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BACKGROUND In this study the effects of sex, meat cut and thermal processing on the carnosine, anserine, creatine, betaine and carnitine contents of Korean native chicken ( KNC) meat were determined. Forty 1-day-old chicks (20 chicks of each sex) from a commercial KNC strain (Woorimatdag™) were reared under similar standard commercial conditions with similar diets, and ten birds of each sex were randomly selected and slaughtered at 14 weeks of age. Raw and cooked meat samples were prepared from both breast and leg meats and analyzed for the aforementioned functional compounds. RESULTS Female KNCs had significantly higher betaine and creatine contents. The breast meat showed significantly higher carnosine and anserine contents, whereas the leg meat had a higher betaine and carnitine content. The content of all functional compounds was significantly depleted by thermal processing. CONCLUSION This study confirms that KNC meat is a good source of the above-mentioned functional compounds, which can be considered attractive nutritional quality factors. However, their concentrations were significantly affected by thermal processing conditions, meat cut and sex. Further experiments are needed to select the best thermal processing method to preserve these functional compounds. © 2014 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Freeze-drying is a preservation method known for its effectiveness in dehydrating food products while minimizing their deterioration. However, protein denaturation and oxidation during freezing and drying can degrade the quality of meat and aquatic products. Therefore, finding the strategies to ensure the dried products' sensory, functional, and nutritional attributes is crucial. This study aimed to summarize protein denaturation mechanisms and overall quality changes in meat and aquatic products during freezing and drying, while also exploring methods for quality control. Different freeze-drying conditions result in varying levels of oxidation and functionality in meat and aquatic products, leading to changes in quality, such as altered fatty and amino acid compositions, protein digestibility, and sensory attributes. To obtain high-quality dried products by freeze-drying, several parameters should be considered, including sample type, freezing and drying temperatures, moisture content, pulverization effects, and storage conditions. • The impact of freeze-drying on the quality of meat and aquatic products was reviewed. • Protein denaturation and oxidation occur during freeze-drying. • Nutritional and sensory attributes are altered after freeze-drying. • The sample type and operating conditions should be planned to obtain high-quality products. • Future studies are required to optimize the quality of freeze-dried animal products. [ABSTRACT FROM AUTHOR]

This study investigated whether the freezing-then-aging treatment of beef affects protein digestibility and release of potentially bioactive peptides using an in vitro infant digestion model. After 28 days of storage, aged-only (AO) and frozen-then-aged (FA) beef exhibited higher α-amino group contents in the 10% trichloroacetic acid-soluble fraction compared to day 0 (P < 0.05). Following in vitro digestion in the infant model, FA showed higher contents of α-amino groups and smaller proteins (<3 and 1 kDa) than day 0 and AO (P < 0.05). Relative contributions of myofibrillar, sarcoplasmic, and stromal proteins to the bioactive peptides released from AO and FA differed from those of day 0. In addition, FA exhibited a higher proportion of potential bioactive peptide sequences. Overall, freezing-then-aging treatment can enhance the potential health benefits of beef to be used as a protein source for complementary foods. • Freezing-then-aging increased beef proteolysis during storage and in vitro digestion. • Alteration in protein digestibility changed peptide profile after in vitro digestion. • Myofibrillar and stromal proteins primarily contributed to peptide release. • Beef protein had ACE, DPP-IV, and α-glucosidase inhibitory and antioxidant activities. • Freezing increased the ratio of released peptides with potential bioactivity. [ABSTRACT FROM AUTHOR]

Beef is an ideal protein source for use as a complementary food in infants. Considering the limited protein-digesting capacity of infants, it is required to enhance protein digestibility while minimizing the deterioration of beef quality. Thus, this study aimed to determine the effects of high-pressure processing (HPP) on the physicochemical properties and in vitro digestibility of beef proteins in an infant digestion model. HPP at 200 and 300 MPa decreased the tryptophan fluorescence intensity of the myosin and actin fractions relative to that at 0.1 MPa (P < 0.05). Compared to treatment at 0.1 and 100 MPa, HPP at 300 MPa decreased α-helix and β-turn contents in the myosin and actin fractions (P < 0.05), whilst increasing the β-sheet content (P < 0.05). Beef actomyosin content decreased (P < 0.05) during HPP at 200 and 300 MPa (c.f., 0.1 and 100 MPa). After in vitro digestion of beef, HPP at 200 and 300 MPa increased the α-amino group content and the abundance of proteins below 3 kDa in the digesta (P < 0.05). However, due to the considerable lipid oxidation at 300 MPa, HPP at 200 MPa is ideal for improving the protein digestibility of beef when incorporated into complementary foods for infants. • The effects of high-pressure processing (HPP) on beef protein quality were studied • HPP at 300 MPa induced conformational changes in the myosin and actin fractions • HPP at 200 and 300 MPa decreased the actomyosin content of beef • HPP at 200 and 300 MPa improved the beef protein digestibility in vitro [ABSTRACT FROM AUTHOR]

This study evaluated the correlation between hot carcass weight (HCW), back fat thickness (BFT), and fatness of whole pork belly and belly slices. Pork bellies were obtained from 50 barrows and 50 gilts. The fat content (v/v) of the whole pork belly and belly slices was measured using computer tomography and hyperspectral image analysis, respectively. Barrows and gilts showed significant differences only for HCW (p<0.05). The fat content of pork belly slices varied with location and was the highest at the 10 th thoracic vertebra (TV). Although no significant difference was observed in the fat content between the belly slices of the 6 th TV and the 12 th -14 th TVs (p>0.05), a difference in the fat distribution was observed. HCW and BFT were significantly correlated with the fat content of whole pork belly, but not with the fat content of pork belly slices. Therefore, HCW and BFT are not suitable for monitoring the fatness of pork belly slices, and further research on the factors that can be used for monitoring the fatness of pork belly is necessary., Competing Interests: The authors declare no potential conflicts of interest., (© Korean Society for Food Science of Animal Resources.)

Processed meat products play a vital role in our daily dietary intake due to their rich protein content and the inherent convenience they offer. However, they often contain synthetic additives and ingredients that may pose health risks when taken excessively. This review explores strategies to improve meat product quality, focusing on three key approaches: substituting synthetic additives, reducing the ingredients potentially harmful when overconsumed like salt and animal fat, and boosting nutritional value. To replace synthetic additives, natural sources like celery and beet powders, as well as atmospheric cold plasma treatment, have been considered. However, for phosphates, the use of organic alternatives is limited due to the low phosphate content in natural substances. Thus, dietary fiber has been used to replicate phosphate functions by enhancing water retention and emulsion stability in meat products. Reducing the excessive salt and animal fat has garnered attention. Plant polysaccharides interact with water, fat, and proteins, improving gel formation and water retention, and enabling the development of low-salt and low-fat products. Replacing saturated fats with vegetable oils is also an option, but it requires techniques like Pickering emulsion or encapsulation to maintain product quality. These strategies aim to reduce or replace synthetic additives and ingredients that can potentially harm health. Dietary fiber offers numerous health benefits, including gut health improvement, calorie reduction, and blood glucose and lipid level regulation. Natural plant extracts not only enhance oxidative stability but also reduce potential carcinogens as antioxidants. Controlling protein and lipid bioavailability is also considered, especially for specific consumer groups like infants, the elderly, and individuals engaged in physical training with dietary management. Future research should explore the full potential of dietary fiber, encompassing synthetic additive substitution, salt and animal fat reduction, and nutritional enhancement. Additionally, optimal sources and dosages of polysaccharides should be determined, considering their distinct properties in interactions with water, proteins, and fats. This holistic approach holds promise for improving meat product quality with minimal processing., Competing Interests: No potential conflict of interest relevant to this article was reported., (© Copyright 2023 Korean Society of Animal Science and Technology.)

This study investigated the protein digestibility of chicken breast and thigh in an in vitro digestion model to determine the better protein sources for the elderly in terms of bioavailability. For this purpose, the biochemical traits of raw muscles and the structural properties of myofibrillar proteins were monitored. The thigh had higher pH, 10% trichloroacetic acid-soluble α-amino groups, and protein carbonyl content than the breast (p<0.05). In the proximate composition, the thigh had higher crude fat and lower crude protein content than the breast (p<0.05). Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) of myofibrillar proteins showed noticeable differences in the band intensities of tropomyosin α-chain and myosin light chain-3 between the thigh and breast. The intrinsic tryptophan fluorescence intensity of myosin was lower in the thigh than in the breast (p<0.05). Moreover, circular dichroism spectroscopy of myosin revealed that the thigh had higher α-helical and lower β-sheet structures than the breast (p<0.05). The cooked muscles were then chopped and digested in the elderly digestion model. The thigh had more α-amino groups than the breast after both gastric and gastrointestinal digestion (p<0.05). SDS-PAGE analysis of the gastric digesta showed that more bands remained in the digesta of the breast than that of the thigh. The content of proteins less than 3 kDa in the gastrointestinal digesta was also higher in the thigh than in the breast (p<0.05). These results reveal that chicken thigh with higher in vitro protein digestibility is a more appropriate protein source for the elderly than chicken breast., Competing Interests: The authors declare no potential conflicts of interest., (© Korean Society for Food Science of Animal Resources.)

The last decades have witnessed a surge of interest in the fate of dietary proteins during gastrointestinal (GI) digestion. Although several in vitro digestion models are available as alternatives to clinical experiments, most of them focus on the digestive conditions of healthy young adults. This study investigates the static/dynamic models used to simulate digestion in infants and the elderly and considers the related in vivo conditions. The in vitro digestive protocols targeting these two groups are summarized, and the challenges associated with the further development of in vitro digestion models are discussed. Static models rely on several factors (e.g., enzyme concentration, pH, reaction time, and rotation speed) to differentiate digestive conditions depending on age. Dynamic models can more accurately simulate the complex digestion process and allow the inclusion of further parameters (sequential secretion of digestive fluids, gradual changes in pH, peristaltic mixing, GI emptying, and the inoculation of luminal microbiota). In the case of infants, age or growth stage clarification and the differentiation of digestive protocols between full-term and preterm infants are required, whereas protocols dealing with various health statuses are required in the case of the elderly, as this group is prone to oral cavity and GI function deterioration.

Chicken meat is a low-fat and high-protein food and consumption of chicken meat has been increasing globally. Various food ingredients are widely added for their specific purpose to processed chicken meat. Nonetheless, concerns about the association between high sodium intake and various diseases as well as negative perceptions of artificial additives are increasing. Therefore, in meat products, it is necessary to reduce the amount of salt and to replace artificial additives with natural ingredients. Our aim was to investigate the quality characteristics of low-salt chicken sausages manufactured with the addition of a winter mushroom powder. Sausages was manufactured with sodium pyrophosphate (0.3%) or winter mushroom powder (0%, 0.5% and 1.0%) to ground chicken breast. As a result of addition of the winter mushroom powder to low-salt chicken sausages, pH of the meat batter increased, and the proportion of jelly and melted fat exuded from sausages was reduced. The texture of sausages was softened and lipid oxidation in sausages was inhibited by the winter mushroom powder. This powder did not negatively affect the color and sensory properties of the sausages. According to the results of this study, the winter mushroom powder can serve as a natural ingredient to improve quality of low-salt chicken sausages.

This study was aimed to investigate the effects of the type O foot-and-mouse disease vaccine (FMDV) on the incidence of abnormal meat such as granuloma or abscess formation at the injection site in pork and its associated economic losses. At 56 d of age, piglets were inoculated with FMDV by one of three administration routes: N-Neck (a conventional needle-syringe injection into the neck), N-Ham (a conventional needle-syringe injection into the ham), and Non-Neck (injection with a needle-free device into the neck). The injection sites were visually examined for the presence of a granuloma or abscess, and the incidence rate of abnormal meat was calculated. The gross weight of the portion of the pork carcasses condemned because of granuloma or abscess formation was measured and multiplied by the weekly sales price to calculate the total economic losses. After implementation of FMDV, the economic losses were approximately six times higher than before implementation. Granuloma or abscess formation was significantly higher in the N-Neck and Non-Neck groups, in which the vaccine was inoculated into the neck area, than in the N-Ham group (N-Neck and N-Ham vs Non-Neck, p <0.05). These results suggest that the incidence of lesions could be reduced if the ham route was used for vaccination.

The effects of irradiation source (electron beam [EB] and X-ray [XR]), aging temperature (4°C and 14°C), and aging time (0, 3, 7, and 14days) were evaluated on microbial quality, physicochemical properties, and calpain-1 autolysis in beef M. semimembranosus. Regardless of irradiation source, irradiation prior to aging reduced the total number of aerobic bacteria in beef and this reduction was maintained during aging. Irradiation did not affect the pH, b ⁎ value, shear force, or myofibrillar fragmentation index of beef at day 0. Degradation of sarcoplasmic and myofibrillar proteins was greater in beef aged at 14°C compared with beef aged at 4°C. EB- or XR-irradiated samples showed slower autolysis of calpain-1; however, beef tenderness was not affected. Therefore, EB or XR irradiation can be applied to beef prior to aging to control microbial growth during high temperature (14°C) aging, thus shortening the aging time without adversely affecting the physicochemical properties of beef., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Enhanced meat is defined as fresh meat that has been minimally processed to improve quality and consistency. The present work investigated the quality of enhanced pork loins manufactured with the extract of red perilla leaves (ERP). ERP was prepared by the aqueous extraction of red perilla leaves followed by lyophilization. Enhanced pork loins were produced by injecting brine (15% v/w). The treatments consisted of a control (brine containing no ERP), ERP 0.2 (brine containing ERP at a concentration of 2 g/kg of pork loin), and ERP 0.4 (brine containing ERP at a concentration of 4 g/kg of pork loin). The enhanced pork loins were stored at 4℃ for 7 d, and its quality parameters were investigated. Addition of ERP decreased the L *-value and increased the a *- and b *-values of enhanced pork loins compared to those of the control group at all storage intervals ( p <0.05). A significantly lower pH than that of the control was found in ERP 0.4 after 7 d of storage. The malondialdehyde contents of the cooked pork loins were significantly lower in ERP 0.2 and ERP 0.4 than in those of the control after 4 and 7 d of storage ( p <0.05). While ERP 0.4 received relatively low scores in taste, flavor, and overall acceptability of the cooked pork loins ( p <0.05), no significant differences were found between the control and ERP 0.2. Enhanced pork loins can be produced using ERP to improve their oxidative stability.

The effects of bird age and the cooking process on the levels of several taste-active compounds, including inosine 5'-monophosphate (IMP), glutamic acid, cysteine, reducing sugars, as well as oleic, linoleic, arachidonic, and docosahexaenoic acids (DHA), in the breast and leg meats from a certified meat-type commercial Korean native chicken (KNC) strain (Woorimatdag) were investigated. KNC cocks were raised under similar standard conditions at a commercial chicken farm, and breast and leg meats from birds of various ages (10, 11, 12, 13, and 14 wk; 10 birds/age group) were obtained. After raw and cooked meat samples were prepared, they were analyzed for the aforementioned taste-active compounds. Compared to the leg meat, KNC breast meat had higher levels of IMP, arachidonic acid, and DHA, but lower levels of the other taste-active compounds (P < 0.05). KNC meat lost significant amounts of all the taste-active compounds, excluding oleic and linoleic acids, during the cooking process (P < 0.05). However, bird age only had a minor effect on the levels of these taste-active compounds. The results of this study provide useful information regarding the levels of taste-active compounds in KNC meat from birds of different ages, and their fate during the cooking process. This information could be useful for selection and breeding programs, and for popularizing native chicken meat., (© 2015 Poultry Science Association Inc.)

This study was aimed at comparing the taste-related compound content in the breast and leg meat from 100-d-old Korean native chickens (KNC-100) and 32-d-old commercial broilers (CB-32) and determining the changes in these compounds during cooking. Cocks from certified meat-type commercial broiler (Ross) and Korean native chicken (Woorimatdag) strains were raised under similar standard commercial conditions, and a total of 10 birds from each breed were slaughtered at 32 and 100 d of age, which represents their market ages, respectively. Raw and cooked meat samples were prepared separately from the breast and leg and analyzed. The KNC-100 showed significantly higher concentrations of inosine 5'-monophosphate, reducing sugars, glutamic acid, linoleic acid, arachidonic acid, and docosahexaenoic acid than CB-32 did. Additionally, significantly higher inosine 5'-monophosphate, cysteine, arachidonic acid, and docosahexaenoic acid concentrations were observed in the breast meat, whereas the leg meat had higher concentration of glutamic acid, oleic acid, and linoleic acid (P < 0.05). Significant depletions in the concentration of all taste-related compounds occurred during the cooking process, except oleic and linoleic acids. We suggest that the higher levels of taste-related compounds present in KNC-100 meat compared with CB-32 meat may result in the unique taste of the former meat, as has been previously reported. In addition, the results of this study may provide useful information for selection and breeding programs., (©2014 Poultry Science Association Inc.)

We evaluate the effect of supplementation, at 300 mg kg(-1) body weight (BW), with the antioxidants α-lipoic acid (AL), betaine (BT), l-carnitine (LC), and the combination of these and exercise on obesity induced by a 9 week high-fat diet (HFD) in mice. Healthy 5 week-old male C57BL/6J mice were divided into 9 groups: (1) CON, control group fed with a commercial mice chow containing 10% crude fat; (2) HFD, high fat diet group fed with a commercial mice chow containing 60% crude fat; (3) HFD-AL, HFD group fed with AL; (4) HFD-BT, HFD group fed with BT; (5) HFD-LC, HFD group fed with LC; (6) HFD-SW, HFD with swimming as an exercise; (7) HFD-SWAL, HFD-AL with swimming; (8) HFD-SWBT, HFD-BT with swimming, and (9) HFD-SWLC, HFD-LC with swimming. The BW of mice with LC and swimming reduced the increase of BW after 9 weeks. Relative adipose tissue weights were reduced by the combinations of antioxidant supplementation and swimming. Levels of serum glucose and leptin were reduced in the HFD-SWLC group when compared with the HFD group. Serum triglyceride and total cholesterol and the size of adipose were also decreased in the HFD-LC and HFD-SWLC groups. These results show that LC at a dose of 300 mg kg(-1) BW was the most effective for reducing fat accumulation in mice with HFD for 9 weeks. In addition, exercise should be given in combination to enhance the BW reduction and serum lipid level.

This study aimed to examine the effect of bird age on the contents of endogenous bioactive compounds, including carnosine, anserine, creatine, betaine, and carnitine, in meat from a certified meat-type commercial Korean native chicken strain (KNC; Woorimatdag). Additionally, the effects of the meat type (breast or leg meat) and the state of the meat (raw or cooked) were examined. Cocks of KNC were raised under similar standard commercial conditions at a commercial chicken farm. At various ages (10, 11, 12, 13, and 14 wk), breast and leg meats from a total of 10 birds from each age group were obtained. Raw and cooked meat samples were then prepared separately and analyzed for bioactive compounds. The age of the KNC had a significant effect only on the betaine content. The breast meat of KNC had higher amounts of carnosine and anserine but had lower amounts of betaine and carnitine than the leg meat (P < 0.05). The KNC meat lost significant amounts of all bioactive compounds during cooking (P < 0.05). Leg meat had high retention percentages of carnosine and anserine after cooking, whereas breast meat showed almost complete retention of betaine and carnitine. The results of this study provide useful and rare information regarding the presence, amounts, and determinants of endogenous bioactive compounds in KNC meat, which can be useful for selection and breeding programs, and also for popularizing indigenous chicken meat., (© 2014 Poultry Science Association Inc.)

The objective of this study was to compare the characteristics that define the quality of Woorimatdag (TM) (WM, a certified meat-type commercial Korea indigenous chicken breed) and a commercial broiler breed (Ross, CB). Two hundred WM and 200 CB chickens that were 1-d-old and mixed sex were obtained from a commercial hatchery and randomly assigned to floor pens (20 chickens per pen, 3.0×2.0 m) and raised under the same environmental conditions. WM breast meat contained significantly higher crude protein and ash as well as lower crude fat than CB breast meat (p<0.05). WM breast meat had slightly higher alanine, histidine, isoleucine, and glycine as well as lower phenylalanine content than CB breast meat (p<0.05), and the WM breast meat had a low ratio of unsaturated to saturated fatty acid composition (p<0.05). However, arachidonic acid composition was higher in the WM than the CB breast meat. In addition, the inosin-5'-monophosphate content was also higher in the WM compared with the CB breast (p<0.05). The WM breast meat had higher total collagen content compared with CB breast meat. WM soup taste received higher scores with regard to sensory evaluation compared with CB soup (p<0.05). From these results, we conclude that higher amount of protein and flavor precursors and lower amount of fat in the breast meat of WM could be attractive by consumer when compared with CB.

The aim of this study was to examine the effect of chicken line on the contents of endogenous compounds, including carnosine, anserine, creatine, and inosine 5'-monophosphate (IMP), in breast and thigh meats from 5 lines of Korean native chicken for the development of high-quality meat breeds. Additionally, the effects of sex (male or female) and meat type (breast or thigh meat) were examined. In total, 595 F1 progeny [black: 90 (male: 45, female: 45); gray-brown: 110 (male: 52, female: 58); red-brown: 136 (male: 68, female: 68); white: 126 (male: 63, female: 63); and yellow-brown: 133 (male: 62, female: 71)] from 70 full-sib families were used. The male chicken from the red-brown line and the female chicken from the black line showed the highest BW among the 5 lines. Carnosine content was higher in female chicken and breast meat than in male chicken and thigh meat, respectively. Breast meat contained higher anserine content compared with thigh meat. The sex effect on anserine was not consistent between breast and thigh meat. Creatine content was not consistently influenced by sex between breast and thigh meat, and no meat type effect was observed. The IMP contents were higher in female chicken and breast meat compared with male chicken and thigh meat, respectively. In addition, we clearly observed line effects by the comparison of the contents of carnosine, anserine, creatine, and IMP for each meat type according to each sex. These data are useful for selection and development of high-quality, meat-type chicken breeds.

The Korean native chickens (Woorimotdak™, KNC) and commercial broilers (Ross, CB) show obvious differences in meat flavor after cooking. To understand the contribution of protein and peptide for meat flavor, 2-dimensional (2-D) gel electrophoresis and matrix-assisted laser desorption-ionization time-of-flight (MALDI-TOF) mass spectrometry was performed. A total of 16 protein spots were differentially expressed in the breast and thigh meat between the two breeds. A total of seven protein spots were represented by different levels between KNC and CB for breast meat. Among them three protein spots (TU39149, TU40162 and TU39598) showed increases in their expressions in KNC while other four protein spots (BU40125, BU40119, BU40029 and BU39904) showed increases in CB. All nine protein spots that were represented by different levels between KNC and CB for thigh meat showed increases in their expression in KNC. Phosphoglucomutase 1 (PGM 1), myosin heavy chain (MyHC), heat shock protein B1 (HSP27), cytochrome c reductase (Enzyme Q), Glyoxylase 1, DNA methyltransferase 3B (DNA MTase 3) were identified as the main protein spots by MALDI-TOF mass spectrometry. These results can provide valuable basic information for understanding the molecular mechanism responsible for breed specific differences in meat quality, especially the meat flavour.