Hypercholesterolemic Fatty Acids Research Articles

The effect of feeding diets markedly differing in the proportion of grass and maize silages on bovine milk fat composition

Ten Czech Pied cows in the mid-lactation stage were fed diets based on grass silage and maize silage. The composition of milk fats differed. The proportions of even-chain saturated fatty acids (SFAs) up to C<sub>14:0</sub> were insignificant and the content of C<sub>16:0</sub> was significantly higher (<i>P</i> < 0.05) when feeding a diet based on maize silage, while the proportions of the individual polyunsaturated fatty acids (PUFAs) were significantly (except for C<sub>18:2</sub>) higher when feeding a diet based on grass silage. The total SFA proportions were 67.60 and 62.93% (<i>P</i> < 0.05) of maize and grass silages, respectively, while an opposite relation was observed for the sum of PUFAs (3.56 and 4.74%; <i>P</i> < 0.001). Feeding of grass silage resulted in a significantly lower proportion of hypercholesterolaemic fatty acids C<sub>12:0</sub>, C<sub>14:0</sub> and C<sub>16:0</sub> (49.38 and 44.98%, respectively; <i>P</i> < 0.05) and in lower values of the atherogenic index (3.03 and 2.44; <i>P</i> < 0.05). Thus, the results could be used for the improvement of milk fat composition.

Influence of stearoyl-coenzyme A desaturase 1 genotype and stage of lactation on fatty acid composition of Canadian Jersey cows

Bovine milk contains high proportions of saturated fatty acids (SFA) because of the extensive biohydrogenation of dietary fatty acids in the rumen. Stearoyl-coenzyme A desaturase 1 (SCD1) catalyzes the conversion of C10 to C18 SFA into their monounsaturated (MUFA) counterparts in the mammary glands of ruminant animals; and 2 alleles (A and V) have previously been identified at the SCD1 locus. Genotypes at this locus were identified and fatty acid contents of milk were measured for 525 Canadian Jersey cows. Association analysis indicated that allele A is positively associated with higher C10 (C10I), C12 (C12I) and C14 (C14I) indices and, consequently, with greater contents of C10:1 and C12:1, but not C14:1, relative to allele V. Allele A was also positively associated with increased 305-d milk and protein yields. Allele A, however, had no influence on C16 (C16I), C18 (C18I), or conjugated linoleic acid indices (CLAI) compared with the V allele. Stage of lactation had an influence on desaturase indices and consequently on the MUFA contents of milk fat. The indices C10I, C12I, C14I, and CLAI increased from early to mid lactation as did their respective MUFA. Genetic selection for increased unsaturation of the hypercholesterolemic fatty acids in milk fat is feasible and may be accompanied by increased lactation milk and protein yields.

Comparing milk yield, chemical properties and somatic cell count from organic and conventional mountain farming systems

A study was undertaken to investigate the effects of farming systems (organic vs. conventional), diet (hay/concentrate vs. pasture) and their interaction on milk yield, gross composition and fatty acid (FA) profile of dairy cows bred in mountainous areas. For this purpose four dairy farms (two organic and two conventional) were chosen in the alpine territory of Aosta Valley (NW Italy); individual milk yield was recorded daily and bulk milk samples were collected monthly from February to September 2007 to cover dietary variations. Higher levels of milk production (P<0.05) and lower milk protein amounts (P<0.01) were observed in the organic farms with respect to the conventional ones, while no significant differences were noticed in milk fat and lactose contents and in somatic cell count. Concerning fatty acids, only small differences were detected between organic and conventional milk and such differences seemed to be related mainly to the stabled period. Diet affected almost all variables studied: pasture feeding provided a significant improvement in the fatty acid composition in both organic and conventional systems leading to lower hypercholesterolemic saturated fatty acids, higher mono- and polyunsaturated fatty acids and conjugated linoleic acid amounts (P<0.001).

Sensory Evaluation of Butterfat‐Vegetable Oil Blend Spread Prepared with Structured Lipid Containing Canola Oil and Caprylic Acid

ABSTRACTStructured lipid (SL) was synthesized from canola oil and caprylic acid with sn‐1,3 specific lipase from Rhizomucor miehei. Cold‐spreadable butter was made by blending butterfat with the SL at a weight ratio of 80:20. Its sensory attributes were compared with pure butter and butterfat‐canola oil 80:20 blend spread by headspace solid‐phase microextraction (SPME) procedure and sensory analyses (descriptive analysis and triangle test) to determine the effect of the SL on the sensory profiles of the spread. Butterfat‐SL blend had significantly (P &lt; 0.05) lower contents of hypercholesterolemic fatty acids (FAs) and the lowest atherogenic index (AI) compared with the others. In the volatile compounds analysis, free caprylic acid was detected in the butterfat‐SL blend spread only. Descriptive analysis results indicated that butterfat‐SL blend spread was significantly (P &lt; 0.05) more cold‐spreadable than pure butter, whereas its overall textural profile was very similar to that of butterfat‐canola oil blend spread. However, no significant (P &lt; 0.05) differences were found between all the spread samples in the flavor attributes including caprylic acid flavor. Triangle test results also showed that significant (P &lt; 0.001) difference was found in cold‐spreadability between pure butter and butterfat‐SL blend spread, but there was no significant (P &lt; 0.05) difference between butterfat‐canola oil blend spread and butterfat‐SL blend spread. Our results indicate that SL can counterbalance the hypercholester‐olemic attributes of butterfat as well as improve the cold‐spreadability of the experimental spread without any adverse effect on the flavor attributes of the spread.

Chemical and Physical Properties of Butterfat−Vegetable Oil Blend Spread Prepared with Enzymatically Transesterified Canola Oil and Caprylic Acid

Structured Lipid was synthesized from canola oil and caprylic acid with sn-1,3 specific lipase from Rhizomucor miehei. Cold spreadable butter was made by blending butterfat with the SL at a weight ratio of 80:20. Its chemical and physical properties were compared with pure butter and butterfat-canola oil 80:20 blend spread. The butterfat-SL blend had lower contents of hypercholesterolemic fatty acids (FAs) and the lowest atherogenic index (AI) as compared to the others. Melting and crystallization behaviors of butterfat-SL blend were similar to those of butterfat-canola oil blend above 0 degrees C. It showed solid fat contents (SFCs) similar to butterfat-canola oil blend but lower than pure butterfat. The butterfat-SL blend was shown to crystallize in the beta' form. There were no differences between the hardness of butterfat-SL blend spread and butterfat-canola oil blend spread. Rheological analysis showed that butterfat-SL blend spread lost its elastic behavior at 5 degrees C, a lower temperature than pure butter.

The effects of supplementation with sunflower and soybean oils on the fatty acid profile of milk fat from grazing dairy cows

The objective of this study was to observe the effect of supplementation with vegetable oils (VO) on the fatty acid profiles and conjugated linoleic acid (CLA) content of milk fat. Twelve dairy cows in mid lactation fed on pasture were blocked by body weight, milk production and days in lactation and randomly allocated from blocks to 3 treatments repeated in a Latin square design with periods of 28 day duration. The treatments were as follows: cows on pasture supplemented with 5 kg concentrate per head per day (C), supplemented with 4.5 kg concentrate + 0.5 kg sunflower oil per head per day (SFO) and supplemented with 4.5 kg concentrate + 0.5 kg soybean oil per head per day (SBO). The animals were grazed as a group and were stocked at 2.5 heads per hectare. The treat- ments had no effect on milk yield or protein yield and content, but decreased milk fat yield and content (P < 0.05). Milk fat from the cows supplemented with VO had a lower concentration of short and medium chain fatty acids (P < 0.05) and a higher concentration of long chain fatty acids (P < 0.05). The addition of VO to the diet also resulted in a reduction in saturated and an increase in unsaturated fatty acids of milk fat (P < 0.05). The hypercholesterolemic fatty acids in milk fat (i.e. C12:0, C14:0 and C16:0) decreased while the concentration of oleic and linoleic acids increased with VO (P < 0.05). There was no effect on linolenic acid. Finally, the inclusion of VO in the diet increased (P < 0.05) the contents in milk fat of the various cis/trans isomers of oleic acid (including trans-vacenic, TVA) and of CLA which increased by 61%. dairy cow / conjugated linoleic acid / fatty acids / pasture / vegetable oils

Influence of canola oil on the fatty acid profile in goats’ milk

Four Alpine does were used in a 4 × 4 Latin square design to determine the effects of feeding canola oil at four levels: 0, 2, 4 and 6% on milk fatty acid profile. The sum of C12:0 + C14:0 + C16:0 (hypercholesterolemic fatty acids) decreased linearly and C18:0 + C18:1: C16:0 (indicator of cholesterolemic tendency of fat source) increased linearly (P &lt; 0.01) with increased canola oil intake. Key words: Goat, milk, fatty acids, canola oil

Serum cholesterol predictive equations with special emphasis on trans and saturated fatty acids. an analysis from designed controlled studies.

The effects of dietary trans fatty acids on serum total and low density lipoprotein (LDL) cholesterol have been evaluated by incorporating trans fatty acids into predictive equations and comparing their effects with the effects of the individual saturated fatty acids 12:0, 14:0, and 16:0. Trans fatty acids from partially hydrogenated soybean oil (TRANS V) and fish oil (TRANS F) were included in previously published equations by constrained regression analysis, allowing slight adjustments of existing coefficients. Prior knowledge about the signs and ordering of the regression coefficients was explicitly incorporated into the regression modeling by adding lower and upper bounds to the coefficients. The amounts of oleic acid (18:1) and polyunsaturated fatty acids (18:2, 18:3) were not sufficiently varied in the studies, and the respective regression coefficients were therefore set equal to those found by Yu et al. [Yu, S., Derr, J., Etherton, T.D., and Kris-Etherton, P.M. (1995) Plasma Cholesterol-Predictive Equations Demonstrate That Stearic Acid Is Neutral and Monounsaturated Fatty Acids Are Hypocholesterolemic, Am. J. Clin. Nutr. 61, 1129-1139]. Stearic acid (18:0), considered to be neutral, was not included in the equations. The regression analyses were based on results from four controlled dietary studies with a total of 95 participants and including 10 diets differing in fatty acid composition and with 30-38% of energy (E%) as fat. The analyses resulted in the following equations, where the change in cholesterol is expressed in mmol/L and the change in intake of fatty acids is expressed in E%: delta Total cholesterol = 0.01 delta(12:0) + 0.12 delta(14:0) + 0.057 delta(16:0) + 0.039 delta(TRANS F) + 0.031 delta(TRANS V) - 0.0044 delta(18:1) - 0.017 delta(18:2, 18:3) and deltaLDL cholesterol = 0.01 delta(12:0) + 0.071 delta(14:0) + 0.047 delta(16:0) + 0.043 delta(TRANS F) + 0.025 delta(TRANS V) - 0.0044 delta(18:1) - 0.017 delta(18:2, 18:3). The regression analyses confirm previous findings that 14:0 is the most hypercholesterolemic fatty acid and indicate that trans fatty acids are less hypercholesterolemic than the saturated fatty acids 14:0 and 16:0. TRANS F may be slightly more hypercholesterolemic than TRANS V or there may be other hypercholesterolemic fatty acids in partially hydrogenated fish oil than those included in the equations. The test set used for validation consisted of 22 data points from seven recently published dietary studies. The equation for total cholesterol showed good prediction ability with a correlation coefficient of 0.981 between observed and predicted values. The equation has been used by the Norwegian food industry in reformulating margarines into more healthful products with reduced content of cholesterol-raising fatty acids.

Production of a rapid hypercholesterolemia in young chick by feeding coconut oil from two different sources and fatty acid composition

In this work, we have studied comparatively the effects of supplementation to a standard diet with the same proportion (20%) of saturated fat (coconut oil) from two different commercial sources and with clear differences in their fatty acid composition. Both experimental diets produced a rapid (24 h) and significant hypercholesterolemia in 14-day-old chicks. However, plasma cholesterol levels were higher in animals fed a diet supplemented with coconut oil for commercial cooking use (“Pastry”) than in those fed a diet with coconut oil for pharmaceutical use (“Pharmacy”). Both dietary manipulations rapidly (24 h) increased the percentages of the more hypercholesterolemic fatty acids (12:0 and 14:0) in plasma. This increase was higher after “Pastry” than after “Pharmacy” diet feeding. Likewise, the percentages of the hypocholesterolemic fatty acids (18:1 n-9 and 18:2 n-6) were lower in plasma from treated animals than in control, especially after feeding the “Pastry” diet. All these differences may be implied in the high hypercholesterolemic effects showed by “Pastry” diet. The hyper-cholesterolemia was not accompanied by changes in the levels of liver cholesterol.

Interesterification of butter fat by partially purified extracellular lipases from Pseudomonas putida, Aspergillus niger and Rhizopus oryzae

Three extracellular lipases were produced by batch fermentation of Pseudomonas putida ATCC 795, Aspergillus niger CBS 131.52 and Rhizopus oryzae ATCC 34612 during the late phase of growth, at 72, 96 and 96 h, respectively. The lipases were partially purified by (NH4)2SO4 fractionation. The lipase of P. putida was optimal at pH 8.0 whereas those from A. niger and R. oryzae were optimal at pH 7.5. The A. niger lipase had the lowest V max value (0.51×10(-3) U/min) and R. oryzae the highest (1.86×10(-3) U/min). The K m values for P. putida, A. niger and R. oryzae lipases were 1.18, 0.97, and 0.98 mg/ml, respectively. Native PAGE of the partially-purified lipase extracts showed two to four major bands. The interesterification of butter fat by A. niger lipase decreased the water activity as well as the hydrolytic activity. The A. niger lipase had the highest interesterification yield value (26%) and the R. oryzae lipase the lowest (4%). In addition, A. niger lipase exhibited the highest decrease (17%) in long-chain hypercholesterolemic fatty acids (C12:0, C14:0 and C16:0) at the sn-2-position; the P. putida lipase demonstrated the least favourable changes in specificity at the same position.

Interesterification of butter fat by lipase fromRhizopus niveus in cosurfactant-free microemulsion system

Butter fat was interesterified in a cosurfactant-free microemulsion system containing nonionic and ionic surfactants, using commercial lipase obtained fromRhizopus niveus, at different concentrations of surfactant mixtures and hydrophilic-lipophilic balance (HLB) values. The results indicated that the interesterification yield (IY) of lipasecatalyzed interesterified butter fat reached its maximum in the microemulsion system prepared with the surfactant mixture of HLB value of 9, followed by that of HLB value of 10. In addition, increasing concentrations of surfactant mixtures, from 3 to 6 mM, resulted by an increase in the IY. The interesterification of butter fat in the microemulsion prepared with 3 mM of surfactant mixture of HLB value of 10 showed a minimum hydrolytic activity. The results showed that the interesterified selected triacylglycerol molecules were enriched with the hypocholesterolemic fatty acid C18:l, originally located onsn-1,3 positions, on theirsn-2 positions; this fatty acid was favorably interchanged with the hypercholesterolemic fatty acid C16:0, originally located onsn-2 position. The results also indicated that the use of 6 mM of surfactant mixtures increased the acyl exchange reaction toward the long-chain saturated fatty acid C16:0 on the sn-2 position of triacylglycerol molecules.

Determination of the positional distribution of fatty acids in butterfat triacylglycerols

Triacylglycerol (TAG) standards were separated by analytical high‐performance liquid chromatography (HPLC) with laser light‐scattering detection (LLSD). A high sensitivity for TAGs was observed with LLSD whereas poor sensitivity was observed with ultraviolet detection. The HPLC‐LLSD analytical separation of butterfat TAGs showed that the TAGs were eluted according to increasing carbon number. Preparative HPLC‐LLSD was used to characterize butterfat TAGs that contained hypercholesterolemic fatty acids (laurate, myristate, palmitate) with carbon chainlengths of 12 or greater. These TAG fractions accounted for 29.2% of the total butterfat TAGs. Analysis of the positional distribution of fatty acids of selected butterfat TAGs containing hypercholesterolemic fatty acids showed the presence of positional isomers in each of these fractions. These butterfat TAGs also showed the predominant presence of hypercholesterolemic fatty acids at thesn‐2 position. The characterization of the positional distribution of hypercholesterolemic fatty acids in butterfat TAGs is the first step for the determination of the metabolic role of the positional distribution in the hypercholesterolemic effects of butter.