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1.
This research was aimed at evaluating the inhibition of oxidative changes of beef patties packaged in modified atmosphere (70% O2+20% CO2+10% N2) by natural antioxidants: ascorbic acid (500 ppm), taurine (50 mM), carnosine (50 mM), rosemary powder (1000 ppm) and their combinations with the first. Beef patties stored at 2±1°C for 20 days were evaluated for colour (L*, a*, b*, C* and H*), TBARS, metmyoglobin formation (% of total myoglobin), psychrotrophic microbial counts and sensory odour and discolouration. Rosemary, either alone or with ascorbic acid, was highly effective in inhibiting both metmyoglobin formation and lipid oxidation; sensory analysis was in agreement with these results. Ascorbic acid, ascorbic acid+taurine and ascorbic acid+carnosine treatments showed a limited inhibitory effect of myoglobin oxidation, while carnosine and carnosine+ascorbic acid were effective in inhibiting lipid oxidation. Taurine alone failed to exert any antioxidant effect. Principal components analysis confirmed these results.  相似文献   

2.
The effects of modified atmosphere (80% O2: 20% CO2) and illumination on the discoloration rate of pork bone (lumbar vertebrae) and muscle (longissimus lumborum), and on muscle lipid stability were studied in vitamin E-supplemented and unsupplemented pigs. Bone-in pork chops were placed in 80% O2: 20% CO2 at 0 °C and stored for 5 days in the dark. The chops were then displayed under (a) fluorescent light in air or modified atmosphere or (b) in air with or without illumination. Lipid oxidation was increased by the modified atmosphere packaging but this detrimental effect was offset by vitamin E supplementation. Higher supplementation levels (198 and 207mg/kg) improved bone color stability regardless of the packaging atmosphere or the lighting conditions. Although vitamin E supplementation improved muscle color stability during display in air or modified atmosphere, the benefit of supplementation on muscle color was detectable only for illuminated storage.  相似文献   

3.
The effects of addition of tea catechins (TC) and vitamin C (VC) on sensory evaluation, colour and lipid stability in cooked or raw beef and chicken meat patties during refrigerated storage were studied. Fresh beef striploin and chicken breast muscles were minced, following removal of external fat and connective tissue. Following mincing, beef and chicken were assigned to one of the following five treatments: control (meat treated with no antioxidant); TC200, meat plus 200 mg TC/kg muscle; TC400, meat plus 400 mg TC/kg muscle; VC200, meat plus 200 mg VC/kg muscle, VC400, meat plus 400 mg VC/kg muscle. Sodium chloride (1%) was added to all samples. Patties (125 g portions), formed from the above-treated minced meat, were oven cooked, cooled, and packaged in 30% CO2:70% N2. Fresh raw beef and chicken patties were packaged in 80% O2:20% CO2. All samples were stored for up to 7 days under fluorescent lighting at 4 °C. Sensory parameters (colour, flavour, taste, tenderness and overall acceptability) were evaluated on cooked beef and chicken patties after 1, 3 and 6 days of storage. Surface colour (Hunter L, a and b values), and lipid oxidation (2-thiobarbituric acid reactive substances) were measured on days 1, 3 and 6 of storage for cooked meats and on days 2 and 7 for raw beef and chicken. Tea catechins addition (200 or 400 mg/kg) to minced meat caused (P < 0.05) discolouration in cooked beef and chicken meat patties and significantly reduced (P < 0.001) lipid oxidation in cooked or raw beef patties compared to the control. Beef, either raw or cooked, was more susceptible (P < 0.01) to oxidation compared to chicken. Raw meat stored in high oxygen conditions was more susceptible to lipid oxidation than cooked meat stored in anaerobic conditions. Tea catechins treatments (TC200 and TC400) inhibited (P < 0.05) lipid oxidation in raw beef to a greater extent than vitamin C treatments (VC200 and VC400). These results indicate that tea catechins are potent natural antioxidants and exhibit greater antioxidant efficacy compared to vitamin C.  相似文献   

4.
5.
The effect of dietary vitamin E supplementation on modified-atmosphere packed lamb meat during storage was studied. Thirty-six weaned male Manchego breed lambs were fed diets supplemented with three different vitamin E concentrations (0, 250, 500 and 1000 mg/kg feed) for an average of 37 days, in the 13–26 kg live weight growth range. Slices of m. longissimus dorsi were packaged under modified atmosphere (70% O2 and 30% CO2), stored at 2 ± 1 °C in darkness for 14 and 28 days. Meat quality parameters after both storage periods were assessed. Dietary vitamin E supplementation significantly increased -tocopherol concentration in muscle. Initially, lipid oxidation (TBARS), meat colour and bacterial load were similar in all groups. Lipid and colour oxidation of meat increased significantly (P < 0.001) throughout storage. The increase was greater in non-supplemented lambs than in supplemented ones. The bacterial counts after 28 days of storage reached the limit for microbiological shelf life (7 log10cfu/cm2). Dietary vitamin E supplementation increased the shelf life of meat packaged under modified atmosphere to 14 days. TBARS, pigment oxidation and bacterial load were inside the acceptable limit. The meat maintained its quality for 28 days of storage only when lambs were fed with the 1000 mg/kg dietary supplement, though the bacterial load was at the limit of acceptability.  相似文献   

6.
The effect of supplementation of vitamin E (200 W kg−1 feed) in the diet of pigs on colour stability and lipid oxidation in minced pork was studied. Control and enriched diets were provided for the last 12 weeks before slaughter. Half of the samples of minced shoulder meat from control and supplemented pigs were packaged on trays with oxygen-permeable overwraps and half in modified atmosphere packs (initial gas mixture: O2/CO2/N2 = 66/ 27/7). Meats were stored for 10 days at 7 °C in an illuminated retail display cabinet. The meat from vitamin E-supplemented pigs was more resistant to lipid oxidation than was the control meat. Gas packaging appeared to increase lipid oxidation in control meat, whereas lipid oxidation was stable in meat from vitamin E-supplemented pigs. Colour stability for gaspacked meat was comparable for both dietary groups. However, oxygen-permeable overwraps had a negative effect on colour stability in vitamin E-enriched meat. The reason for this is not known. The shelf-life of enriched and control meat was similar. Thus supplementation of pig feeds with vitamin E is recommended if an improved stability against lipid oxidation of (minced) pork is required.  相似文献   

7.
The effect of supplementation of pig diets with grape seed extract (GSE) (100, 300, 700 mg/kg feed) and bearberry (BB) (100, 300, 700 mg/kg feed) for 56 days pre-slaughter, on the oxidative stability and quality of raw and cooked M. longissimus dorsi (LD) was examined. Susceptibility of porcine liver, kidney and heart tissue homogenates to iron-induced (1 mM FeSO4) lipid oxidation was also investigated. In raw LD steaks, stored in modified atmosphere packs (75% O2:25% CO2) (MAP) for up to 16 days at 4 °C, surface lightness (CIE ‘L’ value), redness (CIE ‘a’ value), lipid stability (TBARS, mg MDA (malondialdehyde)/kg muscle) and pH were not significantly affected by supplemental GSE or BB. Similarly, the oxidative stability and sensory properties of cooked LD steaks, stored in MAP (70% N2:30% CO2), for up to 28 days at 4 °C, were not enhanced by dietary GSE or BB. Iron-induced lipid oxidation increased in liver, kidney and heart tissue homogenates over the 24 h storage period and susceptibility to oxidation followed the order: liver > heart > kidney. Dietary GSE or BB did not significantly reduce lipid oxidation in tissue homogenates. Potential reasons for the lack of efficacy of supplemental GSE and BB on pork quality were explored.  相似文献   

8.
The storage life of chilled pork packaged under carbon dioxide   总被引:2,自引:0,他引:2  
Gill CO  Harrison JC 《Meat science》1989,26(4):313-324
Pork cuts of longissimus dorsi muscle with overlaying fat and skin were packed under vacuum in film of low oxygen transmission rate, or under CO2 in gas impermeable aluminium foil laminate. Cuts were stored at +3 or −1·5°C. Vacuum packaged cuts were grossly spoiled by Brochothrix thermosphacta after 2 weeks' storage at 3°C and after 5 weeks at −1·5°C. Cuts packaged under CO2 were grossly spoiled by B. thermosphacta after 5·5 weeks' storage at 3°C. Growth of B. thermosphacta was suppressed when CO2 packaged cuts were stored at −1·5°C. At that temperature, slow growth of enterobacteria was detected after a lag of about 18 weeks. The enterobacteria caused gross spoilage of an increasing proportion of cuts between 18 and 26 weeks. Muscle tissue with pale, soft, exudative (PSE) characteristics tended to lose colour after long storage periods, apparently because of loss of myogglobin with exudate. Until spoilage, the eating qualities of pork appeared little affected by prolonged storage.  相似文献   

9.
The physical and chemical properties of Trachurus trachurus (horse mackerel) as well as a food product in the presence and absence of natural antioxidants, were investigated. The rate of lipid oxidation in the freeze-dried horse mackerel product stored at room temperature (22 °C) was investigated, using peroxide value (PV), thiobarbituric acid reactive substances (TBARS) and hexanal concentration to determine primary, secondary and tertiary oxidation products. Natural antioxidants were used to slow down oxidation processes and to improve nutritional and eating quality. These included vitamin E + vitamin C + citric acid (250, 250, 100 mg kg−1, respectively), vitamin E + vitamin C + citric acid + rosemary (250, 250, 100, 250 mg kg−1, respectively) and rosemary (250 mg kg−1). Biochemical analysis such as PV and TBARS measurements showed that the combination of vitamin E + vitamin C + citric acid (250, 250, 100 mg kg−1) were found to be the most significant (P ≤ 0.01) in controlling the rate of lipid oxidation in freeze-dried food followed by rosemary (250 mg kg−1). There was an initial rise in the PV of all samples, which dropped after 8 weeks, because of formation of secondary oxidation products. The rise in PV was much higher in the control samples with no antioxidants added, compared with the antioxidant-treated samples. Combinations of E + C + citric acid treatment group followed by rosemary alone were the most significant in lowering PV, hence, reducing formation of primary oxidation products (P ≤ 0.01). Once the primary oxidation products were lowered, TBARS levels (secondary oxidation products) increased in control samples after 12 weeks; however, in E + C + citric acid treatment group and rosemary-treated samples, this increase was significantly lower (P ≤ 0.01). There was a rise in hexanal concentration for up to 8 weeks, which dropped only in the antioxidant-treated groups and continued to rise in the control samples.  相似文献   

10.
Adults of Tribolium castaneum (Herbst) and T. confusum du Val exposed to various mixtures of N2 or He and O2 were killed when the O2 concentration reached to 1·7% or below, whereas the adults exposed to CO2 : O2 mixtures were killed mostly due to the deleterious effects of CO2 itself. At 26·7°C and 38 ± 6%r.h., 95 per cent mortality of T. confusum adults was obtained by an exposure of 271 hr to 45% CO2 : 55% air mixture; 58 hr to 62% CO2 : 38% air mixture; and 47·5 hr to 80% CO2 : 20% air mixture, while for T. castaneum adults 95 per cent mortality required 192, 60, and 44 hr respectively. Data obtained by exposing mature and immature stages of both species to 100% CO2 suggest that adults were the most susceptible, followed by larvae, eggs and pupae. Generally speaking, inactive stages (egg and pupal) were more tolerant to CO2 than active stages (larval and adult). Increasing the temperature from 15·6° to 26·7°C resulted in increased insect mortalities; the degree of response varying in different stages. Increasing r.h. decreased the susceptibility of adult insects to 100% CO2.

Under airtight conditions 200 adult T. castaneum with 8 g of food medium sealed in 1·2 1. glass flasks depleted the O2 supply from 20·9% to a critical 1·7% level in 7 days, and adults of T. confusum depleted to the 1·6% level in 5 days of airtightness, and both species produced about 20% of carbon dioxide gas.  相似文献   


11.
The use of atmospheres with low concentrations of CO (0.1 to 1%), in combination with O2 (24%), high CO2 (50%) and N2 (25 to 25.9%), for preserving chilled beef steaks was investigated. The atmosphere used as reference contained 70% O2+20% CO2+10% N2. Bacterial counts showed that all atmospheres containing CO greatly reduced total aerobic population numbers, including Brochothrix thermosphacta. Lactic acid bacteria, however, were not affected. CO concentrations of 0.5–0.75% were able to extend shelf life by 5–10 days at 1±1°C, as demonstrated by delayed metmyoglobin formation (less than 40% of total myoglobin after 29 days of storage), stabilisation of red colour (no change of CIE a* and hue angle after 23 days), maintenance of fresh meat odour (no variation of sensory score after 24 days) and significant (P<0.01) slowing of oxidative reactions (TBARS).  相似文献   

12.
The three halothane genotypes (NN, Nn, and nm) were identified by measuring the capacity for Ca2+ accumulation by sarcoplasmic reticulum in whole muscle homogenate preparations of M. longissimus dorsi with a Ca2+ specific electrode at 35°C. Significant differences (P < 0·001) in deterioration (%) of Ca2+ accumulation, 12% for NN, 35% for Nn, and 81% for nn pigs, were observed after ageing the whole muscle homogenate preparations for 24 h in ice.

Predictions of meat quality in live pigs (n = 34) based on the values for water-holding capacity, assessed as fluid (g/0·5 g wet wt LD), and pH (fluid) by using small biopsy LD samples (Cheah et al. 1993) were performed on all the halothane genotypes. The halothane genotype NN (n = 11) showed a fluid value of 0·37 ± 0·01 and a pH (fluid) value of 6·62 ± 0·03 as compared with 0·61 ± 0·02 and 5·84 ± 0·04, respectively, for the halothane genotype nn (n = 13). The Nn pigs (n = 10) showed fluid (0·49 ± 0·03) and pH (fluid) (6·19 ± 0·11) values between those values observed for the two homozygotes (NN and nn). Predictions of meat quality in live pigs from biopsy LD muscles were confirmed from assessments on post-mortem LD muscles based on pH1 and fibre optic probe (FOP) measurements.

The extent of deterioration (%) in Ca2+ accumulation showed high correlations with fluid (r = −0·861) and pH (fluid) (r = −0·831) in the biopsy LD samples, and with pH1 (r = 0·663), FOP (r = −0·812), and drip (%) loss (r = −0·777) in the post-mortem LD samples.  相似文献   


13.
Enthalpy-Entropy compensation in food vapor adsorption   总被引:1,自引:0,他引:1  
Enthalpy-entropy compensation was analysed for sorption isotherms of potatoes, macadamia nuts, apricots, figs, currants, prunes and raisins. Plots of (ΔHdif)T vs (ΔSdif)T for potatoes and macadamia nuts presented two isokinetic temperatures: TB1 = 272.0 ± 57.7 K (− 1 °C) for potatoes, TB1 = 265.0 ± 18.8 K (− 8 °C) for macadamia nuts and TB2 = 382.5 ± 7.3 K (109.5 °C) for both products. The first isokinetic temperature (TB1) appeared only at the upper portion of the temperature range tested (50, 60 and 70 °C for potatoes and 50 and 60 °C for macadamia nuts). The two isokinetic temperatures observed for potatoes and macadamia nuts suggested that during the initial stages at low aw TB1 is controlled by changes in the entropy of water, whereas the second isokinetic temperature (TB2) is considered to be enthalpy-controlled. Dried fruits presented only one isokinetic curve TB = 315.7 ± 3.5 K (42.7 °C), for raisins, currants and figs (75.2–82.3% d.b. sugars) and TB = 317.7 ± 4.6 K (44.7 °C) for prunes and apricots (51.5–54.5% d.b. sugars), indicating an enthalpy-controlled adsorption process for the whole range of moisture contents covered.  相似文献   

14.
《Food chemistry》2002,76(4):407-415
Fresh beef steaks were sprayed on the surface with vitamin C (500 ppm), taurine (50 mM), rosemary (1000 ppm) and vitamin E (100 ppm), the three latter in combination with 500 ppm of Vitamin C, packaged in modified atmosphere (70% O2+20% CO2+10% N2) and stored at 1±1 °C for 29 days. Metmyoglobin formation, lipid oxidation (TBARS), instrumental colour (CIE a1), psychrotrophic bacterial counts (PCA) and sensory discolouration and odour were determined. Results demonstrated that surface application of antioxidant combinations resulted in an effective delay of oxidative deterioration of fresh beef steaks. Shelf life was extended beyond that of control, according to evaluation of sensory attributes. Both combinations of vitamin C with either rosemary or taurine significantly (P<0.01) extended the shelf life of fresh beef steaks by about 10 days. Rosemary was the most effective in delaying oxidation processes. The combination of vitamins E and C was significantly (P<0.01) less effective than those combinations in delaying meat oxidation.  相似文献   

15.
A novel use of modified atmospheres: Storage insect population control   总被引:2,自引:0,他引:2  
The research described here aimed to establish the feasibility of using modified atmospheres (MA) to protect commodities throughout their storage life by using oxygen (O2) levels that disrupt the life cycles of the target beetle species. Rather than achieving complete mortality of all stages, the aim was to identify more easily obtainable MAs that would kill the most susceptible stage and prevent population growth. Simulated burner gas and nitrogen (N2) atmospheres with O2 contents between 3% and 6%, were tested, along with a N2-based MA with elevated carbon dioxide (CO2) (10–20%).

Laboratory tests were carried out on five species of stored-product beetles, Cryptolestes ferrugineus, Oryzaephilus surinamensis, Sitophilus granarius, S. oryzae and Tribolium castaneum. After exposure to the MAs for 28 d an assessment was made of the mortality of adults, the number of adults from progeny produced under the MAs and, for the simulated burner gas, the number of adults from progeny produced in a 28-d period after exposure to the MA. The tests were carried out at 20 and 25 °C with 75% and 85% r.h. at each temperature.

The O2 content preventing population growth varied with species and temperature. For simulated burner gas or N2 it was about 4% for O. surinamensis, S. granarius and S. oryzae, and about 3% for C. ferrugineus and T. castaneum at 25 °C. At 20 °C it was about 3% for all species tested. When CO2 was increased to 10% or 20%, reducing O2 to 5% was sufficient to eliminate emergence of S. granarius at 20°C, but a few individuals emerged at 25 °C. For C. ferrugineus there was a 95% reduction with 5% O2 plus 20% CO2 at 20 °C, but not at 25 °C.  相似文献   


16.
Gill CO  McGinnis JC 《Meat science》1995,39(3):387-394
Samples of beef longissimus dorsi (LD), approximately 5 × 5 × 1 cm, were packaged in pairs under 10 litre volumes of N2 or CO2 containing O2 at concentrations between 100 and 1000 ppm. The packaged samples were stored at temperatures of 5, 1, 0 or −1·5°C, for times between 4 and 48 h. Samples of beef psoas major (PM) were packaged under N2 or CO2 containing O2 at between 100 and 600 ppm, and stored at −1·5°C for 24 or 48 h. After storage, each sample was assessed for colour deterioration and discoloration, and for the fraction of metmyoglobin in the surface pigment.

The results obtained with N2 and CO2 atmospheres were similar. The colours of all LD samples had deteriorated after 4 h storage at 5 or 1°C, although the degree of deterioration increased with increasing O2 concentration. All LD samples stored for 12 h at 5 or 1°C were extensively discoloured, with metmyoglobin fractions generally exceeding 60%, but those stored at −1·5°C for 48 h or less, under O2 concentrations ≤ 400 ppm had undergraded colours. The colours of some LD samples stored at −1·5°C under about 600 ppm of O2 were also undergraded, but the colours of samples stored under 800 or 1000 ppm had deteriorated by 24 h. The colours of LD samples stored at 0°C under > 200 ppm had deteriorated after 24 h storage, and the colours of samples stored under 100 ppm O2 had deteriorated after 48 h storage. All PM samples were wholly discoloured after storage at −1·5°C. Evidently, the colour of beef muscle of high colour stability is resistant to degradation by atmospheres containing < 600 ppm of O2 when the meat is stored at sub-zero temperatures, but not when the storage temperature is at or above 0°C. Beef muscle of low colour stability, such as the PM, will discolour at all low concentrations of O2 irrespective of the storage temperature.  相似文献   


17.
Pulp composition, lipid classes, fatty acid composition, fatty acid distribution in triglycerides and triglyceride composition of pulp oil from the fruit of the Astrocaryum vulgare (Mart) palm have been studied. Triglycerides were the major species, accounting for 86·8% of the oil. Palmitic and oleic acids were the dominant fatty acids in whole oil, triglycerides and in the 2-position of triglycerides.

A. vulgare pulp oil contained a broad range of triglycerides, the major types of which were S2U (31·4mol.%) and SU2 (43·1 mol.%). S3 and U3 accounted for 6·9mol.% and 18·6mol.%, respectively.

Proximate analysis of pulp gave: protein, 5·9%; crude fibre, 5·7%; ash, 1·9%; carbohydrate, 19·5%; oil, 22·0% and moisture, 45·0%.  相似文献   


18.
Roch-chui Yu  Y.D. Hang   《Food chemistry》1991,40(3):301-308
Glucoamylase (EC 3.2.1.3) of Rhizopus oryzae NRRL 395 was purified approximately sevenfold by sequential ammonium sulfate fractionation, Biogel P-100 gel filtration, Q-Sepharose anion exchange and S-Sepharose cation exchange. The pH and temperature optima were 4·8 and 60°C, respectively. Enzyme was stable at temperatures up to 40°C and pH values between 3 and 8. The molecular weight was 67 000 daltons as determined by sodium dodecylsulfate-polyacrylamide gel electrophoresis, and the pI was 8·7 as determined by chromatofocusing. The Km for amylopectin and soluble starch were 0·98 and 1·34 mg/ml, respectively. The Vmax for amylopectin and soluble starch were 782 and 136 μmoles of glucose produced per mg of protein per min, respectively. The enzyme activity was inhibited by Hg2+, Pb2+ and Cd2+, but not by EDTA.  相似文献   

19.
The incidence of tumours in mice fed a standard chow diet and given either N-nitrosopyrrolidine (NPyr), nitrite (NO2) or nitrite plus pyrrolidine (NO2 + Pyr) in the drinking water for 12 months at 100mg, 1 g and 1 g plus 100mg/litre, respectively, was compared with that for a control group (C) receiving no additives. Differences between groups in weight gain and feed consumption were not significant. Group 3 (NO2) drank less water (P < 0·05) than those in groups 1 (C) and 2 (NPyr). Water intake of mice in group 4 (NO2 + Pyr) did not differ from that of any of the other three groups. Survival rates were: 94% (C), 80% (NPyr), 92% (NO2) and 83% (NO2 + Pyr); but the differences were not statistically significant. Gross examination upon autopsy revealed that the incidence of all tumours in group 2 (NPyr) was 10- to 20-fold higher than that in any other group. Histological examination confirmed that NPyr induced more (P < 0.05) malignant tumours in liver and lungs with any other treatment; otherwise there were no significant differences. Results indicated that NO2 + Pyr (nitrite plus a secondary amine) did not increase the frequency of carcinogenic tumours in mice.  相似文献   

20.
The effect of grape seed extract (GSE) and bearberry (BB), on lipid oxidation (TBARS, mg malondialdehyde (MDA)/kg muscle), colour (CIE ‘a’ redness value), pH, microbial status (log10CFU colony forming units/g pork) and sensorial properties of cooked pork patties was investigated. GSE (0–1000 μg/g muscle) and BB (0–1000 μg/g muscle) were added to raw pork (M. longissimus dorsi) patties which were stored in modified atmosphere packs (MAP) (75% O2:25% CO2) for up to 12 days at 4 °C. Cooked pork patties were stored in MAP (70% N2:30% CO2) for up to 4 days at 4 °C. Mesophilic plate counts and pork pH were unaffected by GSE and BB. GSE and BB addition decreased (P < 0.05) lipid oxidation (TBARS) in raw pork patties on days 9 and 12 of storage, relative to controls. Antioxidant activity of GSE and BB was observed in cooked pork patties demonstrating the thermal stability of GSE and BB. The ‘a’ redness values of raw and cooked pork patties marginally increased with increasing GSE concentration. The sensory properties of cooked pork patties were unaffected by GSE and BB addition. Results obtained demonstrate the potential for using health promoting nutraceuticals in meat and meat products.  相似文献   

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