The effect of pasteurisation temperature on the CLA content and fatty acid composition of white pickled cheese

In this study, the effect of pasteurisation temperature on fatty acid composition of cheese was investigated. The fatty acid composition of raw and different heat‐treated milk, salt and salt‐free cheese were determined using cheese made from raw milk at temperatures varying between 70 and 90°C for 5 min. Generally, C 16:0 palmitic acid was the major fatty acid present in all milk and cheese samples. C 18:1 t11 vaccenic acid was the major trans fatty acid (TFA) in all samples. C 18:2 cis‐9, trans‐11 (Rumenic acid) was the major CLA isomer in these samples. Pasteurisation temperatures had no effect on TFA, CLA and fatty acid composition of the milk and cheese samples.     

Liver pâté from pigs fed conjugated linoleic acid and monounsaturated fatty acids

Three levels (0, 1 and 2%) of an enriched conjugated linoleic acid (CLA) oil (28% cis-9, trans-11 and 28% trans-10, cis-12 CLA) were combined with two levels of monounsaturated fatty acids (MUFAs) (low: 19% average and high: 39% average) for pig feeding. Experimental liver patés were produced using the meat and liver of pigs. Chemical composition, thiobarbituric acid reactive substances (TBARs) and fatty acid composition of the neutral lipids (NL), polar lipids (PL) and free fatty acids (FFAs) fractions of liver paté at 0, 30 and 200 days of storage were studied. In general, the storage of liver paté throughout the 200 days did not lead to relevant changes in the content of total saturated fatty acids (SFA), MUFA and polyunsaturated fatty acids (PUFA) of NL and PL as a consequence of the assayed dietary treatment. Total SFA, MUFA, PUFA, cis-9, trans-11 CLA and trans-10, cis-12 CLA contents from FFA significantly decreased in patés from pigs fed 2% CLA at 200 days of storage, regardless the MUFA treatment. Both at the beginning and at the end of storage, the TBARs were higher for 0% CLA patés compared to 1 and 2% CLA patés. Both at day 0 and day 30 of storage, the TBARs’ values for 2% CLA patés were higher than those for 1% CLA patés. Therefore, dietary CLA at levels lower than 2% could show a protective effect in paté against lipid oxidation, but the susceptibility to lipid oxidation could be increased at higher levels of CLA supplementation.     

Fatty acid composition,including isomeric profile of conjugated linoleic acid,and cholesterol in Mertolenga‐PDO beef

This paper describes the fatty acid composition, including the isomeric distribution of conjugated linoleic acid (CLA), total lipids and cholesterol in longissimus dorsi (LD) and semitendinosus (ST) muscles of Mertolenga beef from young bulls reared according to Protected Designation of Origin (PDO) specifications. Mertolenga purebred young bulls (n = 30) were raised in a semi‐extensive production system, including a finishing period on concentrate feeds for the last 5 or 3 months (October and June samplings, respectively). Mertolenga‐PDO beef showed seasonal changes in the levels of some fatty acids (including the predominant 18:2n‐6), sums of trans fatty acids and n‐3 polyunsaturated fatty acids, some CLA isomers (t11,t13, t11,c13 and t10,c12), sums of geometric groups of CLA isomers and total cholesterol. In addition, significant differences were obtained between LD and ST muscles for most of the analysed parameters. From a nutritional perspective, beef‐PDO from June seems to be more healthful than that from October as a consequence of its lower n‐6/n‐3 ratio. Moreover, the results suggest that the polyunsaturated fatty acid/saturated fatty acid ratio in the ST muscle is consistently above the recommended guideline for human diets, although the values were below that guideline for the LD muscle. Taken together, the data indicate that, although the finishing period of Mertolengo young bulls on concentrate attenuates most of the beneficial grass effects on meat fat throughout the year, beef‐PDO from late spring is of greater nutritional value than that from early autumn. Copyright © 2006 Society of Chemical Industry     

Dietary CLA alters intramuscular fat and fatty acid composition of pig skeletal muscle and subcutaneous adipose tissue

The present study was conducted to determinate the responsiveness of different levels of dietary conjugated linoleic acid (CLA) on intramuscular fat (IMF) and fatty acid composition of skeletal muscle and fat in pigs fed from 59.5 to 133.5 kg. Forty female Large White × (Large White × Landrace) pigs were used. Four levels (0%, 0.5%, 1% and 2%) of a commercial enriched CLA oil supplementation (60% of CLA isomers, 30% cis-9, trans-11 and 30% trans-10, cis-12) were fed to pigs. Carcass, ham, foreleg and loin weights were recorded. Dietary CLA enrichment increased the loin weight (P < 0.01) and the combined weights of hams + forelegs + loins (P < 0.02). IMF content in Longissimus dorsi was also increased by dietary CLA treatment (P < 0.001) and a linear response was observed. Dietary CLA increased saturated fatty acids (SFA) and decreased monounsaturated fatty acids (MUFA) in muscle and adipose tissue (P < 0.001). Feeding 1% CLA to finishing swine increases IMF in heavy pigs slaughtered at an average weight of 133.5 kg.     

Production and structural analysis of triacylglycerols containing capric acid and conjugated linoleic acid isomers obtained by enzymatic acidolysis

BACKGROUND: Structured lipids containing medium‐chain fatty acids have interesting applications as reduced‐calorie fats; moreover, conjugated linoleic acid (CLA) isomers have shown interesting biological properties. The aim of this study was to synthesize triacylglycerols (TAGs) containing capric acid in the sn‐1‐ and sn‐3‐ positions and CLA isomers in the sn‐2‐ position, using different commercial available lipases. RESULTS: The homogeneous CLA‐TAGs (Tri‐CLA) were chemically synthesized starting from glycerol and CLA isomers, 9‐cis,11‐trans and 10‐trans,12‐cis CLA. The acidolysis reactions of Tri‐CLA with capric acid were carried out at 55 °C for different times in hexane; after 96 h the acidolysis average yield was 65%. The best capric acid incorporation in total TAGs was obtained after 96 h with Lipozyme IM (56.6%). The results of structural analysis carried out on the obtained TAGs showed that both Novozyme 435 and anhydrous Lipozyme IM gave the best incorporation of capric acid in sn‐1(3)‐ positions (61.8%). However, anhydrous Lipozyme IM gave also the highest CLA percent content in sn‐2‐ position (73.2%). CONCLUSION: Anhydrous Lipozyme IM appears to be the more effective enzyme in acidolysis reactions to obtain structured TAGs containing CLA isomers in the central position and capric acid at external positions. Copyright © 2009 Society of Chemical Industry     

Supplementation with extruded linseed cake affects concentrations of conjugated linoleic acid and vaccenic acid in goat milk

The aim of this research was to determine the effect of adding extruded linseed cake to the dry diet of goats on the concentrations of conjugated linoleic acid (CLA) and vaccenic acid (VA) in milk fat. Thirty crossbreed dairy goats were divided into 3 groups. Their diet was supplemented with 0% (control group), 5% (low group), or 10% (high group) of extruded linseed cake (ELC), which supplied 0, 16, and 32 g/d of linseed fat, respectively. The milk fat percentage (overall mean 3.5%) and yield did not differ with the different diets, but fatty acid composition was affected by the ELC supplements. The inclusion of ELC in the diets did not influence the concentration of fatty acids from C6:0 to C12:0. The concentrations of C14:0 and C16:0 decreased as the quantity of ELC supplements increased. The concentrations (mg/100 mg of total fatty acid methyl esters) of VA (0.70, 1.23, and 1.39 in control, low, and high groups respectively) and cis-9,trans-11 CLA (0.63, 0.96, and 1.05 in control, low, and high groups, respectively) were increased by ELC supplements. The milk fat content of VA and cis- 9,trans-11 CLA were closely correlated (R² = 0.82). Desaturation of VA in the mammary gland to produce cis-9,trans-11 CLA was higher in the control group than in the groups with ELC diets. Extruded linseed cake supplementation to lactating goats may enhance the nutritional profile of milk lipids.     

Effect of plant oils and camelina expeller on milk fatty acid composition in lactating cows fed diets based on red clover silage

Five multiparous Finnish Ayrshire cows fed red clover silage-based diets were used in a 5 × 5 Latin square with 21-d experimental periods to evaluate the effects of various plant oils or camelina expeller on animal performance and milk fatty acid composition. Treatments consisted of 5 concentrate supplements containing no additional lipid (control), or 29 g/kg of lipid from rapeseed oil (RO), sunflower-seed oil (SFO), camelina-seed oil (CO), or camelina expeller (CE). Cows were offered red clover silage ad libitum and 12 kg/d of experimental concentrates. Treatments had no effect on silage or total dry matter intake, whole-tract digestibility coefficients, milk yield, or milk composition. Plant oils in the diet decreased short- and medium-chain saturated fatty acid (6:0-16:0) concentrations, including odd- and branched-chain fatty acids and enhanced milk fat 18:0 and 18-carbon unsaturated fatty acid content. Increases in the relative proportions of cis 18:1, trans 18:1, nonconjugated 18:2, conjugated linoleic acid (CLA), and polyunsaturated fatty acids in milk fat were dependent on the fatty acid composition of oils in the diet. Rapeseed oil in the diet was associated with the enrichment of trans 18:1 (Δ4, 6, 7, 8, and 9), cis-9 18:1, and trans-7,cis-9 CLA, SFO resulted in the highest concentrations of trans-5, trans-10, and trans-11 18:1, Δ9,11 CLA, Δ10,12 CLA, and 18:2n-6, whereas CO enhanced trans-13-16 18:1, Δ11,15 18:2, Δ12,15 18:2, cis-9,trans-13 18:2, Δ11,13 CLA, Δ12,14 CLA, Δ13,15 CLA, Δ9,11,15 18:3, and 18:3n-3. Relative to CO, CE resulted in lower 18:0 and cis-9 18:1 concentrations and higher proportions of trans-10 18:1, trans-11 18:1, cis-9,trans-11 CLA, cis-9,trans-13 18:2, and trans-11,cis-15 18:2. Comparison of milk fat composition responses to CO and CE suggest that the biohydrogenation of unsaturated 18-carbon fatty acids to 18:0 in the rumen was less complete for camelina lipid supplied as an expeller than as free oil. In conclusion, moderate amounts of plant oils in diets based on red clover silage had no adverse effects on silage dry matter intake, nutrient digestion, or milk production, but altered milk fat composition, with changes characterized as a decrease in saturated fatty acids, an increase in trans fatty acids, and enrichment of specific unsaturated fatty acids depending on the fatty acid composition of lipid supplements.     

Seasonal changes of CLA isomers and other fatty acids of milk fat from grazing dairy herds in the Azores

BACKGROUND: Season of the year associated with dietary changes has been recognized as a factor implicated in milk fat fatty acid (FA) profile in dairy cows. However, a lack of information exists concerning cows grazing all year round as is practiced in the Azores, where cows are supplemented in winter with maize silage plus concentrates, while in spring the higher grass allowance only requires supplementation with concentrate. The main objective of this study was to detect any seasonal variation of FA profile of milk fat from milk sampled in bulk tanks of 12 Azorean dairy herds. RESULTS Compared to winter milk, milk fat from spring presented a higher proportion of CLA cis‐9,trans‐11 (14.3 versus 9.6 g kg^?1 FA), C18:1 trans‐11 (32 versus 22 g kg^?1 FA), C18:2 trans‐11,cis‐15 (3.7 versus 2.2 g kg^?1 FA), CLA trans‐11,cis‐13 (0.34 versus 0.23 g kg^?1 FA) and C18:3 n‐3 (5.7 versus 5.4 g kg^?1 FA). The C18:2 n‐6/C18:3 n‐3 ratio was lower (P < 0.05) in spring. Branched‐chain FA, except the anteiso‐C15:0, were higher in spring, while odd‐chain FA (C15:0) were higher in winter. CONCLUSION: Dairy herd management in the Azores presents a seasonal variation of milk fat FA composition, where the spring milk may present increased potential benefits for human consumers. Copyright © 2008 Society of Chemical Industry     

Conjugated linoleic acid content in fermented goat milk as affected by the starter culture and the presence of free linoleic acid

The effect of yoghurt starter cultures and probiotic Lactobacillus casei on the formation of conjugated linoleic acid (CLA) and microbial populations of fermented goat milk was investigated during 35 days of cold storage. The addition of hydrolysed sunflower oil as a source of free linoleic acid was investigated. The fermentation process enhanced the content of the cis9, trans11‐CLA isomer in milk, whereas the trans10, cis12‐CLA isomer was not detected in goat milk or control fermented milks. The use of both starters generated trans10, cis12‐CLA only when hydrolysed sunflower oil was supplemented. Populations of streptococci and lactobacilli were affected by the presence of hydrolysed sunflower oil.     

Effect of a diet enriched in whole linseed and sunflower oil on goat milk fatty acid composition and conjugated linoleic acid isomer profile

The aim of the present research was to study changes in milk composition and fatty acid profile, specifically conjugated linoleic acid (CLA) and its isomers, in goat milk as affected by dietary supplementation of sun-flower oil and whole linseed (0.81 and 1.84% of dry matter on basal diet, respectively) and to assess the persistency of the response. To achieve this objective, bulk milk from a herd and from 6 individual dairy goats fed a diet supplemented with sunflower oil and whole linseed was monitored for a period of 3 mo. Gas chromatography and silver ion HPLC were used to analyze total CLA content and the isomeric profile of these fatty acids, respectively. The contents of α-linolenic acid increased from 0.35% with the reference diet to 0.62% with the supplemented diet. Similarly, CLA milk content increased from 0.46 to 1.18%. The same pattern was also observed for trans-11 C18:1 (1.38 to 4.05%, respectively) in goat milk after 3 mo of lipid supplementation. In contrast, changes in other trans C18:1 isomers were less remarkable. There was a strong linear correlation between cis-9, trans-11 C18:2, the main CLA isomer, and trans-11 C18:1 under the conditions assayed and their concentration remained stable throughout the duration of the study. Levels of the minor CLA isomers were also enhanced as a consequence of lipid supplementation. The most remarkable increases were observed for 11-13 (trans-trans and trans-cis geometric isomers), whereas trans-7, cis-9 (the second most important CLA isomer from a quantitative point of view) and trans-10, cis-12 increased only slightly with lipid supplementation.     

Stability of fatty acid composition after thermal,high pressure,and microwave processing of cow milk as affected by polyunsaturated fatty acid concentration

Interest has been increasing to enhance the contents of healthy polyunsaturated fatty acid (PUFA) in milk. However, trans fatty acids and conjugated linoleic acid (CLA) can be altered after thermal processing and high pressures disrupt the milk fat globule membrane, exposing the lipid core and helping its oxidation. The objective of the present research was to study whether processing can alter the fatty acid composition of milk and if these changes are affected by PUFA concentration as previous studies suggest. Two cow milk batches (500 L each), one naturally enriched in PUFA, were processed to obtain pasteurized; high temperature, short time; UHT; high pressure; and microwave pasteurized samples. The detailed fatty acid composition was analyzed with special attention to trans fatty acids and CLA isomers. Results showed that after high temperature, short time processing, total CLA content increased in both milk batches, whereas sterilization resulted in a sigmatropic rearrangement of C18:2 cis-9,trans-11 to C18:2 trans-9,trans-11. The extent of these effects was greater in milks naturally enriched in PUFA.     

The fatty acid and phospholipid composition of longissimus dorsi muscle from Pietrain and Large White pigs

An examination was made of the fatty acid and phospholipid composition of longissimus dorsi muscle from Pietrain and Large White pigs. The neutral lipid fraction from Pietrain muscle had a more unsaturated fatty acid composition possibly because of a reduced rate of intramuscular fat deposition in these pigs. The phospholipid content of muscle and muscle sarcoplasmic reticulum was similar in both breeds. The fatty acid composition of phospholipid and the concentrations of individual phospholipids were also similar. Differences in the lipid composition of muscle between the breeds appear to reflect a reduced capacity for carcass fat deposition in Pietrains rather than the propensity of pigs of this breed to produce muscle which is pale, soft and exudative (p.s.e.).     

Conjugated linoleic acid content and isomer distribution during ripening in three varieties of cheeses protected with designation of origin

Cheeses have been identified as important sources of conjugated linoleic acid (CLA), a mixture of positional and geometric isomers with potential anticarcinogenic activity and other beneficial properties. The objectives of this study were to examine the effects of ripening on the overall CLA content as well as on the isomers profile using GC and Ag⁺-HPLC. Three Spanish cheeses Protected with Designation of Origin (Mahón, Manchego and Cabrales) were manufactured in different cheesemaking plants and monitored at different times during the ripening period. Total CLA content varied from 3 to 9 mg/g of total fatty acids and rumenic acid (9-cis, 11-trans C18:2, RA) represented more than 75% of total CLA. After RA, 7–9 (cis/trans plus trans/cis), 11-trans, 13-trans and 11-trans, 13-cis C18:2 were the main CLA isomers. The results achieved confirm that the effect of ripening on the total CLA concentration and isomer distribution was negligible.     

Examination of the persistency of milk fatty acid composition responses to fish oil and sunflower oil in the diet of dairy cows

Based on the potential benefits of cis-9, trans-11 conjugated linoleic acid (CLA) for human health, there is a need to develop effective strategies for enhancing milk fat CLA concentrations. Levels of cis-9, trans-11 CLA in milk can be increased by supplements of fish oil (FO) and sunflower oil (SO), but there is considerable variation in the response. Part of this variance may reflect time-dependent ruminal adaptations to high levels of lipid in the diet, which lead to alterations in the formation of specific biohydrogenation intermediates. To test this hypothesis, 16 late lactation Holstein-British Friesian cows were used in a repeated measures randomized block design to examine milk fatty acid composition responses to FO and SO in the diet over a 28-d period. Cows were allocated at random to corn silage-based rations (8 per treatment) containing 0 (control) or 45 g of oil supplement/kg of dry matter consisting (1:2; wt/wt) of FO and SO (FSO), and milk composition was determined on alternate days from d 1. Compared with the control, the FSO diet decreased mean dry matter intake (21.1 vs. 17.9 kg/d), milk fat (47.7 vs. 32.6 g/kg), and protein content (36.1 vs. 33.3 g/kg), but had no effect on milk yield (27.1 vs. 26.4 kg/d). Reductions in milk fat content relative to the FSO diet were associated with increases in milk trans-10 18:1, trans-10, cis-12 CLA, and trans-9, cis-11 CLA concentrations (r² = 0.74, 0.57, and 0.80, respectively). Compared with the control, the FSO diet reduced milk 4:0 to 18:0 and cis 18:1 content and increased trans 18:1, trans 18:2, cis-9, trans-11 CLA, 20:5 n-3, and 22:6 n-3 concentrations. The FSO diet caused a rapid elevation in milk cis-9, trans-11 CLA content, reaching a maximum of 5.37 g/100 g of fatty acids on d 5, but these increases were transient, declining to 2.35 g/100 g of fatty acids by d 15. They remained relatively constant thereafter. Even though concentrations of trans-11 18:1 followed the same pattern of temporal changes as cis-9, trans-11 CLA, the total trans 18:1 content of FSO milk was unchanged because of the concomitant increases in the concentration of other isomers (Δ^4-10 and Δ^12-15), predominantely trans-10 18:1. In conclusion, supplementing diets with FSO enhances milk fat cis-9, trans-11 CLA content, but the high level of enrichment declines because of changes in ruminal biohydrogenation that result in trans-10 replacing trans-11 as the major 18:1 biohydrogenation intermediate formed in the rumen.     

Milk production, conjugated linoleic acid content, and in vitro ruminal fermentation in response to high levels of soybean oil in dairy ewe diet

Feeding vegetable oils rich in linoleic acid has been demonstrated to be an effective strategy to enrich milk with conjugated linoleic acid (CLA). However, high amounts of vegetable oil in the diet in free form could adversely affect animal performance, mainly in sheep. The aim of this work was to improve the ewe milk fatty acid profile by increasing potentially healthy acids such as CLA without any detrimental effects on milk production and ruminal fermentation with soybean oil (SBO) diet supplementation. Twenty-four ewes were assigned to 2 treatments and fed 2 diets (control or supplemented with 6% of SBO; 2 lots of 6 animals per treatment) and fed ad libitum for 4 wk. The forage:concentrate ratio was 20:80. Batch cultures of rumen microorganisms were used to study in vitro rumen fermentation. Changes in fatty acid profile were characterized as a reduction in C6:0 to C16:0 at the expense of an increase in C18:0, C18:1 isomers, and CLA concentrations. Proportions of milk CLA and trans-11 C18:1 (vaccenic acid) went from 1.04 to 3.44 and 2.08 to 6.20 g/100 g of total fatty acids, respectively. However, the SBO diet also increased trans-10 C18:1 and other trans C18:1 content. No significant decreases were found in the treatments for dry matter intake and milk production. The notable increases in trans-10, cis-12 and trans-9, cis-11 were not accompanied by fat level decreases in ewe milk. Concerning in vitro ruminal fermentation, no significant differences were found in the extent and rate of gas production, effective degradability, in vitro true digestibility, and volatile fatty acid production. The results demonstrate that dairy sheep milk CLA content can be substantially increased (more than 3-fold) by adding high levels of SBO in the diet as free oil, without any negative effects on animal performance.     

Oxidative modifications of conjugated and unconjugated linoleic acid during heating

The oxidative stability of conjugated linoleic (CLA) and linoleic (LA) acids in different chemical forms (free acids, methyl esters and homogeneous triacylglycerols) was compared. All model systems were heated at 180 °C for different times (15, 30, 45 and 60 min). The primary oxidation products were evaluated by spectrophometric analysis, while the volatile compounds were determined by solid phase micro-extraction (SPME), coupled with gas chromatography–mass spectrometry (HRGC–MS). The isomer profile modifications were investigated by silver-ion high performance liquid chromatography (Ag⁺-HPLC) equipped with an UV detector. Generally, peroxide values decreased during the heating time. Among the volatiles, saturated aldehydes were the most represented compounds. Isomerization of cis,trans and trans,cis CLA to trans,trans isomers was observed mainly for the methyl form of CLA. The three different chemical forms of LA never showed isomerization phenomena.     

Diet and plasma evaluation of the main isomers of conjugated linoleic acid and trans-fatty acids in a population sample from Mediterranean north-east Spain

The aim of the present study was to describe the dietary pattern of a representative sample of 516 adult participants (203 men and 313 women) from Catalonia, a Spanish Mediterranean region, to assess their current dietary and plasma levels of trans C18:1, the major trans-fatty acid (TFA), and cis-9, trans-11 CLA, and trans-10, cis-12 CLA, the two major conjugated linoleic acid (CLA) isomers, and to evaluate their correlation with several cardiovascular disease risk factors. The population was a random sample derived from the Catalan Nutrition Survey. Plasma levels of the CLA isomers were determined in a subsample of 100 volunteers. The Catalan diet seemed to maintain some traits of the ‘traditional’ Mediterranean diet, although other components were lost. The dietary intakes of saturated fatty acids (SFA), TFA, cis-9, trans-11 CLA, and trans-10, cis-12 CLA were 12.3%, 0.84% (2.0 g/d), 0.030% (71.5 mg/d), and 0.0015% (3.4 mg/d) of the energy intake, respectively. Trans C18:1 accounted for 0.19% of the total plasma fatty acids, while the sum of cis-9, trans-11and trans-10, cis-12 CLA isomers represented about 0.09% of the plasma fatty acids. Trans C18:1 isomers correlated significantly with the intake of French fries and pastries, while cis-9, trans-11 CLA significantly correlated with the intake of dairy products and ruminant meat. None of the cardiovascular disease risk factors were found to be associated with the plasma levels of TFA or CLA. The results of this study suggest that monounsaturated fatty acids (MUFA) are the main dietary fat source in the Catalan population, due to their regular olive oil consumption. Moreover, plasma levels of the main TFA and CLA suggest that the Catalan diet is not at present strongly influenced by the occidental dietary patterns. However, a reduction of the intake of SFA in the Catalan population should be recommended.     

Concentration‐dependent antioxidant activities of conjugated linoleic acid and α‐tocopherol in corn oil

BACKGROUND: Antioxidants prevent rancidity (lipid peroxidation) and natural antioxidants, e.g., α‐tocopherol, likely provide additional value to oil‐based food products because of their health benefits. Conjugated linoleic acid (CLA) has potential health benefits and may exhibit antioxidant properties. The main aim of this study was to compare the antioxidant efficacy of α‐tocopherol, trans‐10, cis‐12‐CLA and cis‐9, trans‐11‐CLA (in graded concentrations) added to antioxidant‐stripped corn oil. RESULTS: As compared to α‐tocopherol, both CLA isomers displayed significant inhibition of corn oil lipid peroxidation induced by copper. Inhibition of thiobarbituric acid reactive substances (TBARS) were CLA concentration dependent for both isomers but with significant inhibition occurring at 0.1 and 1 ppm of CLA isomers or α‐tocopherol, respectively (P < 0.05). Graded concentrations of α‐tocopherol, and for both CLA isomers and time, had significant effects on TBARS formation (P < 0.0001). There were significant effects in interactions between graded concentrations and time for both CLA isomers (P < 0.0001) but not for α‐tocopherol (P > 0.05). CONCLUSION: CLA compounds could serve as useful food antioxidants and provide additional value because of their potential bioactivity in disease prevention. Copyright © 2007 Society of Chemical Industry     

Volatile compounds of experimental liver pâté from pigs fed conjugated linoleic acid in combination with monounsaturated fatty acids

BACKGROUND: Feeding conjugated linoleic acid (CLA) to pigs leads to CLA‐enriched meat products, which are of current interest owing to the potential health properties of CLA. However, dietary CLA increases the ratio of saturated to monounsaturated fatty acids (MUFA) in pig tissues. Combining CLA with high MUFA levels in pig diets may counteract this effect. Owing to the modification of fatty acid composition, variation in the volatile profile of derived meat products might be expected. The aim of the present work was to study the volatile profile, and its change during storage, of experimental liver pâté manufactured from pigs fed different levels of CLA and MUFA. RESULTS: Regardless of the CLA or MUFA level, 98 compounds were identified. Lower area units were observed for most branched aldehydes, ketones and alcohols and some furans, sulfur compounds and nitrogen compounds with increasing CLA and MUFA contents. Levels of nonanal, propan‐2‐one, dodecane, 2‐pentylfuran and ethylbenzene were higher in CLA pâtes. The effect of experimental diets on the change in volatiles during storage was not significant. CONCLUSION: Supplementation of pig diets with CLA isomers in combination with low or high MUFA levels seems to have a significant effect on the volatile profile of pork liver pâté. Copyright © 2009 Society of Chemical Industry