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1.
The influence of two diets with different fatty acid compositions has been studied with regard to overall pork quality and significance of specific fatty acids on sensory attributes in fried chops and oven roasts. Twenty castrates and 20 females were in a balanced experimental set-up fed with a standard diet supplemented with α-tocopherol (200mg/kg feed) where the fat source was either 3% of palm oil or 3% rapeseed oil. After slaughter, despite differences in lipid composition and sensory attributes, no significant difference in overall meat quality parameters and flavour precursors was found. Comparison of the two diets showed that supplementation with rapeseed oil resulted in a significantly higher content of C18:3n-3 (polar lipid (PL), neutral lipid (NL)), C18:2n-6c (NL) and C20:2 (NL) in LD and C18:1n-9c, C18:2n-6c, C18:3n-3, C20:3n-3, C22:5n-3 in backfat, while supplementation with palm oil resulted in a higher content of C16:0 (NL), C16:1 (PL), C18:1n-9t (NL) in LD and C16:0, C17:0, C18:0, C16:1, C20:4n-6 in backfat. A positive and significant correlation between the contents of C18:2n-6c, C20:3n-6 in the PL fraction and the sensory attributes fried meat odour and sweet odour were found in fried pork chops from female pigs. Likewise, positive correlations were seen between the content of C18:1n-9c in the PL fraction and sensory attributes such as sourish odour, piggy odour and piggy flavour in whole oven roasts. These data substantiate the view that specific fatty acids in the PL fraction influences flavour attributes in pork.  相似文献   

2.
The aim of this study was to evaluate the inclusion of different oil sources and dietary supplementation with vitamin E on the composition of fatty acids in rooster meat. Two hundred and forty 30‐week‐old White Leghorn roosters were distributed in a completely randomized factorial arrangement of 5 × 2, using five oil sources (sunflower, soybean, canola, linseed and fish) and two levels of antioxidant (30 and 400 mg vitamin E kg?1 of diet). The intake of fish and canola oil in the diet reduced (P < 0.05) the content of saturated and unsaturated fatty acids in the thigh meat. Amongst the unsaturated fatty acids in the thigh, the fish and canola oil reduced (P < 0.05) the level of ω6 fatty acid, with a consequent decrease in the ratio ω6:ω3. The diet with fish oil increased (P < 0.05) the content of C22:6ω3 in the thigh meat. The use of linseed oil resulted in a significant reduction of the ratio of ω6:ω3 fatty acid in the thigh. The use of soybean oil in the diet increased (P < 0.05) the content of saturated and unsaturated fatty acids in the thigh, specifically in the content of ω6. The inclusion of vitamin E increased the polyunsaturated fatty acids in the chest meat, such as C18:3ω3, C20:5ω3 and C22:6ω3. Copyright © 2004 Society of Chemical Industry  相似文献   

3.
 α-Linolenic acid and unusual fatty acids of the ω3 and ω6 series play an important role in the modulation of human metabolism. The presence of these acids in the leaves of several edible wild plants has recently been reported. In this study, six edible wild species were selected in order to establish the fatty acid compositions in their leaf lipids. Thus, young leaves from Amaranthus viridis L.(blet), Chenopodium album L. (goosefoot), Crithmum maritimum L. (rock samphire), Plantago major L. (plantain), Portulaca oleracea L. (purslane) and Verbena officinalis L. (vervain) yielded 1.50, 2.20, 3.02, 1.46, 3.81, and 2.28 g of lipids per 100 g dry plant material. Silica gel chromatography yielded 0.64 g (Plantago major) to 2.19 g (Crithmum maritimum) neutral lipids, 0.37 g (Plantago major) to 1.60 g (Portulaca oleracea) glycolipids, and 0.26 g (Crithmum maritimum) to 0.57 g (Verbena officinalis) phospholipids per 100 g (dry weight). Gas chromatography (GC) showed the major fatty acids to be 18 : 3ω3, 18 : 2ω6 and 16 : 0 in all fractions, with high concentrations of 18 : 3ω3 in the glycolipid fraction. GC-mass spectrometric analyses did not reveal the presence of unusual fatty acids. Carotenes were found in high concentrations, ranging from 30.5 mg/100 g (Chenopodium album) to 89.2 mg/100 g (Portulaca oleracea). The analyzed plants are rich sources of essential fatty acids (18 : 2ω6 and 18 : 3ω3) and also of carotenes. Received: 29 October 1998  相似文献   

4.
Ahn DU  Lutz S  Sim JS 《Meat science》1996,43(3-4):291-299
Effects of dietary α-linolenic acid on the fatty acid composition, storage stability and sensory characteristics of cooked pork were studied. Dietary α-linolenic acid (LNA) significantly (p < 0.05) increased the proportion of n−3 fatty acids and the degree of unsaturation in the neutral lipids and phospholipids. The increases in n−3 fatty acids were observed in the total lipids, triglycerides, phosphatidylethanolamine and phosphatidylcholine, and mainly consisted of C18:3n3, C20:5n3 and/or C22:5n3.The thiobarbituric acid reactive substances (TBARS) values (mg malondialdehyde per kg meat) of cooked vacuum packaged loins remained below 1.5, but in loose packaged loins TBARS values increased more than 3 times those of 0 time values during 2-day storage at 4 °C. The TBARS values of loins after LNA-enrichment were significantly higher than those of the control in both vacuum and loose packaging, and the increase of unsaturation in fatty acids had a strong prooxidant effect. The increase in dietary LNA enrichment increased oxidation (TBARS values) and had a detrimental effect on the acceptability of cooked pork loins held for 2 days in loose packaging.  相似文献   

5.
The survival of 4 strains of Campylobacter jejuni was studied in raw minced beef and raw pork sausage mixture stored in plastic stomacher bags at freezer temperatures (−19°C) for up to 10 weeks, refrigirator temperatures (< 10°C) for 6 days and 22°C for 24 h. At each of the 3 storage temperatures survival was better in minced beef. Similarly, there was less variation in percentage survival between the 4 strains in minced beef than in sausage mixture after storage at each temperature. Detailed studies were carried out with one strain of C. jejuni. Viable counts were relatively unchanged in minced beef at refrigerator temperatures and 22°C, but showed a decrease in corresponding samples of sausage mixture. At freezer temperatures decreases in count of approximately 1 log unit were observed during the first week for both meats followed by a more gradual decrease. The effect of desiccation by exposure was studied in minced beef and lamb outer carcass meat (breast) at refrigerator temperatures (≤ 10°C). Decreases in viable count were observed in lamb carcass meat after 32 h although large variations were sometimes observed between duplicate samples for the same strain of C. jejuni. Counts were unchanged in exposed minced beef after storage for 48 h.  相似文献   

6.
Broiler chickens were fed diets supplemented with redfish meal at levels of 4,8 and 12 %. A control group was fed with an all-vegetable protein diet. After 42 days the birds were slaughtered and edible tissues (white, dark and skin) were analysed for lipid content and composition. The white and dark meats were tasted organoleptically for the possible presence of ‘fishy’ off-flavours. There was no change in the content or class composition of the lipids with diet or sex of the bird, but in meats an increase in fish meal in the diet caused an increase in the level of n-3 polyunsaturated fatty acids present, especially 20: 5n-3 eicosapentaenoic acid, 22: 5n-3 docosapentaenoic acid and 22: 6n-3 docosahexaenoic acid at the expense of n-6 fatty acids. The enrichment was most pronounced in white meat of both male and female birds and could make a contribution of n-3 polyunsaturated fatty acids to the human diet quantitatively similar to that of an equal portion of lean white fish. Taste panel results showed that there was no significant difference in flavour or taste among any of the samples. There was a tendency for the 12% dietary group birds to be the least preferred, but no panelist detected ‘fishy’ flavours or objected to the taste of the meat.  相似文献   

7.
 The fatty acid composition of "fish wurst", a fermented salami-type sausage made of pork, lard and Baltic herring fillets (Clupea harengus var. membras) was investigated. Changes in the proportions of the 35 most abundant fatty acids were examined throughout the 1-month ripening period followed by a 4-month storage period. The fat composition of the product was stable (32–35%) and retained the characteristics of the main ingredients: oleic acid (37.4%, mean of three production batches) palmitic acid (23.7%) and linoleic acid (10.7%) from lard and fish, stearic acid (11.7%) mainly from lard, and palmitoleic acid (3.0%) and long-chain (C20–C24), polyunsaturated fatty acids (c.a. 6%) mainly from fish. During the 4-week ripening period a statistically significant increase (P≤0.05) was detected in the proportions of minor fatty acids only, i.e. eicosenoic acid (20 : 1n-9), eicosadienoic acid (20 : 2n-6), docosadienoic acid (22 : 2n-6) and docosatrienoic acid (22 : 3n-3). During the 4-month storage of the ripe sausage, the fatty acid composition stabilized. Only the proportion of stearic acid increased significantly during storage, from 11.7% to 12.5%. Received: 23 January 1998 / Revised version: 1 April 1998  相似文献   

8.
Fatty acid content and sensory characteristics of meat from light lambs fed three diets supplemented with different sources of n−3 fatty acids (fish oil, extruded linseed and extruded linseed plus microalgae) and a control diet during refrigerated storage have been studied. The meat from lambs fed linseed diets had the highest levels of C18:3 n−3, while animals fed fish oil had the highest long-chain n−3 polyunsaturated fatty acids (PUFA). Thus, 100 g of meat from lamb fed the fish oil diet provided 183 mg of long-chain n−3 PUFA, representing 40% of the daily recommended intake. The levels of n−3, n−6 and long-chain n−3 PUFA decreased during a 7-day storage period. The meat from lambs fed the fish oil diet had high scores of fish odour and flavour and rancid odour and flavour and the lowest overall liking. Rancid odour and flavour increased after storage, mainly in supplemented groups.  相似文献   

9.
 The fatty acid composition of "fish wurst", a fermented salami-type sausage made of pork, lard and Baltic herring fillets (Clupea harengus var. membras) was investigated. Changes in the proportions of the 35 most abundant fatty acids were examined throughout the 1-month ripening period followed by a 4-month storage period. The fat composition of the product was stable (32–35%) and retained the characteristics of the main ingredients: oleic acid (37.4%, mean of three production batches) palmitic acid (23.7%) and linoleic acid (10.7%) from lard and fish, stearic acid (11.7%) mainly from lard, and palmitoleic acid (3.0%) and long-chain (C20–C24), polyunsaturated fatty acids (c.a. 6%) mainly from fish. During the 4-week ripening period a statistically significant increase (P≤0.05) was detected in the proportions of minor fatty acids only, i.e. eicosenoic acid (20 : 1n-9), eicosadienoic acid (20 : 2n-6), docosadienoic acid (22 : 2n-6) and docosatrienoic acid (22 : 3n-3). During the 4-month storage of the ripe sausage, the fatty acid composition stabilized. Only the proportion of stearic acid increased significantly during storage, from 11.7% to 12.5%. Received: 23 January 1998 / Revised version: 1 April 1998  相似文献   

10.
The transgenic and non-transgenic soybean seeds oils were extracted and the composition and concentration of the fatty acids were analyzed by gas chromatography. Sixteen different fatty acids were detected in both transgenic and non-transgenic soybean oil: C14:0, C16:0, C18:1, C18:2, C18:3, C20:0, C20:1, C20:2, C22:0, C20:5, C22:1, C24:0 and C22:6. The concentration of 12 of 16 fatty acids (C14:0, C16:0, C18:1, C18:2, C20:0, C20:1, C20:2, C22:0, C20:5, C22:1, C24:0 and C22:6) in transgenic soybean oil were higher than those in non-transgenic one (P < 0.05). The concentration of C17:0 and C18:3 were lower than those in non-transgenic one (P < 0.05). The total fatty acids concentration increases by 12.6 % (P < 0.01). The degree of saturation of transgenic soybean oil increased from 58.7 to 69.8 % (P < 0.01). All the data above show that the insertion of foreign genes can change the concentration of fatty acids in plant oil. The mechanism for these changes should be studied.  相似文献   

11.
The effectiveness of increasing CLA in pork products through animal dietary supplementation or direct addition in the product formulation has been studied, and the effect of grilling on dry matter and fat contents and fatty acid composition has been analysed. Sausages made with meat and back fat from pigs with CLA dietary supplementation had the highest saturated fatty acid content. Sausages from dietary supplementation and direct addition had CLA levels between 6% and 7% of total fatty acids. Moisture and fat contents decreased and increased respectively after cooking for the three sausage types (control, dietary supplementation, direct addition). Grilling had little effect on fatty acid levels, especially for sausages with direct addition in the product formulation. In general, saturated fatty acids increased and poly-unsaturated fatty acids decreased due to the increase of C16:0 and to the decrease of C18:2 n − 6c and C18:3 n − 3 fatty acids. Added CLA, both from animal dietary supplementation or direct addition, remained at similar levels in cooked sausages to those found in raw sausages.  相似文献   

12.
ABSTRACT: The polyunsaturated ω3-fatty acids, eicosapentaenoic acid and docosahexaenoic acid, have positive effects against to cardiovascular diseases. This work was carried out to investigate the fatty acid composition of the most popular fish from Turkey (mainly Istanbul area) and their nutritive values. Total lipid amounts and fatty acid compositions of 6 commonly consumed fish species were determined. Analyses of fatty acid methyl esters were performed by capillary gas chromatography. Palmitic acid (C16:0) and oleic acid (C18:1ω9) were the predominant saturated and monoenoic fatty acids. The predominant polyunsaturated fatty acids were eicosapentaenoic acid (C20:5ω3) and docosahexaenoic acid (C22:6Ω3). European anchovy and European pilchard are concluded to be good dietary sources of ω3-polyunsaturated fatty acids, which are known to reduce the risk of cardiovascular diseases because of their high C20:5ω3 and C22:6ω3 content.  相似文献   

13.
Seasonal variations in the amino acid and fatty acid compositions of wild sea bass (Dicentrarchus labrax) captured in the north eastern Mediterranean were investigated. In all seasons, the major amino acids in sea bass fillets were determined to be aspartic acid, glutamic acid and lysine. Methionine, tyrosine and histidine composition of the fillets were lower than those of the other amino acids in all seasons. The ratios of essential (E, g amino acid/16 g N)/nonessential (NE, g amino acid/16 g N) amino acids were observed to be 0.75 for winter, 0.76 for autumn, 0.77 for both spring and summer. Results showed that, sea bass fillets are well-balanced food source in terms of E/NE ratios in all seasons. In addition, seasonal differences in polyunsaturated fatty acid (PUFA) composition of the fillets were observed in all seasons. The major fatty acids of sea bass fillets were observed to be palmitic acid (16:0), oleic acid (18:1ω9), eicosapentaenoic acid (EPA, 20:5ω3) and docosahexaenoic acid (DHA, 22:6ω3). The amounts of EPA+DHA in autumn, winter, spring and summer were determined as 0.16, 0.12, 1.14 and 1.02 g/100 g wet weight, respectively.  相似文献   

14.
Sixteen Holstein–Friesian dairy cull cows were offered either ad libitum grass (G) or red clover (RC) silage for 12 weeks. Dry matter (DM), total nitrogen, and pH was higher for the RC than the G silage and organic matter, water-soluble carbohydrate, fibre, DM digestibility, ammonia-N, vitamin E and acetic acid higher for the G silage (P < 0.05). Fatty acid compositions were different (P < 0.05) with G silage having higher levels of C12:0, C14:0, C16:1cis−9, C18:3n−3 and total fatty acids whereas RC had higher levels of C18:0, C18:2n−6 and C20:0. Daily liveweight gain was high and not different between groups (average 1.22 kg/d). Body condition score and back fat thickness at slaughter along with conformation, fat grade and slaughter weight were not different between groups. Animals offered the G silage produced larger M. longissimus length (P < 0.01) and a trend (P < 0.1) for width. RC fed animals had higher proportions of C18:3n−3 (P < 0.001), total n−3 fatty acids (P < 0.01) and total PUFA compared to animals offered the G silage despite greater intakes of these fatty acids on G (P < 0.001). Vitamin E concentration and stability of aged meat during simulated retail display, were lower (P < 0.05) from animals offered RC than animals offered G. Shear force and ultimate pH, however were not different in steaks and sensory attributes were similar; the only difference being a higher score (P < 0.01) for fishy in the RC steaks. The results suggest that feeding high DMD silage to dairy cull cows can result in a high standard of finish and liveweight gain. Furthermore RC silage as opposed to G silage can increase the beneficial fatty acid profile of the resultant meat.  相似文献   

15.
 Danish Landrace× Danish Yorkshire female pigs were fed either a standard diet or a standard diet enriched with 6% rapeseed oil and supplemented with increasing amounts of vitamin E (0, 100 or 200 mg all-rac-α-tocopheryl acetate/kg feed) and copper (0, 35 or 175 mg CuSO4/kg feed), and the effect of dietary regimen on the oxidative stability of (1) frozen-stored raw pork chops packed in atmospheric air, (2) chill-stored pre-frozen pork chops packed in atmospheric air, and (3) freezer-stored, vacuum-packed pre-cooked sausages was investigated. The addition of 6% rapeseed oil did not influence the oxidative stability of the pork chops negatively, whereas the oxidative stability of a product such as the pre-cooked sausages (Danish dinner sausages) with a higher fat content (15%) decreased as a result of rapeseed oil feeding. Inclusion of rapeseed oil in the diets increased the amount of monounsaturated fatty acids and polyunsaturated fatty acids (PUFAs) in the meat and fat for the production of sausages at the expense of the content of the saturated fatty acids, and the higher content of PUFAs readily explains the decreased oxidative stability of the pre-cooked sausages. Feeding pigs 100 mg or 200 mg all-rac-α-tocopheryl acetate/kg feed significantly increased the oxidative stability of the pork chops and the detrimental effect of rapeseed oil observed in the pre-cooked sausages was effectively neutralised by both levels of vitamin E supplementation. Supplementation with copper did not affect the oxidative stability of any of the products. The presented results show that it is possible to produce pork products with a nutritionally improved fatty acid profile by inclusion of 6% rapeseed oil, without affecting the oxidative stability of the products negatively, through the protection provided by dietary vitamin E. Received: 23 March 1998 / Revised version: 28 May 1998  相似文献   

16.
A total of 72 crossbred [(Norwegian Landrace × Yorkshire) × Duroc] male and female growing-finishing pigs were restrictedly fed diets containing fish oil to study the fatty acid composition of Musculus longissimusdorsi and sensory quality of belly and neck. Six diets were used: two low-fat diets with or without 0.5% fish oil added, and four medium-fat diets with palm kernel oil to fish oil in ratios given as % inclusion: 4.1:0.0, 3.9:0.3, 3.6:0.5 and 3.4:0.7. Feeding fish oil gave a dose-dependent response between fatty acids in the diets and in the M.longissimusdorsi and increased the level of very long chain n−3 fatty acids, especially the C22:5n−3 (DPA). A more efficient n−3 fatty acids deposition was obtained when given as a medium-fat diet rather than the low-fat diet. Female pigs had a significant higher percentage of monounsaturated fatty acids and C18:1 than males suggesting a gender related difference in the delta-9-desaturase activity. No significant differences were found in sensory attributes for short-term stored neck and belly. For pigs fed the highest level of fish oil (0.7%) long-term stored (12 months at −80 °C, 6 months at −20 °C) belly showed a slight increase in fish oil flavour. After warmed-over treatment, fish oil odour and flavour as well as rancid flavour were increased in this group. The results suggest levels of dietary fish oil up to 0.5% produce a healthier meat fatty acid composition, without negative effects on sensory attributes, even in long-termed stored belly.  相似文献   

17.
 Gas chromatography-olfactometry of headspace samples revealed that (Z)-3-hexenal, methanethiol, (Z)-1,5-octadien-3-one, dimethyl trisulphide, octanal, 2-isopropyl- and 2-sec-butyl-3-methoxypyrazine are potent odorants of raw spinach. Boiling the spinach led to a change, such that dimethyl sulphide, methanethiol, dimethyl trisulphide, methional and 2-acetyl-1-pyrroline became the most important odorants. A further change was observed after drying and storage of raw spinach: methylpropanal, 2- and 3-methylbutanal and propanal were identified as the odorants with higher odour activity values. It was also found that (Z)-1,5-octadien-3-one and methional, in a concentration ratio of about 1 : 100, are responsible for the fishy off-flavour as dry spinach stored at lower temperatures under nitrogen. The hay-like flavour was caused by oxidative degradation of furan fatty acids, yielding 3-methyl-2,4-nonanedione. Received: 24 July 1997  相似文献   

18.
 Gas chromatography-olfactometry of headspace samples revealed that (Z)-3-hexenal, methanethiol, (Z)-1,5-octadien-3-one, dimethyl trisulphide, octanal, 2-isopropyl- and 2-sec-butyl-3-methoxypyrazine are potent odorants of raw spinach. Boiling the spinach led to a change, such that dimethyl sulphide, methanethiol, dimethyl trisulphide, methional and 2-acetyl-1-pyrroline became the most important odorants. A further change was observed after drying and storage of raw spinach: methylpropanal, 2- and 3-methylbutanal and propanal were identified as the odorants with higher odour activity values. It was also found that (Z)-1,5-octadien-3-one and methional, in a concentration ratio of about 1 : 100, are responsible for the fishy off-flavour as dry spinach stored at lower temperatures under nitrogen. The hay-like flavour was caused by oxidative degradation of furan fatty acids, yielding 3-methyl-2,4-nonanedione. Received: 24 July 1997  相似文献   

19.
This study aims to compare chemical, physical and sensorial parameters of the Wels catfish (Silurus glanis), hot smoked using vine, poplar, lemon tree and oak sawdust as well as corncob. Significant differences (P < 0.05) in proximate composition were found between fresh and smoked samples; however, the changes in fatty acid composition were less significant. In the fatty acid composition of control group, monounsaturated fatty acids (41.60%) had the highest share in fatty acids, which was followed by saturated fatty acids (29.95%) and polyunsaturated fatty acids (28.34%). The major fatty acids were observed to be C16:0, C18:0; C16:1 n‐7, C18:1 n‐9c, C18:1 n‐9t and C18:2 n6c. There were significant differences (P < 0.05) between the groups considering their colour measurement results. General preference criteria such as appearance, odour, texture, colour and taste were chosen for the sensorial analysis, which were rated by the panellists. According to the results of overall appearance, the fillet pieces smoked with lemon tree (9.00), poplar (8.66), corncob (8.00), oak (7.33) and vine (5.33) sawdust were determined as the most preferred, in order.  相似文献   

20.
Lipase-catalyzed enrichment of rice bran oil with n-3 fatty acid in order to obtain a structured lipid containing essential fatty acids has been optimized by response surface methodology. In this process, α-linolenic acid was used as an acyl donor using lipase-catalyzed acidolysis in hexane in presence of immobilized lipase from Rhizomucor miehei. The effect of incubation time and temperature, enzyme concentration and substrates mole ratio and their complex interaction on percentage incorporation of n-3 fatty acid, ratios of saturated fatty acid to polyunsaturated fatty acids, monounsaturated fatty acids to polyunsaturated fatty acids and n-6 to n-3 (18:2 to 18:3) fatty acids have been studied using a central composite rotatable design of experiments. The results showed that at the optimum conditions such as reaction time 4.5 h and reaction temperature 37. 5°C, substrate ratio ranging from 1.0 to 1.9, enzyme concentration varying from 1.0% to 2.0% are needed to fulfill the conditions such as percentage incorporation of n-3 fatty acid ≤18%, ratio of saturated fatty acid to poly unsaturated fatty acid ≥0.42, ratio of mono unsaturated fatty acid to poly unsaturated fatty acid ≥0.8, and ratio of n-6 to n-3 ≥1.30.  相似文献   

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