• Asian-Australasian Journal of Animal Sciences
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• v.32 no.10
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• pp.1611-1620
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• 2019

Objective: The aim was to investigate the influence of ultrasound and adenosine 5'-monophosphate (AMP) marination (UAMP) on tenderness and structure of myofibrillar proteins of beef. Methods: Five groups, the untreated meat (Control), deionized water marination (DW), ultrasound followed by DW (UDW), AMP marination (AMP), and ultrasound followed by AMP (UAMP) were studied. Myofibrillar fragmentation, cooking loss, shear force, thermograms, histological observation of meats and myofibrillar proteins properties were investigated in these different treatments. Results: The results showed that UAMP significantly increased myofibrillar fragmentation index from 152 (Control), 231 (AMP), and 307 (UDW) to 355 (p<0.05), respectively. The lowest cooking loss, shear force and peak denaturation temperature were observed in UAMP. In histological observation, UDW and UAMP had more fragmented muscular bundles than the others. Furthermore, a drastic increase in ${\alpha}$-helix and decrease in ${\beta}$-sheet of myofibrillar proteins was observed in UAMP, implying the disaggregation of protein samples. The synchronous fluorescence spectra of myofibrillar proteins in UAMP suggested the combination of ultrasound and AMP could accelerate the unfolding molecular structure and destroying hydrophobic interactions. The results of circular dichroism and synchronous fluorescence spectra for myofibrillar proteins coincided with the microstructures of beef. Conclusion: The results indicate that ultrasound combined with AMP improved meat tenderness not only by disruption in muscle integrity, increasing water retention, but also altering their spatial structure of myofibrillar proteins.

• Animal Bioscience
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• v.35 no.2
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• pp.236-246
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• 2022

Objective: The objective of this study was to investigate the effect of dietary pumpkin (Cucurbita moschata) seed meal (PSM) on laying hens' performance, quality, fatty acids, cholesterol, antioxidant compounds and shelf life of eggs. Methods: Eighty Tetra SL laying hens, 50-week-old, were randomly divided into two equal groups, having 10 replicates with 4 birds in each. The control (CON) treatment was fed with basal diet, while experimental treatment was fed a diet with 9% PSM, for a 6 week period. Results: Dietary PSM significantly decreased average daily feed intake (p<0.05), with no significant effect on other performance parameters. The PSM, enriched the eggs with polyunsaturated fatty acids, especially α linolenic acid (0.33 vs 0.21 g/100 g) and linoleic acid (20.65 vs 18.37 g/100 g), whereas it reduced the amount of arachidonic acid with 3.91% and n-6/n-3 ratio in PSM eggs compared with CON. The inclusion of 9% PSM significantly (p<0.05) diminished the cholesterol concentration in yolk with 11.31% and in egg with 10.38%, in respect to the CON samples. The significantly (p<0.05) higher concentration of polyphenols and antioxidant compounds, determined in PSM eggs, proved to be effective on shelf life of eggs preserved at refrigerator (5℃) and room temperature (21℃) for 28 days, by delaying the lipid oxidation and protein denaturation. This effect was reflected in significantly (p<0.05) higher Haugh unit in eggs stored 28 days at 21℃ and lower albumen pH values for the overall storage time, both at 5℃ and 21℃, proving the antioxidant effect of pumpkin. Conclusion: Dietary PSM supplementation was significantly effective on average daily feed intake and egg quality by increasing some fatty acids while lowering the cholesterol concentration. Also, PSM proved to be effective improving shelf life of eggs for 28 days storage time.

• Animal Bioscience
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• v.36 no.11
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• pp.1738-1746
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• 2023

Objective: The aim of this study was to investigate quality characteristics of reduced-salt, low-fat pork sausage (PS) using pre-rigor muscle and sea tangle extract (STE) to reduce salt level of sausages during refrigerated storage. Methods: Pork ham was prepared with pre-rigor and post-rigor muscle from the local market. Sausages using post-rigor muscle were manufactured with the 1.5% of salt content, and samples with pre-rigor muscle were processed by different salt concentrations (0.8%). Accordingly, PSs were prepared in 4 treatments (REF, PS with 1.5% of salt using post-rigor muscle; CTL, PS with 0.8% of salt using pre-rigor muscle; TRT1, PS with 0.8% of salt and 5% of STE using pre-rigor muscle; TRT2, PS with 0.8% of salt and 10% of STE using pre-rigor muscle). For the evaluation of quality characteristics and shelf-life of reduced-salt PS, pH and color values, cooking loss (%), expressible moisture (%), textural properties, lipid oxidation (thiobarbituric reactive substances), protein denaturation (volatile basic nitrogen), and microbiological analysis (total plate counts and Enterobacteriaceae counts) were determined. Results: The pH and temperature of pre-rigor raw pork ham were higher than those of post-rigor pork ham. Hardness of TRT2 was higher than that of REF or CTL. TRT2 had higher gumminess and chewiness than CTL. TRT1 and TRT2 had lower volatile basic nitrogen than CTL. Total plate counts of TRT2 were lower than those of CTL. Expressible moisture values of TRT1 and TRT2 were similar to those of REF. The addition of STE into PS improved functional properties and shelf-life of PS. Conclusion: Reduced-salt PS containing pre-rigor muscle and STE had similar functional properties to those of regular-salt ones, while containing approximately 47% less salt compared to regular-salt level.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.17 no.4
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• pp.280-290
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• 1984

An extensive study has been made on the relationship between the freshness and the compositions of the muscle protein of prawn, Pandalus japonica during the storage under partially frozen condition. The variations of the subunit distribution for sarcoplasmic protein and myofibrillar protein extracted from the samples by changes of freshness were discussed by sodium dodecylsulfate-poly-acrylamide gel (SDS-PAG) electrophoresis. On the other hand, the denaturation constant ($K_D$) of the myofibrillar protein extracted from the prawn stored at $-3^{\circ}C\;and\;-20^{\circ}C$ were successively compared. The prawn muscle contained about $18\%$ of protein with the composition of $32\%$ in sarcoplasmic protein, $56\%$ in myofibrillar protein, $10\%$ in residual intracellular protein and $2\%$ in stroma. The indices for estimating freshness of the muscle were approached to the early stage of putrefaction on the 26th day of the storage with $25.29mg\%$ of total volatile basic nitrogen, $31.36\%$ of K-value and 8.83 of pH. The content of the myofibrillar protein was remarkably decreased with the time during the storage while that of residual intracellular protein was increased. The $K_D$ values of the myofibrillar protein were $9.03{\times}10^{-6}sec^{-1}\;at\;-3^{\circ}C\;and\;4.42{\times}10^{-6}sec^{-1}\;at\;-20^{\circ}C$. The results of the analysis of SDS-PAG electrophoretograms indicated that the sarcoplasmic protein and the myofibrillar protein were composed of 12 subunits and 17 subunits in the muscle of instantaneously killed prawn ana were changed into 8 subunits and 22 subunits in the muscle stored for 26 days, respectively. It is noticeable that 30,000, 41,000, 107,000, 136,000, 170,000 173,000, 185,000, and 198,000 daltons of the newly appeared 8 subunits were found in the myofibrillar protein from the prawn muscle stored for 26 days. The amino acid composition of the muscle protein showed that the most of amino acids were slightly decreased with the days of the storage. With respect to the free amino acid composition of the muscle of instantaneously killed prawn, glycine, proline, arginine, alanine and taurine comprised $93\%$ of the total free amino acids. Taurine, valine, leucine, phenylalanine, serine, lysine, methionine, isoleucine and histidine were increased during the storage period but exceptionally proline was decreased.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.31 no.1 s.49
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• pp.51-58
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• 2005

Alkyl ethoxy sulfate type surfactants, widely used in commercial cleansers, are easily adsorbed to skin to often cause skin irritation and inflammation if not thoroughly rinsed nut. In order to replace or complement existing surfactants, we screened the existing surfactants through protein denaturation method, cell cytotoxicity assay and human IL-1$\alpha$ assay, etc. Fourteen surfactants have been chosen from among too irritant anionic, cationic and/or zwitter-ionic ones and investigated for cell cytotoxicity in human fibroblast cell lines using monolayer culture with the thirteen commercially available cleansers for sensitive skin. From these results, we selected 5 surfactants and 2 commercial cleansers (names not shown), such as sodium laureth sulfate (anionic), sodium cocoyl isethionate (anionic), sodium lauroamphoacetate (zwitter-ionic), and cocamidopropyl betaine (zwitter-ionic), alkyl polyglycoside (non-ionic). 20 formulations were made out of 5 surfactants and five of them were chosen through a protein denaturation method (lower than 3 M sodium dodecyl sulfate solution ($13.2\%$)), cell cytotoxicity and human patch test. These five selected formulations containing preservatives were compared to two selected commercial cleansers by cell cytotoxicity and human IL-1$\alpha$ ELISA assay using dermal equivalent. Finally, we selected the best formulation. To this formulation, fructan ($3\%$ or $5\%$) or/and portulaca extract ($3\%$ or $5\%$) well known for its anti-inflammatory and moisturizing effects were added and investigated for cell cytotoxicity using dermal equivalent. In cytotoxicity assay using dermal equivalent, two formulations containing $5\%$ fructan and $3\%$ or $5\%$ portulaca extract were less toxic than the others. In cytotoxicity assay and human IL-1$\alpha$ ELISA using 3D culture, the selected formulation containing $5\%$ fructan and $5\%$ portulaca extract showed better efficiency than those of the others and 2 commercial cleansers. As a result, we could develop a low irritant and safe liquid cleanser.

• Journal of Animal Science and Technology
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• v.52 no.2
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• pp.131-140
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• 2010

This study was conducted to investigate the effects of Cordyceps ochraceostromat, silkworm cocoon, and conjugated linoleic acid (CLA) on the quality and storage properties of pork sausage manufactured with protein recovered from breast of spent laying hen during 4 wks of storage at $4^{\circ}C$. Pork sausages were prepared using 100% ham (control) and 40% recovered protein from breast of spent laying hen to replace pork (T1), and with added different sources to final concentrations of 0.1% Cordyceps ochraceostromat powder (T2), 0.1% silkworm cocoon powder (T3), 0.1% CLA (T4), 0.05% Cordyceps ochraceostromat + 0.05% silkworm cocoon (T5), 0.05% Cordyceps ochraceostromat + 0.05% CLA (T6), and 0.05% silkworm cocoon + 0.05% CLA (T7). The treatments T5 and T7 had higher (p<0.05) protein content than control, but control had lower fat content than other samples during 4 wks of storage at $4^{\circ}C$. Lightness was significantly lower in the treatment samples than control. However, there was no significant difference in water holding capacity between the sausage samples, whereas, cohesiveness and chewiness were significantly higher (p<0.05) in the control than other treatments. All sausage samples showed a significant increase in volatile basic nitrogen (VBN) and total plate counts with extending storage time (p<0.05), and VBN values of treatments were lower than the control. However, the treatment samples showed a significant decrease (p<0.05) in thiobarbituric acid reactive substances over the increasing storage time. Therefore, our results suggested that the 40% recovered protein to replace pork and with added different sources decreased lipid oxidation and protein denaturation of pork sausages, thereby enhancing self-life, compared to normal pork sausage (control).

• Journal of Plant Biotechnology
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• v.33 no.1
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• pp.1-9
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• 2006

Peroxiredoxins (Prxs) are ubiquitously distributed and play important functions in diverse cellular signaling systems. The proteins are largely classified into three groups, such as typical 2-Cys Prx, atypical 2-Cys Prx, and 1-Cys Prx, that are distinguished by their catalytic mechanisms and number of Cys residues. From the three classes of Prxs, the typical 2-Cys Prx containing the two-conserved Cys residues at its N-terminus and C-terminus catalyzes $H_2O_2$ with the use of thioredoxin (Trx) as an electron donor. During the catalytic cycle, the N-terminal Cys residue undergoes a peroxide-dependent oxidation to sulfenic acid, which can be further oxidized to sulfinic acid at the presence of high concentrations of $H_2O_2$ and a Trx system containing Trx, Trx reductase, and NADPH. The sulfinic acid form of 2-Cys Prx is reduced by the action of sulfiredoxin which requires ATP as an energy source. Under the strong oxidative or heat shock stress conditions, 2-Cys Prx in eukaryotes rapidly switches its protein structure from low-molecular-weight species to high-molecular-weight protein structures. In accordance with its structural changes, the protein concomitantly triggers functional switching from a peroxidase to a molecular chaperone, which can protect its substrate denaturation from external stress. In addition to its N-terminal active site, the C-terminal domain including 'YF-motif' of 2-Cys Prx plays a critical role in the structural changes. Therefore, the C-terminal truncated 2-Cys Prxs are not able to regulate their protein structures and highly resistant to $H_2O_2$-dependent hyperoxidation, suggesting that the reaction is guided by the peroxidatic Cys residue. Based on the results, it may be concluded that the peroxidatic Cys of 2-Cys Prx acts as an '$H_2O_2$-sensor' in the cells. The oxidative stress-dependent regulation of 2-Cys Prx provides a means of defense systems in cells to adapt stress conditions by activating intracellular defense signaling pathways. Particularly, 2-Cys Prxs in plants are localized in chloroplasts with a dynamic protein structure. The protein undergoes conformational changes again oxidative stress. Depending on a redox-potential of the chloroplasts, the plant 2-Cys Prx forms super-molecular weight protein structures, which attach to the thylakoid membranes in a reversible manner.

• The Korean Journal of Food And Nutrition
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• v.25 no.4
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• pp.1068-1074
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• 2012

Ohmic heating uses electric resistance heat which occurs equally and rapidly inside of food when electrical current is flown into. In other study, we researched about soybean protein's characteristic changes by ohmic heating. Nevertheless treated same temperature, denaturation of soybean protein were accelerated by ohmic heating than conventional heating. In this time, we studied thermal property change of potato starch by ohmic heating besides conventional heating. For this purpose, potato starch was heated at same subgelatinization temperature by ohmic and conventional heating. And thermal properties were tested using DSC. Annealing of starch is heat treatment method that heated at 3~4% below the gelatinization point. DSC analysis results of this study, the $T_o$, $T_p$, $T_c$ of potato starch levels were increased, whereas $T_c{\sim}T_o$ was narrowed. This thermal property changes appear similar to annealing's result. It is thought the results shown in this study, because the heating from below the gelatinization point. 6, 12, 24, 72, and 120 hours heating at $55^{\circ}C$ for potato starch, $T_o$, $T_p$, $T_c$ values continue to increased with heating time increase. The gelatinization temperature of raw potato starch was $65.9^{\circ}C$ and the treated starch by conventional heating at $55^{\circ}C$ for 120 hr was $72^{\circ}C$, ohmic was $76^{\circ}C$. The gelatinization range of conventional (72 hr) was $10^{\circ}C$, ohmic was $8^{\circ}C$. In case of 24 hours heating at 45, 50, 55, 60, $65^{\circ}C$ for potato starch, the result was similar to before. $T_o$, $T_p$, $T_c$ values continue to increased and gelatinization range narrowed with heating temperature increase. In case of conventional heating at $60^{\circ}C$, the results of gelatinization temperature and range were $70.1^{\circ}C$ and $9.1^{\circ}C$. And ohmic were $74.4^{\circ}C$ and $7.5^{\circ}C$. When viewed through the results of the above, the internal structure of starch heated by ohmic heating was found that the shift to a more stable form and to increase the homology of the starch internal structure.

• Food Science and Preservation
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• v.18 no.2
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• pp.208-211
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• 2011

Limonoids are abundant as bitter taste in citrus fruit and other plants. Interestingly. limonoid UDP-glucosyltransferase (LUGT) effectively ameliorates the bitterness from limonoid. The high level of LUGT expression in Escherichia coli can result in the formation of insoluble aggregates known as inclusion bodies. We isolated the soluble LUGT protein when this inclusion body was renaturated with ${\beta}$-cyclidextrin treatment after protein denaturation by urea. Our present results suggest that the isolation of LUGT from inclusion body in cells leads to shed light to characterize the enzyme for food industry purposes.

• Korean Journal of Food Science and Technology
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• v.31 no.4
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• pp.957-963
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• 1999

Effects of cryoprotectants on protein denaturation of soybean curd, tofu, during frozen storage were examined. A whole-coagulated non-press tofu was prepared by adding 2% of isolated soybean protein to soy milk in order to prevent loss of added cryoprotectants. The cryoprotectants added were glocose, glycerol, sorbitol, propylene glycol, and tripolyphosphate. The texture characteristics of soybean curds before and after frozen storage were measured by sensory evaluation and Texture analyzer, and the results were evaluated by response surface methodology (RSM). Glucose, glycerol, sorbitol, and sodium tripolyphosphate were effective as single cryoprotectant, and the mixtures of glucose and sodium tripolyphosphate, and sorbitol and propylene glycol were also effective in minimizing textural change during freezing. Overall, the mixture of cryoprotectants were more effective than single cryoprotectant. According to the RSM, the maximum effect of cryoprotectants in minimizing textural changes during freezing was obtained with the mixture of 2.1% glucose, 6.7% glycerol, 2.1% sorbitol, 0.4% propylene glycol, and 0.3% sodium tripolyphosphate. However, considering the sensory acceptability, the optimum use of cryoprotectants in frozen tofu was 1% glucose, 2% glycerol, 1% sorbitol, 0.2% propylene glycol, and 0.5% sodium tripolyphosphate.