Korean Journal for Food Science of Animal Resources最新文献

The present study was designed to investigate the effects of calpain system on the formation of volatile flavor compounds in Hanwoo beef. In the first experiment (exp.1), Longissimus lumborum (LL) muscle samples were injected with solutions containing 50 mM CaCl₂ or 50 mM ZnCl₂ and 154 mM NaCl respectively, and aged for 7 d at 4°C. In the second experiment (exp.2), the ground LL muscle was incubated with the aforementioned solutions containing cathepsin inhibitor. The injection with CaCl₂ solution greatly elevated the calpain activity and concomitantly, significantly decreased the Warner-Bratzler shear force (p<0.05). The pH, meat color and cooking loss did not differ (p>0.05) between the treatment groups. A total of 51 volatile compounds were identified using the solid phase microextraction with gas chromatography (SPME-GC). Results on volatile analyses from the both experiments showed that the injection with calcium ions led to significant increase (p<0.05) concentrations of pyrazines and sulfuric compounds. These results coincide with a higher rate of protein degradation due to the CaCl₂ injection as compared to the control group. Significantly (p<0.05) higher levels of lipid oxidation derived-aldehydes were found in the samples with ZnCl₂. The exp.1 showed that cathepsin inhibitors had no effect on the formation of volatile flavor components after 7 d of aging. These results imply that the proteolytic activity of the calpain system is associated with generation of volatile compounds of chiller-aged beef, while the role of cathepsins is likely very limited.

This study was conducted to determine the effects of breed and sex on meat quality and sensory properties of the loin in three-way crossbred pigs: Landrace× Yorkshire×Duroc (LYD) and Landrace×Yorkshire×Woori (LYW) black pig synthesized by Korean native breed. Carcass traits did not differ by breed. Carcass weight and backfat thickness were higher in castrates than in gilts (p<0.01). LYW showed significant high values in fat content, cooking loss, and water-holding capacity (WHC) than LYD (p<0.05). Redness and yellowness of the meat were higher in LYW than in LYD (p<0.01). Further, LYW had lower pH and shear force than LYD (p<0.001). Significant high scores in color and flavor were obtained in LYW or gilts compared to LYD or castrates by sensory panel, respectively (p<0.05). However, other sensory traits did not differ by breed or sex. Capric acid (C10:0) was higher in LYD than LYW (p<0.001). However, stearic acid (C18:0) and saturated fatty acid (SFA) contents were higher in LYW than LYD (p<0.05). Eicosenoic acid (C20:2) and the n6/n3 ratio were higher in gilts than in castrates, whereas SFA content was higher in castrates than in gilts. These results suggest that certain physicochemical qualities of meat and sensory properties are improved in LYW compared to LYD. This study could provide basic data on meat quality of crossbred pigs with Woori black pig as a terminal sire.

This study investigated the effect of rice bran fiber (RBF) and wheat fibers (WF) on microbiological and physicochemical properties of fermented sausages during ripening and storage. The experimental design included three treatments: Control, no addition; RBF, 1.5%; and WF, 1.5%. During the ripening periods, the addition of dietary fibers rapidly decreased pH and maintained high water activity values of fermented sausages (p<0.05). Lactic acid bacteria were more prevalent in fermented sausages with rice bran fiber than control and sausages with added wheat fiber. During cold storage, lower pH was observed in sausages with dietary fibers (p<0.05), and the water activity and color values were reduced as the storage period lengthened. Fermented sausages containing dietary fibers were higher in lactic acid bacteria counts, volatile basic nitrogen and 2-thiobarbituric acid reactive substance values compared to the control (p<0.05). The results indicate that, the addition of dietary fibers in the fermented sausages promotes the growth of lactic bacteria and fermentation, and suggests that development of functional fermented sausages is possible.

Cronobacter species have been associated with disease outbreaks and sporadic infections, particularly in premature and immunocompromised infants. Cronobacter species can cause foodborne infections such as neonatal meningitis, septicaemia and necrotising enterocolitis. Accordingly, there is an urgent need to control and monitor the Cronobacter species in food, especially in powdered infant formula (PIF) and other baby foods. Therefore, in this review, the isolation and prevalence of Cronobacter species in infant food including PIF and the recent advance of detection methods are discussed for the better understanding on the current research status of Cronobacter species.

[This corrects the article DOI: 10.5851/kosfa.2017.37.6.823.].

This study proposed a rapid microscopic examination method for pork freshness evaluation by using the self-assembled hyperspectral microscopic imaging (HMI) system with the help of feature extraction algorithm and pattern recognition methods. Pork samples were stored for different days ranging from 0 to 5 days and the freshness of samples was divided into three levels which were determined by total volatile basic nitrogen (TVB-N) content. Meanwhile, hyperspectral microscopic images of samples were acquired by HMI system and processed by the following steps for the further analysis. Firstly, characteristic hyperspectral microscopic images were extracted by using principal component analysis (PCA) and then texture features were selected based on the gray level co-occurrence matrix (GLCM). Next, features data were reduced dimensionality by fisher discriminant analysis (FDA) for further building classification model. Finally, compared with linear discriminant analysis (LDA) model and support vector machine (SVM) model, good back propagation artificial neural network (BP-ANN) model obtained the best freshness classification with a 100 % accuracy rating based on the extracted data. The results confirm that the fabricated HMI system combined with multivariate algorithms has ability to evaluate the fresh degree of pork accurately in the microscopic level, which plays an important role in animal food quality control.

The aim of the present work was to provide information about Enterococcus strains isolated from pre-packaged chicken samples in Ankara (Turkey), focusing on their prevalence, phenotypic and genotypic characteristics, and antibiotic resistance. We report the first study on the occurrence of antibiotic resistant enterococci in pre-packaged chicken samples in Ankara. A total of 97 suspicious enterococcal isolates were identified from 122 chicken samples. All isolates were identified to species level by phenotypic and molecular methods. In the 16S rDNA sequence analysis, Enterococcus faecium (61.85%) and Enterococcus faecalis (38.15%) were found to be the most frequently detected Enterococcus spp. Of the 97 isolates tested for hemolytic activity, 12.37% enterococcal strains were β-hemolytic. β-Hemolysin was most prevalent among E. faecium (58.33%) compared to E. faecalis (41.66%). Disk diffusion method was used for determining of antibiotic resistance. The analysis of the antimicrobial resistance of the 97 Enterococcus isolates revealed that the resistance to kanamycin (98.96%), rifampicin (80.41%) and ampicillin (60.82%) was most frequent. Furthermore, resistance to erythromycin (38.14%) and ciprofloxacin (34.02%) was also observed. The frequencies of resistance to tetracycline (9.27%), penicillin G (8.24%), and chloramphenicol (3.09%), gentamicin (2.06%) and streptomycin (1.03%) were low. None of the isolates was resistant to vancomycin. Multi-drug resistance was found in 97.93% of Enterococcus strains. E. faecium strains showed a more resistant phenotype than E. faecalis strains according to the antibiotic resistance levels. The results of this study indicated that chicken meat is a potential reservoir for the transmission of antibiotic resistance from animals to humans.

In this study, the possible changes in the quality characteristics of pastırma, Turkish-type dry-cured meat product, produced by using two different salts (NaCl-KCl) in a curing mixture and two different production techniques (natural and controlled condition) were examined. Moisture, pH, salt, sodium, potassium, TBA, fat, water activity, instrumental colour, texture, and sensory analyses were implemented in order to determine the possible effects of these applications. Fat, aw, pH, colour, tiobarbituric acid (TBA), texture, salt, Na and K values may allow these desired modifications in pastirma production to be limited. The substitution of 15% KCl instead of NaCl was acceptable in terms of the sensorial properties of the pastirma. However, the sensory analyses did not allow for using a higher KCl instead of NaCl because both the hardness and chewiness in the texture of the pastirma samples salted with 30% of KCl were not scored positively. Besides this, negative effects, which may occur during the pastirma production under natural conditions, can be eliminated by the production being under controlled conditions.

Preheating conditions (low-, medium-, and high heat-) did not significantly affect the buffering capacity (BC) of skim milk powder (SMP), whereas the level of demineralization significantly affected the BC of whey powders (WP). Heat treatment (85°C for 30 min) of both SMP and WP (90% demineralized) mixtures (88:12, 76:24, 64:36 and 52:48; SMP:WP) resulted in a reduced BC, and the extent of this reduction increased with the proportion of WP increased in the samples. High-buffering milk prepared by the addition of phosphate salts (40 mM NaH₂PO₄ and 60 mM Na₂HPO₄) delayed the rate of pH decline during yoghurt fermentation. The high-buffering yoghurt showed a significantly higher water holding capacity (WHC) than that of control yoghurt (p<0.05), as well as a more uniform and interconnected microstructure with small pore sizes than those of control yoghurt. No significant differences were found between high-buffering and control yoghurt regarding the viable bacterial counts of starter. The manipulation BC can potentially improve the quality characteristics of yoghurts, such as WHC and texture.

In this study, the dietary effects of probiotics with a liquid application system on meat quality and physicochemical characteristics of pigs were evaluated. A total of 80 Landrace×Yorkshire×Duroc (LYD) 3-way crossbred pigs (average age 175±5 d) were assigned to a conventional farm and a probiotics farm equipped with a liquid probiotics application system (40 pigs in each farm). The two treatments were: CON (diet without probiotics) and PRO (diet with probiotics). Dietary probiotics decreased shear force in the longissimus muscle compared to the control group (p<0.05). The treatment diet did not affect backfat thickness, carcass weight, meat color, cooking loss, water holding capacity (WHC), and drip loss. Dietary probiotics significantly reduced ash, salinity, and pH (at 5 and 15 d) (p<0.05). There was no significant effect on thiobarbituric acid reactive substance (TBARS) values. Polyunsaturated fatty acid (PUFA) and omega fatty acids (ω3 and ω6) were significantly (p<0.05) higher in the PRO group, whereas monounsaturated fatty acid (MUFA) was decreased. The free amino acid composition, serine, lysine, histidine, and arginine levels were significantly lower in the PRO than in the control group. The treatment group exhibited higher nucleotide compounds (hypoxanthine, inosine, GMP, IMP) than the controls. Also, levels of ascorbic acid and thiamin were significantly different (p<0.05), while minerals were not significantly different between the groups. In conclusion, feeding of probiotics had effects on shear force, ash, salinity, pH, PUFA, and some amino acids which related to taste and flavor without any negative effects on the pigs' carcass traits.