• Korean Journal of Food Science and Technology
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• v.22 no.5
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• pp.596-601
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• 1990

The effects of peroxidized lipid on the protein in the biological system of rice bran was studied by determining the changes in the content of functional groups under two different storage conditions. One stored at controlled atmosphere of $35^{\circ}C$ with relative humidity 65% and the other one was exposed to the air of $25^{\circ}-30^{\circ}C$ with relative humidity 70-90%. The lipid peroxidation started after the lipolysis was almost completed. The autoxidation occurred much faster in the bran exposed to the air than that stored in the controlled atmosphere. Substantial changes in the physiochemical characteristics were observed in all of the major functional groups in both of the samples. The content of sulfhydryl and available lysine decrease·1 as lipid peroxidation progressed. Protease activity was lost almost completely. Protein solubility and in vitro digestibility also decreased during storage. The lipid peroxidation and contents of major protein functional groups were significantly correlated (p<0.05) and the correlation coefficients were higher than -0.8, for the both of the sample. peroxidized lipid was found to deteriorate protein in the biological system as well.

• Journal of Environmental Health Sciences
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• v.30 no.4
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• pp.308-313
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• 2004

Native and acetylated soybean protein with acetylation percentage of $25\%$ were incubated with glucose to induce Maillard reaction. Acetylation of ${\varepsilon}$-amino group of lysine residues changed the conformation of soybean protein. The direct uv spectrum of native and acetylated soybean protein showed conformational changes with accessibility of tyrosine and tryptophan residues increased. Acetylation suppressed Maillard reaction between soybean protein and glucose. Acetylated soybean protein showed improved water sorption, fat binding, foam formation, and emulsion activity of the protein, but depressed brown pigment development and trypsin digestion. Thus aceylation prevented deterioration of certain functional characteristics that occurred during storage, besides causing functional characteristics to be improved on its own.

• Journal of the Korean Society of Food Science and Nutrition
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• v.28 no.1
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• pp.145-152
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• 1999

To explore the possibility of using freeze dried loach for instant choo o tang(Korean traditional loach soup), protein qualities and fatty acid composition were evaluated on boiled and steamed loach. Total lipid and ash content were lowered in both heated(boiled and steamed) loaches due to deboning and eviscerating during cooked meat preparation. Profiles of total amino acids were not changed seriously by the type of cooking, but the amount of essential amino acids were comparable in all samples. Two times more free amino acids were quantified in cooked samples compared to raw meat. Available lysine was marginally decreased by cooking, and that caused some measurable change in typsin indigestible substrate(TI) in streamed whole loach. In vitro protein digestibility of the heated loaches was not altered drastically and the protein quality determined as computed protein efficiency ratio(C PER) was similar for the raw, boiled and steamed loach. The ratios of unsaturated to saturated fatty acids changed measurably in heated whole loach. The results shows that heating caused apparent oxidative deterioration of the polyunsaturated fatty acids.

• Journal of the Korean Society of Food Science and Nutrition
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• v.23 no.5
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• pp.867-878
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• 1994

A general overview of the lipid peroxidation and its nutritional significance are presented ,with emphasis on the reaction mechaisms, peroxidized products, further interaction and nutritional/biological deterioration in a series of oxidative process. Overall mechanism with various factors and elements for initiation , propagation and termination of free radical reaction is reviewed and the primary /secondary products of peroxidized lipids are defined. Since these products are potentially reactive substances that can cause deterioration of proteins /amino acids and vitamins (carotene, tocopherols and ascorbic acid etc), mechanism and actual damages of their deterioration in some foods and biological models are outlined. Especially , chemical changes caused by interaction of peroxidized products (related hydroperoxides, radicals and malonaldehye etc) and protein are emphasized here. And also, the detailed mechanisms on radical scavenging of the these vitamins which are the most prominent natural antioxidants are presented . Additionally , the possible roles of peroxidicaed lipids and their secondary products in the process of aging an carcinogenesis are briefly discussed . However, it is important to not that more detailed and integrated studies on the reaction kinetics, energetics of peroxidation, their decomposed products , biochemical interaction potential damaging/aging / carcinogenic effects, protection from their oxidative spoilage and novel antioxidants in food and heterogeneous biological systems will be essential in order to assessing the implication of lipid peroxidation to human nutrition and health.

• Food Science of Animal Resources
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• v.37 no.1
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• pp.114-122
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• 2017

This study was conducted to evaluate the effects of clove extract (CE) (0.25%, 0.5%, 1%, and 2%) on the oxidative stability and quality deterioration of Chinese-style sausage stored for 21 d at $4^{\circ}C$. The addition of clove extract to sausages significantly retarded increases in Thiobarbituric Reactive Substances (TBARS) values (p<0.05), while also controlling the production of protein carbonyls (p<0.05). However, the addition of clove extract promoted reduced thiol group content in sausages (p<0.05). Sausages amended with clove extract also had decreased $L^*$ values (p<0.05) and increased $a^*$ values (p<0.05) when compared with the control. Similarly, texture deterioration was retarded in sausage containing added clove extract when compared with the control during refrigerated storage. Moreover, the addition of clove extract had no negative effects on the sensory properties of sausages. These results suggested that clove extract was effective at protecting sausages from oxidation and quality deterioration during refrigerated storage for 21 d.

• BMB Reports
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• v.39 no.3
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• pp.335-338
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• 2006

Methylglyoxal (MG) is an endogenous physiological metabolite which is present in increased concentrations in diabetics. MG reacts with the amino acids of proteins to form advanced glycation end products. In this in vitro study, we investigated the effect of MG on the structure and function of ceruloplasmin (CP) a serum oxidase carrier of copper ions in the human. When CP was incubated with MG, the protein showed increased electrophoretic mobility which represented the aggregates at a high concentration of MG (100 mM). MG-mediated CP aggregation led to the loss of enzymatic activity and the release of copper ions from the protein. Radical scavengers and copper ion chelators significantly prevented CP aggregation. CP is an important protein that circulates in plasma as a major copper transport protein. It is suggested that oxidative damage of CP by MG may induce perturbations of the copper transport system and subsequently lead to harmful intracellular condition. The proposed mechanism, in part, may provide an explanation for the deterioration of organs in the diabetic patient.

• Journal of Nutrition and Health
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• v.29 no.10
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• pp.1059-1071
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• 1996

This study was performed to investigate the effect of dietary protein level on renal senescence. Male rats of 337.8$\pm$5.7g body weight were underlateral nephrectomy or shamoperation. The rats were divided into high protein(40% casein), normal protein(15% casein) and low protein(8% casein)diets and fed experimental diets ad libitum for 24 weeks. The results are summarized as follows. There was a hypertophy of the remnant kidney of uninephrectomized rats of 40% or 15% protein group, coming up to the comparable weights of both kidneys of sham-operated rats. However, the hypertrophic effect was not seen in uninephrectomized rats of 8% protein group. Serum albumin was lower in uninephrectomized rats. With increasing dietary protein level blood urea nitrogen was increased, whereas, urinary urea nitrogen excretion was decreased. Urinary solute excretion was higher in uninephrectomized group than in sham-operated group. However, effect of dietary protein level on urinary solute excretion varied dpending on th solutes tested. GFR and urinary protein excretion, throughout experiment, increased with feeding period and with dietary protein level. Proteinuria was most severe in uninephrectomized rats fed 40% casein diet. Maximum urine concentration ability measured after dehydration was not different among the experimental groups. Light microscopic examination showed focal segmental glomerulosclerosis and mild increas of glomerular mesangial matrix in uninephrectomized rats fed 40% and 15% protein diet, however, which was not observed in uninephrectomized rats fed 8% protein diet and in sham-operated rats fed 40% diet. Immunofluorescence studies revealed segmental deposits of albumin in the mesangium and capillary loops in high protein and uninephrectomized groups. Minimal granular deposition of IgG was noted in the mesangium of all experimental groups. In conclusion, high protein intake accelerated deterioration of renal function and it was correlated with morphological change. Low protein intake was effective in preventing these changes.

• Journal of the Korean Society of Food Science and Nutrition
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• v.28 no.1
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• pp.153-160
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• 1999

Storage stability of boiled and freeze dried loach and antioxidative effect of Zanthoxylum schinifolium were studied to confirm the possibility in development of instant choo o tang(Korean traditional loach soup). Packaging and storage temperature did not cause a measurable change in in vitro protein digestibility and trypsin indigestible substrate within 45 days of storage but remarkable quality changes were occurred in all samples stored after 60 days. Vacuum packaging and low temperature storage(4 oC) had some effect in retarding protein quality deterioration due to delaying polyunsaturated fatty acid oxidation. Maximum peroxide value and TBA value were reached in 15 days, and there were a slow(TBA value) and rapid reduction(POV) after peaks were reached. In contrast, increasing brown pigment development and fluorescence intensity continued until 90 days of storage. Treatment of ethanolic extracts from Zanthoxylum schinifolium prior to freeze drying could protect against lipid oxidation of freeze dried loach products.

• Journal of the Korean Society of Food Science and Nutrition
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• v.20 no.5
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• pp.503-508
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• 1991

The salted and dried mullet(Mugil Japonicus) roe had about 42% of protein and 41% of lipid content as major compoments. Therefore the lipid oxidation and the deterioration of protein occurred during drying and storage periods. In order to keep the good quality of the dried roe, acid, peroxide, thiobarbituric acid value and the contitutional amino acid were studied in the different drying air velocities at the conditions of 60% R.H. and $20^{\circ}C$ of drying air temperature. The optimum air velocity showed 2m/sec, which was excellently superior to the lipid and protein quality than those of other air velocities on the dried mullet roe. The drying period shortened from 20 days in the conventional processing method to 7 days in the modified processing method that had 2m/sec of drying air velocity. The drying rate curve had only a falling-rate drying period and not to have a constant-rate drying period.

• Journal of Nutrition and Health
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• v.34 no.8
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• pp.843-849
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• 2001

This study was performed to investigate the effect of n-3 fatty acids and dietary protein levels on renal function. Fifteen-month old male Sprague-Dawley rats were divided into 4 diet groups. Two-month old rats were used as a control group. The experimental diets contained either a% or 25% casein and lipid levels of the diets were 20% by weight. For the control group, the lipid was composed of beef tallow and corn oil on a 1:1 basis, and fish oil was comprised 75% of the fat mixture for the fish oil group. Rats were fed the diets ad libitum for 8 weeks. GFR and urinary protein excretion were higher in high protein groups, while fish oil exhibited no effects. Renal medulla TXB$_2$and PGE$_2$ concentrations tended to be higher in high protein groups and lower in fish oil groups. Light microscopic examinations showed that glomerulosclerosis, tubular atrophy, tubular cast, interstitial inflammation and interstitial fibrosis fended to be higher in aged rats and in high protein groups and lower in fish oil groups. Serum levels of total lipid, triglyceride and total cholesterol were higher in aged rats and lower in fish oil groups while serum HDL-cholesterol level was higher in young rats and in fish oil groups. However, dietary protein level had no effect on serum lipid levels. Serum TBARS concentration was higher in aged rats and in fish oil groups. In conclusion, fish oil caused changes in serum lipid concentrations and eicosanoids metabolism. The effect of fish oil on renal function was less obvious than dietary protein. However, fish oil seemed to be effective in lessening deterioration of renal function due to aging and/or high protein diets through changes in lipid and eicosanoids metabolism.