Inhibition of protein and lipid oxidation by rapeseed, camelina and soy meal in cooked pork meat patties

In this study protein-containing by-products of deoiling processes rich in phenolics were applied to meat to be used as potential food ingredients in developing meat products with antioxidant effect. The effect of rapeseed meal (Brassica rapa L.), camelina meal (Camelina sativa), soy meal and soy flour (from soybean, Glycene max L.), in inhibiting oxidation of lipids and proteins was tested in cooked pork meat patties. A commercial CO₂ extract from rosemary (Rosmarinus officinalis) was used as a reference material alone and in combination with the other plant materials. The cooked pork meat with added plant materials was oxidized for 10 days at 5 °C under light. The oxidation was followed by measuring the formation of hexanal, pentanal and propanal by headspace gas chromatography and the formation of protein carbonyls by converting them to 2,4-dinitrophenylhydrazones (DNPH). Rapeseed meal (0.5 and 0.7 g/100 g meat) and camelina meal (0.7 g/100 g meat) as such and their combination (addition of 0.5 g/100 g) with rosemary extract (0.04 g/100 g) were effective antioxidants toward both protein and lipid oxidation while soy meal and flour were effective only in combination with rosemary extract.     

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     

Pork liver protein hydrolysates as extenders of pork patties shelf-life

The growing demand for the consumption of more natural products challenges the food industry to meet consumer expectations. In this regard, bioactive peptides obtained from flavourzyme, bromelain and alcalase activity were added to pork patties with the aim of improving their shelf-life. Five treatments were prepared: control (CON, without enzymatic extract), positive control (ASA, with 150 mg kg⁻¹ of ascorbic acid) and three batches with 250 mg kg⁻¹ of different porcine liver hydrolysates [flavourzyme (FLA), bromelain (BRO) and alcalase (ALC)]. The analysis of raw burgers included proximate composition (moisture, protein, fat and ash contents), colour parameters (L*, a*, b*), metmyoglobin, lipid oxidation, volatile compounds profile and sensory evaluation. Hydrolysate obtained from bromelain enzyme showed the best a* parameter (5.15), the least lipid oxidation (0.63 mg MDA kg⁻¹) and the lowest percentage of metmyoglobin (56.02%). Furthermore, this batch also presented the lowest content of aldehydes and alcohols resulting from lipid oxidation. Our results suggested that the hydrolysates obtained from bromelain activity possessed a good antioxidative activity, and therefore, they could be used as a natural antioxidant to extend the shelf-life of pork burgers.     

Effects of oleoresin-tocopherol combinations on lipid oxidation, off-odor, and color of irradiated raw and cooked pork patties

Lipid oxidation, color, and volatiles of double-packaged pork loins with various oleoresin or oleoresin-tocopherol combinations were determined to establish the best oleoresin-tocopherol conditions that can improve the quality of irradiated raw and cooked pork loins. Rosemary and α-tocopherol combination at 0.05% and 0.02% of meat weight, respectively, showed the most potent antioxidant effects in reducing both TBARS values and the amounts of volatile aldehydes in irradiated raw and cooked pork loins. The antioxidant combination, however, did not affect the production of sulfur volatiles responsible for irradiation off-odor and showed little effects on color changes in irradiated raw and cooked pork loins. Exposing double-packaged irradiated pork to aerobic conditions for 3days during the 10-day storage was effective in controlling both lipid oxidation and irradiation off-odor, regardless of packaging sequences.     

Effects of dietary soybean oil on lipid and protein oxidation in pork patties during chill storage

The effect of dietary soybean oil on lipid and protein oxidation in low and high fat pork patties made from quadriceps femoris during chill storage in a high oxygen atmosphere packaging (80% O(2)/20% CO(2)) in the dark for 7 days was investigated. Pigs were fed either a standard diet or a diet added 2% soybean oil. After slaughter high fat pork patties were prepared for both feeding regimes by addition of back fat from pigs fed the same diet whereas low fat pork patties were prepared without addition of back fat. The 2% soybean diet increased the amount of unsaturated fat in the pork. Secondary lipid oxidation products determined as thiobarbituric acid reactive substances (TBARS) were found to increase in the pork patties with increased unsaturated fat. Increased unsaturated fat in the pork patties had no effect on protein oxidation determined as free protein thiol content and protein carbonyl content. A small, but significant increase in protein oxidation was found in the high fat pork patties independent on dietary fat. In conclusion, protein oxidation is unaffected by dietary fat in pork patties during chill storage for periods normally used in retail trade, and lipid and protein oxidation are not coupled under these conditions.     

猪皮胶原蛋白肽在熟肉糜中抗氧化效果研究

研究猪皮胶原蛋白肽对熟猪肉糜在贮藏期间的抗氧化效果。测定熟肉糜在贮藏期间色差、pH值、硫代巴比妥酸反应物值(TBARS)及进行感官评定,并与BHT进行比较。结果表明,与对照组相比,添加猪皮胶原抗氧化肽段的处理组在贮藏期间能明显抑制脂肪的氧化,且肽段的添加量越大抑制效果越好,添加2%的猪皮胶原抗氧化肽效果最好但不如BHT处理组效果好,同时感官评定也获得了相同的结果。结论:猪皮胶原蛋白肽对熟肉糜在贮藏过程中的脂肪氧化具有显著的抑制作用,可作为食源性抗氧化剂。     

Oxidative stability of frozen pork patties: Effect of fluctuating temperature on lipid oxidation

The mobility of solutes in fat from pork belly, in lean pork belly and in lean pork longissimus dorsi, containing 1% NaCl was characterized by the ESR spin probe technique using the nitroxyl spin probes TEMPO and TEMPOL. The mobility of TEMPO in fat increased for temperature above -60 °C and the mobility of TEMPOL in lean meat increased for temperature above -40 °C. Temperatures for studying the effect of fluctuating temperatures during frozen storage of meat were selected based on the ESR characterization of the mobility of solutes. The oxidative stability of pork patties during frozen storage was measured as thiobarbituric acid reactive substances (TBARS), during storage at -10, -23 and -40 °C and with fluctuations between these temperatures, of pork patties made from pork loin (low fat 1.8%) or pork belly (high fat 22.7%). Lower storage temperatures resulted in less lipid oxidation, and temperature fluctuations between -40 and -23 °C and fluctuations between -23 and -10 °C resulted in oxidation intermediate to oxidation in samples stored at constant low or high temperatures of the fluctuation interval. The level of α-tocopherol was unaffected by the extent of oxidation in the frozen samples, an observation which is discussed in relation to differences in molecular mobility between oxygen and α-tocopherol.     

Lipid oxidation and color change of salted pork patties

The purposes of this study were to explore the interaction of lipid oxidation and pigment oxidation in salted pork patties and to study the mutual relationship between lipid and pigment oxidation caused by replacing sodium chloride with potassium chloride at low salt levels. For fresh pork patties, a^∗ and b^∗ values decreased with the replacement of sodium chloride by potassium chloride. However, there were no significant differences of L^∗ values, pH values, total pigments and heme irons by replacement of NaCl with KCl; however, the replacement reduced 2-thiobarbituric acid reactive substances (TBARS).     

Use of antioxidants to reduce lipid oxidation and off-odor volatiles of irradiated pork homogenates and patties

Pork homogenates and patties treated with antioxidants (200 μM, final) were irradiated with an electron beam. Lipid oxidation of the pork homogenates and patties were determined at day 0 and 5 and volatile compounds were analyzed soon after irradiation. Ionizing radiation accelerated lipid oxidation and produced S-containing volatiles in pork homogenates and patties. Addition of an antioxidant (sesamol, gallate, Trolox, or α-tocopherol) and their combinations decreased, but carnosine did not affect the production of off-odor volatiles and lipid oxidation of pork homogenates and patties by irradiation. Antioxidant combinations showed distinct beneficial reduction in lipid oxidation of aerobically packaged irradiated pork patties. The effect of antioxidant combinations in reducing sulfur volatiles of irradiated pork patties was clearer under vacuum than aerobic conditions.     

Effects of onion on physicochemical properties,lipid oxidation and microbial growth of fresh pork patties

Onions with or without heating (100 °C, 30 min) were extracted with water or methanol, and antioxidant and antimicrobial activities of onion extracts were evaluated. Product characteristics of fresh pork patties containing various onion extracts were measured during refrigerated storage. Water extracts of onions showed higher extraction yield and iron chelating ability than methanol extracts (P < 0.05), whereas, the latter was more effective than the former in phenolic compounds and reducing power (P < 0.05). The addition of onion extracts [water extract from fresh onion (WEFO), methanol extract from heated onion (MEHO) and their combinations (WEFMEHO)] to pork patties decreased redness, increased yellowness, and inhibited lipid peroxidation (P < 0.05). One per cent of WEFMEHO in pork patties had antioxidant activities as effective as butylated hydroxyl toluene (BHT, 0.01%). Redness and yellowness decreased and increased with the addition of onion extract, respectively (P < 0.05).     

Microwave heating of cooked pork patties as a function of fat content

ABSTRACT:  In this study, the parameters heating rate, dielectric factors, and specific heat capacity, which determine the heating profiles and the dissipation of energy during microwave heating, were obtained for precooked pork patties. The pork patties studied were lean meat, pure back fat, and several lean meat/back fat mixtures. Microwave heating at 798 W power was not sufficient to accelerate the heating rates in 100% lean meat compared to 415 W. However, samples were able to heat up faster and dissipate more energy at 798 W power as fat content increased and moisture content decreased. The recorded differences in the specific heat capacity of the studied materials as a function of temperature seemed not to be the key factor to explain the observed temperature rises. Temperature rise seemed to have more to do with the interactions of fat with the electromagnetic field, and with viscosity changes during phase transitions. Trends found for the dielectric properties over microwave heating of meat products agree with data from other authors, but the influence of parameters related to the sample composition and structure should be taken into account. The dissipation factors (ɛ"/ɛ') provided a good approximation to the capacity of the samples containing lean meat and the lean meat/fat mixtures to transform the electromagnetic energy into heat. Neither the dielectric constant nor the loss or dissipation factors were able to clarify the high amount of energy transformed into heat in 100% back fat. Penetration depth and reflected power indicated that back fat allowed microwave energy to be repeatedly redirected to the material.     

The triacylglycerol preparation of conjugated linoleic acid reduces lipid oxidation in irradiated, cooked ground beef patties

It is proposed that conjugated linoleic acid (CLA) would depress the lipid oxidation caused by irradiation of cooked, aerobically stored ground beef patties. The free fatty acid (FFA–CLA) and triacylglycerol (TAG–CLA) preparations of CLA were added at 0%, 1%, 2%, or 4% during the grinding process. Patties were irradiated at 1.5–2.0 kGy and frozen at −20 °C. Subsequently, the patties were tempered to 4 °C, cooked to 70 °C and held at 4 °C for 7 d. Enrichment of ground beef with CLA increased the cis-9,trans-11 and CLA trans-10,cis-12 CLA isomers in ground beef patties, even after cooking. Weight loss (P = 0.03) and percentage fat (P = 0.05) were higher in irradiated beef patties than in control patties. Irradiation decreased the concentration of α-linolenic acid (18:3n − 3) in the ground beef by over 60% (P = 0.07), whereas thiobarbituric acid reactive substances (TBARS) values were higher (P = 0.004) in irradiated beef patties than in control patties. The 1% concentration of added TAG–CLA reduced TBARS in irradiated ground beef patties, whereas 2% and 4% FFA–CLA depressed TBARS (CLA type × percentage interaction P = 0.04). Irradiation increased the cardboard and painty aromatic attributes (P  0.05), and FFA–CLA preparation increased the painty aromatic attribute and afterburn aftertaste, but these effects were not observed with the TAG–CLA preparation (CLA type × treatment interaction P < 0.04). Adding 1% TAG–CLA to ground beef during grinding can reduce lipid oxidation in irradiated, cooked ground beef patties without the negative aftertastes associated with the FFA–CLA preparation.     

Phenolic-rich extracts from Willowherb (Epilobium hirsutum L.) inhibit lipid oxidation but accelerate protein carbonylation and discoloration of beef patties

An extraction procedure of phenolics from Willowherb (Epilobium hirsutum L.) was optimized; extracts were characterized in terms of phenolic content, composition, and in vitro antioxidant activity. Additionally, the effect of 50, 200, and 800 ppm Willowherb extracts on the oxidative stability (formation of thiobarbituric acid-reactive substances, α-aminoadipic, and γ-glutamic semialdehydes) of beef patties was studied. Acetone (50 %) extract, rich in ellagic acid, myricetin, hydroxybenzoic, and hydroxycinnamic acids, had the highest phenolic content compared to methanol (25, 50, 75, and 100 %), acetone (100 %), or water extracts and displayed intense in vitro antioxidant properties. Lipid oxidation levels in processed beef patties with added Willowherb extract remained as similar to that of 100 ppm gallic acid. A dose-dependent effect of Willowherb extract was observed on protein carbonylation and myoglobin oxidation. The lack of correlation between lipid and myoglobin oxidation and the underlying mechanisms involved in the pro-oxidant action of phenolics on meat proteins are thoroughly discussed.     

Antioxidant effects of soy sauce on color stability and lipid oxidation of raw beef patties during cold storage

This study was conducted to evaluate the antioxidant effects of soy sauce on lipid oxidation and color stability of raw beef patties. Raw beef patties were formulated with four solutions such as NaCl (sodium chloride solution), NaCl/SS (1:1 ratio of sodium chloride and soy sauce solution), SS (soy sauce solution), or SS/A (soy sauce solution combined with 0.05% ascorbic acid) in the same salt concentration. Addition of soy sauce resulted in the decreased pH, lightness, and increased yellowness. Treatment SS/A had the lowest percent of metmyoglobin during storage (P < 0.05). A reduction (P < 0.05) in the 2-thiobarbituric acid, peroxide, and conjugated diene concentration as result of soy sauce addition were observed in treatments SS and SS/A at the end of the storage period. There were no differences (P > 0.05) in free fatty acid concentration at the end of storage. The combined addition of soy sauce and ascorbic acid greatly improved (P < 0.05) color stability and retarded lipid oxidation.     

Nutritional quality of model low‐fat pork patties manufactured with the use of soy protein isolate

Proximate composition and amino acid and fatty acid profiles of low‐fat pork patties manufactured with the addition of soy protein isolate (SPI) were determined and their energy values were calculated. Patties with SPI were characterised by a higher content of protein than the control. Although the 10% SPI added sample showed the highest energy value of all samples, it contained the lowest amount of fat and therefore the share of energy from the fat of this sample was lower than those of the other samples. The essential amino acid indices of SPI added patties were lower than those of the control, but they were still favourable compared to the FAO/WHO/UNU reference pattern of protein. The fatty acid composition of fat was positively influenced by the addition of SPI, as an increase in C18:2, C18:3, total PUFA and PUFA/SFA ratio along with an increased amount of SPI added to patties was observed.     

Antioxidative effect of crackling hydrolysates during frozen storage of cooked pork meatballs

The effect of acid (CAH) and enzymatic (CEH) hydrolysates prepared from pork cracklings on the oxidative stability of frozen pork meatballs was investigated. Meatballs were stored at −18 °C for 180, 270 and 360 days during which time peroxide value (PV), TBARS, profiling sensory analysis and cholesterol oxidation products (COPs) were determined. The oxidation products of cholesterol, such as epimers 7-hydroxy, 5,6-epoxy, 7-keto, triol and 25-hydroxy, after transesterification and SPE fractionation, were detected by capillary gas chromatography. CAH and CEH possessed similar antioxidant efficacy. Inhibition activity of cracklings hydrolysates against PV was 38–45%, and against TBARS was 30–39%. The antioxidant properties of CAH and CEH against the oxidation of lipids were poorer than that of BHT. The addition of hydrolysates changed sensory profiles and had a significant (P<0.05) effect on the taste and odour of meatballs. The total COPs in all meatballs increased during storage. 7-Keto-cholesterol was the dominant oxysterol in fresh samples. After 360 days of storage, levels of oxysterols in samples treated with hydrolysates were about 20% lower than that of the control sample. The most toxic derivative, triol-cholesterol, was detected at the lowest level in samples treated with hydrolysates. The protection of BHT against cholesterol oxidation was poorer than that of CEH.     

Honey inhibits lipid oxidation in ready-to-eat ground beef patties

Our objective was to evaluate the antioxidant capabilities of clover (CH) and wildflower honeys (WH) in delaying lipid oxidation in cooked and reheated ground beef patties stored in refrigerated and frozen states. CH and WH (5%, 10%, or 15% w/w) were each mixed separately into ground beef chuck (18% fat) and formed into 30 g patties mixed with 1% salt (w/w). A control (CON) with no honey and a control with sodium tripolyphosphate (STP; 0.25% w/w) were used for comparison. Patties were cooked to 71 °C, overwrapped with oxygen-permeable PVC film and either stored refrigerated (4 °C) for 12 days or frozen (−18 °C) for 45 days. Cook yield, pH and water activity were measured on day 0. On designated sampling days, patties were reheated to 71 °C. Thiobarbituric acid-reactive substances (TBARS) and lipid hydroperoxides (LOOH) were measured spectrophotometrically to assess lipid oxidation. TBARS and LOOH of ready-to-eat (RTE) ground beef patties containing either CH or WH were lower (P < 0.01) than CON patties following storage; however, STP patties had lower TBARS values than honey-containing patties (P < 0.01). WH and CH at 15% were equally effective in suppressing LOOH compared to STP in refrigerated and frozen patties. All honey concentrations improved cook yield, with 10% WH being more effective than STP. Both CH and WH delayed lipid oxidation in RTE ground beef patties stored at 4 °C and −18 °C, with WH decreasing LOOH formation in refrigerated patties as effectively as STP. Honey may be a natural alternative to phosphates to delay lipid oxidation.     

水解大豆蛋白膜法分级特性的研究

为了得到富含带正电荷组分、具有潜在免疫调节功能的活性肽,探讨了平均分子量为726.5,带正电荷组分相对含量为44%的酶水解大豆蛋白在截留分子量为8 000、3 500的复合材质膜上的分离特性.结果显示,稳态膜通量随pH的变化不明显,然而含氮组分的透过率却随pH升高明显降低.当pH＞7时,透过液中分子量＞1 200的组分含量显著降低,而带正电荷组分的相对含量明显增加.