• Journal of the Korean Society of Food Science and Nutrition
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• v.28 no.3
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• pp.579-585
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• 1999

Proteins from the loin tissues age ranged from 0 to 24 months of ten Korean cattle were extracted, separated and compared on two dimensional(2 D) gels to identify the proteins whose expression is highly correlated to marbling. We also compared the difference of loin proteins between castrated and non castrated bull cows on two dimensional gels. As the marbling in the loin of the cattle is optimized at 18 to 24 months, eight proteins expressed significantly higher level in 24 month than in 0 or 6 month were selected in terms of isoelectric points(pIs) and molecular weights. Using these values, we searched the Swiss Prot database via the ExPASy molecular biology server with TagIdent program. The proteins with the nearest molecular weights and isoelectric points were selected from the lists. These possible candidates were confirmed by N terminal microsequencing of the eight selected proteins. Three proteins, myoglobin, hemoglobin and ATPase, whose N termini were not blocked could be microsequenced and found to be exactly matched to the selected candidates. It is suggested that the proteins increasingly expressed in marbling periods can be involved in meat color, lipid transport and flavor improvement.

• Preventive Nutrition and Food Science
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• v.7 no.4
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• pp.432-436
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• 2002

A proteomic map of Hanwoo loin was obtained using 2-D SDS-PAGE and mass spectrometric analysis: 27 bovine proteins plus 2 proteins having similarities to other mammal proteins out of 52 proteins analyzed. The identified proteins consisted of 50 % basic house keeping proteins involved in metabolism, 30% muscle proteins, and other miscellaneous proteins. Many proteins on the 2-D gel with different molecular weights and isoelectric points were identified as same proteins due to posttranslational modification. As many of the identified house keeping proteins showed the high sequence similarities to other mammal equivalent proteins, searching the mammal databases could confirm the annotation. The preliminary identification of the proteome in bovine loin tissue could reveal the functions of proteins at over 50 % of chance with high fidelities. Using the established loin proteome map, proteomic difference between 1 yr and 2 yr Hanwoo loin tissues were compared on 2D gel. Regardless of the difficulty normalizing protein concentrations and sample-to-sample variations, three unidentified proteins and myoglobin were selected as up-regulated proteins during the fat deposition period. This study contributes to a move thorough and holistic understanding of beef meat, helping to build the basis for future identification of new markers for good quality meat.

• Food Science of Animal Resources
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• v.39 no.6
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• pp.1008-1014
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• 2019

This study investigated the effects of pressure-mediated protein changes on the ice nucleation temperature of pork loins. To variate chemical state of meat proteins, pork loin was pressurized at varying pressure levels (100-500 MPa) for 3 min, and moisture content, expressible moisture (EM) and differential scanning calorimetry (DSC) were analyzed. Although, all treatments showed similar moisture content, EM and degree of protein unfolding of pork loin showed different features as of 300 MPa. At moderate pressure treatments (100-200 MPa), all protein fractions were detected in DSC experiments, and pork loin had lower EM than control (p<0.05). Meanwhile, myosin and actin of pork loin treated at greater than 300 MPa were completely unfolded, and the treatments showed high EM compared to control (p<0.05). Unfolding of meat proteins was a factor suppressing ice nucleation, and the ice nucleation temperature tended to decrease with increasing applied pressure level. The ice nucleation characteristics of pressurized pork loin exhibited a potential application in freezing storage of pressurized meat with less tissue damage comparing to freeze fresh meat, and further exploration regarding the quality change after freezing of fresh and pressurized meat was warranted.

• Applied Biological Chemistry
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• v.42 no.1
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• pp.39-44
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• 1999

Protein profiles of beef loin were constructed by comparing two-dimensional gel electrophoresis patterns of the proteins from different growth stages of Hanwoo, Korean cattle. Proteins from the lean muscle of 0, 6, 12 and 24 months old Hanwoo were separated by isoelectric focusing (IEF) on 16 cm tube gels, and further processed second dimensionally by 12% SDS-polyacrylamide gel electrophoresis (PAGE) using $18{\times}20$ cm gel. Proteins with pI values ranging 3.0 to 9.0 and molecular weight of 15 to 100 kDa could be clearly detected on gel by silver staining. Interestingly, many of the proteins significantly increased and decreased during growth happened to be low molecular ones. To isolate the increased proteins, the soluble proteins were obtained from the tissue by 1% Triton X-100 extraction, then, fractionated by 30% and 50% ammonium sulfate. The isolation condition of each particular protein was determined. According to the conditions, two of the increased proteins were isolated, and transferred to PVDF membrane and microsequenced.

• Food Science of Animal Resources
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• v.44 no.3
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• pp.551-569
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• 2024

This study was conducted to compare and analyze the changes in the biochemical characteristics and biological activity of peptide extracts derived from Chickso, Hanwoo, and Wagyu beef during digestion. The results of the in vitro digestion analysis revealed that the digestion rate, total free amino acid content, and antioxidant and antihypertensive activities of Chickso loin and shank myofibrillar proteins were significantly higher (p<0.05) than those of Hanwoo and Wagyu loin and shank myofibrillar proteins. Particularly, the peptide extracts of Chickso loin and shank had a high angiotensin-converting enzyme inhibitory activity. In mice in vivo digestion experiment, the blood serum of mice fed with Chickso loin peptide extract (<10 kDa) showed the highest antioxidant enzyme activity. Thus, Chickso peptide extracts were deemed to be similar or more bioactive than Hanwoo and Wagyu peptide extracts, and can be used as bioactive materials.

• Journal of Animal Science and Technology
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• v.62 no.5
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• pp.741-752
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• 2020

Herein, the in vitro protein digestibility of lyophilized Protaetia brevitarsis larvae flour with and without defatting using 70% ethanol was compared with beef loin. Proximate analysis showed that the defatted larvae contained the highest protein content (p < 0.05). The viable counts of total aerobic bacteria, Escherichia coli, and coliform bacteria decreased significantly after defatting the larval samples with 70% ethanol (p < 0.05). Measurement of α-amino group content and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) revealed higher amounts of low molecular weight proteins in the larvae compared to beef loin (p < 0.05). After in vitro digestion, the degree of protein hydrolysis of the digesta was higher for both larvae samples compared to beef loin (p < 0.05). No change was observed in the in vitro larval protein digestibility after defatting. These results highlight the excellent protein digestibility of P. brevitarsis larvae with high protein content. Defatting insect flour with 70% ethanol could enhance microbial safety while maintaining excellent protein digestibility.

• Food Science of Animal Resources
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• v.25 no.1
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• pp.45-51
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• 2005

This study was carried out to get the informations on microbes and protein extractability through comparing the quality attributes of Hanwoo fed in Korea, Hanwoo fed in Japan and Japanese Wagyu. The fresh beefs were stored at 4±l℃ for 13 days. In microbiological test, the total plate counts were higher in rump than in other beef portion as loin, chuck (p<0.000l). The number of psychrotrobes in the rump were maintained high levels (p>0.0001) for storage period, whereas the loin from Hanwoo fed in Korea, Hanwoo fed in Japan and Wagyu were lowest levels. The number of E. coli were no significantly different among the samples. In lactic acid bacteria, the loin form 3 grade Hanwoo (K3) had highest levels (p<0.0001). Comparing to the protein extractability, water soluble proteins were high in chuck (p<0.001). In the case of loin, water soluble proteins of K3 (3 grade Hanwoo) and Wagyu were high as 3.010 mg/g and 2.977 mg/g, respectively (p<0.001). Salt soluble protein of K1 (1 grade Hanwoo) was high as 7.437 mg/g (p<0.0001).

• Asian-Australasian Journal of Animal Sciences
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• v.16 no.3
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• pp.417-424
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• 2003

Inhibitory activities against angiotensin I-converting enzyme (ACE) of enzymatic hydrolysates of porcine skeletal muscle proteins were investigated. Myosin B, myosin, actin, tropomyosin, troponin and water-soluble proteins extracted from pork loin were digested by eight kinds of proteases, including pepsin, $\alpha$-chymotrypsin, and trypsin. After digestion, hydrolysates produced from all proteins showed ACE inhibitory activities, and the peptic hydrolysate showed the strongest activity. In the case of myosin B, the molar concentration of peptic hydrolysate required to inhibit 50% of the activity increased gradually as digestion proceeded. The hydrolysates produced by sequential digestion with pepsin and $\alpha$-chymotrypsin, pepsin and trypsin or pepsin and pancreatin showed weaker activities than those by pepsin alone, suggesting that ACE inhibitory peptides from peptic digestion might lose their active sequences after digestion by the second protease. However, the hydrolysates produced by sequential digestion showed stronger activities than those by $\alpha$-chymotrypsin, trypsin or pancreatin alone. These results suggested that the hydrolysates of porcine meat were able to show ACE inhibitory activity, even if they were digested in vivo, and that pork might be a useful source of physiologically functional factors.

• Food Science of Animal Resources
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• v.20 no.2
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• pp.146-151
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• 2000

The objective of this study was to investigate the characteristics on the thermal denaturation of free drip released from pork loin during chilled storage using DSC(differential scanning calorimetry). DSC thermogram of drip released from normal pork(NORD) was characterized by a minor peak and two major peaks with temperature maxima at $61.5^{\circ}C$, $71.7^{\circ}C$ (associated with sarcoplasmic proteins) and $84.3^{\circ}C$ (associated with protein-protein interaction and aggregation). In the denaturation temperature of drip released from PSE pork (PSED), the peak(Tmax) at $59.0^{\circ}C$ was reduced by $2.5^{\circ}C$. When the thermograms were divided into segments correponding to the three peaks, $\Delta$H2 was shown to be reduced by 10% in PSED as compared to NORD. With the decrease in the solubility of sarcoplasmic proteins in PSE muscle, there was a corresponding increase the drip loss during the storage.

• Preventive Nutrition and Food Science
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• v.6 no.2
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• pp.91-95
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• 2001

Competitive indirect enzyme linked immunosorbent assay (Ci-ELISA) was used to obtain the preliminary data for the detection of irradiated beef. Ci-ELISA was individually formatted with polyclonal antibodies produced from 2 kinds of bovine proteins, myosin and bovine serum albumin (BSA). Beef round, loin and tender loin were vacuum-packaged and subdivided into 3 groups of 1) irradiation; 2) irradiation and chilled at 4$^{\circ}C$ for 7 day; 3) irradiation and frozen at 2$0^{\circ}C$ for 2 months to observe the changes under different storage and/or distribution conditions. Irradiation was performed at 3, 5 and 7 kGy. Protein solutions prepared from the sample were tested by formatted Ci-ELISA. Detected concentrations of myosin and BSA decreased with the increased irradiation dose in all samples with different reduction rates. Myosin was more susceptible to freezing than BSA. Samples irradiated at 5 kGy or above could be differentiated from non-irradiated ones by Ci-ELISA. These results indicate that immunological assay can be used as a detection method for irradiated beef.