Mechanisms for the interaction of the milk fat globule membrane with the plasma membrane of gut epithelial cells.

The milk fat globule membrane (MFGM) provides infants and adults with several health benefits. These are not derived solely from its unique composition, but also from arrangement of lipids in the MFGM that, in the case of newborns, could reach the intestine partially intact. Fluorochromes associated with lipid derivatives were used to prove a fusion process between the MFGM and the cellular membrane of differentiated Caco-2 cells. To explore the mechanism of this interaction, incubations of MFGM with Caco-2 cells were carried out in the presence of fusogenic agents or compounds that block other MFGM interaction pathways with cells. Confocal fluorescence microscopy provided visual evidence of the fusion process. Lastly, determination on the lipid profile of cells after their interaction with MFGM indicated a metabolic rearrangement of lipids leading to accumulation of triacylglycerols.

Milk and blood biomarkers associated to the clinical efficacy of a probiotic for the treatment of infectious mastitis.

Previous studies have shown the efficacy of oral administration of selected lactobacilli strains to treat mastitis. The objective of this study was to find microbiological, biochemical and/or immunological biomarkers of the probiotic effect. Women with (n=23) and without (n=8) symptoms of mastitis received three daily doses (10(9) cfu) of Lactobacillus salivarius PS2 for 21 days. Samples of milk, blood and urine were collected before and after the probiotic intervention, and screened for a wide spectrum of microbiological, biochemical and immunological parameters. In the mastitis group, L. salivarius PS2 intake led to a reduction in milk bacterial counts, milk and blood leukocyte counts and interleukin (IL)-8 level in milk, an increase in those of immunoglobulin (Ig)E, IgG3, epidermal growth factor and IL-7, a modification of the milk electrolyte profile, and a reduction of some oxidative stress biomarkers. Such biomarkers will be useful in future clinical studies involving a larger cohort.

Combined effect of Lactobacillus acidophilus and ß-cyclodextrin on serum cholesterol in pigs.

A total of twenty-four Yorkshire gilt pigs of 6-7 weeks of age were used in a 2×2 factorial experiment to determine the individual and combined effects of the inclusion of two dietary factors (cholesterol rich, 3% ß-cyclodextrin (BCD) and Lactobacillus acidophilus cultures) on total cholesterol and LDL-cholesterol levels in blood serum. Pigs were assigned randomly to treatment groups (n 6). Total serum cholesterol concentrations decreased after 3 weeks in all the experimental treatment groups, including diets with BCD, L. acidophilus or both. Similar trends were observed for serum LDL-cholesterol concentrations among the experimental treatments. No statistically significant differences from the control group were observed in either total serum cholesterol or LDL-cholesterol concentrations (P<0·05) for each of the individual treatment groups: BCD or L. acidophilus. However, significant differences in total serum cholesterol concentrations were observed when comparing the combined treatment group (BCD and L. acidophilus) with the control group, which consisted of a basal diet and sterile milk. The combined treatment group exhibited 17·9% lower total serum cholesterol concentration after 3 weeks. Similar significant differences were observed when comparing the combined effect experimental group with the control group after 3 weeks. The combined treatment group exhibited 27·9% lower serum LDL-cholesterol concentrations.

Relevance of dietary glycerophospholipids and sphingolipids to human health.

Glycerophospholipids and sphingolipids participate in a variety of indispensable metabolic, neurological, and intracellular signaling processes. In this didactic paper we review the biological roles of phospholipids and try to unravel the precise nature of their putative healthful activities. We conclude that the biological actions of phospholipids activities potentially be nutraceutically exploited in the adjunct therapy of widely diffused pathologies such as neurodegeneration or the metabolic syndrome. As phospholipids can be recovered from inexpensive sources such as food processing by-products, ad-hoc investigation is warranted.

NFC as a Childhood Obesity Treatment Tool.

Childhood Obesity is associated with a wide range of serious health complications and constitutes an increased risk of premature syndromes, including diabetes or heart diseases. Its treatment seems to be complicated. So, in order to help parents we have developed a system that will try to make easier the process of choosing foodstuff for overweight and obese children at the supermarket. To interact with the system, Near Field Communication mobile phones and tags are used. Those tags would have nutritional information such as energy or fat contain of each product. When the interaction takes place, the system will generate an alert determining if the product is adequate for the user diet or not. Decision will be influenced by specific prescript diets, which would have been previously generated by the system based on user profile parameters. At the same time the diet is established, the shopping list would be generated automatically. Therefore, the user could download and print both things at home easily by the PC application. The system also takes into account physical activity of the user. Children mobile phone includes an accelerometer that will detect and collect user activities in order to modify calorical requirements and, if necessary, to change physical activity too. In the future, it would be possible to extend this project system for adults, managing diets not just for obese and overweight, but also to diabetic or celiac people.

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.

Total milk fat extraction and quantification of polar and neutral lipids of cow, goat, and ewe milk by using a pressurized liquid system and chromatographic techniques.

Although milk polar lipids such as phospholipids and sphingolipids located in the milk fat globule membrane constitute 0.1 to 1% of the total milk fat, those lipid fractions are gaining increasing interest because of their potential beneficial effects on human health and technological properties. In this context, the accurate quantification of the milk polar lipids is crucial for comparison of different milk species, products, or dairy treatments. Although the official International Organization for Standardization-International Dairy Federation method for milk lipid extraction gives satisfactory results for neutral lipids, it has important disadvantages in terms of polar lipid losses. Other methods using mixtures of solvents such as chloroform:methanol are highly efficient for extracting polar lipids but are also associated with low sample throughput, long time, and large solvent consumption. As an alternative, we have optimized the milk fat extraction yield by using a pressurized liquid extraction (PLE) method at different temperatures and times in comparison with those traditional lipid extraction procedures using 2:1 chloroform:methanol as a mixture of solvents. Comparison of classical extraction methods with the developed PLE procedure were carried out using raw whole milk from different species (cows, ewes, and goats) and considering fat yield, fatty acid methyl ester composition, triacylglyceride species, cholesterol content, and lipid class compositions, with special attention to polar lipids such as phospholipids and sphingolipids. The developed PLE procedure was validated for milk fat extraction and the results show that this method performs a complete or close to complete extraction of all lipid classes and in less time than the official and Folch methods. In conclusion, the PLE method optimized in this study could be an alternative to carry out milk fat extraction as a routine method.

Characterization of an array of Love-wave gas sensors developed using electrospinning technique to deposit nanofibers as sensitive layers.

The electrospinning technique has allowed that very different materials are deposited as sensitive layers on Love-wave devices forming a low cost and successful sensor array. Their excellent sensitivity, good linearity and short response time are reported in this paper. Several materials have been used to produce the nanofibers: polymers as Polyvinyl alcohol (PVA), Polyvinylpyrrolidone (PVP) and Polystirene (PS); composites with polymers as PVA+SnCl4; combined polymers as PS+Poly(styrene-alt-maleic anhydride) (PS+PSMA) and metal oxides (SnO2). In order to test the array, well-known chemical warfare agent simulants (CWAs) have been chosen among the volatile organic compounds due to their importance in the security field. Very low concentrations of these compounds have been detected by the array, such as 0.2 ppm of DMMP, a simulant of sarin nerve gas, and 1 ppm of DPGME, a simulant of nitrogen mustard. Additionally, the CWA simulants used in the experiment have been discriminated and classified using pattern recognition techniques, such as principal component analysis and artificial neural networks.

Array of Love-wave sensors based on quartz/Novolac to detect CWA simulants.

An array of Love-wave sensors based on quartz and Novolac has been developed to detect chemical warfare agents (CWAs). These weapons are a risk for human health due to their efficiency and high lethality; therefore an early and clear detection is of enormous importance for the people safety. Love-wave devices realized on quartz as piezoelectric substrate and Novolac as guiding layer have been used to make up an array of six sensors, which have been coated with specific polymers by spin coating. The CWAs are very dangerous and for safety reasons their well known simulants have been used: dimethylmethyl phosphonate (DMMP), dipropyleneglycol methyl ether (DPGME), dimethylmethyl acetamide (DMA), dichloroethane (DCE), dichloromethane (DCM) and dichloropentane (DCP). The array has been exposed to these CWA simulants detecting very low concentrations, such as 25 ppb of DMMP, a simulant of nerve agent sarin. Finally, principal component analysis (PCA) as data pre-processing and discrimination technique, and probabilistic neural networks (PNN) as patterns classification technique have been applied. The performance of the sensor array has shown stability, accuracy, high sensitivity and good selectivity to these simulants.

Major lipid classes separation of buttermilk, and cows, goats and ewes milk by high performance liquid chromatography with an evaporative light scattering detector focused on the phospholipid fraction.

An improved HPLC-ELSD method has been developed for the analysis of the lipid classes of buttermilk and milk from different species, focused in the phospholipids fraction without a prior fractionation step and in a single run. The total lipid profile analysis showed the major and minor lipid compounds as cholesterol esters, triacylglycerides, cholesterol, diacylglycerides, free fatty acids, monoacylglycerides, and also the polar compounds as glucosylceramide, lactosylceramide, phosphatidyl-ethanolamine, phosphatidylinositol, phosphatidylserine, phosphatidylcholine, sphingomyelin and lysophosphatidylcholine. The identification and quantification of the different compounds, using calibration curves made with individual standards and the low coefficients of variation obtained in the inter- and intra-assays showed the suitability of the developed method. In this study, we optimized and validated a quantitative HPLC-ELSD method at a concentration level suitable for routine analysis of the major lipid classes in milk and dairy products.

Use of beta-cyclodextrin to decrease the level of cholesterol in milk fat.

This study was carried out to determine optimum conditions (beta-cyclodextrin concentration, mixing time, and holding time) for cholesterol removal from pasteurized nonhomogenized milk at 4 degrees C on a commercial scale by adding beta-cyclodextrin in a specially designed bulk mixer tank. The beta-cyclodextrin (0.4, 0.6, 0.8, and 1.0%) removed from 65.42 to 95.31% of cholesterol at 4 degrees C in 20 min. Treatment of milk with 0.8 and 1.0% (wt/vol) beta-cyclodextrin was no better than treatment with 0.6% beta-cyclodextrin. Maximum cholesterol removal was seen with 6 h of treatment. The beta-cyclodextrin cholesterol complex was precipitated from milk during 20 min without stirring at 4 degrees C and removed by centrifugation. After separating the milk, approximately 0.35% of residual beta-cyclodextrin remained in the skim fraction and 0.1% in the cream from milk treated with 0.6% beta-cyclodextrin. The rest of the beta-cyclodextrin was complexed with the cholesterol and eliminated via the discharger of the separator. Individual fatty acid and triglyceride compositions did not differ between control milk and milk treated with 0.6% beta-cyclodextrin.

Hot topic: Fatty acid and conjugated linoleic acid (CLA) isomer composition of commercial CLA-fortified dairy products: evaluation after processing and storage.

Conjugated linoleic acid (CLA) exerts a strong positive influence on human health but intake of these fatty acids is typically too low, and increased consumption of CLA is recommended. A good way to raise the CLA content in the diet without a radical change in eating habits seems to be the enrichment of commonly consumed food products with CLA supplements. This study analyzed the total fatty acid content and the CLA isomer composition of 6 commercially available CLA-fortified dairy products during processing and 10 wk of refrigerated storage. Research was carried out by combining gas chromatography and silver-ion HPLC. The tested samples were a CLA oil supplement, and several skim milk dairy products fortified with the supplement (milk, milk powder, fermented milk, yogurt, fresh cheese, and milk-juice blend). The CLA oil supplement was added such that the consumer received 2.4 g/d of CLA by consuming 2 servings. The predominant isomers present, C18:2 cis-9, trans-11 CLA and C18:2 cis-10, trans-12 CLA, were in at a similar ratio, which ranged from 0.97 to 1.05. These major isomers were not significantly affected by processing but a decrease in total CLA in fresh cheese samples was detected after 10 wk of refrigerated storage. Refrigerated storage and thermal treatment resulted in significant decreases or disappearance of some of the minor CLA isomers and a significant increase of trans, trans isomers from both cis, trans, trans, cis, and cis, cis isomers especially in CLA-fortified milk powder but also in fermented milk, yogurt, and milk-juice blend.

Triacylglycerol composition of protected designation of origin cheeses during ripening. Authenticity of milk fat.

Triacylglycerol (TAG) composition by carbon number in 2 protected designation of origin cheeses, Mahón (cheese from cow milk) and Manchego (cheese from ewe milk) that were manufactured by 3 different producers was analyzed during cheese ripening using gas chromatography with a short capillary column. The TAG composition at different times during cheese ripening was also analyzed in cheeses from different batches produced at the same plant. Lipolysis levels in the Mahón and Manchego cheeses during ripening were low; free fatty acid values ranged from 2,500 to 4,000 ppm at the end of ripening. The TAG composition did not change significantly during ripening. The TAG values obtained from each cheese sample were substituted into the multiple regression equations that have been proposed to detect foreign fats in milk fat. The values obtained using the equations for bovine (proposed by the European Union) and ovine milk (proposed by our laboratory) were within the normal range. Accordingly, these equations can be considered useful for detecting foreign fat in these cheeses during the ripening period contemplated during this study.

Differentiation of red wines using an electronic nose based on surface acoustic wave devices.

An electronic nose, utilizing the principle of surface acoustic waves (SAW), was used to differentiate among different wines of the same variety of grapes which come from the same cellar. The electronic nose is based on eight surface acoustic wave sensors, one is a reference sensor and the others are coated by different polymers by spray coating technique. Data analysis was performed by two pattern recognition methods; principal component analysis (PCA) and probabilistic neuronal network (PNN). The results showed that electronic nose was able to identify the tested wines.

Purification and characterization of a pregastric esterase from a hygienized kid rennet paste.

Rennet pastes obtained by maceration of gastric tissues from suckling kids are used traditionally to produce some artisanal cheeses in Spain. Besides milk-clotting function, rennet pastes provide proteolytic activity and lipolytic system, essentially pregastric, necessary in the development of piquant flavor typical of these cheeses. A simple and reproducible procedure allows us to obtain a standardized rennet paste that posses the desired activity and is of good microbiological quality. Concomitantly, a kid pregastric esterase (KPGE) was purified to homogeneity. The purification procedure was based on an aqueous extract of hygienized rennet paste (HRP), which was chromatographed on DEAE-Sepharose Fast Flow then adsorbed on phenyl superose followed by a re-chromatography on the same column. The final enzymatic preparation, where the overall activity recovery was 3%, showed a molecular mass of 53 kDa. The highest activity was determined on p-nitrophenyl butyrate, but marked hydrolysis was also detected on beta-naphthyl caprylate. In contrast, low activity on tributyrin (substrate under emulsion form) was detected, thus confirming the esterase character of purified enzyme.

Effect of different membrane separation technologies (Ultrafiltration and microfiltration) on the texture and microstructure of semihard low-fat cheeses.

Semihard low-fat cheeses made from ultrafiltered (UF) or microfiltered (MF) milk were compared. The use of MF membranes and milder pasteurization of the milk reduced the retention of whey proteins in the retentate to 35%, compared with approximately 100% retained in the UF process. Microbiological development, physicochemical composition, and cheese ripening were not altered by the concentration processes. The lower retention of whey protein in MF cheeses accounted for their higher hardness, which correlated with higher firmness values in the textural analysis. Microstructure showed a protein matrix with open spaces through the protein network, although micrographs of UF cheeses showed the presence of spongy structures linked to the casein, which did not appear in MF cheeses and which correspond to the denatured whey protein bound to the casein. Firmness was scored better in MF cheeses, although when MF membranes were used, the optimum yields achieved using UF membranes were not attained.

Fatty acid composition of caprine milk: major, branched-chain, and trans fatty acids.

The fatty acid composition of caprine milk fat was studied using capillary gas chromatography. Milk was obtained from five goat herds belonging to different breeders in the Murcia region (Spain) and collected monthly (from November to May). The results showed significant differences among herds mainly in long-chain fatty acids (C16:0, C18:0, and C18:2). There were five branched-chain fatty acids (iso- and anteiso-C15:0, iso- and anteiso-C17:0, and iso-C16:0) with > 0.1% of the total fatty acid methyl esters and another 31 (the most monomethylated) with < 0.1%, including 4-ethyloctanoate, which is implicated in goat-like flavors. To study the content of trans unsaturated fatty acids, the fatty acid methyl esters were previously fractionated by AgNO3-thin layer chromatography. The mean contents of trans-C16:1 and trans-C18:1 were 0.16 and 2.12%, respectively. The distribution profile of trans-C18:1 was also studied.