The thermal-death times of Listeria monocytogenes were determined in inoculated restructured goat steak at 60℃, 65℃, and 70℃ of sous-vide temperatures. D-values of L. monocytogenes in inoculated restructured goat steak ranged from 7.27 min at 60℃ to 0.46 min at 70℃. Times need to yield at least a 6 log reduction of L. monocytogenes at their temperatures for this product were 47, 12, and 3 min, respectively. After sous-vide, all microbial counts in non-inoculated samples were not detectable, except the aerobic and anaerobic mesophilie and lactic acid bacteria counts were lower than 2 Log CFU/g. For sous-vided and grilled sous-vided samples, sous-vide loss and surface shrinkage were the lowest in samples sous-vided at 60℃ for 47 min (p<0.05). These samples demonstrated the lowest CIE L^*, shear force, hardness, gumminess and chewiness and the highest CIE a^* and hue angle (p<0.05). Therefore, sous-vide at 60℃ for 47 min provided convenient ready-to-cook restructured goat steak for microbiology safety and optimization of physicochemical quality.

This study was performed to determine changes in mutagenicity and biogenic amine concentrations in sausages fermented with six different starter cultures treated with vitamins C and E. Six different types of fermented sausages with different combination of starter cultures were manufactured. T1, Pediococcus acidilactici; T2, P. pentosaceus and Staphylococcus carnosus; T3, S. carnosus, S. xylosus, Debaryomyces hansenii, Lactobacillus curvatus, and P. pentosaceus; T4, S. carnosus and L. sakei; T5, S. xylosus and L. plantarum; and T6, Penicillium nalgiovensis. After treatment with vitamins C and E in fermented sausages, changes in mutagenicity and biogenic amine concentrations were measured. The sausages fermented with Staphylococcus xylosus and Lactobacillus plantarum starter cultures showed the most effective antimutagenic activity (p<0.05). The mutagenicity was further decreased in the sausages treated with vitamins C and E (p<0.05), regardless of the starter cultures. The use of Pediococcus acidilactici, S. xylosus, L. plantarum, and Penicillium nalgiovensis as starter cultures was effective in decreasing biogenic amine concentrations (p<0.05). In addition, vitamin E was more effective in decreasing the biogenic amine concentrations than vitamin C. In conclusion, we recommend the use of S. xylosus and L. plantarum as starter cultures, in addition to the use of vitamins C and E, to reduce the potential risk of meat mutagens in fermented sausages.

Our aim was to investigate the effects of bromelain embedded in double emulsion (DE) on physicochemical properties of pork loin. We evaluated DE characteristics such as size, zeta potential, and microscopy after fabrication. We marinated meat with distilled water (DW), 1% (w/v) bromelain solution, blank DE, and 1% (w/v) bromelain loaded in double emulsion (DE E) for 0, 24, 48, and 72 h at 4℃, and prepared raw meat for control. The marinated samples were assessed for color, water holding capacity, cooking loss, moisture content, pH, protein solubility, Warner-Bratzler shear force (WBSF) and gel electrophoresis. The droplet size of 1% (w/v) bromelain embedded in DE was increased compared with blank DE (p<0.05) and values of zeta potential decreased. The increase in lightness and color difference range of the DE-treated group was lower than that of the DW-treated group (p<0.05). Moreover, treatment by immersion in 1% (w/v) DE E resulted in the highest water holding capacity values (p<0.05) and lower cooking loss values than water base treatment (p<0.05). Results for myofibrillar protein solubility and WBSF showed a similar trend. 1% (w/v) DE E showed degradation of myosin heavy chain after 48 h in sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Thus, bromelain-loaded DE is useful for controlling and handling enzyme activity in food industry.

This study aimed to extend the shelf-life of coffee-containing milk beverage by adding Theobroma cacao (cacao nibs) extract. To prepare the beverage sample containing cacao nibs extract, 0.8% cacao nibs hydrothermal extract was aseptically injected. Qualitative changes in the beverage samples, including antioxidant effect, peroxide value (POV), caffeine content, and sensory parameters were monitored regularly during storage at 10℃, 20℃, and 30℃ for 4 wk. The inclusion of cacao nibs extract produced higher antioxidant activity compared to the control. As the storage temperature increased, the POV of all samples increased. Samples with cacao nibs extract generally displayed lower POV than the control. The caffeine content of all samples tended to decrease during storage, with the decrease accentuated by higher storage temperatures. In the shelf-life prediction using the Arrhenius model, the kinetic regressions of the cacao nibs extract-added sample and control were Y_POV=1.2212X-2.1141 (r²=0.9713) and Y_POV=1.8075X-2.0189 (r²=0.9883), respectively. Finally, the predicted shelf-life of cacao nibs-added group and control to reach the quality limit (20 meq/kg POV) were approximately 18.11 and 12.18 wk, respectively. The results collectively indicate that the addition of cacao nibs extract extends the shelf-life of the coffee-containing milk beverage and heightened the antioxidant effect.

Cacao has been shown to have antioxidant effects and health benefits. However, the applicability of cacao as a meat preservative has not been thoroughly evaluated. Here, we examined the effects of cacao nib extracts (CEs) on suppression of fat oxidation and enhancement of quality characteristics of pork patties. Cacao nib powder was extracted in distilled water or 50%, 70%, or 99% ethanol. CEs prepared using 70% ethanol had the highest total phenolic and total flavonoid contents, and the highest 1,1-diphenyl-2-picrylhytdrazyl radical and 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) radical scavenging activities. Decompression-concentrated CEs prepared using 70% ethanol and 0.1% ascorbic acid were added to pork patties, and the physiochemical properties of the patties were measured. The pH of all pork patties increased during storage, but tended to decrease according to the CEs content. CEs enhanced the preservation of redness and texture of the pork patties during storage. Analysis of thiobarbituric acid reactive substances (TBARS) in patties revealed that fat oxidation was highly suppressed in all treatment groups containing CEs during storage, and TBARS values decreased according to CE content. Treatment with 0.1% CE reduced fat oxidation to a level similar to that of treatment with 0.1% ascorbic acid. Consumer flavor preference increased according to CE content, and overall preference was the highest for patties prepared with 0.05% and 0.075% CEs. Overall, 70% ethanol was found to be the optimal concentration for extraction of cacao nibs, and adding 0.05% or 0.075% CEs to pork patties yielded the highest quality.

Previous studies on dry aged beef, which substantially increases the value of low-grade raw beef and non-preferred cuts, are currently limited to the observation of aged beef changes in laboratory settings or under particular aging conditions, whereas the factors influencing aging have so far been underexplored. Herein, we attempt to establish a technique for distinguishing between fresh and aged beef by observing changes in quality during beef aging. Specifically, we analyzed the effect of time on the quality of aged beef sourced from three Korean manufacturers and identified quality indicators that can be used to distinguish between fresh and aged beef, regardless of supplier. Storage/trimming/aging/cooking losses, moisture/fat/protein/collagen contents, and water holding capacity were tested as potential indicators, among other parameters. As a result, the quality of dry aged beef was shown to be supplier-dependent, which made the identification of factors for the above origin-independent discrimination difficult. Nevertheless, as storage loss, water holding capacity, and cooking loss significantly changed with dry aging time in all cases, these parameters were concluded to be potentially suited for discrimination purposes. The insights gained in this work may help promoting further research in this field and contribute to the development of a standard for consistent aged beef production.

This study was performed to investigate the antioxidative and sensory properties of Allium hookeri fermented by Leuconostoc mesenteroides in pork patties. The patties were divided into three groups: CON, with no Allium hookeri powder; AH, containing 1% Allium hookeri powder; and FAH, containing 1% fermented Allium hookeri powder. Allium hookeri fermented by L. mesenteroides significantly increased the radical scavenging activities of 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) compared to that in normal Allium hookeri (p<0.05). The cooking loss and expressible drip for FAH were significantly lower than the corresponding values of other groups (p<0.05). The pH and 2-thiobarbituric acid reactive substances value of the FAH were significantly lower than that of CON on the day 3 and 7 (p<0.05). In the texture analysis (TPA), FAH showed significantly decreased hardness and chewiness grades compared to the CON and AH (p<0.05). FAH had significantly higher color, flavor, tenderness, juiciness, and overall acceptability scores than the CON and AH (p<0.05). This study suggests that the adding fermented Allium hookeri effectively improved the quality characteristic of the food.

In this study, the Opuntia humifusa f. jeollaensis (Wanggasi-Chunnyuncho) fruit (WCF) was used as a source of viscous dietary fiber and color pigmentation in sausage production to improve quality characteristics, including cooking loss and emulsion stability. Control and treatment sausages were formulated with 0%, 1%, 5%, and 10% WCF powder, respectively, and the following quality measures were investigated: general composition, fiber content, cooking loss, emulsion stability, chromaticity, pH, texture, and sensory properties. The moisture, dietary fiber, and ash contents showed increasing trends (all p<0.05) with increasing concentrations of fruit powder. Conversely, crude protein and crude fat contents exhibited decreasing trends with increasing fruit powder concentrations (p<0.05). Moreover, both the moisture and dietary fiber contents affected cooking loss, water retention capacity, and the sausage texture, causing the cooking loss to decrease, while the water and oil retention capacity increased (p<0.05) with increasing concentrations of WCF powder. Furthermore, hardness exhibited a significant decreasing trend as the concentration of WCF powder increased (p<0.05). This finding suggested that both dietary fiber and viscous materials, along with the protein and moisture content, affected the product hardness. In addition, sensory evaluation of the WCF powder groups showed better results than did the control group, and the strongest results obtained for the group containing 5% fruit powder (p<0.05). Therefore, this study suggests that WCF powder improves the quality of emulsified sausages and can potentially be applied as a naturally-derived additive.

Muscle-based by-products are often undervalued although commonly reported having a high amount of natural bioactive peptides. In this study, elastin was isolated from the protein of broiler hen skin while its hydrolysate was prepared using Elastase. Assessment of antioxidative properties of elastin-based hydrolysate (EBH) was based on three different assays; 2,2-diphenyl-1-picryl-hydrazyl-hydrate (DPPH) radical, 2,2'-azinobis (3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) radical and metal chelating ability. The EBH was purified further using ultrafiltration, gel filtration and Reverse- Phase High-Performance Liquid Chromatography (RP-HPLC). The IC₅₀ of ABTS radical activities for EBH were decreased as EBH further purified using ultrafiltration (EBH III; 0.66 mg/mL)>gel filtration (EB-II; 0.42 mg/mL)>RP-HPLC (EB-II4; 0.12 mg/mL). The sequential identification of the peptide was done by matrix-assisted laser desorption/ionization time-of-flight/time-of-flight mass spectrometry (MALDI-TOF/ TOF-MS) of the potent fractions obtained from RP-HPLC (EB-II4). The presence of hydrophobic amino acids (Val and Pro) in the peptide sequences could potentially contribute to the high antioxidant activity of EBH. The sequences GAHTGPRKPFKPR, GMPGFDVR and ADASVLPK were identified as antioxidant peptides. In conclusion, the antioxidative potential from poultry skin specifically from elastin is evident and can be explored to be used in many applications such as health and pharmaceutical purposes.

This study was conducted to investigate the hypotensive effect of egg white protein (EWP) hydrolysate (EWH) in spontaneously hypertensive rats (SHRs). The hydrolysis of EWP was effectively performed with a combination of 0.5% bromelain and 1% papain at 50℃ for 60 min. The resulting hydrolysate did not elicit an allergic reaction as confirmed by human mast cell activation test. The systolic and diastolic blood pressures of the SHRs fed the EWH diet were observed to be significantly or numerically lower than those of the other groups during the experimental period of 28 d. EWH treatment significantly (p<0.05) upregulated the nitric oxide levels in hCMEC/D3 cells and the plasma of the SHRs compared to those in the control. Moreover, EWH ingestion significantly (p<0.01) reduced the plasma angiotensin II level of the SHRs compared with that in the control. In conclusion, beyond its basic nutritional value, EWH prevents and manages hypertension, and thus can be an invaluable resource for functional food development.

To investigate the relationship between muscle fiber characteristics and meat quality traits by age of Korean native black goat (KNBG), four muscles (longissimus dorsi, LD; psoas major, PM; semimembranosus, SM; gluteus medius, GM) were obtained from five adult goat (AG; 18 months old) and five young goat (YG; 9 months old). PM muscle had the highest fiber number percentage (FNP) and fiber area percentage (FAP) of type I, followed by SM, GM, and LD muscles. FNP and FAP of type IIB were significantly (p<0.001) higher in AG than those in YG. YG had higher L^* values but lower b^* values than AG. The highest L^* and b^* values were observed in LD muscle (p<0.001). Age and muscle type had detrimental (p<0.001) effect on shear force and collagen content for all muscle in AG as compared to YG. YG had significantly (p<0.001) higher myofibrillar fragmentation index (MFI) than AG for all four muscles. These results suggest that muscle fiber compositions of different muscle types of KNBG depend on age, resulting in variations of meat color, MFI, collagen content, and shear force.

This study investigated protein digestibility of beef puree in infant and adult in vitro digestion models. The simulated digestive juices for infant and adult were prepared. Protein digestibility of beef puree was calculated in the gastric and gastrointestinal compartments. The 10% trichloroacetic acid soluble nitrogen and α-amino group contents of gastric digesta were lower in the infant in vitro digestion model than those in the adult in vitro digestion model (p<0.05). In addition, the gastrointestinal digesta from the infant in vitro digestion model had lower value of the 10% trichloroacetic acid soluble nitrogen and α-amino group contents than those of the adult in vitro digestion model (p<0.05). The results of sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed that the remarkable bands of actin and myosin light chain B were found in the digesta of beef puree from the infant in vitro digestion model. The results of this study revealed the lower protein digestibility of beef puree in infants compared to that in adults. Therefore, the development of ways to increase digestibility of meat protein can improve the nutritional quality of meat products for infants.

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.

Staphylococcus aureus is a representative pathogenic bacterium carefully controlled in the dairy industry because it causes bovine mastitis and thus, can enter the dairy chain. Furthermore, the emergence of multi-drug resistant S. aureus is a big problem. We previously isolated a Lactococcus lactis strain producing a bacteriocin that exhibited strong antimicrobial activity against S. aureus. In this study, we investigated the synergistic inhibition of S. aureus by the bacteriocin and a bacteriophage (SAP84) which is specific to the organism. The bacteriocin (12.5-100 AU/mL) inhibited the growth of S. aureus KCTC 3881 in a dose-dependent manner, as did the bacteriophage SAP84 (0.001-1 MOI; multiplicity of infection). Co-treatment with the bacteriocin (100 AU/mL) and the bacteriophage (0.1 MOI) significantly inhibited the growth of S. aureus compared to each treatment alone (bacteriocin or bacteriophage), indicating the two components showed synergistic inhibition of S. aureus. Therefore, the bacteriocin and bacteriophage combination can be used as a good strategy for controlling pathogenic bacteria.