Oxidative stability and alpha-tocopherol retention in turkey burgers during refrigerated and frozen storage as influenced by dietary alpha-tocopheryl acetate

A comparison of warmed-over flavour in pork by sensory analysis, GC/MS and the electronic nose

Pork muscle samples (M. longissimus dorsi and M. psoas major) were obtained from pigs given one of 4 dietary treatments, (i) control diet, (ii) supplemental iron (300 mg iron (II) sulphate/kg feed), (iii) supplemental vitamin E (200 mg dl-α-tocopheryl acetate/kg of feed) and (iv) supplemental vitamin E+supplemental iron. Warmed-over flavour (WOF) was evaluated by a trained sensory panel (n=8) for the four treatments cooked and refrigerated at 4 °C for up to 5 days. Gas chromatography mass spectrometry (GC/MS) and Electronic nose analysis was performed on a subset of the full design which included samples of M. longissimus dorsi, treatments (ii) and (iii) and M. psoas major with treatment (i) for 0 days of WOF development. Day 5 of WOF development was included in the subset and represented by samples of M. longissimus dorsi, treatment (iv) and M. psoas major, treatments (ii) and (iii). Bi-linear modeling was used to determine the correlation of GC/MS and electronic nose data to sensory data. Also, the reproducibility and reliability of electronic nose data was evaluated by repeating the analysis of samples in a different laboratory and with a time difference of approximately 11 months. Mean-centring was used to normalise the data from these two different electronic noise data sets. GC/MS data correlated to sensory data with specific compounds (e.g., pentanal, 2-pentylfuran, octanal, nonanal, 1-octen-3-ol and hexanal), proving to be good indices of oxidation in cooked samples of M. longissimus dorsi and M. psoas major. Electronic nose data correlated to sensory data and separated the sensory variation. The reproducibility of this data was high with the second set of samples being predictive of the first set.

Lipid and protein oxidation of chicken breast rolls as affected by dietary oxidation levels and packaging

The objective of this study was to determine the effects of dietary treatment and packaging on the oxidative stability of breast rolls. A total of 120 4-wk-old broiler chickens were randomly assigned to control, oxidized diet (5% oxidized oil, PV = 100), or antioxidants-added diet (500 IU vitamin E + 200 ppm BHA) and fed for 2 wk. Breast muscles were separated from the carcasses and breast rolls were prepared. The rolls were cooked in a smoke house (85 °C) to an internal temperature of 74 °C, cooled, sliced to 2-cm thick pieces, individually packaged in oxygen permeable bags or vacuum-packaged in oxygen impermeable bags, and stored in a 4 °C cold room for 7 d. Lipid, protein oxidation and volatiles were determined at 1, 4, and 7 d of storage. Dietary supplementation of antioxidants significantly reduced lipid oxidation (TBARS) and protein oxidation (carbonyls) in breast rolls, and the effect of dietary antioxidants on lipid oxidation was more pronounced than protein oxidation. Chicken breast rolls from antioxidants treatment group produced significantly lower amounts of hexanal and pentanal than those from control and oxidized oil treatments (P < 0.05). However, dietary oxidized oil did not increase lipid and protein oxidation in breast rolls. Vacuum-packaging significantly delayed the onset of lipid oxidation and protein oxidation in chicken rolls during 7-day refrigerated storage (P < 0.05). Therefore, it is suggested that appropriate use of dietary supplementation of antioxidants in combination with packaging could minimize lipid oxidation in chicken breast rolls.

Effect of retorting and oven cooking on the nutritional properties of beef frankfurters blended with palm oils

The effect of retorting and oven cooking on the nutritional properties of beef frankfurters blended with palm oil (PO), red PO35 and red PO48 were compared against the control beef fat treatment. Red PO oven-cooked beef frankfurters resulted in a significant loss of vitamin E from 538.5 to 287.5 microg after 6 months. Oven cooked sausages stored at -18 degrees C and retorted sausages stored for the 6 months of shelf studies resulted in more than 90% loss of alpha-carotene and beta-carotene in red PO beef frankfurters. Cholesterol was reduced at the range of 29.0-32.2 mg/100 g when beef fat was substituted with palm-based oils, in beef frankfurters. Differences of heat treatments did not significantly change THE cholesterol content, within all treatments. This study showed the potential of utilizing red palm oils as animal fat analogues in improving vitamin E, reducing cholesterol but not carotenes in beef frankfurters.

Food composition database development for between country comparisons

Nutritional assessment by diet analysis is a two-stepped process consisting of evaluation of food consumption, and conversion of food into nutrient intake by using a food composition database, which lists the mean nutritional values for a given food portion. Most reports in the literature focus on minimizing errors in estimation of food consumption but the selection of a specific food composition table used in nutrient estimation is also a source of errors. We are conducting a large prospective study internationally and need to compare diet, assessed by food frequency questionnaires, in a comparable manner between different countries. We have prepared a multi-country food composition database for nutrient estimation in all the countries participating in our study. The nutrient database is primarily based on the USDA food composition database, modified appropriately with reference to local food composition tables, and supplemented with recipes of locally eaten mixed dishes. By doing so we have ensured that the units of measurement, method of selection of foods for testing, and assays used for nutrient estimation are consistent and as current as possible, and yet have taken into account some local variations. Using this common metric for nutrient assessment will reduce differential errors in nutrient estimation and improve the validity of between-country comparisons.

Influence of the dietary polyunsaturation level on chicken meat quality: lipid oxidation

The present study was carried out to evaluate the influence of increasing amounts of dietary polyunsaturated fatty acids (PUFA) and alpha-tocopheryl acetate (alpha-TA) supplementation on lipid oxidation of raw and cooked thigh meat stored under refrigeration. One hundred ninety-two female, 1-d-old, broiler chickens were randomly distributed into 16 experimental treatments resuIting from the combination of 4 levels of dietary PUFA (15, 34, 45, and 61 g/kg) and 4 levels of supplementation with alpha-TA (0, 100, 200, and 400 mg/kg). Thiobarbituric acid reactive substance (TBARS) values in cooked meat and cooked refrigerated meat were 12- and 24-fold higher, respectively, than in raw meat. Dietary polyunsaturation and alpha-TA supplementation affected lipid oxidation more markedly in cooked meat and cooked refrigerated meat than in raw meat and raw refrigerated meat. Lipid oxidation in cooked meat showed a significant linear increase as the concentration of PUFA in raw meat increased. The oxidative stability of meat was not affected by an increase in the dietary alpha-TA level from 200 to 400 mg/kg. Nonlinear relationship between TBARS values in cooked meat and alpha-tocopherol content of raw meat showed saturation in the antioxidant effect of alpha-Toc. The equation y = x (11.88 + 63.38e(-0.007z) was calculated to predict the minimum inclusion of alpha-tocopherol to diets (z) of chickens with certain dietary PUFA content (x) to assure a certain TBARS value (y).

Effect of dietary oregano oil and alpha-tocopheryl acetate supplementation on iron-induced lipid oxidation of turkey breast, thigh, liver and heart tissues

Twenty-five 12-week-old turkeys randomly divided into five groups were given a basal diet, or a basal diet supplemented with 200 mg alpha-tocopheryl acetate/kg, or 100 mg oregano oil/kg or 200 mg oregano oil/kg, or 100 mg oregano oil plus 100 mg alpha-tocopheryl acetate/kg diet, for 4 weeks prior to slaughter. Breast, thigh, liver and heart tissues were subjected to iron-induced lipid oxidation, the extent of which was determined by third-order derivative spectrophotometry. Results showed that dietary oregano oil at the inclusion level of 200 mg oregano oil/kg diet was more effective in delaying lipid oxidation compared with the inclusion level of 100 mg/kg, but equivalent to the inclusion of 200 mg alpha-tocopheryl acetate/kg diet, which in turn was inferior to the combined inclusion of 100 mg oregano oil plus 100 mg alpha-tocopheryl acetate/kg, which was superior to all dietary treatments. Thigh tissue was more susceptible to oxidation than breast tissue, although it contained alpha-tocopherol at higher concentrations. Also, lipid oxidation in heart was relatively high, although it contained the highest alpha-tocopherol levels. This indicates that tissue alpha-tocopherol is one important factor influencing the level of lipid oxidation, but the distribution of lipids, iron and oregano oil in tissues must also be taken into consideration. Tissue alpha-tocopherol levels responded to dietary intake of 30-200 mg alpha-tocopheryl acetate/kg in the order heart > liver > thigh > breast. Breast, thigh and heart tissues from the oregano groups presented significantly (p < 0.05) higher levels of alpha-tocopherol compared with the control, the increase being positively correlated with the supplementation level. The increased levels of alpha-tocopherol in these tissues indicated that the dietary oregano oil exerted a protective action on alpha-tocopherol.

Oxidative stability of dark chicken meat through frozen storage: influence of dietary fat and alpha-tocopherol and ascorbic acid supplementation

We used factorial design to ascertain the influence of dietary fat source (linseed, sunflower and oxidized sunflower oils, and beef tallow) and the dietary supplementation with alpha-tocopheryl acetate (alpha-TA) (225 mg/kg of feed) and ascorbic acid (AA) (110 mg/kg) on dark chicken meat oxidation (lipid hydroperoxide and TBA values and cholesterol oxidation product content). alpha-TA greatly protected ground and vacuum-packaged raw or cooked meat from fatty acid and cholesterol oxidation after 0, 3.5, or 7 mo of storage at -20 C. In contrast, AA provided no protection, and no synergism between alpha-TA and AA was observed. Polyunsaturated fatty acid-enriched diets (those containing linseed, sunflower, or oxidized sunflower oils) increased meat susceptibility to oxidation. Cooking always involved more oxidation, especially in samples from linseed oil diets. The values of all the oxidative parameters showed a highly significant negative correlation with the alpha-tocopherol content of meat.

Effects of alpha-tocopheryl acetate supplementation and salt addition on the oxidative stability (TBARS) and warmed-over flavour (WOF) of cooked turkey meat

1. Day-old turkey poults (n = 14) were randomly divided into 2 groups (n = 7) and fed diets containing 20 (E20) and 600 (E600) mg all-rac-alpha-tocopheryl acetate/kg food for 21 weeks prior to slaughter. Following slaughter, breast and leg meat was removed and 4 batches of patties were produced from each. Two of the batches were formed from E20 meat (E20) and E20 plus 1% salt (E20S). Two similar batches were formed from E600 meat (E600) and E600 plus 1% salt (E600S). 2. Patties were fried, cooled and overwrapped with high oxygen-permeable film. Overwrapped patties were displayed in a 4 microC cabinet under fluorescent light (616 lux). Lipid oxidation (TBARS numbers) was determined on d 0, 2, 4, 6, 8 and 10, while taste panels to assess warmed-over flavour (WOF) were carried out on d 0, 2 and 4 of refrigerated (4 degrees C) display. 3. In the case of both leg and breast meat, E600 patties were the least susceptible of the 4 treatment batches to lipid oxidation. Salt had the effect of promoting lipid oxidation, with E20S and E600S patties having higher TBARS numbers than the corresponding patty batches where salt was absent. 4. Taste panel results showed that leg and breast patties formed from the meat of turkeys given alpha-tocopheryl acetate enriched diets developed significantly (P < 0.05) less WOF than those formed from control turkey meat on d 2 and 4 of refrigerated (4 degrees C) display. Patties containing 1% salt generally exhibited a greater degree of WOF than patties without salt. 5. A linear relationship was observed between TBARS numbers and WOF percentages for all batches of leg and breast patties.

Assessment of alpha-tocopheryl acetate supplementation, addition of salt and packaging on the oxidative stability of raw turkey meat

1. One-day-old turkey poults (n = 14) were randomised into 2 groups (n = 7) and fed diets containing 20 (E20) and 600 (E600) mg all-rac-alpha-tocopheryl acetate/kg food for 21 weeks prior to slaughter. Two batches were formed from E20 meat (E20) and E20 plus 10 g salt/kg (E20S). Two similar batches were formed from E600 meat (E600) and E600 plus 10 g salt/kg (E600S). 2. The effects of alpha-tocopheryl acetate supplementation and salt addition on the oxidative stability of raw turkey patties was investigated during aerobic and vacuum-packaged refrigerated (4 degrees C) storage. 3. Dietary alpha-tocopheryl acetate supplementation reduced TBARS (thiobarbituric acid reacting substances) numbers for raw overwrapped and vacuum-packaged turkey leg and breast patties. 4. Dietary alpha-tocopheryl acetate had the greatest influence on TBARS numbers for raw overwrapped turkey leg patties. 5. The addition of 10 g salt/kg increased TBARS numbers for overwrapped and vacuum-packaged turkey leg and breast patties. 6. Vacuum-packaged patties remained more oxidatively stable than similarly treated overwrapped patties throughout the experimental period.

Effects of dietary vitamin E supplementation on lipid oxidation and volatiles content of irradiated, cooked turkey meat patties with different packaging

A study was conducted to determine the effects of dietary vitamin E supplementation on the storage stability and volatiles production in irradiated cooked turkey meat. Turkeys, raised with diets containing 25, 50, 75, or 100 IU of dl-alpha-tocopheryl acetate (TA)/kg diet from 1 to 105 d of age, were fed with diets containing 25, 200, 400, or 600 IU of TA/kg diet from 105 to 122 d of age. Breast and leg meat patties were prepared, irradiated at 0 or 2.5 kGy dose, cooked to an internal temperature of 78 C, and stored in either vacuum or aerobic packaging. Thiobarbituric acid reactive substance (TBARS) values gradually decreased as the dietary TA increased and > 200 IU TA/kg diet treatments were helpful in maintaining low TBARS values in irradiated breast and leg meat patties during the 7-d storage period. With vacuum-packaging, irradiated cooked breast patties developed more oxidation than nonirradiated patties but the prooxidant effect of irradiation in cooked leg meat patties was not consistent. In aerobic-packaged cooked meat, irradiated patties had lower TBARS than nonirradiated patties in both breast and leg meat stored in oxygen permeable bags for 7 d. Propanal, pentanal, hexanal, 1-pentanol, and total volatiles were highly correlated with the TBARS values of meat. However, hexanal represented the lipid oxidation status of cooked meat better than any other volatiles component. The amount of hexanal and total volatiles in cooked breast and leg meat shows decreasing trends as dietary TA increased. In vacuum packaging, irradiated breast and leg meat had higher hexanal and total volatiles content than nonirradiated meat at both 0 and 7 d of storage. In aerobic packaging, the amount of hexanal and total volatiles greatly increased in both irradiated and nonirradiated meat patties during the 7-d storage periods. The results illustrated that the antioxidant effect of TA was not strong enough to control lipid oxidation and off-odor generation in cooked meat stored under aerobic conditions because the progress of lipid oxidation in cooked meat under aerobic condition is very rapid. However, the combination of dietary TA and vacuum packaging of cooked meat immediately after cooking could be a good strategy to minimize oxidation and volatiles production in cooked meat.

Influence of dietary vitamin E and oxidised sunflower oil on the storage stability of cooked chicken muscle

1. The effects of oxidised dietary sunflower oil and dietary alpha-tocopheryl acetate supplementation on alpha-tocopherol concentrations in broiler muscle and on the storage stability of refrigerated, cooked, minced muscle were determined. Broiler chicks were fed on diets containing fresh sunflower oil and 30 (FS30) or 200 (FS200) mg alpha-tocopheryl acetate/kg, or oxidised sunflower oil and 0 (OS0), 30 (OS30) or 200 (OS200) mg alpha-tocopheryl acetate/kg. 2. Inclusion of oxidised sunflower oil significantly reduced dietary and hence, muscle alpha-tocopherol concentrations. 3. Oxidised oil increased oxidation in raw and cooked muscle, and reduced the oxidative stability of muscle during refrigerated and frozen storage. 4. Supplementation with alpha-tocopheryl acetate improved the stability of muscle, with stability increasing as muscle alpha-tocopherol concentrations increased, when fresh or oxidised oil was fed. Supplementation with 200 mg alpha-tocopheryl acetate/kg offset the effects of oxidised oil in breast, but not in thigh. 5. The results show that the prooxidising effects of oxidised oils in muscle foods can be overcome, but alpha-tocopherol content needs to be adequately adjusted to compensate for increased oxidative stress. Supplementation with 200 to 400 mg alpha-tocopheryl acetate/kg may be necessary to achieve an optimum muscle alpha-tocopherol concentration.