Kimchi extracts as inhibitors of colour deterioration and lipid oxidation in raw ground pork meat during refrigerated storage.

BACKGROUND: Kimchi is a Korean, traditional fermented food made from Korean cabbage, radish, fermented jeotgal, ginger, garlic, and red pepper powder. It is a good source of natural antioxidants such as phenolic compounds, flavonoids, vitamins, and carotenoids. In this study, the antioxidant effects of various kimchi extracts on raw ground pork during refrigerated storage were investigated. Raw ground pork samples were treated with ascorbic acid, butylated hydroxyl toluene, baechu kimchi extract (BKE), gat kimchi extract (GKE), puchu kimchi extract (PKE), and white kimchi extract (WKE) and compared with raw ground pork without antioxidant treatment (NC). RESULTS: Increased metmyoglobin (MetMb), thiobarbituric acid reacting substance (TBARS), and total bacterial counts (TBC) were observed in all meat samples after storage, whereas pH, lightness, and redness values tended to decrease with increased storage time. All treated samples had lower TBARS and MetMb values and TBC compared to the control samples. Various kimchi ethanol extracts protected raw ground pork from lipid oxidation. The most potent antioxidant was GKE, whereas WKE was the weakest. CONCLUSIONS: This study suggests that the tested extracts, especially kimchi, have potential as natural preservatives to reduce colour degradation, lipid oxidation, and bacterial count in raw ground pork meat. © 2018 Society of Chemical Industry.

Evaluations of physicochemical and anti-oxidant properties of powdered leaves from lotus, shepherd's purse and goldenrod in restructured duck/pork patties.

The objective of this study was to determine the effects of powdered leaves of lotus (LP), shepherd's purse (SP) and goldenrod (GP) on oxidation stability and quality characteristics of cooked duck/pork patties. Fresh duck tenderloin (M. pectoralis) and pork meat (M. biceps femoris, semitendinosus, and semimembranosus) were ground, formulated with LP, SP, GP or butylated hydroxytoluene (BHT), and mixed with other non-meat ingredients. The manufactured patties were cooked, packaged, and stored at 3 °C for 4 weeks. The patties containing 1% of LP, SP and GP had significantly lower values in redness, thiobarbituric acid reactive substances, conjugated dienes and total volatile basic nitrogen compared to control. No significant differences in sensory tenderness between the control and treated samples were observed. Addition of LP had a similar warmed-over flavor extent compared to patties with BHT. These results indicate that incorporation of the natural leaves could effectively inhibit oxidation and maintain freshness of cooked patties without any detrimental effects on sensory attributes during storage.

Effect of chicken skin on the quality characteristics of semi-dried restructured jerky.

The objective of this study was to evaluate the effect of skin on the textural properties of semi-dried jerky produced with different acid treatments. Jerky was prepared with no skin (control) or with 1, 3, or 5% chicken skin. After hand mixing (for 3 min) and tumbling (for 30 min) to distribute the curing ingredients, the cured meats were dried for 180 min at 55°C, for 180 min at 65°C, and finally for 60 min at 75°C. The presence of skin was shown to result in a higher fat content, TBA value, and metmyoglobin due to the high fat content of the skin. In contrast, acid treatment decreased the TBA value and metmyoglobin in jerky relative to samples that were not subjected to acid treatment. The presence of skin also improved the moisture contents, processing yields, and mechanical tenderness.

Germinated barley as a functional ingredient in chicken sausages: effect on physicochemical and technological properties at different levels.

The objective of this study was to evaluate the effect of germinated barley (GB) levels on physicochemical and technological properties of cooked chicken sausages. The chicken sausages were formulated with 0-4 % GB. Addition of GB increased pH and yellowness but decreased lightness of the cooked chicken sausages. However, there was no difference in redness among treatments (P > 0.05). Based on the positive effects of GB on measurements related to water and/or fat retention ability, such as emulsion stability, cooking loss, and thawing loss, such results depended upon the added amount of GB. In addition, apparent viscosity increased with increasing levels of GB, resulting in hardness, springiness, and chewiness (P < 0.05). These results could be associated with polysaccharides contained in GB, such as insoluble fiber, ß-glucan, and starch. Therefore, our results suggests that GB could be a functional ingredient to improve physicochemical and technological properties of chicken sausages and optimal level of GB was determined as minimum 2 %.

Combined effects of presalted prerigor and postrigor batter mixtures on chicken breast gelation.

We examined the combined effects of prerigor and postrigor batter mixtures on protein gelation. The postrigor batter was prepared with 2% salt, whereas the prerigor meat at 5 min postmortem was used to prepare postrigor batters at different salt levels. For 5 treatments, prerigor batters were mixed with postrigor batter that had 2% salt (control) as follows: T1: ground presalted (1%) hot-boned breast with 1% salt for 50% total batch; T2: ground presalted (2%) hot-boned breast for 50% total batch; T3: ground presalted (3%) hot-boned breast for 30% total batch that was mixed with cold-boned batter for 50% total batch; T4: ground presalted (4%) hot-boned breast for 25% total batch that was mixed with cold-boned batter for 50% total batch; and T5: ground presalted (5%) hot-boned breast for 20% total batch that was mixed with cold-boned batter for 50% total batch. Treatments with both presalted prerigor and postrigor muscle showed less cooking loss and lower emulsion stability than the control, except T5. The protein solubility and apparent viscosity of the control was the lowest. Thus, presalted hot-boned muscle combined with cold-boned muscle positively affected physicochemical properties.

Capsaicin and tocopherol in red pepper seed oil enhances the thermal oxidative stability during frying.

Thermal oxidative stability of red pepper (Capsicum annuum) seed oil added with different levels of capsaicin or tocopherol as antioxidant during heating up to 48 h at 140±5°C was studied. Lipid oxidation of soy and pepper oil with different levels of capsaicin (0.12, 0.24%) and tocopherol (0.3, 0.6%) were evaluated during storage at 1400C for 0, 12, 24 and 48 h by monitoring peroxide value (PV), thiobarbituric acid reactive substances (TBARS) and chemiluminiscence (CL). Capsaicin content of crude pepper oil (0.16 mg/ml) was much higher than that of commercial brands (0.004-0.02 mg/ml). Oleate content was significantly (p<0.05) higher in soy oil (53.7%) than pepper oil (9.5%), however, linoleate and linolenate contents were significantly (p<0.05) higher in pepper oil (70.6, 5.8%) than in soy oil (25.9, 5.8%). TBARS, PV, and CL of pepper oil were significantly (p<0.05) lower than soy oil after frying. TBARS and CL values of pepper oil with different levels of capsaicin or tocopherol showed significantly (p<0.05) lower values than untreated pepper oil during frying and storage. TBARS and CL values of 0.6% tocopherol treated pepper oil showed significantly (p<0.05) lower values than those of soy oil. The study suggests that capsaicin and tocopherol may play a key role to prevent the thermal oxidation of pepper oil during frying.

Characteristics of low-fat meat emulsion systems with pork fat replaced by vegetable oils and rice bran fiber.

The effects of vegetable oils prepared from olive, corn, soybean, canola, or grape seed, and rice bran fiber on the composition and rheological properties of meat batters were studied. Pork fat at 30% in the control was partially replaced by one of the vegetable oils at 10% in addition to reducing the pork fat to 10%. The chemical composition, cooking characteristics, texture properties, and viscosity of low-fat meat batters were analyzed. The moisture, protein, ash content, uncooked and cooked pH values, b(∗)-value, hardness, cohesiveness, gumminess, chewiness, and viscosity of meat batters with vegetable oil and rice bran fiber were all higher than the control. In addition, batters supplemented with vegetable oil and rice bran fiber had lower cooking loss and better emulsion stability. Low-fat meat batters with reduced pork fat content (10%) and 10% vegetable oil plus rice bran fiber had improved characteristics relative to the regular fat control.

Effects of pork/beef levels and various casings on quality properties of semi-dried jerky.

The aim of this study was to investigate the effects of pork/beef levels and the casings on the quality properties of semi-dried jerky. The pork/beef levels in the four test formulations were as follows: T-1 (pork: beef=100:0), T-2 (95:5), T-3 (90:10), and T-4 (80:20). After tumbling for 30min with curing solution, the cured meats were stuffed into natural sheep casings, collagen casings, or cellulose casings, and then dried. The restructured jerky with cellulose casing had the lowest water content and the highest protein content, with no significant differences between various formulations. There were no significant differences among all formulations with regard to pH and total microbial counts, and jerky with cellulose casing had the lowest value of water activity. The processing yields of jerky made from the T-3 formulation were not significantly different with the various casings. The shear force of jerky with cellulose casing was lower than with other casings, and the metmyoglobin contents were more than 85% in all formulations. With regard to sensory properties, jerky made with the T-3 formulation and cellulose casings rated most favorable in evaluations than other treatments.

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.

Combined Effects of Wheat Sprout and Isolated Soy Protein on Quality Properties of Breakfast Sausage.

The objective of this study was to investigate the effects of different concentrations of WSP (wheat sprout powder) and ISP (isolated soy protein) on the quality of breakfast sausage. Treatments were formulated as follows: Control, T1 (2.0% ISP), T2 (1.5% ISP + 0.5% WSP), T3 (1.0% ISP + 1.0% WSP), T4 (0.5% ISP + 1.5% WSP) and T5 (2.0% WSP). The treatments were analyzed for color, pH, cooking loss, emulsion stability, protein solubility, viscosity, texture properties and sensory evaluation. Lightness and redness were reduced and yellowness was increased as increased level of WSP, due to the dark green color of WSP (p<0.05). The pH values of all samples were affected by WSP which has lower pH (p<0.05). The emulsion stability and cooking loss of treatments were improved with increasing level of WSP (p<0.05). The protein solubility, viscosity and overall texture properties of the sausage indicated significant differences in relation to the level of WSP and ISP (p<0.05). The sensory evaluation indicated that the greatest flavor and overall acceptability in sausage was achieved at WSP 1% combination with ISP 1% (T3) (p<0.05). Therefore, these results indicate that breakfast sausage containing 1% WSP and 1% ISP is the optimal formulation, taking into consideration the overall physico-chemical properties and sensory evaluation.

Lotus (Nelumbo nucifera) Rhizome as an Antioxidant Dietary Fiber in Cooked Sausage: Effects on Physicochemical and Sensory Characteristics.

The objective of this study was to determine the physicochemical and sensory properties of cooked emulsion sausages containing different levels of lotus rhizome powder (0, 1, 2, and 3%, based on total weight). Lotus rhizome powder had no significant (p>0.05) impact on pH, moisture, protein, or ash content of sausage. However, fat content was slightly but significantly (p<0.05) decreased when the level of lotus rhizome powder was increased in the sausages. The addition of lotus rhizome powder to sausages at over 1% resulted in significantly (p<0.05) darker and less red color of cooked sausage compared to control. Increase in lotus rhizome level slightly improved the emulsion stability and apparent viscosity. Significant (p<0.05) reduction in cooking loss was observed when more than 1% of lotus rhizome powder was added to sausages. The textural properties of sausages were unaffected by the inclusion of lotus rhizome except for springiness and chewiness. On the manufacture day, control sausage had significantly (p<0.05) higher TBARS value than treatments. Regarding sensory characteristics, increased levels of lotus rhizome powder decreased (p<0.05) color and juiciness scores. However, cooked sausages exhibited similar overall acceptability regardless of the level of lotus rhizome powder added to sausages. Therefore, lotus rhizome powder, an antioxidant dietary fiber, could be used as an effective natural ingredient in meat products for the development of healthier and functional food.

Impacts of Irradiation Sources on Quality Attributes of Low-salt Sausage during Refrigerated Storage.

This study was performed to investigate the impacts of irradiation sources on quality attributes of low-salt sausage during refrigerated storage. Control sausage was prepared with 1.5% sodium chloride (NaCl), whereas low-salt sausage was formulated with 0.75% NaCl (a 50% reduction; L-control). Sausage samples were vacuum-packaged, and low-sausages were irradiated with gamma-ray, electron-beam and X-ray at 5 kGy, respectively. The samples were stored at 4°C for 28 d to determine changes in quality attributes. The pH of low-salt sausages was unaffected by irradiation at 5 kGy (p>0.05). Higher redness values were found at irradiated low-salt sausages compared to control (p<0.05). The hardness, gumminess and chewiness of control sausage were higher than those of low-salt sausages (p<0.05). However, there were no significant differences in the textural parameters between low-salt sausage treatments. The overall sensory acceptability score of irradiated/low-salt sausages were lower than L-control due to decreased scores for cooked meat flavor but increased radiolytic off-flavor (p<0.05). The initial 2-thiobarbituric acid-reactive substances (TBARS) values of irradiated/low-salt sausages were higher than control and L-control (p<0.05). However, the TBARS values of irradiated treatments were significantly lower than control at the end of storage. Irradiation could effectively inhibit the microorganism growth (total aerobic bacteria, coliforms, Enterobacteriaceae, and Pseudomonas spp.) in low-salt sausages (p<0.05). Therefore, our findings show that irradiation could be to improve microbial safety of low-salt sausages, and suggest that further studies should be necessary to reducing radiolytic off-flavor of irradiated/low-salt sausages.

A water extract of Artemisia capillaris prevents 2,2'-azobis(2-amidinopropane) dihydrochloride-induced liver damage in rats.

A water extract of Artemisia capillaris Thunberg (Compositae) was investigated for protective effects against oxidative stress induced by 2,2'-azobis(2-amidinopropane) dihydrochloride (AAPH) in Sprague-Dawley male rats. Rats were orally administered A. capillaris water extract (ACWE; 7.5 g/kg) for 7 days before AAPH treatment (60 mg/kg). AAPH intoxication significantly elevated enzyme markers of liver injury (glutamic oxaloacetic transaminase and glutamic pyruvic transaminase). The pre-administration of ACWE significantly reduced the liver-damaging effects of AAPH as indicated by the low levels of these enzymes. Moreover, the ACWE administration significantly attenuated the accumulation of thiobarbituric acid-reactive substances in both plasma and liver tissues compared with those of rats administered AAPH alone. Furthermore, ACWE administration slightly improved the liver reduced glutathione levels and enhanced the production of antioxidant enzymes like catalase. A. capillaris contained 10.1 mg of catechin in 100 g of dried sample; the high-performance liquid chromatography results showed catechin composition in the ACWE to be 28% (-)-epigallocatechin gallate, 49% (-)- epigallocatechin, and 23% other catechins. These observations clearly indicate that ACWE contains antioxidant catechins capable of ameliorating the AAPH-induced hepatic injury by virtue of its antioxidant activity.

Identification of lactic acid bacteria isolated from kimchi and studies on their suitability for application as starter culture in the production of fermented sausages.

The aim of the investigation was to identify strains of lactobacilli coming from kimchi with properties suitable for use as starter cultures in sausage fermentation. A total of 31 strains of lactobacilli were isolated from kimchi on the 4-6th day of fermentation at 20°C using MRS agar plates and identified on the basis of morphological, biochemical, and physiological characteristics. The isolates were identified as Leuconostoc mes.mes./dent (12.9%), Lactobacillus curvatus (9.7%), Lactobacillus brevis (35.5%), Lactobacillus sake (25.8%), and Lactobacillus plantarum (16.1%). Thus, 51.6% of the isolates were homo-fermentative or facultative hetero-fermentative bacteria and the rest (48.4%) were hetero-fermentative bacteria. Among them L. brevis, L. curvatus, L. plantarum, and L. sake were investigated for their growth profile and metabolism characteristics in the fluid (submerged) model-medium modified according to the special conditions of fermented sausages. Relatively good growth properties were found for L. brevis, L. plantarum, and L. sake with maximum numbers of 8.18, 8.51 and 8.17cfu/ml, respectively, whereas L. curvatus could not adapt to the special environmental conditions. Regarding souring properties, L. brevis showed little ability to decrease pH, whereas L. curvatus, L. plantarum, and L. sake showed relatively good acidifying properties. According to the results of glucose fermentation and its products, only L. plantarum exhibited homo-fermentative characteristics. As a result only L. plantarum among the isolates from kimchi had an ability to adapt to the complex environment of fermented sausage, which will thereby allow them to act as starter cultures and natural preservatives in sausage production.

The Quality Characteristics of Salted Ground Pork Patties Containing Various Fat Levels by Microwave Cooking.

This study was carried out to evaluate the effects of fat level on the microwave cooking properties of ground pork patties with NaCl (1.5%). Ground pork patties were processed from pork hams to achieve fat levels of 10%, 15%, 20%, and 25%, respectively. Each patty was cooked from a thawed state to 75℃ in a microwave oven at full power (700 W). After microwave cooking, protein content, moisture content, fat retention, and shear force values in patties decreased as fat level increased from 10 to 25%. As fat level increased, cooking time decreased but total cooking loss and drip loss were increased, whereas slight differences in diameter reduction and thickness of patties were observed. In raw patties, 10% fat patties had lower L* values and higher a* values compared to patties with more fat, but these differences were reduced when patties were cooked. Patties with 10% fat showed a more pink color on the surface and interior than patties with a higher fat content but more air pockets were noted in higher-fat patties. Higher-fat patties were more tender, juicy, and oily than lower-fat patties.

Effect of Gaeddongssuk (Artemisia annua L.) Powder on Quality and Shelf Stability of Emulsion Sausages during Refrigerated Storage.

The objective of this study was to evaluate effects of Gaeddongssuk powder (GP) on quality characteristics and shelf stability of emulsion sausages during storage. Proximate composition properties showed no significant differences in all treatment (p>0.05). Control showed the highest cooking loss while the treatment with GP showed decreased cooking loss depending on increasing GP content (p<0.05). Apparent viscosity of batter was increased as the amount of GP increased, whereas hardness of emulsion sausages was decreased with increasing GP level. In sensory evaluation, emulsion sausage with 0.1% GP resulted in the highest score in overall acceptability. The pH values of all treatments decreased at the early storage stage, followed by gradual increase. The lightness and redness of treatments were decreased when the level of GP was increased. However, the yellowness of sausages with GP were higher than that of control (p<0.05). The addition of GP inhibited lipid oxidation of emulsion sausages during storage depending on its level. The aerobic bacteria population and VBN was unaffected by addition of GP during the storage (p>0.05). Therefore, Gaeddongssuk powder up to 0.1% has a potential as a natural antioxidant for meat products because it can inhibit lipid oxidation of sausages without decreasing their sensory properties.

Isolation and Characterization of Pepsin-soluble Collagens from Bones, Skins, and Tendons in Duck Feet.

The objectives of this study were conducted to characterize pepsin-soluble collagen (PSC) extracted from bones (PSC-B), skins (PSC-S), and tendons (PSC-T) of duck feet and to determine their thermal and structural properties, for better practical application of each part of duck feet as a novel source for collagen. PSC was extracted from each part of duck feet by using 0.5 M acetic acid containing 5% (w/w) pepsin. Electrophoretic patterns showed that the ratio between α1 and α2 chains, which are subunit polypeptides forming collagen triple helix, was approximately 1:1 in all PSCs of duck feet. PSC-B had slightly higher molecular weights for α1 and α2 chains than PSC-S and PSC-T. From the results of differential scanning calorimetry (DSC), higher onset (beginning point of melting) and peak temperatures (maximum point of curve) were found at PSC-B compared to PSC-S and PSC-T (p<0.05). Fourier transform infrared spectroscopy (FT-IR) presented that PSC-S and PSC-T had similar intermolecular structures and chemical bonds, whereas PSC-B exhibited slight difference in amide A region. Irregular dense sheet-like films linked by random-coiled filaments were observed similarly. Our findings indicate that PSCs of duck feet might be characterized similarly as a mixture of collagen type I and II and suggest that duck feet could be used for collagen extraction without deboning and/or separation processes.

Effect of apple pomace fiber and pork fat levels on quality characteristics of uncured, reduced-fat chicken sausages.

The effects of reducing pork fat level from 30 to 25 and 20% by partially substituting pork fat with 1 and 2% apple pomace fiber were investigated based on the evaluation of physicochemical properties and textural properties of uncured, reduced-fat chicken sausages. Increased fat level resulted in decreased moisture content, cooking loss, total expressible fluid separation, fat separation, and yellowness of uncured, reduced-fat chicken sausages, whereas, an increase in fat content, caloric energy, pH, lightness, redness, hardness, cohesiveness, gumminess, and chewiness was observed. The results showed that uncured, reduced-fat chicken sausage samples with increased apple pomace fiber level had lower cooking loss, total expressible fluid separation, fat separation, pH, and redness. The results from this study show that inclusion of apple pomace fiber in the formulation will successfully reduce fat content in emulsion sausages, while improving quality characteristics relative to regular-fat (30%) control.

Effects of Various Salts on Physicochemical Properties and Sensory Characteristics of Cured Meat.

This study was carried out to investigate the effects of refined, solar, and bamboo salt on the physico-chemical properties and sensory characteristics of cured pork loin. Moisture, protein, fat, and ash content, lightness, yellowness, cooking yield, and color, juiciness, and tenderness of sensory properties on curing pork loin exhibited no significant differences regardless of the nature of salts. The pH of raw and cooked cured pork loin with added bamboo salt was higher that of other salt treatments. However, the cooking loss, and Warner-Bratzler shear force of cured pork loin with added refined salt was lower than those of solar and bamboo salt pork loins cured. The flavor and overall acceptability scores of treatments with refined salt was higher than those of solar and bamboo salt treatments. The unique flavor of bamboo salt can render it as a functional material for marinating meat products. In addition, the results of this study reveal potential use of bamboo salt in meat curing.

Combined effects of Laminaria japonica and transglutaminase on physicochemical and sensory characteristics of semi-dried chicken sausages.

The effects of Laminaria japonica, Transglutaminase (TGase) and their combinations were investigated based on the physicochemical properties, textural properties, and sensory characteristics of semi-dried chicken sausages. The moisture content, ash content, and water activity of the semi-dried chicken sausage containing a combination of Laminaria japonica and TGase were higher than the control (P < 0.05). The semi-dried chicken sausage with 1.0% Laminaria japonica and 1.0% TGase (T3) had less cooking loss compared to the control and other treatments (P < 0.05). The protein content and fat content, pH of batters and sausages, springiness, and cohesiveness of the semi-dried chicken sausages were not significantly different between the control and treatments with a combination of Laminaria japonica and TGase (P > 0.05). Among the sensory traits, color score was highest in the control and in the treatment with 2.0% TGase (T5) (P < 0.05). The flavor score was highest in the control, while the treatments with 1.0% Laminaria japonica combined with 1.0% TGase (T3) had the highest tenderness and juiciness scores (P < 0.05). The results of this study show that the combination of Laminaria japonica and TGase successfully improved textural properties and sensory characteristics of the semi-dried chicken sausages, and the combination of 1.0% Laminaria japonica and 1.0% TGase improved quality of the semi-dried chicken sausages the most.