Total Conjugated Linoleic Acid Research Articles

A Rapid Method of Screening Lactic Acid Bacterial Strains for Conjugated Linoleic Acid Production

A more rapid and simpler method than those currently used was developed to screen conjugated linoleic acid (CLA)-producing bacteria isolated from cow milk. The screening of 500 strains was completed in 10 d and the screening efficiency was 10%. One strain resembling a Lactobacillus paracasei strain and two resembling L. helveticus strains converted free linoleic acid to total CLA ≥85%.

Replacing canola meal as the major protein source with wheat dried distillers’ grains alters omasal fatty acid flow and milk fatty acid composition in dairy cows

Chibisa, G. E., Christensen, D. A. and Mutsvangwa, T. 2013. Replacing canola meal as the major protein source with wheat dried distillers’ grains alters omasal fatty acid flow and milk fatty acid composition in dairy cows. Can. J. Anim. Sci. 93: 137–147. Wheat dried distillers’ grains with solubles (W-DDGS) has a high fat content and is now commonly fed to dairy cows in western Canada. The objective was to determine the effects of replacing canola meal (CM) with W-DDGS on omasal fatty acid (FA) flow and milk FA composition. Four ruminally-cannulated lactating dairy cows were used in a 4×4 Latin square design with 28-d periods. Cows were fed either a standard barley silage-based total mixed ration (TMR) (0% W-DDGS, control) or TMR containing 10, 15 and 20% W-DDGS, with W-DDGS replacing CM as the major protein source. The omasal flow of C18:1 trans-10, C18:1 trans-11, C18:2n-6, C18:3n-3, conjugated linoleic acid (CLA) cis-9, trans-11, and total CLA increased linearly with increasing levels of W-DDGS. There were quadratic changes in milk concentrations of total C18:2, C18:3n-3, total n-3 polyunsaturated fatty acid (PUFA), and total n-6 PUFA as the level of W-DDGS increased. Feeding increasing amounts of W-DDGS resulted in a linear increase in milk concentrations of CLA cis-9, trans-11, CLA trans-11, trans-13, and total CLA, whereas milk concentrations of C18:1 trans-11 tended to increase linearly when level of W-DDGS increased. Feeding increasing amounts of W-DDGS resulted in quadratic changes in milk concentrations of C18:2n-6 and C18:3n-3. In summary, feeding increasing amounts of W-DDGS increased milk concentrations of key FA like C18:2n-6, C18:3n-3, CLA cis-9, trans-11, and total CLA, which can potentially improve human health.

Starter cultures and cattle feed manipulation enhance conjugated linoleic acid concentrations in Cheddar cheese

Conjugated linoleic acid (CLA) is a fatty acid (FA) that provides several health benefits to humans. The feeding of fish oil-supplemented diets to dairy cows has been extensively studied as a means to improve the CLA content in milk. Several studies have also been conducted on the ability of many microorganisms to produce CLA by utilizing substrates containing linoleic acid. In the present study, the dietary manipulated milk was used in combination with the CLA-producing culture to manufacture Cheddar cheese. The two diets fed to cattle were control and treatment diets to obtain control and treatment milk, respectively. The treatment diet containing fish oil (0.75% of dry matter) was fed to 32 dairy cows grouped in a pen for 18 d to increase the total CLA content in milk. Treatment milk had a CLA content of 1.60g/100g of FA compared with 0.58g/100g of FA in control milk obtained by feeding the control diet. A 2 × 2 factorial design with 3 replicates was used to test the combined effect of the CLA-producing starter culture of Lactococcus lactis (CI4b) versus a commercial CLA nonproducing cheese starter as the control culture, and type of milk (control vs. treatment milk) on CLA content in Cheddar cheese. Chemical composition (moisture, salt, fat, and protein) was not affected by the type of culture used. However, the age of the cheese affected the sensory properties and microbiological counts in the different treatments. Ripening with the CI4b culture was found to be effective in further enhancing the CLA content. The CI4b cheeses made from control milk and treatment milk contained 1.09 and 2.41 (±0.18) g of total CLA/100g of FA after 1 mo of ripening, which increased to 1.44 and 2.61 (±0.18) g of total CLA/100g of FA after 6 mo of ripening, respectively. The use of treatment milk resulted in an increase in the CLA isomers (trans-7,cis-9+cis-9,trans-11, trans-9,cis-11+cis-10,trans-12, trans-10,cis-12, cis-9,cis-11, trans-11,cis-13, cis-11,cis-13, trans-11,trans-13, and trans-9,trans-11). The CI4b culture specifically increased cis-11,cis-13 and trans-10,cis-12 isomers in cheese. The total CLA content in cheese was significantly higher when the CI4b culture was used compared with CLA nonproducing culture cheeses made from control milk and treatment milk after 1 mo [1.09 and 2.14 (±0.18) g of total CLA/100g of FA] and 6 mo [0.99 and 2.05 (±0.18) g of total CLA/100g of FA] of ripening, respectively. The results indicated that the combination of a CLA-producing starter culture and milk from cattle fed fish oil-supplemented diets (0.99g of CLA/100g of FA) could enhance levels of total CLA in Cheddar cheese by up to 2.6 times compared with cheese made from control milk with CLA nonproducing starter culture (2.61g of CLA/100g of FA) after 6 mo.

The Content of Conjugated Linoleic Acid (CLA) Isomer Groups in Milk of two Polish Sheep Breeds Determined by Silver Ion Liquid Chromatography (Ag+-HPLC)

Sheep milk is rich in CLA isomers which are biologically active components influencing human health. There are four geometric CLA isomer pairs: cis, trans; trans, cis; trans, trans and cis, cis. The aim of the present study was the analysis of CLA isomer groups content by Ag+-HPLC in milk fat of Zelazneńska (ZS) and Wrzosówka (WS) sheep breeds. The ewes of both breeds were kept under the same environmental and nutritional conditions. Milk samples were collected from 60 suckling ewes (30 from each breed), at the age of 3-4 years and in their 4th week of lactation. A higher total amount of all CLA isomer groups was obtained in milk of ZS ewes, however, this result was statistically insignificant. The percentage of the main c9, t11 isomer in total CLA was higher in Wrzosówka milk (68% vs. 74%). The content of the trans, trans isomer group in milk fat of the studied breeds was similar. The percentage of this group in total CLA in milk of WS and ZS constitutes 7.2% and 7.7%, respectively. The amount of cis,cis isomers in milk fat of ZS was higher thanWS (P < or = 0.01).

Conjugated linoleic acid content in milk of Chilean Black Friesian cows under pasture conditions and supplemented with canola seed (Brassica napus) concentrate

At present, there is limited and contradictory information about the effects of the use of canola (Brassica napus) seed as supplement on the contents of conjugated linoleic acid (CLA) in milk of grazing cows. The objective of this study was to evaluate the effect of a dietary supplement with canola seed on the production and composition of milk, and CLA concentration in Chilean Black Friesian cows under pasture conditions. Three experiments were done. Experiment 1: control group was fed 5 kg d-1 of commercial concentrate without canola (0-TC1) and treatment group that was fed 3.75 kg of commercial concentrate plus 1.16 kg of whole canola seed (1.16-TC1). Experiment 2: Control group was fed 8 kg d-1 commercial concentrate without canola (0-TC2) and treatment group that was fed 6.2 kg of commercial concentrate plus 1.2 kg of ground canola seed (1.2-TC2). Experiment 3: control group was fed 6 kg d-1 commercial concentrate without canola (0-TC3) and treatment group was fed 6 kg of commercial concentrate with 20% of whole canola seed (1.2 kg d-1, 1.2-TC3). The duration of each experiment was 60 days. No differences in milk production and quality were observed among the experimental groups in every assay. The CLA isomers trans-10, cis-12 and cis-10, cis-12 were higher than those normally found in the scientific literature. There was no effect of the inclusion of canola seed on total CLA content or the content of cis-9, trans-11, trans-10, cis-12 and cis-10, cis-12 isomers.

Influence of season and pasture feeding on the content of CLA isomers in milk from three different farming systems in Sicily

It has been shown that several factors such as pasture feeding, farming system and season might influence the content of conjugated linoleic acid (CLA) isomers in milk. Four Sicilian traditional dairy farms were selected, two had both Holstein and Brown Swiss cows, which were both at low pasture intake regimen and the other two farms had exclusively Modicana local-breed cows fed at higher pasture intake regimen. Pasture was available during spring and autumn but not during summer. Additional hay and concentrate was supplemented during all periods. The objective of this study was to assess the season effect (spring, summer and autumn) and farming system effect on CLA isomers and total CLA contents in cows’ milk. Autumn compared to summer milk had higher levels of total CLA (3,991.4 vs. 2,804.9 μg.g−1 of fat, respectively). Higher CLA levels in autumn compared to spring milk (3,991.4 vs. 2,662.7 μg.g−1 of fat, respectively) may be explained by different plant phenological stage. Spring compared to summer milk had surprisingly similar levels of total CLA (2,662.7 vs. 2,805.0 μg.g−1 of fat, respectively) this might be explained by higher diet content of concentrate in summer compared to the two grazing seasons (44.5 vs. 36.3% of DM). Milk total CLA levels did not differ significantly among farming systems. A significant variation of cis,trans (c,t) 11–13 and c,t 9–11 levels was only detected in milk from farms with higher pasture intake.

Immobilization of Candida rugosa lipase on hexagonal mesoporous silicas and selective esterification in nonaqueous medium

Candida rugosa lipases (CRLs) immobilized by physical adsorption, cross-linking and covalent binding methods on a MSU-H type mesoporous silica previously modified organically by different strategies, respectively, were examined as biocatalysts for esterification of conjugated linoleic acid (CLA) and ethanol in nonaqueous medium. MSU-H silica was modified by nonionic surfactant of triblock copolymer Pluronic P123, amino-functionalization and glutaraldehyde-grafting and confirmed by FT-IR analysis. Interaction mechanisms of CRLs and supports involve covalent and non-covalent interactions including electrostatic repulsion and hydrophobic interaction at pH 7. The immobilized CRLs containing surfactant were prepared by cross-linking via entrapping CRL aggregates inside the pores of silicas. The surfactant located inside the silicas could interfacially activate the immobilized CRLs and favored catalytic esterification. The biocatalyst containing 38wt.% of surfactant afforded 1111.1U/mg of specific activity about eight times higher than soluble CRL, and maximal 56.7% of total CLA esterification with 96.5% of 9c, 11t-CLA isomer esterification degree. The immobilized-CRL with 64.5mg/g of loading amount of protein exhibited maximal hydrolytic activity of 2945.3U/g-support for grafting glutaraldehyde. This derivative showed a high level of esterification activity and operational stability and remained 43.2–46.9% of total esterification for 32h consecutive four runs.

Dietary linseed oil and selenate affect the concentration of fatty acids in selected tissues of sheep

The aim of the study was to determine the influence of the addition of 5% linseed oil (LO) and 2 &amp;micro;g Se as selenate (SeVI) per g of diet on body mass gain (BMG), feed conversion efficiency (FCE), and concentrations of fatty acids (FA), especially conjugated linoleic acid (CLA) isomers, in the liver, heart, m.&amp;nbsp;longissimus dorsi (MLD), m. biceps femoris (MBF), subcutaneous fat (SF), perirenal fat (PF), and intermuscular fat (IF) of sheep. Each group comprised 5 lambs with an average initial body weight of 25 &amp;plusmn; 2 kg. For 35 days the sheep were fed the control or experimental diets enriched with 5% LO, SeVI, or LO and SeVI combined. The diets with LO, regardless of the presence of SeVI, increased BMG, FCE, and the mass of MBF, MLD, and the liver. The LO treatment increased the concentration of total CLA isomers in the liver, SF, PF, and MLD in comparison with the control. Dietary LO with or without SeVI resulted in negligible changes in the concentration of total CLA isomers in MBF. The diet enriched with LO, irrespective of the presence of SeVI, increased the concentrations of cis- monounsaturated fatty acids (cis-MUFA), polyunsaturated fatty acids (PUFA), as well as unsaturated fatty acids (UFA) in the liver, heart, and especially in SF and PF (i.e. energy storage tissues) compared with the control group and SeVI-fed sheep. Dietary SeVI more effectively increased the capacity of ∆9-desaturation in all adipose tissues as the concentration of cis9,trans11CLA increased in these tissues. The addition of SeVI to the diet decreased the yield of the catabolism of fatty acids in these adipose tissues and both muscles compared with the control sheep or other experimental groups. The diets enriched with LO with or without SeVI increased the nutritional value of MBF, MLD, and adipose tissues as the ratio of unsaturated FA/saturated FA increased. Our results of a short-term study provide useful information for nutritionists carrying out further investigations to improve the nutritional quality of feed for ruminants as well as humans. &amp;nbsp;

Effects of method of barley grain processing and source of supplemental dietary fat on duodenal nutrient flows, milk fatty acid profiles, and microbial protein synthesis in dairy cows

The objective of this study was to determine the interactive effects of barley grain processing and source of supplemental fat on ruminal nutrient digestion, duodenal nutrient flow, microbial protein synthesis, and milk fatty acid (FA) profiles in dairy cows. Four Holstein cows (656±28kg of BW; 80±12d in milk) fitted with permanent ruminal and duodenal cannulas were used in a 4×4 Latin square design with a 2×2 factorial arrangement of experimental treatments, in which barley was either dry-rolled (DRB) or pelleted (PB) and supplemented with full-fat canola seed (canola) or full-fat flaxseed (flaxseed). Cows fed DRB consumed 1.8 to 3.5kg/d more dry matter compared with those fed PB. Mean ruminal pH was lower and the duration (min/d) and area (pH × min) of total ruminal acidosis (RA; ruminal pH <5.8), mild RA (5.8 >ruminal pH >5.5), and severe RA (5.5 >ruminal pH >5.2), and the duration of acute RA (ruminal pH <5.2) were greater in cows fed PB compared with those fed DRB. Milk yield was unaffected by diet. Milk fat content and yield were greater in cows fed DRB than in cows fed PB. Cows fed PB had greater duodenal flows of C18:1 trans, C18:1 cis, C18:2 trans-9,trans-12, C18:2 trans-9,cis-12, C18:2 trans-11,cis-15, and C18:2 trans-10,cis-12 compared with those fed DRB. Duodenal flows of C18:1 cis, C18:1 trans, total C18:1, C18:2n6, C18:2 cis-9,trans-11, C18:2 trans-10,cis-12, C18:2 trans-11,trans-13, total conjugated linoleic acid (CLA), and C18:3n3 were greater in cows fed flaxseed compared with those fed canola. Milk concentrations of C18:3n3 and total CLA tended to be greater in cows fed PB compared with those fed DRB. When compared with cows fed canola, milk concentrations of C18:2 trans-11,cis-15, C18:2 cis-9,trans-11, C18:2 trans-11,trans-13, total CLA, and C18:3n3 were greater in cows fed flaxseed. Ruminal digestion of neutral detergent fiber and acid detergent fiber was greater in cows fed DRB compared with those fed PB. Duodenal flow of ammonia-N tended to be greater in cows fed PB compared with those fed DRB. Duodenal flow of nonammonia nonmicrobial N was greater in cows fed flaxseed compared with those fed canola; however, barley grain processing did not affect duodenal nonammonia nonmicrobial N flow. Duodenal flow of microbial nonammonia N and microbial efficiency were not affected by diet. In summary, barley grain processing and source of fat altered ruminal FA biohydrogenation, and this was reflected in changes in duodenal FA flow and milk FA profiles; however, ruminal microbial protein synthesis was unaltered.

Predicting conjugated linoleic acid (CLA) composition in Brazilian dairy products by multiple regression analysis based models

The analysis of conjugated linoleic acids (CLA) in dairy products is of concern for human health, but requires a combination of different analytical methods that are laborious and time consuming. The aims of the present study were to develop mathematical models based on data of the CLA and fatty acid composition of Brazilian dairy products and to apply the developed models for the calculation of CLA based on a basic analysis of fatty acid composition. The fatty acid composition of five types of dairy products was determined by gas chromatography (GC); analysis of CLA was achieved by silver-ion high-performance liquid chromatography and GC-mass spectrometry. Stepwise multiple regression analysis was performed to model the composition of CLA. All the six significant models of CLA composition (total CLA; total cis,trans, trans,cis CLA; cis-9,trans-11 CLA; trans-7,cis-9 CLA; trans-11,cis-13 CLA; and total trans,trans CLA) were physiologically consistent, had appropriate goodness of fit, and were fairly robust. According to the results of Pearson correlation analysis between estimates and experimental data (r = 0.78–0.91 and 0.0000 < P < 0.0028), the models could be used to rank dairy products according to the estimates of total CLA, trans-7,cis-9 CLA; trans-11,cis-13 CLA; total cis,trans, trans,cis CLA; and total trans,trans CLA, but not for cis-9,trans-11. The adjusted regression models allowed the estimation of CLA composition in a variety of Brazilian dairy products.

Conjugated Linoleic Acid Conversion by Six Lactobacillus plantarum Strains Cultured in MRS Broth Supplemented with Sunflower Oil and Soymilk

Six strains of Lactobacillus plantarum, isolated from traditional dairy products of minority nationalities, were evaluated for their ability to produce conjugated linoleic acid (CLA) from free linoleic acid in vitro. All the 6 strains were found to be capable of converting linoleic acid to CLA when using sunflower oil as substrate or during soymilk fermentation. The inhibitory effect of linoleic acid on the growth of the L. plantarum was also discussed. The production of CLA was increased with adding high concentration of substrate in sunflower oil and IMAU60042 produced the highest CLA both in sunflower oil and soymilk. The CLA was composted by 2 isomers: cis9, trans11-CLA and tran10, cis12-CLA, and cis9, tran s11-CLA covered the most part of the total CLA formed except for L. plantarum P8. The production of CLA was decreased during the storage of fermented soymilk. The CLA contents decreased significantly in the first week, also more quickly in 2 wk. Especially, tran10, cis12-CLA decreased more rapidly than cis9, tran11-CLA. No dramatic change was observed among other 8 fatty acids in soymilk. The proportion of unsaturated fatty acids varied after fermentation with different L. plantrum strains, but all decreased the during storage. The research on the ability of converting CLA of L. plantrum strains could be basis for the future research and development of fermented soymilk products. Desirable probiotic traits, such as acid and bile tolerance, aggregation activity, and antibacterial activity, have been proved for the 6 Lactobacillus plantarum strains. The 6 L. plantarum strains might be used in the fermentation of soymilk to produce multifunctional probiotic soymilk products, especially the rich CLA contents.

Effect of extruded whole soybean dietary concentrate on conjugated linoleic acid concentration in milk in Jersey cows under pasture conditions

Contradictory results has been found on the effects of soybean supplementation and conjugated linoleic acid (CLA) content in milk on feeding systems based on fresh forage The objective of the study was to evaluate the effect of a dietary supplement with different quantities of extruded whole soybean on the production and composition of milk, and CLA concentration or their isomers in Jersey cows under pasture conditions. Twenty-one Jersey cows were randomly assigned into 3 groups of 7 animals each. The cows were supplemented with a dietary concentrate (5 kg d-1), and each group received one of the three next treatments: control without soybean (0-SB), with extruded whole soybean at 0.5 kg d-1 (0.5-SB) or at 1 kg d-1 (1-SB). The basic diet was a pasture composed of Lolium perenne (70%), Trifolium repens (25%) and other species. The duration of the study was 75 d. Milk production (p = 0.706) and protein production (p = 0.926) were not affected by treatments. Fat (p = 0.015) and protein (p = 0.045) content as well as fat production (p = 0.010) were lower in the 1-SB group. There was no effect of the inclusion of extruded soybean on total CLA content (p = 0.290) or the content of cis-9, trans-11 (p = 0.582), trans-10, cis-12 (p = 0.136) and cis-10, cis-12 (p = 0.288) isomers. However, concentrations of all isomers were affected by the nutritional quality of the pasture, with low values observed at greater maturity stages of pasture.

Effects of different levels of roasted soybeans in high forage-based rations on conjugated linoleic acid of longissimus dorsi muscle, subcutaneous fat and liver of beef cattle

Twelve 24-month-old crossbred beef cattle with initial live weight of 532.6±20.9 kg were used to study the effect of feeding different levels of roasted soybeans on conjugated linoleic acid (CLA) and other fatty acids of longissimus dorsi muscle, subcutaneous fat and liver. The cattle were randomly divided into three groups with 4 cattle in each group and were fed rations containing 3.6, 10.1 and 15.7% of roasted soybeans as Treatments I, II and III, respectively. The cattle were slaughtered after feeding for 28 days and the samples of longissimus dorsi muscle, subcutaneous fat and liver were obtained. The fatty acid composition of the samples was analysed and statistically compared. In longissimus dorsi muscle, it was found that c9t11-CLA content was significantly increased with soybean level (P 0.05). In subcutaneous fat, both c9t11-CLA (P=0.056) and total CLA (P = 0.067) tended to increase with soybean level while all other fatty acids were unchanged (P > 0.05). In liver, content of C18:1 was significantly decreased while contents of C18:2n-6 and C18:3 were significantly increased with soybean level (P < 0.01). Significant correlations were found between intake and contents of fatty acids C18:0, C18:1, C18:2n-6 and C18:3 in liver. This study concludes that feeding beef cattle with soybeans up to 15.7% in high forage-based ration is not an effective way to increase total CLA content of tissues. Key words: Soybeans, conjugated linoleic acid, longissimus dorsi muscle, subcutaneous fat, liver, beef cattle.

Intramuscular lipids of Mertolenga-PDO beef, Mertolenga-PDO veal and “Vitela Tradicional do Montado”-PGI veal

Three quality branded meats (n=68), “Vitela Tradicional do Montado”-PGI veal, Mertolenga-PDO veal and Mertolenga-PDO beef were analysed for cholesterol (HPLC-UV), α-tocopherol (HPLC-FD), fatty acid composition (GC-FID), including conjugated linoleic acid (CLA) isomeric profile (Ag+-HPLC), and nutritional value of lipids. All the meats analysed had similar contents (P>0.05) of cholesterol, α-tocopherol and intramuscular fat. In contrast, the percentage of 18:0 was lower for PGI veal, and that of 18:1 c9 was higher in PDO veal, whilst the percentage of 18:2 n−6 was higher in PDO beef, relative to other two meats. The content of total CLA and the percentage of its t11,c13 isomer were higher, and the n−6/n−3 ratio was lower, in PDO veal, relative to the other two meats. The data suggested that PGI veal has higher variability for most fatty acids than the other two types of meat. Finally, a discriminant analysis was conducted and the three meat types were well discriminated using the meat fatty acid profile as variables.

Lipolysis in probiotic and synbiotic cheese: The influence of probiotic bacteria, prebiotic compounds and ripening time on free fatty acid profiles

The influence of probiotic bacteria (Lactobacillus casei-01, Bifidobacterium lactis B94), prebiotic compounds (FOS and inulin) and ripening time (0–60days) on the free fatty acid (FFA) profile of cheese, with special emphasis on the conjugated linoleic acid (CLA) content, was investigated. After 60days of ripening, 109–1010cfug−1 cheese were recorded in both probiotic and synbiotic cheeses, despite harsh conditions of low pH values (4.1–5.1) and low moisture content (<30%, w/w). Increases in total FFA and CLA were observed throughout the ripening period, especially in synbiotic cheeses containing FOS and inulin (50:50) inoculated with B. lactis B94. The addition of FOS alone or combined with inulin did not significantly affect probiotic strain growth and viability during the ripening period; however, the advantage of the addition of prebiotic compounds in probiotic cheese manufacture is that it may allow the production of cheeses with improved performance as far as functional CLA compounds are concerned, as well as an improved nutritional quality reflected in a lower atherogenicity index.

Effects of different forage:concentrate ratios in dairy ewe diets supplemented with sunflower oil on animal performance and milk fatty acid profile

The aim of this study was to evaluate the effect of different forage:concentrate (FC) ratios in dairy ewe diets supplemented with sunflower oil (SO) on animal performance and milk fatty acid (FA) profile, particularly focusing on trans C18:1 FA and conjugated linoleic acid (CLA). Sixty lactating Assaf ewes were randomly assigned to 6 treatments in a 3 × 2 factorial arrangement: 3 FC ratios (30:70, 50:50, and 70:30) and 2 levels of SO addition (0 and 20g/kg of dry matter). Both the diet FC ratio and SO supplementation affected milk yield, but differences between treatments were small. Although the proportion of concentrate induced limited changes in milk FA profile, dietary SO significantly decreased saturated FA and enhanced total CLA. Furthermore, the incorporation of SO in ewe diets decreased the atherogenicity index value by about 25% and doubled the contents of potentially healthy FA such as trans-11 C18:1 and cis-9,trans-11 CLA. However, the inclusion of SO in a high-concentrate diet (30:70) could switch linoleic acid biohydrogenation pathways, resulting in a significant increase in trans-10 C18:1, trans-9,cis-11 C18:2, and trans-10,cis-12 C18:2 milk fat percentages.

Measurement of Conjugated Linoleic Acid (CLA) in CLA-Rich Potato Chips by ATR-FTIR Spectroscopy

A conjugated linoleic acid (CLA)-rich soy oil has been produced by photoisomerization of soy oil linoleic acid. Nutritional studies have shown that CLA possesses health benefits in terms of reducing certain heart disease and diabetes risk factors. Potato chips are snacks that are readily produced in the CLA-rich soy oil containing CLA levels similar to those of the oil used for frying. The objective of this study was to develop an FTIR method to rapidly determine the CLA content of oil in potato chips. Photoirradiated soy oil samples with ∼25% total CLA were mixed with control soy oil, and 100 soy oil samples with total CLA levels ranging from 0.89 to 24.4% were made. Potato chips were fried using each of these 300 g CLA rich soy oil mixtures at 175 °C for approximately 3 min. Duplicate GC-FID fatty acid analyses were conducted on oil extracted from each batch of potato chips. The chip samples were ground and then scanned using ATR-FTIR spectroscopy with the aid of a high-pressure clamp, and duplicate spectra of each sample were averaged to obtain an average spectrum. Calibration models were developed using PLS regression analysis. These correlated the CLA isomer concentrations of potato chips obtained by GC-FID fatty acid analysis with their corresponding FTIR spectral features. The calibration models were fully cross validated and tested using samples that were not used in the calibration sample set. Calibrations for total CLA, trans,trans CLA, trans-10,cis-12 CLA, trans-9,cis-11 CLA, cis-10,trans-12 CLA, and cis-9,trans-11 CLA had coefficients of determinations (R2v) between 0.91 and 0.96 and corresponding root-mean-square error of prediction (RMSEP) ranging from 0.005 to 1.44. The ATR-FTIR technique showed potential as a method for the determination of the CLA levels in unknown potato chip samples.

Conjugated Linoleic Acids in Cattle Slaughtered for Human Consumption

Conjugated Linoleic Acids (CLAs) are group of positional and geometric isomers of octadecadienoic acid with conjugated double bonds and believed to have many health promoting effects. The present study focused on the quantitative analysis of CLAs in liver, Superficial Pectoral (SP), Longissimus Dorsi (LD) and Semimembranosus (SM) muscles of local Malaysian_Kedah-Kelantan (KK) cattle slaughtered for human consumption. Fatty acids were extracted using Folch method and determined by gas chromatography. The average content of CLAs in the liver, SP, LD and SM muscles were 38.71, 18.24, 11.03 and 13.04 mg/100 g of sample, respectively. The quantity of CLAs in the liver was significantly (p<0.05) higher than other samples. The percentages of cis-9, trans-11 CLA isomer were 63.39, 76.04, 90.66 and 82.82% of total CLAs in the liver, SP, LD and SM muscles, respectively. Positive correlations between CLAs and trans-11-octadecenoic acid concentration were observed in all samples. This study confirmed that meat from KK cattle could be the potential source of CLA but still its content has to be improved to make their meat more beneficial for consumers.

Triacylglycerols, fatty acids and conjugated linoleic acids in Italian Mozzarella di Bufala Campana cheese

Water buffalo Mozzarella di Bufala Campana, a protected designation of origin (PDO) cheese that complies with European Union legislation, has shown potential nutritional value for its conjugated linoleic acid (CLA) content. In the current study, triacylglycerols (TAGs) and fatty acids (FAs) in commercial samples of Mozzarella di Bufala Campana were characterized over a 1-year period. The distribution of TAGs represented by CN, where N equals the number of carbon atoms, ranged between N = 24 and N = 56. The TAG and FA pattern in Mozzarella di Bufala Campana was similar to the pattern of the parent milk and the bovine counterparts. The data acquired over four seasons showed a significant difference between winter-spring and summer-autumn water buffalo milk fat composition. Using high-resolution gas chromatography, a cis9- trans11 C18:2 isomer was found to represent approximately 80% of the total CLA fraction.

Fatty acid and CLA composition of Brazilian dairy products, and contribution to daily intake of CLA

In the present study, the conjugated linoleic acid (CLA) contents of dairy products most consumed by the population living in the southeast region of Brazil (whole milk, “Prato” cheese and butter) were determined. In addition, the contribution of these dairy foods to the daily intake of CLA isomers was estimated. Fatty acid composition was determined by gas chromatography. Quantitative analysis of CLA isomers was done by silver-ion high-performance liquid chromatography (HPLC) and their identification was achieved by gas chromatography–mass spectrometry (GC–MS) of dimethyloxazoline (DMOX) derivatives. Eleven CLA isomers were identified and the predominant were cis-9, trans-11 and trans-7, cis-9. The total CLA contents in whole milk, “Prato” cheese and butter ranged from 4.0 to 8.4 mg/g fat and were similar to those reported for dairy products from other countries. Whole milk samples had significantly higher contents of total CLA, when compared to “Prato” cheese and butter, and the total CLA contents were significantly different between the commercial brands of each dairy product. The estimated average daily intake of total CLA in southeastern Brazil was 36 mg/day, which was lower than those of European and North American countries, and milk was the main food source of CLA in the diet.