Antioxidant activity of carnosine in cooked ground pork

Carnosine (0·5-1·5%) reduced (P < 0·05) the formation of thiobarbituric acid reactive substances (TBARS) in cooked unsalted ground pork after 7 days of storage at 4°C. The antioxidant activity of carnosine was less in cooked salted ground pork, with only 1·5% carnosine inhibiting (P < 0·05) TBARS formation during refrigerated storage. The antioxidant activity of carnosine in cooked salted and unsalted ground pork was greater than those of the lipid-soluble free radical scavengers, butylated hydroxytoluene and α-tocopherol (P < 0·05) but less than that of sodium tripolyphosphate (P < 0·05). These data suggest that carnosine could be used to reduce the oxidative deterioration of cooked salted and unsalted ground pork.     

Effect of carnosine preblending on the quality of ground buffalo meat

A study was conducted on carnosine preblending at 0%, 0.5%, 1.0% and 1.5% levels with ground buffalo meat obtained from spent, adult, male Murrah buffalo carcasses, to identify the level of carnosine required for improving the quality of the meat during refrigerated storage at 4 ± 1 °C. It was observed that meat samples containing 1.0% and 1.5% carnosine significantly inhibited metmyoglobin formation and brown colour development. Carnosine also improved meat pH, and water-holding capacity and lowered cooking loss and 2-thiobarbituric acid-reacting substances (TBARS) values as compared to control sample. Carnosine also improved desired visual colour and odour, and gave higher LTCU ‘R’ and chroma of meat samples. Visual colour was inversely correlated with metmyoglobin, aerobic mesophiles and psychrotrophs plate count, and odour was inversely correlated with TBARS values. Use of 1.0% carnosine for preblending extended the shelf life of ground buffalo meat up to 8 days under refrigerated storage.     

肌肽对猪肉的氧化抑制和保鲜作用

肌肽是一种具有抗氧化等功能的天然的二肽,本试验比较了肌肽对猪肉匀浆的抗氧化作用,同时比较了不同保鲜剂对冷鲜肉保藏期的延长作用。实验发现,1mmol/L肌肽标准液对猪肉匀浆中丙二醛的形成量就能起到显著的抑制作用(P<0.05),此时对体系中脂类氧化的抑制率即达到12%,5mmol/L肌肽对体系中脂类氧化的抑制率达15%,20mmol/L肌肽对体系中脂类氧化的抑制率达47%,表明不同浓度的肌肽均能对猪肉匀浆中脂类氧化起显著的抑制作用,其中随浓度的增加效果增强。与BHT和α-生育酚相比,肌肽对TBARS的抑制能力较高。肌肽可以延长冷鲜肉的保存时间,添加了肌肽的冷鲜肉保藏时间由不添加保鲜剂的9天增加到15天,其效果要优于抗坏血酸,肌肽牛肉预煮液也可以延长冷鲜肉的贮藏时间。     

INTERACTIONS BETWEEN CARNOSINE AND SELECTED ANTIOXIDANTS IN GROUND TURKEY1

The antioxidant activity of 0.5% carnosine alone and in combination with selected antioxidants was investigated in uncooked ground turkey stored at 4C. A combination of tocopherol (0.05%) and carnosine exhibited additive antioxidant activity in salted and unsalted ground turkey. An ascorbyl palmitate (0.05%)/carnosine combination decreased TBARS 1.5 fold in salted ground turkey but was less effective in unsalted muscle (0.15% ascorbyl palmitate). Combining carnosine with STP (0.5%) or citrate (0.01 or 0.05%) did not increase the antioxidant activity of carnosine in ground turkey. These data suggest that tocopherol and ascorbyl palmitate could enhance the antioxidant activity of carnosine.     

Antioxidative activity of carnosine in gamma irradiated ground beef and beef patties

The activity of carnosine as a natural antioxidant in gamma irradiated ground beef and beef patties was studied. Samples of ground beef, in the absence and presence of 0.5% or 1.0% carnosine, as well as raw and cooked beef patties prepared with 1.5% salt (NaCl), in the absence and presence of 0.5% or 1.0% carnosine, were gamma irradiated at doses of 0, 2, and 4 kGy. The extent of oxidation in irradiated and non-irradiated samples of ground beef and raw beef patties was then determined during refrigerated (4 ± 1 °C) and frozen (−18 °C) storage, while determined for cooked beef patties during refrigerated storage only. Moreover, the determination of metmyoglobin (MetMb) accumulation and sensory evaluation for the visual color were carried out for samples of ground beef and raw patties. The results indicated that salt or salt and cooking accelerated the oxidative processes and significantly increased the peroxide value (PV) and thiobarbituric acid reactive substances (TBARS) in the prepared non-irradiated samples. However, salt slowed down the accumulation of MetMb in raw patties. Irradiation treatments and storage in the absence of carnosine significantly (P < 0.05) increased the PV and TBARS in samples, at higher rates in salted or salted and cooked beef. Moreover, irradiation and storage significantly (P < 0.05) increased the formation of MetMb in ground beef and raw patties in the absence of carnosine. Addition of carnosine significantly (P < 0.05) reduced the oxidative processes and MetMb formation (proportionally to the used concentration) in samples post-irradiation and during storage. Furthermore, carnosine exerted significant efficacy in maintaining an acceptable visual red color post-irradiation and during storage of ground beef and raw patties. These results demonstrate that carnosine can be successfully used as a natural antioxidant to increase the oxidative stability in gamma irradiated raw and cooked meat products.     

Antioxidant activity of mechanically separated pork extracts

Utilization of synthetic carnosine as a food additive is limited by both regulatory and economic hurdles. Therefore, the potential of producing carnosine-containing antioxidant extracts from an underutilized skeletal muscle source, mechanically separated pork (MSP), was investigated. Carnosine-containing MSP extracts were capable of inhibiting lipid oxidation both in vitro and in salted ground pork. Heating (60-80°C) the MSP extract removed iron and increased in vitro antioxidant activity. Isolation of a low molecular weight fraction of the MSP extract by ultrafiltration was effective at decreasing iron but did not substantially increase in vitro antioxidant activity. Freeze dried extracts (untreated, 80°C, ultrafiltration permeate) were capable of inhibiting both TBARS and lipid peroxide formation in ground, salted pork stored at -15°C. While MSP extracts were capable of inhibiting lipid oxidation both in vitro and in salted, ground pork, their antioxidant activity was low suggesting that their use as a food additive would be impractical.     

Influence of dietary β-alanine and histidine on the oxidative stability of pork

Carnosine (β-alanine-L-histidine) and anserine (β-alanine-1-methyl histidine) are endogenous antioxidants found in skeletal muscle. The objective of this research was to determine if supplementation of swine diets with histidine (histidine; 0.40%) and/or β-alanine (β-alanine; 0.225%) was an effective method to increase carnosine and anserine concentrations and the oxidative stability of Longissimus dorsi (LD) and Vastus intermedius (VI) muscles. Dietary treatments had no effect on carnosine and anserine concentrations in LD; however, histidine + β-alanine supplementation increased carnosine and anserine in VI muscle compared to β-alanine supplementation. Dietary supplementation had no effect on the formation of thiobarbituric acid reactive (TBARS) or lipid peroxides in cooked VI and LD. In salted VI and LD muscle, differences in TBARS and peroxides were observed; however, these differences did not consistently correlate with differences in anserine and carnosine concentrations. Therefore, the results of this research suggest that supplementation of swine diets with β-alanine and/or histidine is not an efficient method to increase the oxidative stability of pork.     

Inhibition of Lipid Oxidation and Rancidity in Precooked Pork Patties by Radical‐Scavenging Licorice (Glycyrrhiza glabra) Extract

This study investigated the efficacy of licorice extract (LE) to curtail lipid oxidation and protect sensory attributes of ground pork during refrigerated and frozen storage. Pork patties (20% fat) were formulated with 0%, 0.02%, 0.05%, and 0.1% (meat basis) LE or rosemary extract (RE) as comparison or 0.01% (fat basis) BHA with 0 or 1.5% NaCl. Raw and precooked (75 °C) patties were packaged in polyvinylchloride overwrapped trays and stored at 2 °C up to 7 and 14 d, respectively, or at –20 °C up to 6 mo. Lipid oxidation (thiobarbituric acid‐reactive substances [TBARS]) and sensory attributes of stored patty samples were evaluated, radical scavenging activity of the LE was measured, and the active phenolic compounds were identified. Cooking yield (<85%) was similar among antioxidant treatments, and lipid oxidation was minimal in refrigerated or frozen raw samples. However, TBARS values in refrigerated precooked control patties (0.22 mg/kg) rose to 9.3 to 9.4 mg/kg after 14 d, compared to 3.4 to 4.4 and 4.4 to 6.9 mg/kg in patties treated with 0.1% LE and RE, respectively. In frozen precooked samples, TBARS (0.22 mg/kg) increased to 1.3 mg/kg (P < 0.05) in control patties after 6 mo and had no significant change in patties treated with 0.1% LE or 0.01% butylated hydroxyanisol. Sensory panel evaluation confirmed strong inhibition of rancidity production by LE, corroborating its remarkable antiradical activity due to the presence of multiple phenolics. The results indicate that licorice has great potential as a natural antioxidative additive to extend the shelf‐life of precooked pork.     

Influence of sodium chloride on antioxidant enzyme activity and lipid oxidation in frozen ground pork

Ground pork containing 0–2.0% NaCl was stored at −15 °C for 10 weeks. During storage both thiobarbituric acid reactive substances (TBARS) and lipid peroxides increased with increasing NaCl concentrations. The activity of catalase (CAT), glutathione peroxidase (GSH-Px) and Superoxide dismutase (SOD) decreased 8, 32 and 27%, respectively, after 10 weeks of storage. CAT and SOD activity decreased primarily during the first week while GSH-Px activity decreased for up to 4 weeks. To determine if NaCl influenced enzyme inactivation rates, the activity of the antioxidant enzymes from stored, salted (0.5–2.0%) ground pork were determined at equal ionic strengths. Under these conditions, NaCl was not observed to accelerate CAT, SOD and GSH-Px inactivation in ground muscle during storage. However, altering ionic strength (0.5–2.0% NaCl) in the enzymes assays decreased the activity of muscle-extracted CAT, SOD and GSH-Px suggesting that NaCl could alter the activity of these enzymes in salted pork. The ability of NaCl to reduce the activity of the antioxidant enzymes could be partially responsible for the lower oxidative stability of salted muscle foods.     

Antioxidant Activity of Phosvitin in Phosphatidylcholine Liposomes and Meat Model Systems

ABSTRACT: Phosvitin, an iron-chelating protein, was tested for its ability to inhibit lipid oxidation in phosphatidylcholine (PC) liposomes and meats. Inhibition of thiobarbituric acid reactive substances (TBARS) formation increased with increasing phosvitin concentrations with maximal inhibition occurring at 40 and 15 mM in PC liposomes and pork muscle homogenates, respectively. Phosvitin lost only 2 to 15% of its antioxidant activity after being heated for 10 min at 60 to 100 °C. The ability of phosvitin to inhibit TBARS formation was maximal at pH 7.0. Phosvitin was a more effective antioxidant in cooked ground pork with 20 mM inhibiting 11 to 39% of oxidation compared with 0 to 20% inhibition in uncooked, salted ground pork containing 60 mM phosvitin.     

Culinary herbs inhibit lipid oxidation in raw and cooked minced meat patties during storage

The effect of dried spices and the ethanol extract of those spices was studied on the stability of fresh chicken minced meat, and fresh and cooked pork patties pretreated with NaCl during refrigerated and frozen storage. The antioxidant activities of the spices were measured by thiobarbituric acid reactive substances (TBARS) and peroxide value (POV) in meat samples. The lipid oxidation was effectively inhibited in the chicken meat treated with several dry spices diminishing the TBARS to a range of 32% and 83% of those found in the control samples in frozen stored meat for 6 months. Marjoram, wild marjoram and caraway were the most effective dry spices. Ethanolic extracts of the same spices were more potent as antioxidants by lowering the concentration of the TBARS to a range of 20–27% of those found in the control samples. Addition of sodium salt to the minced pork resulted very high concentrations of the oxidation products originated from the polyunsaturated fatty acids. The treatment with ethanolic extract of spices (sage, basil, thyme and ginger) significantly inhibited the lipid peroxidation in refrigerated and chilled pork patties pretreated with NaCl by reducing both POV and TBARS. Heat treatment with microwaves produced significantly elevated levels of both lipid peroxides and TBARS, but the amount of these oxidation products was less than 10% in spice‐treated salted meat samples compared to that in untreated ones. Lipid peroxidation also grew continuously during the storage period at −18°C in raw and cooked samples. Ethanolic extracts of spices had a very strong antioxidative effect inhibiting lipid peroxidation in heat‐treated meat products during frozen storage. The highest antioxidant activity was observed in the case of ginger. High correlation coefficients were found between TBARS and POV both in raw and cooked pork patties (0.86, 0.91, respectively) during frozen storage. It is supposed that these compounds originated from the polyunsaturated fatty acids during oxidation processes but at different stages. Utilization of spices, spice mixtures or spice extracts in semi‐prepared meat products intended to be frozen for up to 6 months or more before consumption is proved to be advantageous in regard of shelf life of the food, as well as of human health, because of the beneficial effect of spices in inhibition of lipid peroxidation during heat treatment and chilling storage. © 1999 Society of Chemical Industry     

Lipid Oxidation and Warmed-Over Aroma in Cooked Ground Pork from Swine Fed Increasing Levels of Iron

Fifteen crossbred feeder pigs were fed to market weight on corn-soy rations containing either 62, 131, or 209 ppm iron. After slaughter, pork was ground, cooked, and stored at 4°C for 12 days. Heavily fortifying swine rations with iron (≥200 ppm) increased nonheme iron (NHI) and thiobarbituric acid reactive substances (TBARS) in cooked, stored ground pork (GP) but did not increase warmed-over aroma (WOA) (p>0.05). NHI, TBARS, and WOA increased during storage. TBARS strongly correlated with WOA during storage (r=0.903) and with NHI (r=0.901).     

Sensory Properties and Lipid Oxidation in Prerigor Processed Fresh Pork Sausage

Fresh pork sausage prepared from prerigor ground and salted meat had higher pH, lower cooking losses, higher juiciness scores, and less easily fragmented cooked patties than that prepared from post-rigor ground and salted meat. Sausage from prerigor ground-post-rigor salted meat was intermediate in these properties to prerigor ground and salted and postrigor ground and salted products. Prerigor grinding and salting reduced the rate of autoxidation (TBA number) during storage at 0°C contrasted to oxidation in sausage that was salted postrigor after either prerigor or postrigor grinding.     

Effect of dietary α-tocopherol supplementation on color and lipid stability in pork

Myoglobin and lipid oxidation are major causes of quality deterioration in fresh pork. A process to enhance color and lipid stability would prove valuable to the pork industry given the current trend of centralized packaging and distribution to retail markets. Our objective was to determine the effects of dietary α-tocopherol (α-Toc) supplementation on color and lipid stability in ground pork, and loin chops stored in modified atmosphere packaging (MAP). Yorkshire crossbred pigs (n=20) were randomized into two groups and fed diets containing 48 (CON) or 170 mg α-Toc acetate/kg feed (VIT-E) for 6 weeks before slaughter. Plasma α-Toc concentration was measured weekly. Post-slaughter, Boston butt shoulders were ground, formed into patties with or without 1.5% salt, and stored fresh at 4°C for 0, 2, 4, or 6 days, and frozen at −20°C for 45 or 90 days. Pork loin chops were packaged aerobically and stored at 4°C for 0, 2, 4 or 6 days, or in MAP at 4°C for 7, 10 or 13 days prior to Hunter L*,a*,b* and TBARS analyses. α-Toc concentration of longissimus dorsi, psoas major, biceps femoris, semimembranosus and semitendinosus muscles was determined. Plasma α-Toc was greater (P<0.05) in VIT-E animals compared with CON and α-Toc concentrations were greater (P<0.05) in all VIT-E muscles compared with CON. TBARS values of both fresh and salted patties were less in VIT-E than in CON meat following 6 days at 4°C; VIT-E TBARS of salted patties were less (P<0.05) after 45 days at −20°C compared with CON. α-Toc supplementation did not influence (P>0.05) color of aerobically packaged or MAP chops, or of fresh or salted pork patties. α-Toc supplementation reduced TBARS formation in fresh and salted pork but had no significant impact on color.     

Compositional Factors that Influence Lipid Peroxidation in Beef Juice and Standard Sausages

In order to identify how different additives influenced lipid peroxidation formation, a sausage only using beef juice as pigment source and a standard beef–pork meat sausage were studied. The effects of different additives, including fish oil, myoglobin, nitrite, clove extract, and calcium sources on oxidation and sensory properties were examined. Both sausage systems were stored in 3 different manners prior to testing: (1) frozen immediately at ?80 °C; (2) chilled stored for 2.5 weeks followed by fluorescent light illumination at 4 °C for another 2 wk; (3) frozen at ?20 °C for 5 mo. The frozen group 3 showed the highest peroxide formation and thiobarbituric acid reactive substances (TBARS) for both sausage systems. Unpolar peroxides dominated in both systems. The clove extract could offset the peroxide formation from myoglobin/beef juice and/or fish oil, but the addition of clove flavor was recognized by the sensory panelists. Calcium addition reduced lipid peroxide formation. Added nitrite and fish oil seemed to interact to stimulate nitroso‐myoglobin formation. Nitrite was identified to interact with clove addition and thereby, relatively speaking, increased TBARS. The 2 sausage systems generally ranked the additives similarly as pro– and antioxidants.     

Inhibition of Phosphatidylcholine Liposome Oxidation by Porcine Plasma

Porcine plasma inhibited iron-catalyzed lipid oxidation at the pH range (5.5–7.0) and temperatures (4–37°C) commonly found in food. Increasing concentrations of frozen-thawed plasma resulted in increased antioxidant activity until 100% inhibition was reached at 5.36 mg plasma protein/mL assay. In addition to iron, porcine plasma also inhibited hydrogen peroxide-activated hemoglobin- and photoactivated riboflavin-catalyzed lipid oxidation. The plasma partially lost antioxidant activity during refrigerator storage (4°C) after 8 days but not during frozen storage (?15°C) after 246 days. Dialyzing the plasma increased inhibition of iron-catalyzed lipid oxidation 1.8-fold higher than undialyzed plasma (1.5 mg plasma protein/mL).     

Antioxidant Effects of L-Carnosine on Liposomes and Beef Homogenates

The antioxidant activity of camosine (β-alanylhistidine dipeptide) was investigated using several systems. In the presence of 100 μM ascorbic acid, carnosine inhibited metal ion-catalyzed deoxyribose degradation in a dose-dependent manner, indicating its hydroxyl radical-scavenging activity. Carnosine strongly inhibited metal ion-catalyzed liposomal lipid peroxidation in the presence of 100 μM ascorbic acid or 100 μM H₂O₂. Carnosine also inhibited thiobarbituric acid-reactive substances (TBARS) formation from ground beef homogenates. An increase in TBARS formation was caused by addition of 10 ppm Fe³⁺ to the homogenates. Carnosine presence prevented such increase and it may be useful as an adjunct against oxidative tissue damage or for increasing shelf life.     

Effect of Antioxidants and Cooking on Stability of n-3 Fatty Acids in Fortified Meat Products

ABSTRACT: This study was carried out to determine the effect of processing and cooking on n-3 polyunsaturated fatty acid (PUFA) stability and to determine the efficacy of antioxidants (ANTI) to minimize lipid oxidation in cooked n-3 PUFA-fortified meat products. An emulsion of n-3 PUFAs (25% algal oil) was incorporated into ground turkey, pork sausages, or restructured hams (500 mg n-3 PUFA/110 g meat) with or without an "antioxidant cocktail" containing citrate (0.5% w/w), erythorbate (1 g/kg product), and rosemary (0.2% w/w). Ground turkey and pork sausages were frozen 2 d, then cooked to 71°C, and stored at 4°C for 2 d. Cooked, restructured hams were sliced, vacuum packaged, and stored at 4°C, or frozen and thawed with subsequent storage at 4°C. Treatments were CON (control), n-3 (n-3 PUFAs), CON + ANTI and n-3 + ANTI. Products were analyzed for color, lipid oxidation (TBARS and peroxide values), and n-3 PUFA profile. TBARS of n-3 PUFA-fortified treatments in ground turkey and pork sausages increased with storage ( P < 0.05); there were no changes in TBARS for CON + ANTI and n-3 + ANTI groups ( P > 0.05). For restructured hams nitrite curing appeared to delay lipid oxidation such that antioxidant treatment effects were unobservable ( P > 0.05). Overall recovery of n-3 PUFAs after heat processing was 69% to 85%, and there was no effect of storage on n-3 PUFA concentration in raw or cooked products ( P > 0.05). Sensory scores for n-3 treated restructured hams were lower than controls ( P < 0.05). Results suggested that cooking resulted in some losses of n-3 PUFAs in fortified meat products and that an "antioxidant cocktail" protected against lipid oxidation during subsequent storage in non-cured meat products.     

Oxidative Changes of Heat-Sterilized Meat in Trays

We studied oxidative changes of ground pork meat filled into plastic or aluminum trays, sterilized at 121 or 131°C and stored up to 56 days at 20 or 37°C in the dark or exposed to light, respectively. Sterilization temperature did not influence either thiobarbituric acid reactive substances (TBARS) of the samples or ethane concentrations in headspace of trays. An increase of storage temperature from 20 to 37°C increased TBARS and ethane concentrations regardless of filling method and packaging material. No changes in double-bond indices were observed. Nitrogen flushing in combination with light protection reduced lipid oxidation up to 85–95%