Metabolomics Profiling to Determine the Effect of Postmortem Aging on Color and Lipid Oxidative Stabilities of Different Bovine Muscles.

The objective of this study was to identify metabolites that could be associated with oxidative stability of aged bovine muscles. Three muscles (longissimus lumbrum (LL), semimembranosus (SM), and psoas major (PM)) from seven beef carcasses at 1 day postmortem were divided into three sections and assigned to three aging periods (9, 16, and 23 days). Although an increase in discoloration was found in all muscles with aging, LL was the most color/lipid oxidative stable, followed by SM and PM (P < 0.05). Lower myoglobin and nonheme iron contents were observed in LL compared to those in SM and PM (P < 0.05). The HPLC-ESI-MS-based metabolomics analysis identified metabolites that were significantly responsive to aging and/or muscle type, such as acyl carnitines, free amino acids, nucleotides, nucleosides, and glucuronides. The results from the current study suggest that color and oxidative stability could be associated with aging but are also muscle-specific. Further studies determining the exact role of the identified metabolites in the color and oxidative stability of beef muscles are warranted.

Effect of Persimmon Peel (Diospyros kaki Thumb.) Extracts on Lipid and Protein Oxidation of Raw Ground Pork During Refrigerated Storage.

The inhibition effect of persimmon peel extracts (PPE) (0.05(PPE-0.05), 0.1(PPE-0.1), and 0.2 g(PPE-0.2) per meat sample) on lipid and protein oxidation of pork patties during chilled storage for 12 days were investigated and compared to ascorbic acid (As-0.05) and butylhydroxytoluene (BHT) (BHT-0.01). The meat samples treated with PPE had greater (p<0.05) a* values comparing control in raw pork patties meat from day 4 of storage. The addition of PPE at all concentrations on meat samples effectively inhibited the formation of oxidation products as shown by decreasing conjugated dienes (CD), peroxide values (POVs), thiobarbituric acid reaction substances (TBARS), and carbonyl content during chilled storage for 12 d. The PPE-0.2 and BHT-0.01 had the lowest in decrease rate of free thiol content (0.24 and 0.22 times) during chilled storage. Therefore, results of this study suggest that PPE can be considered a potential antioxidant against lipid and protein oxidation of raw meat products.

Effect of different aging temperatures prior to freezing on meat quality attributes of frozen/thawed lamb loins.

The objective of this study was to determine the effect of different aging temperatures prior to freezing on quality attributes of frozen/thawed lamb loins. The loins (M. longissimus lumborum; n=32) were randomly allocated to one of the four different aging/freezing treatments: aged only (-1.5°C for 14 days) and aged (-1.5°C for 14 days, 3°C for 8 days, or 7°C for 8days) then frozen/thawed loins. The loins aged at elevated temperatures (3°C or 7°C) for 8 days had equivalent shear force, protein degradation and purge loss values compared to the loins aged at -1.5°C for 14 days (P>0.05). However, significantly higher drip loss and less color stability were observed in the loins with increasing aging temperatures compared to the loins aged at -1.5°C. These results suggest that application of elevated aging temperatures could shorten required aging periods prior to freezing, while not adversely affecting tenderness and purge loss of frozen/thawed meat.

Effects of swelled pig skin with various natural vinegars on quality characteristics of traditional Korean blood sausages (Sundae).

This study evaluated effects of swelled pig skin (SPS) with various natural vinegars (Bokbunja, brown rice, cider, and lemon vinegars) on the quality of the Korean traditional blood sausages. Adding SPS with various natural vinegars resulted in increased moisture content, cooking loss, L* values, and a* values and decreases in fat, protein content (p<0.05), hardness and thiobarbituric acid-reactive substance values in the meat product samples compared to those in the control. Treatments containing SPS with various natural vinegars decreased the warmed-over flavor but increased the tenderness. These results indicate that SPS with various natural vinegars would improve the quality characteristics and inhibit lipid oxidation of traditional Korean blood sausages.

Quality Evaluation of Chicken Nugget Formulated with Various Contents of Chicken Skin and Wheat Fiber Mixture.

This study aimed to investigate the effects of various mixtures of the chicken skin and wheat fiber on the properties of chicken nuggets. Two skin and fiber mixtures (SFM) were prepared using the following formulations; SFM-1: chicken skin (50%), wheat fiber (20%), and ice (30%); and SFM-2: chicken skin (30%), wheat fiber (20%), and ice (50%). Chicken nugget samples were prepared by adding the following amounts of either SFM-1 or SFM-2: 0%, 2.5%, 5%, 7.5%, and 10%. The water content for samples formulated with SFM-1 or SFM-2 was higher than in the control (p<0.05), and increased with increasing the concentrations of SFM-1 and SFM-2. The addition of SFM-1 and SFM-2 had no significant effect on the pH of the samples. The lightness value of uncooked chicken nuggets was higher than that of cooked chicken nuggets for all the samples tested. Chicken nuggets formulated with SFM-1 and SFM-2 displayed higher cooking yields than the control sample. The hardness of the control sample was also lower than the samples containing SFM-1 and SFM-2. The sensory evaluation showed no significant differences between the control and the samples containing SFM. Therefore, the incorporation of a chicken skin and wheat fiber mixture improved the quality of chicken nuggets.

Quality Characteristics of Marinated Chicken Breast as Influenced by the Methods of Mechanical Processing.

The aim of this study was to investigate the effects of various marination processes on the quality characteristics of chicken breast prepared with chicken feet gelatin and wheat fiber. The chicken feet gelatin was swollen with hydrochloric solution (0.1 N HCl, pH 1.31±0.02) and dehydrated by freeze-drying. The composition (w/w) of the marinade was water (10%), soy sauce (12%), phosphate (0.3%), wheat fiber (1.5%), and chicken feet gelatin (1.5%). Three samples of chicken breast were manufactured with Tumbler (only tumbler), Tenderizer (tenderizer and tumbler), and Injector (injector and tumbler). The water content of the Injector sample was significantly higher than those of the Tumbler and Tenderizer samples (p<0.05). During heating, the lightness of all chicken breasts increased and the redness decreased. The tumbling and cooking yield of the Injector sample were significantly higher than those of the Tumbler and Tenderizer samples (p<0.05). The shear force of the Tenderizer sample was significantly lower than that of the Tumbler and Injector samples (p<0.05). No significant differences, except for color, were observed in the sensory analysis of the samples. Thus, the proper selection of mechanical processing is important to improve the quality characteristics of marinated chicken breast, considering the types of final products.

Quality of frankfurter-type sausages with added pig skin and wheat fiber mixture as fat replacers.

Pig skin and wheat fiber mixture (PSFM) were assessed as fat replacers in frankfurter-type sausages. The addition of PSFM increased the moisture and protein content in the sausage because of the water binding capacity in wheat fiber and protein content in pig skin. The sausage sample containing 20% PSFM had 50% less fat, 32% fewer calories, and showed 39.5% less cooking loss than those of the control (p<0.05). High PSFM content resulted in more stable meat emulsions and increased hardness, cohesiveness, gumminess, and chewiness. No significant differences were observed in color, flavor, tenderness, juiciness, warm-off flavor, and overall acceptability between the control and sausage sample with PSFM by the sensory panel. Therefore, PSFM could be used as fat replacers to obtain lower calories, and higher moisture, protein contents, and emulsion stability than in low-fat frankfurter-type sausages without PSFM.

Oxidative and color stability of cooked ground pork containing lotus leaf (Nelumbo nucifera) and barley leaf (Hordeum vulgare) powder during refrigerated storage.

This study aimed to evaluate the oxidative and color stability of cooked ground pork containing lotus leaf powder at 0.1 (LP1) and 0.5% (LP2) as well as barley leaf powder at 0.1 (BP1) and 0.5% (BP2) during refrigerated storage for 10 days. The oxidative stability of these powders was compared with butylhydroxytoluene (BHT). LP1 had higher a* and lower b* values than the control (-) over 4 days (p<0.05). The pH values of the ground pork samples made with addition of LP and BHT decreased until day 4 and then increased. Thiobarbituric acid-reactive substance (TBARS) values were lowest in LP2 on day 10 (p<0.05). The ground pork samples containing LP and BP had lower peroxide values (POVs) and conjugated dienes (CD) compared to the control (-).These results indicate that LP or BP can be incorporated into ground pork to effectively retard oxidation after cooking.