da), and BSA (> 10,000 Da) showed an inhibitory activity against interleukin-6 (IL-6) expression. α-LA (> 10,000 Da), β-LG (> 10,000 Da), and BSA (all types) showed an inhibitory activity against inducible nitric oxide synthase (iNOS) expression. α-LA (> 10,000 Da), β-LG (> 10,000 Da), and BSA (all types) showed an inhibitory activity against cyclooxygenase (COX)-2 expression. The lowest level of TNF-α production was measured with α-LA (> 10,000 Da) and β-LG (> 10,000 Da) for all types, and a similar low level was measured for all types of BSA. The highest level of IL- 6 production was measured with α-LA (≤ 10,000 Da) among α-LA, β-LG, and IL-6. The low level of NO production was similar with α-LA, β-LG, and BSA but not with α-LA (≤ 10,000 Da). These potential peptides from whey protein hydrolysates could be used for food, medicinal, and industrial applications.

• Korean Journal of Food Science and Technology
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• v.34 no.4
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• pp.570-576
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• 2002

For the utilization of the by-products of whelk processing, whelk internal organ with the addition of commercial proteolytic enzymes - Flavourzyme, Neutrase, Protease NP, Prozyme - were used to make jeotgal, Korean traditional salted and fermented seafood sauce. The products were prepared at salt concentration of 25% with enzyme contents 0.05 and 0.1%. The samples were stored at $10^{\circ}C$ and the chemical properties were evaluated for 6 months. The pH in all samples were decreased from near 6.8 in the beginning stage to 6.1-6.4 in the final stage of incubation. Amino nitrogen of jeotgal increased with enzyme concentration and showed maximum value, 646 mg%, at 0.1% of Flavourzyme. Total nitrogen content was increased till four months, but rapidly decreased after that. Protein degradations of whelk internal organ during maturation of jeotgals were investigated by SDS-PAGE. The patterns of degradation were different with added enzymes.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.27 no.6
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• pp.839-846
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• 1994

Changing concepts in fishery science increasingly are recognizing depletion of traditional stocks, utilization of alternate(non-traditional) species, demand for high quality products, and a total resource utilization approach. Innovative practices are occurring in fisheries processing wherein solid and liquid discharges are no longer treated as 'waste,' but rather as valuable feedstocks for recovery of a variety of value-added ('value enhanced') by-products. Among these are protein hydrolysates, soluble proteins and amino acids, proteolytic enzymes, flavor and flavor extracts, pigments, and biopolymers such as chitosan. Properties and applications of this deacetylated derivative of chitin are noted. Crustacean processing by-products are discussed in terms of their serving as materials for generation of natural flavors and flavor extracts, and products such as fish sauces using contemporary enzymatic techniques. Various food and feed applications of fisheries processing by-products are illustrated with increased usage seen in formulated diets for an expanding aquaculture market. Examples are given of aquaculture becoming increasingly significant in global fisheries resource projections. Critical issues in the international seafood industry Include those of seafood quality, processing quality assurance (HACCP), and recognition of the nutritional and health-related properties of fisheries products. A variety of current seafood processing research is discussed, including that of alternate fish species for surimi manufacture and formulation of value-added seafood products from crawfish and blue crab processing operations. Increasing emphasis is being placed on international aspects of global fisheries and the role of aquaculture in such considerations. Coupled with the need for the aquatic food industry to develop innovative seafood products for the 21st century is that of total resource utilization. Contemporary approaches in seafood processing recognize the need to discard the traditional concept of processing 'waste' and adapt a more realistic, and economically sound, approach of usable by-products for food and feed application. For example, in a period of declining natural fishery resources it is no longer feasible to discard fish frames following fillet removal when a significant amount of residual valuable flesh is present that can be readily recovered and properly utilized in a variety of mince-based formulated seafood products.

• Food Science of Animal Resources
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• v.35 no.3
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• pp.339-349
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• 2015

The objective of this study was to identify lactic acid bacteria (LAB) isolated from kimchi and to evaluate its characteristics and functional properties for application in fermented dairy products as a probiotic or commercial starter culture. Eight stains isolated from kimchi were selected through an investigation of phenotypic characteristics. Two strains (DK211 and DK303) were identified as Lactobacillus plantarum, another two (DK207 and DK215) as Lactobacillus paracasei, and one (DK301) as Lactobacillus sakei. The remaining three strains were identified as species of Weissella. All selected Lactobacillus strains had acid and bile tolerance, even though there was wide variation in the ability of each strain. DK303 showed a remarkably higher proteolytic activity. There were no significant differences in β-galactosidase activity among the tested strains, except that DK301 showed no activity. Auto-aggregation varied between 82.1 and 90.0%, and hydrophobicity values ranged from 0.5 to 51.6%.The strongest auto-aggregation and hydrophobicity were observed in DK211. All selected strains showed better 1,1-diphenyl-2-picrylhydrzyl (DPPH) scavenging activity than commercial strains. DK211, DK215, DK301, and DK303 had effective inhibitory activity against all pathogens tested except E. coli. When selected strains were used for yogurt preparation as a single starter culture, the time required to reach target titratable acidity (0.9) was 11-12 h. The yogurt fermented with DK211 had favorable panelists ratings for most sensory attributes, which were comparable with yogurt fermented with a commercial strain. The results suggest that strains isolated from kimchi could be potential probiotic and starter cultures for use in yogurt manufacturing.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.17
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• pp.7575-7582
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• 2015

Cyclin E, a key coordinator of the G1 to S transition in the cell cycle, may be deregulated in several malignancies, including breast cancer. The most significant aberration in cyclin E is its elastase mediated proteolytic cleavage into tumor specific low molecular weight isoforms (LMW-Es). LMW-Es are biochemically hyperactive and biologically drive tumorigenesis in transgenic mouse models. Additionally, expression of LMW-Es has been correlated with poor survival in breast cancer cases. Here we determine whether expression of LMW-Es in a breast cancer cell line that is naturally devoid of these deregulated forms would alter their progression through each phase of the cell cycle. The results revealed that LMW-Es expression resulted in an increased doubling time, concomitant with a predominant increase in the population in the S phase of the cell cycle. Moreover, downregulation of p53 in LMW-Es cells resulted in additional shortening of the doubling time and enrichment of cells in the S and G2/M phases of the cell cycle. Furthermore, expression of LMW-Es sensitized cells to ${\beta}$-estradiol (E2) mediated growth and changed expression patterns of estrogen receptor and Bcl-2. Intriguingly, expression of LMW-Es could surpass anti-apoptotic effects raised by p53 upregulation. Taken together these studies suggest that overexpression of LMW-Es in collaboration with p53 loss results in altered g rowth properties of MCF-7 cells, enhancing the oncogenic activity of these ER positive breast cancer cells.

• Food Science of Animal Resources
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• v.44 no.1
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• pp.103-118
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• 2024

The aim of this study is to compare the quality characteristics of dry-cured loins with different levels of proteolysis and lipid oxidation and to investigate the relationship between these factors on quality characteristics. The dry-cured loins were divided into four groups [proteolytic index (PI) and 2-thiobarbituric acid reactive substances (TBARS) of high levels (HH), PI of high level and TBARS of low level (HL), PI of low level and TBARS of high level (LH), and PI and TBARS of low levels (LL)] based on the proteolysis index and TBARS. Moisture, protein, and fat content were all significantly influenced by proteolysis and lipid oxidation (p<0.05). The total fatty acid content in the high proteolysis groups (HH and HL) was significantly lower than that in the low proteolysis groups (LH and LL; p<0.05). For total free amino acid content, HH was the highest, and LL was the lowest (p<0.05). On the other hand, there was no significant difference between HL and LH (p>0.05). In the amount of total volatile compounds, there was no significant difference between HH and HL (p>0.05), but LH and LL significantly differed (p<0.05). In conclusion, proteolysis and lipid oxidation can influence the quality characteristics of dry-cured loin. Additionally, proteolysis might be as influential in generating volatile compounds as lipid oxidation.

• Food Science and Preservation
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• v.23 no.3
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• pp.291-300
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• 2016

Kiwifruit (Actinidia chinensis, Hayward) was stored at $25^{\circ}C$ for 0~30 days and investigated to find out the optimum storage time to obtain the best physical and functional properties for consumers' preference. Kiwifruits was stored at different time period (0, 5, 10, 15, 20, and 30 days) for investigating their physiochemical quality, nutritional components, and functional characteristics. Kiwifruits stored for 20~30 days showed the best physiochemical quality such as higher total acidity and proper firmness. They were also more enriched with dietary fibers, free sugar, and organic acid, although no significant changes were observed in crude protein, crude fat, and moisture content. For functional properties, kiwifruits stored for 20 days showed significantly higher contents of total phenolics, flavonoids, and actinidin. In addition, it showed stronger antioxidant activity, whitening effect, and proteolytic activity when compared with other samples. SDS-PAGE analysis showed the presence of actinidin enzyme in kiwifruits. These results indicated that the kiwifruits stored for 15~20 days possessed excellent quality and high concentrations of nutritional and functional compounds, which could be best for both fresh consumption and product processing.

• Journal of Dairy Science and Biotechnology
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• v.32 no.2
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• pp.131-139
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• 2014

The aim of this study was to manufacture Cutting-Gouda cheese and to investigate the change in physicochemical properties of Cutting-Gouda cheese made with Lactobacillus rhamnosus_p1. Lactic acid bacteria were isolated from Gouda cheese ripened for more than 1 year. They were identified as 2 strains of L. rhamnosus, Lactobacillus casei, Lactobacillus curvatus, and Staphylococcus saprophyticus by 16S rDNA sequencing and named L. rhamnosus_p1, L. casei_p2, L. curvatus_p3, L. rhamnosus_p4 and S. saprophyticus_p5. The proteolytic activities of isolated strains against casein were measured using prepared skim milk agar plates. L. rhamnosus_p1 showed the highest proteolytic activity. Cutting-Gouda cheese was made with L. rhamnosus_p1, and its physicochemical properties (moisture, protein, fat, ash and free amino acid content) were measured during ripening periods. Because of the modified atmosphere packaging ($N_2{^-}$), there was no change in moisture, protein, fat, and ash in the experimental group. The total amount of free amino acids in the control and experimental group gradually increased during ripening periods. The sensory evaluation showed that the experimental group was preferable to the control group. This result suggests that L. rhamnosus_p1 has potential to be developed as a new starter for Gouda cheese.

• Korean journal of food and cookery science
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• v.17 no.1
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• pp.65-79
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• 2001

The effects of ${\alpha}$-chymotrypsin and trypsin treatments on the functional properties (degree of hydrolysis, solubility, and emulsifying capacity) of the soy protein isolate prepared from Jinpum soybean milk(JS milk) which has been developed as low lipoxidase-active soybean variety in Korea and extracted from commercially defatted soybean meal milk(DSM milk). The mixing ratios of JS milk to DSM milk were adjusted to 10:0, 7:3, and 5:5, respectively. The general quality attributes(yield, pH, titrable acidity, moisture contents, crude protein contents, color, textural properties, and sensory characteristics) of soybean cheese which has been prepared with the resulting soy protein hydrolysates were evaluated. Jinpum SPI was better subjected to trypsin than ${\alpha}$-chymotrypsin hydrolyses as indicated by better solubility and emulsifying capacity of the hydrolysates. The degree of hydrolysis and solubility of Jinpum SPI were higher than the soybean isolates from DSM milk. The increased ratios of DSM milk in the mixture resulted in the reduced yields and crude protein content along with the lowered titratable acidity while the pH values and moisture contents showed the opposite trends. In color characteristics, the increased amount of DSM milk brought about the significantly lower Hunter color reflectance values of lightness of the cheese products, along with the higher redness and total color difference value(ΔE). However, the enzyme treatment alone was not enough to cause any color differences. The increased ratios of DSM milk also caused the significantly lowered textural parameters such as hardness, adhesiveness and cohesiveness of the soybean cheese. Between the enzyme treatments, the ${\alpha}$-chymotrypsin treated samples resulted in the higher hardness and cohesiveness values of the products than those from the trypsin-treated ones. In organoleptic properties of the product, the better mouthfeel and overall quality scores were obtained from the trypsin treatments as compared with those from the ${\alpha}$-chymotrypsin ones. The mixing ratios of 10:0 and 7:3 were more favored than that of 5:5 as far as mouth-feel, yellowness and overall quality of the products were concerned. On the overall, the mixing ratio of 7:3(JS milk: DSM milk) and the trypsin treatment of the mixture was recommended for better manufacturing of high-quality soybean cheese.