Korean Journal for Food Science of Animal Resources最新文献

This study assessed the effects of non-stunning (NS) and head-only electrical stunning (HOES) slaughtering condition on meat quality traits of longissimus lumborum (LL) muscle from Korean black goat (KBG). Ten KBGs (18 months) were assigned into two groups and exposed to either NS or HOES treatments. Blood loss (BL) % was measured after exsanguination, and meat quality traits including muscle pH, meat color measurements (CIE L*, a*, b*, Chroma, and hue angle), water-holding capacity (WHC), Warner-Bratzler shear force (WBSF), and sarcomere length were measured at 24 h postmortem. Results indicated that NS and HOES had no significant difference on BL %, the rate of pH decline, meat color properties, and WHC (p>0.05). It has only a small effect on WBSF and sarcomere length values, but the difference was marginal. These results suggested that meat quality of LL muscle from goat might not be affected by slaughter methods because neither NS nor HOES did result in poor quality of meat.

The aims of this research were to examine the effect of heating temperature (65, 75, and 85℃) and CaCl₂ concentration level (3, 4, and 5 mM) on the physicochemical properties of β-lactoglobulin (β-lg) nanoemulsions (NEs) and to study how the droplet size of NEs affects the bioaccessibility (BA) of coenzyme Q₁₀ (CoQ₁₀). The droplet size of NEs and BA of CoQ₁₀ was assessed by particle size analyzer and UV-Vis spectrophotometer, respectively. An increase in heating temperature and CaCl₂ concentration level resulted in a significant (p<0.05) increase in the droplet size of NEs while there were no significant differences in polydispersity index and zeta-potential of NEs. When NEs containing CoQ₁₀ were incubated in simulated small intestinal phases, an increase in the droplet size and polydispersity index of NEs was observed. This indicated that NEs were not stable in small intestine and digestion of NEs occurred. As heating temperature and CaCl₂ concentration level were decreased, a significant (p<0.05) increase in BA of CoQ₁₀ was observed. There was a significant (p<0.05) increase in BA of CoQ₁₀ with a decrease in the droplet size of NEs. In conclusion, heating temperature and CaCl₂ concentration level were key-parameters affecting the initial droplet size of NEs and BA of CoQ₁₀ was negatively correlated with initial droplet size of NEs.

To investigate relationships of electronic taste-traits with muscle fiber type composition (FTC) and contents of nucleotides, porcine longissimus lumborum (LL), psoas major (PM), and infra spinam (IS) muscles were obtained from eight castrated LYD pigs. FTC and taste-traits in these three porcine muscles were measured by histochemical analysis and electronic tongue system, respectively. IS had significantly higher proportion of type I fibers while LL had significantly higher proportion of type IIB than other muscles (p<0.05). IS had the highest inosine monophosphate (IMP) content while LL had the lowest IMP content (p<0.05). In contrast, LL had significantly higher hypoxanthine content compared to PM and IS (both p<0.05). For taste-traits, IS had significantly higher umami and richness values but lower sourness value than LL and PM (p<0.05). Sourness and astringency values of LL were significantly higher than those of IS (p<0.05). The proportion of type IIB fiber was positively correlated with sourness and astringency but negatively correlated with saltiness. These results suggest that sourness and astringency tastes are increased with increasing proportions of type IIB fibers in porcine muscles due to increase of hypoxanthine content. These results also imply that umami and richness tastes are increased with increasing contents of type I and IIA fibers because of increased IMP content in porcine muscles.

Shelf-life is defined as the amount of time during which a food product retains its desired sensory, chemical, and physical characteristics while remaining safe for consumption. The food industry needs to rapidly obtain the necessary information for determining the shelf life of its products. Here we studied the approaches available for conducting accelerated shelf-life tests. Accelerated shelf-life testing is applied to a variety of products to rapidly estimate change in characteristics with time. The aim of this work was to use accelerated shelf-life testing to study the changes in pH, microbiology, and sensory characteristics of ice cream by the application of a kinetic approach and, based on the observations, to estimate its shelf life. As per the current law, there is no shelf life on ice cream. Our results suggest that the shelf life of an ice cream sample was 24.27 months at -18℃, 2.29 months at -6℃, 0.39 months at -1℃, and 0.15 months at 4℃. Results of this study suggest that a set expiration date on ice cream might also contribute to effective management of ice cream characteristics in the retail chilled chain.

The objective of this study was to evaluate the composition, pH, titratable activity, microbial properties, and antioxidant effect of yogurt using ginseng extract powder (GEP), Lactobacillus plantarum NK181, and Streptococcus thermophilus as the starter culture. Different concentration of GEP (0%, 0.5%, 1%, 1.5%, and 2% (w/v)) were used in the yogurt. During yogurt fermentation, pH was decreased; however, titratable acidity and viable cell counts were increased. The addition of GEP to yogurt led to a decrease in moisture content and an increase in the fat, ash, and total solids content. The antioxidant effect using 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging, β-carotene bleaching, and ferric reducing antioxidant power (FRAP) assay gradually increased with added GEP. Overall, yogurt fermented with 1% GEP was acceptable in terms of cell viability and antioxidant effect. These results might provide information regarding development of ginseng dairy products with enhanced antioxidant activities and probiotic properties.

Bacteriocin is ribosomally synthesized by bacteria and inhibits closely related species. In this study we aimed at isolating lactic acid bacteria producing bacteriocin presenting anti-staphylococcal activity. A Lactococcus lactis strain was isolated from kimchi for the purpose and identified by 16S rRNA gene sequencing. As preliminary tests, optimal culture conditions, stabilities against heat, solvents, and enzymes treatments, and type of action (bacteriostatic or bactericidal) of the bacteriocin were investigated. The optimal culture conditions for production of the bacteriocin were MRS broth medium and 25℃ and 30℃ culture temperatures. The bacteriocin was acidic and the activity was abolished by a protease treatment. Its stability was maintained at 100℃ for 15 min and under treatments of various organic solvents such as methanol, ethanol, acetone, acetonitrile, and chloroform. Finally, the bacteriocin showed bactericidal action against Staphylococcus aureus where 200 AU/mL of the bacteriocin decreased the viable cell count (CFU/mL) of S. aureus by 2.5 log scale, compared with a control (no bacteriocin added) after 4-h incubation.

The objective of this study was to determine the antioxidant activity of gamma- irradiated Asparagus cochinchinensis (Asparagi radix) (Lour.) Merr. Extract (ARE) and its inhibition effect on food lipid oxidation using emulsion-type pork sausage as a model. ARE was prepared from dried Asparagi radix root and ARE solution (1.0 g/mL) was gamma-irradiated with designated doses at 5, 10, and 20 kGy. Antioxidant activity of ARE solution was determined by measuring 1,1-diphenyl-e-picrylhydrazyl (DPPH) and 2,2'-azino-bis (3-ethylbenzothiazoline-9-sulphonic acid) (ABTS) radicals. Activities of DPPH and ABTS radicals were decreased, whereas total phenolic contents increased after gamma irradiation with a dose dependence. Addition of gamma-irradiated ARE dose-dependently retarded lipid oxidation of emulsion-type pork sausage during storage at 4℃. These results indicated that gamma-irradiated ARE might have antioxidant activity more than non-irradiated ARE due to increase of the content of polyphenolic compounds by ionizing radiation.

This study aimed to investigate the drying yield, meat quality, oxidation stability and sensory properties of Hanwoo beef loin subjected to different dry-aging conditions. A total of 54 Hanwoo beef loins (bone-in, 6^th-13^th ribs) with fat cover at 2 d postmortem were assigned to four groups and hung in a dry-aging room at a controlled temperature (2℃-4℃), humidity (65%-85%) and air velocity (3 m/s). Four treatment conditions were tested; the respective temperature, humidity and treatment duration are as follows: T1, 2℃, 85%, 60 d; T2, 2℃, 65%, 20 d+2℃, 75%, 20 d+4℃, 85%, 20 d; T3, 2℃, 75%, 20 d+4℃, 85%, 40 d; T4, 4℃, 85%, 60 d. The drying yield, total aerobic counts and fat contents increased, whereas the moisture content, meat color (CIE L*, a*, and b*), and Warner-Bratzler shear force values decreased significantly during the aging period for all treatments (p<0.05). The cooking loss (%) did not change significantly until 40 d, and it was significantly higher in T1 and T4 than in T2 and T3 at 60 d (p<0.05). The water-holding capacity, pH and lipid oxidation [thiobarbituric acid reactive substance (TBARS) values] increased during aging (p<0.05). The sensory scores for tenderness, juiciness, flavor, and overall acceptability of dry-aged loin muscles increased as the aging period increased. T2 and T3 had significantly higher sensory scores and T1 had significantly lower scores for tenderness, juiciness, flavor, and overall acceptability at 20, 40, and 60 d for loin muscles (p<0.05).

Both the calcium and collagen in bone powder are hard to be absorbed by the body. Although enzymatic hydrolysis by protease increased the bio-availability of bone powder, it was a meaningful try to further increase Ca²⁺ release, oligopeptide formation and antioxidant activity of the sheep bone hydrolysate (SBH) by lactic acid bacteria (LAB) fermentation. Lactobacillus helveticus was selected as the starter for its highest protease-producing ability among 5 tested LAB strains. The content of liberated Ca²⁺ was measured as the responsive value in the response surface methodology (RSM) for optimizing the fermenting parameters. When SBH (adjusted to pH 6.1) supplemented with 1.0% glucose was inoculated 3.0% L. helveticus and incubated for 29.4 h at 36℃, Ca²⁺ content in the fermented SBH significantly increased (p<0.01), and so did the degree of hydrolysis and the obtaining rate of oligopeptide. The viable counts of L. helveticus reached to 1.1×10¹⁰ CFU/mL. Results of Pearson correlation analysis demonstrated that LAB viable counts, Ca²⁺ levels, obtaining rates of oligopeptide and the yield of polypeptide were positively correlated with each other (p<0.01). The abilities of SBH to scavenge the free radicals of DPPH, OH and ABTS were also markedly enhanced after fermentation. In conclusion, L. helveticus fermentation can further boost the release of free Ca²⁺ and oligopeptide, enhance the antioxidant ability of SBH. The L. helveticus fermented SBH can be developed as a novel functional dietary supplement product.