Butter Serum Research Articles

Preparation of milk fat globule membrane ingredients enriched in polar lipids: Composition characterization and digestive properties

In this study, milk fat globule membrane (MFGM) ingredients enriched in polar lipids was prepared using membrane filtration, including microfiltration, diafiltration, and ultrafiltration from butter serum powder. Polar lipids (phospholipids, sterols, and gangliosides) in prepared MFGM ingredients were analyzed by 31P NMR, GC-MS, and UPLC-MS/MS, respectively. The lipolysis degree and microstructure of MFGM ingredient and soybean lecithin-emulsification during in vitro digestion were also analyzed. Microfiltration showed higher concentration efficiency than ultrafiltration which increased 2.16% and 2.73% in phospholipid, respectively. Moreover, diafiltration concentrated more polar lipids (6.39% of phospholipid) than microfiltration. MFGM ingredients had high level of sphingomyelin (1.27-1.36%) and ration of GD3 than GM3 of 9.25-9.88-fold of total gangliosides. The different lipolysis behavior between MFGM ingredient-emulsification and soybean lecithin-emulsification were correlated with their different polar lipid compositions. Phospholipids from both MFGM ingredients and soybean lecithin could help maintain the initial structure during the gastric digestion. These results could provide a scientific basic for developing high-polar lipids food, particularly infant formulas and special functional foods.

Fractionation of milk fat globule membrane enriched materials from caprine milk cream

Comparison of typical milk fat globule membrane (MFGM) components was made first among buttermilk, butter serum, α-serum and β-serum produced from caprine milk cream, then subsequently among effects of different demulsification treatments and ripening/churning conditions applied to cream on the resulting buttermilk. Of the four initial materials, buttermilk had the highest yield of MFGM components and best retention of bioactive MFGM proteins. For the resulting buttermilk, ripening followed by churning achieved a MFGM component content comparable with that achieved with freezing followed by churning, and higher than that achieved with ripening or freezing followed by heating. To maximise MFGM component content, ripening cream at 12 °C and pH 6.7 for 12 h in an uncycled mode was indicated. Following optimised ripening, laboratory-scale and small technical-scale churning achieved a comparable content of MFGM components in buttermilk. To further increase the yield of MFGM components, one-time butter washing following cream churning was indicated.

Lipidomic and Proteomic Profiling of the Milk Fat Globule Membrane from Different Industrial By-Products of the Butter and Butter Oil Manufacturing Process.

Recent studies have demonstrated the positive effects of regular intake of milk fat globule membranes (MFGMs) on neural and cognitive development, as well as immune and gastrointestinal health in infants and elders. Dairy products and by-products generated from the butter and butter oil manufacturing process are valuable sources of MFGM. Thus, in view of the growing need to reduce by-products and waste, it is crucial to foster research aimed at the valorization of dairy by-products rich in MFGM. For this purpose, all the by-products coming from butter and butter oil production (from raw milk to the related by-products) were used to study the MFGM isolated fractions, followed by their characterization through a combined lipidomic and proteomic approach. The patterns of polar lipids and proteins indicated that buttermilk (BM), butterserum (BS), and their mix (BM-BS blend) are the most suitable by-products to be employed as starting material for the isolation and purification of MFGMs, thus obtaining MFGM-enriched ingredients for the manufacture of products with high biological activity.

Major Phospholipids of Selected Dairy Products as Determined by the HPLC-UVvis and 31P-NMR Methods

This study was carried out to determine the major phospholipids in selected dairy products (Beta Serum, Procream and Phospholipids-Rich Dairy products), evaluate the accuracy of the developed fat extraction method for liquid dairy samples and to compare the major phospholipids of different dairy samples obtained using the HPLC-UVvis and 31P-NMR methods. It was found that the developed fat extraction method can be used to estimate the lipid content of liquid dairy samples were still a bit satisfactory. Using the HPLC-UVvis method, it was found that the sphingomyelin (SM) consists of 2 curves in Beta Serum, Procream and Phospholipid-Rich products. The phosphatidylethanolamine (PE) separated ahead of phosphatidylcholine (PC) and then PC ahead of SM1 and SM2. The results showed that the data of the major phospholipids (PC, PE and SM) in Butter Serum, Procream and Phospholipids-Rich products as determined by the HPLC-UVvis method compared well with those of the 31P-NMR method It must be noted that the analysis temperature for the HPLC-UVvis method was at 40oC while the 31P-NMR method was at 30oC, and this might have also contributed to the slight variation of the results. Furthermore, the HPLC-UVvis method is rapid and with cheaper analysis cost compared with the 31P-NMR method.

Inhibition of bacterial adherence on stainless steel coupons by surface conditioning with selected polar lipids

AbstractPolar lipids were recently found to have the surfactant property that could interfere with the bacterial adherence process during biofilm formation, a promising effect against the bacterial contamination on food processing surfaces. This study aimed to investigate the effect of surface conditioning of polar lipids such as phosphatidylcholine and sphingomyelin on stainless steel surfaces and subsequently on bacterial adherence. A confocal laser scanning microscope was used to examine formed conditioning layers and bacterial adherence. The thinnest conditioning layer was created by dilute skim milk and by sphingomyelin, while thicker layers were created by phosphatidylcholine, dilute buttermilk, and butter serum. Among surface conditioning treatments of stainless steel coupons, those performed with diluted buttermilk, butter serum, and polar lipids such as phosphatidylcholine, and sphingomyelin were able to scale down the adherence of Lactococcus lactis subsp. lactis NBRC 100676 and Leuconostoc mesenteroides subsp. cremoris NBRC 102479 compared to the surface conditioning with dilute skim milk. For both strains, the higher the phosphatidylcholine concentration (over 0.01%) and the longer the adhesion time (over 12.0 h), the more the adherence‐reducing ability of conditioned surfaces. The higher the sphingomyelin concentration used in surface conditioning, the higher the adherence‐reducing activity on stainless‐steel surfaces was at all adhesion times (0.5, 12.0, and 24.0 h). Our results suggested that, for short bacterial exposure period (0.5, 12.0, and 24.0 h), dilute buttermilk, butter serum, and individual polar lipids may have a bacterial adherence‐reducing effect, and can potentially be used for reducing biofilm formation.

Application of supercritical fluid extraction for extraction or enrichment of phospholipids in egg and dairy products: A review

Phospholipids (PLs) are polar lipids that are found in dairy products, egg, and oilseeds. They are amphiphilic in nature and find application in many foods as a functional ingredient. As PLs are distributed in food matrix in dilute form, attempts to concentrate the same by adopting suitable technical interventions have been widely investigated. One of the more successful approaches that have been reported is the application of supercritical fluid extraction (SCFE) to extract PLs using suitable cosolvents. The extraction protocol to extract PLs from dairy products and eggs using SCFE also includes a two‐step process, namely, separation of neutral lipids using neat CO2 followed by subsequent separation of polar lipids from the residue using cosolvent and CO2. This review is an attempt to compile information on dairy and egg PLs extracted using SCFE under varied operational factors. It is expected that the compilation will serve as resource for investigators working in this research area.Practical ApplicationsMilk fat processing results in valuable by‐products which can be suitably volarized to increase profitability through processing gains and reduce environmental footprints in dairy industry. The by‐products such as buttermilk, butter serum, ghee residue, and so forth can be tapped as potential sources for phospholipid (PL). Eggs have already been recognized as a good source of PLs, which are reported to have preventive effect on pathogens, cancer protective, anti‐inflammation and cardiovascular disease. Two challenges could be anticipated in the fractionation of PLs from egg and milk by‐products. First, extraction of lipids from substrate which include polar and neutral lipids. Second, separation of neutral and polar lipids from the lipid extract. Conventional methods of extraction involve many solvents for the wide range of lipids to be extracted, which often result in incomplete extraction. Supercritical fluid extraction (SCFE) technique is reported to be useful in extraction and separation of PLs from dairy and egg products. Process intervention strategies and optimization approaches have been undertaken by various researchers to quantify and improve extractability of PLs using SCFE. The paper is a compilation of the scientific information related to extraction of dairy and egg PLs using SCFE, which will serve as a knowledge resource for researchers working in related fields.

Comparison of bovine milk fat globule membrane protein retention by different ultrafiltration membranes using a label-free proteomic approach

Ultrafiltration (UF) is an effective method for separating and enriching milk proteins. This study aims to analyze the protein profile of milk fat globule membrane (MFGM) materials enriched by UF membranes from butter serum with different molecular mass cutoffs through a label-free proteomic approach. In total, 616 MFGM proteins were identified in all groups, of which 395, 399, 399 and 484 proteins were identified with a 30 kDa, 50 kDa and 100 kDa UF membrane and without UF, respectively. It was more efficient to enrich fatty acid binding protein and mucin 15 using a 30 kDa membrane, whereas mucin 1 was more abundant when using a 50 kDa membrane. Compared with the 30 kDa and 50 kDa membranes, the 100 kDa membrane led to the optimal efficiency with low permeation of the most major MFGM proteins and high permeation of non-MFGM proteins. Butyrophilin, adipophilin, xanthine oxidase/dehydrogenase, and periodic acid Shiff6/7 were concentrated approximately twofold in the 100 kDa retentate. Meanwhile, the relative abundances of β-lactoglobulin and α-lactalbumin were reduced by approximately 17.3% and 16.2%, respectively. This work will facilitate the development of MFGM protein isolation using membrane separation processes and provide a theoretical reference for the production of MFGM proteins.

Partitioning of the milk fat globule membrane between buttermilk and butter serum is determined by the thermal behaviour of the fat globules

Isolation of the industrially interesting milk fat globule membrane (MFGM) components from dairy streams is challenging, and a full exploitation of their benefits can be gained by better understanding of the behaviour of the fat globule membrane fraction during milk fat processing. In this study, microfiltration of the cream before churning and the comprehensive compositional analysis of the process streams revealed new insights on MFGM partitioning during the phase inversion in butter making. After removal of the smallest fat globules by microfiltration, a reduced phospholipid content was reflected in the buttermilk, but not in the butter serum. Regardless of the cream washing, buttermilk and butter serum lipids were different in PL-to-fat ratio, phospholipid composition, degree of unsaturation and melting behaviour. We suggest that partitioning of the MFGM fraction between butter and buttermilk is a direct result of the physico-chemical properties of the fat globules, partly related to the globule size.

Antioxidant activity toward fish oil triacylglycerols exerted by sphingoid bases isolated from butter serum with α-tocopherol

A mixture of sphingoid bases (SPGs) was prepared from butter serum, a by-product of anhydrous milk fat production. The mixture comprised seven types of SPGs with C16 to C19 alkyl chains. These milk SPGs inhibited the oxidation of fish oil triacylglycerol (TAG) more effectively than did a standard SPG (d18:1) with α-tocopherol. Reaction products were prepared from the combination of d18:0 or d18:1 with acrolein and propanal. Both sets of reaction products showed antioxidant activity toward fish oil TAG. Antioxidant activity of reaction products from d18:0 was stronger than that of reaction products from d18:1, suggesting that the molecule d18:0 may be a significant focus of the difference in antioxidant activity between milk SPGs and d18:1. To use SPGs as food additives in the future, an appropriate source of SPGs will be needed, and butter serum appears to have promise as a source of functional SPGs with strong antioxidant activity.

Cow's milk polar lipids reduce atherogenic lipoprotein cholesterol, modulate gut microbiota and attenuate atherosclerosis development in LDL-receptor knockout mice fed a Western-type diet

Milk sphingomyelin (SM), a polar lipid (PL) component of milk fat globule membranes, is protective against dyslipidemia. However, it is unclear whether ingestion of milk PLs protect against atherosclerosis. To determine this, male LDLr−/− mice (age 6 weeks) were fed ad libitum either a high-fat, added-cholesterol diet (CTL; 45% kcal from fat, 0.2% cholesterol by weight; n=15) or the same diet supplemented with 1% milk PL (1% MPL; n=15) or 2% milk PL (2% MPL; n=15) added by weight from butter serum. After 14 weeks on diets, mice fed 2% MPL had significantly lower serum cholesterol (−51%) compared to CTL (P<.01), with dose-dependent effects in lowering VLDL- and LDL-cholesterol. Mice fed 2% MPL displayed lower inflammatory markers in the serum, liver, adipose and aorta. Notably, milk PLs reduced atherosclerosis development in both the thoracic aorta and the aortic root, with 2% MPL-fed mice having significantly lower neutral lipid plaque size by 59% (P<.01) and 71% (P<.02) compared to CTL, respectively. Additionally, the 2% MPL-fed mice had greater relative abundance of Bacteroidetes, Actinobacteria and Bifidobacterium, and lower Firmicutes in cecal feces compared to CTL. Milk PL feeding resulted in significantly different microbial communities as demonstrated by altered beta diversity indices. In summary, 2% MPL strongly reduced atherogenic lipoprotein cholesterol, modulated gut microbiota, lowered inflammation and attenuated atherosclerosis development. Thus, milk PL content may be important to consider when choosing dairy products as foods for cardiovascular disease prevention.

Stability of listerial bacteriophage A511 in bovine milk fat globules

Raw milk and milk fractions were analysed for their activity against the bacteriophage A511. The whole milk was separated into fat, casein and whey. Fat was fractionated further into butter serum, butter oil, butter milk and milk fat globule membrane. Bacteriophage was inoculated and was enumerated at different time periods (0, 24, 48, 72 and 96 h). Results (plaque-forming units, PFU) showed that raw milk reduced phage counts 2.4 log10 PFU mL−1. Among milk fractions, fat and whey were the most active fractions, reducing the phage titre 2.6 and 2.1 log10 PFU mL−1, respectively, compared with 0.8 log10 PFU mL−1 in casein. Fat fractions also influenced phage stability. The main effect was attributed to the milk fat globule membrane (2.1 log10 PFU mL−1 reduction) followed by butter milk and butter serum (1.0 log10 PFU mL−1 reduction). Butter oil showed no effect on phage stability.

Proteomics analysis of milk fat globule membrane enriched materials derived from by-products during different stages of milk-fat processing

By-products produced during milk-fat processing contain abundant milk fat globule membrane (MFGM) and are usually considered as sources of MFGM proteins. However, the technological conditions during cream processing affect the composition/profile of the MFGM proteins and change the functional properties of MFGM proteins. In this paper, the simulative process of industrial manufacture of cream, butter and anhydrous milk fat was done in the lab, five kinds of by-products were collected from different stages (different technical treatments or different fat content) to isolate MFGM enriched material. Proteomics analysis of MFGM enriched materials was performed by liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS). 357, 429, 323, 578 and 332 proteins were identified in five groups of by-products. Several major MFGM proteins were detected in all samples with the high relative abundance. Samples obtained after phase inversion showed higher protein number and higher concentration of major MFGM proteins compared with centrifuged skimmed milk. Both the number and the concentration in samples collected after phase inversion increased with fat content of cream. GO analysis revealed GTPase activity was the specific molecular function of MFGM proteins in butter serum (BS-1). The MFGM protein profiles also provided novel insights into the individual MFGM product which was rich in certain membrane proteins. Butter serum was the best source for isolating complete MFGM proteins product. This work will facilitate the development of deep processing market for dairy by-products, and provide theoretical reference for the production of MFGM protein products.

Milk Polar Lipids Reduce Atherogenic Lipoprotein Cholesterol and Attenuate Atherosclerosis Development in LDL-Receptor Knockout Mice Fed a Western-Type Diet (P06-051-19)

ObjectivesPurified milk sphingomyelin (SM), a polar lipid (PL) component of milk fat globule membranes, is protective against dyslipidemia in high-fat, diet-fed mice. However, it is unclear whether ingestion of the total milk PL fraction can have similar hypolipidemic effects as purified SM, and if this confers protection from inflammation and atherosclerosis. To determine this, LDLr-/- mice were fed high-fat, high-cholesterol diets with and without added milk PL from butter serum, a dairy co-product rich in PLs and SM. MethodsMale LDLr-/- mice (age 6 weeks) were fed ad libitum either a high-fat, high-cholesterol diet (CTL; 45% kcal from fat, 0.22% cholesterol added by weight; n = 15), or the same diet supplemented with 1% milk PL (1% MPL; n = 15) or 2% milk PL (2% MPL; n = 15) added by weight from butter serum. All diets were adjusted to match in energy density, macronutrient composition, and calcium content. After 14 weeks on diets, mice were fasted for 6 hours prior to blood and tissue collection/processing at sacrifice. ResultsSupplementation with 2% MPL significantly reduced serum cholesterol (–51%) compared to CTL (p < 0.01), with fast protein liquid chromatography (FPLC) showing dose-dependent effects in lowering VLDL- and LDL-cholesterol. Serum CCL2 was 56% lower in 2% MPL compared to CTL (p < 0.05). No other significant differences were found in serum markers of inflammation or insulin resistance. Compared to CTL, 2% MPL-fed mice had significantly lower mRNA expression of Scd1 and Mip1b in liver, and Ccl2 in epididymal adipose tissue (p < 0.05). Notably, milk PL dose-dependently reduced atherosclerosis development in thoracic aorta, with 2% MPL significantly lowering neutral lipid plaque size by 59% (p < 0.01). Ccl2 mRNA expression was also significantly reduced by 67% in the descending aorta with 2% MPL (p < 0.05). ConclusionsMilk PL strongly reduced atherogenic lipoprotein cholesterol in LDLr-/- mice fed a Western-type diet, and modestly lowered inflammatory markers in the serum, liver, adipose, and aorta. These factors likely contributed to the strong reduction in atherosclerosis development in thoracic aorta seen with 2% MPL. Milk PL content may be important to consider when choosing dairy products as food. Funding SourcesThis work was supported by a research grant to C. Blesso from the National Dairy Council.

Determination of lactadherin concentration in dairy by-products by ELISA: Effect of heat treatment and hydrolysis

Lactadherin is a peripheral glycoprotein of the milk fat globule membrane with several attributed biological activities. In this study, we developed an indirect competitive ELISA to determine lactadherin concentration by using a rabbit polyclonal antiserum. The ELISA was applied to quantify lactadherin in several dairy by-products. Of the products tested, raw and commercial buttermilk had the highest concentrations of lactadherin (6.79 and 5.27 mg/g of product, respectively), followed by commercial butter serum (4.86 mg/g), commercial skim milk (4.84 mg/g), and raw whey (1.20 mg/g). The concentration of immunoreactive lactadherin was also determined in dairy by-products after they were subjected to different technological treatments. Thus, raw products were heat treated at combinations of temperature and time typically used in the dairy industry, and commercial products were hydrolyzed using 3 proteolytic enzyme preparations. Heat treatments of whey and buttermilk resulted in a smaller decrease in lactadherin concentration than did hydrolysis as determined by ELISA and electrophoresis. At high temperatures for long durations, the loss of lactadherin was higher in whey than in buttermilk, with the maximal reduction of around 48% found after treating whey at 72°C for 60 min. Hydrolysis of commercial products with proteolytic enzymes resulted in a marked decrease of immunoreactivity within the first 5 min of treatment, which thereafter was constant throughout 4 h of hydrolysis. These results demonstrate that dairy by-products from milk fat processing are good natural sources of lactadherin, although technological processes have to be considered, because they have different effects on lactadherin content.

Antirotaviral Activity of Bovine and Ovine Dairy Byproducts

Rotaviral gastroenteritis is associated with significant morbidity in developed countries and a high rate of infant mortality in developing countries. Diverse studies have demonstrated that a wide range of milk-derived fractions exhibit antirotaviral activity. The present study shows the antirotaviral activity of some bovine and ovine dairy byproducts, buttermilk, butter serum, and milk fat globule membrane (MFGM), and evaluates the effect of cream washing and heat treatment on that activity. Furthermore, the rotavirus-neutralizing activity was evaluated for some MFGM proteins, such as xanthine oxidase and lactophorin. Ovine and bovine buttermilk reached rotavirus-neutralizing values of 51.3 and 32.2%, at 1 mg/mL, respectively. The cream washing process led to a significant decrease in the antirotaviral activity of fractions. This activity was also influenced by heat treatment. Treatment at 75 °C for 20 s caused 24.6 and 36.1% decreases of activity in bovine and ovine buttermilk, respectively, and 85 °C for 10 min caused decreases of 80.9 and 79.0% in both fractions, respectively.

Inhibition of Cronobacter sakazakii Adhesion to Caco-2 Cells by Commercial Dairy Powders and Raw Buttermilk.

Cronobacter sakazakii is a foodborne pathogen that has been associated with severe infections, mainly in neonates. The binding of this bacterium to host cell surfaces represents the first step in the pathogenesis of disease. An ELISA-based assay has been developed using a polyclonal antiserum against C.sakazakii to determine its adhesion to Caco-2 cells. The antiserum used recognized many of the outer membrane proteins of C.sakazakii. A positive correlation was found between the absorbance values obtained by ELISA and the number of bacteria adhered to cells determined by plate counting. The inhibitory effect on bacterial adhesion to cells observed with some dairy products was concentration-dependent. Commercial buttermilk caused the maximal reduction of the adhesion percentage (33.0 ± 5.07) at the highest concentration assayed (20 mg/mL), followed by butter serum (31.9 ± 5.36), skim milk (30.4 ± 5.07), and raw buttermilk (25.6 ± 3.80). In some cases, significant differences (p < 0.05) were found in the inhibition exerted by the different products evaluated. The results obtained in this study demonstrate that dairy products contain some components with the ability to inhibit the adhesion of C.sakazakii to Caco-2 cells.

Quantification of MFGM proteins in buttermilk and butter serum by means of a stain free SDS-PAGE method

In comparison to skim milk and whey, buttermilk and butter serum contain high amounts of functional milk fat globule membrane (MFGM) proteins. Quantification of MFGM proteins is difficult because no analytical standard material is available. By means of conventional SDS-PAGE with subsequent staining, MFGM proteins are analytically separated. However, due to various protein structures (e.g., glycosylation) the affinity to the dye is inconsistent. A direct correlation between measured band intensity and protein concentration and, therefore, absolute protein quantification is not possible. The purpose of this study was to apply a novel stain free SDS-PAGE technique that relies on measuring UV light fluorescence of tryptophan in order to quantify MFGM proteins. Thus, proteins can be quantified without the need for analytical standards, provided that the relative tryptophan content relative to the molecular weight is known. In this study, buttermilk and butter serum obtained from raw cream were examined and the three most abundant membrane proteins were absolutely quantified. Higher amounts of peripheral MFGM proteins were determined in buttermilk (0.9g/L) and butter serum (2.7g/L), in comparison to integral MFGM proteins (0.3–0.5g/L). Conclusions were drawn regarding the absolute protein amount of MFGM material surrounding native milk fat globules.

The lipid content and microstructure of industrial whole buttermilk and butter serum affect the efficiency of skimming

The processes developed to valorize buttermilks and butter serums generally start by a technological step aiming at removing lipids by centrifugation. The efficiency of this skimming step has never been studied yet. The objective of this study was then to characterize the efficiency of the skimming of industrial buttermilk and butter serum and to determine its consequences on the lipid composition and microstructure of related products. This work clearly shows that the efficiency of the skimming step, operated both at pilot and industrial scales, is never complete and depends on the characteristics of the fluids to be treated. There exists a threshold of lipid content (7% total lipids in dry matter for buttermilk; 20% for butter serum) under which the skimming is not efficient. Above this threshold of lipid content, the skimming step removes all particles with a size larger than 1μm (large fat globules, butter fines), but does not succeed in removing small size lipid fraction (fragments of membrane, lipid vesicles), which results in an increase in the polar lipids on total lipid ratio for both products (up to 20±5% and 49±6% for buttermilks and butter serums respectively). The difference of skimming efficiency, threshold values of skimming, and composition of final products between the buttermilks and butter serums could be attributed to differences in the microstructure of the lipids. Even if not totally efficient, the skimming step leads to a standardization of total lipid content of buttermilks and butter serums, useful for a better control of technological processes aiming at valorizing individual compounds of these dairy by-products.

Antioxidant activity of co-products from milk fat processing and their enzymatic hydrolysates obtained with different proteolytic preparations

Different co-products are generated from bovine milk during the manufacture of butter or anhydrous milk fat. Those co-products have a similar composition to milk, though they are enriched in fat and components from the milk fat globule membrane. The antioxidant activity of some commercial products (skim milk, butter serum and buttermilk) and raw buttermilk was assayed using the 2,2-diphenyl-1-picrylhydrazyl radical scavenging assay. Commercial co-products showed higher antioxidant activity than raw buttermilk when tested at >10 mg mL−1. These products were incubated with Alcalase, Prolyve and Corolase PP to determine the effect of enzymatic hydrolysis on their antioxidant activity; hydrolysates obtained were characterised by sodium dodecyl sulphate-polyacrylamide gel electrophoresis and reverse-phase high performance liquid chromatography. Hydrolysis with Corolase PP produced the hydrolysates with the highest antioxidant activity. Products derived from milk fat processing and their hydrolysates may therefore be considered as a natural source of antioxidant compounds for application as value-added ingredients.

Comparison of dairy phospholipid preparative extraction protocols in combination with analysis by high performance liquid chromatography coupled to a charged aerosol detector

Different fat extraction methodologies, Röse Gottlieb (RG), Folch with CaCl2 (F1) and Folch without CaCl2 (F2) were evaluated alongside a high performance liquid chromatography (HPLC)-based analytical protocol involving a charged aerosol detector (CAD) to optimise the separation and quantification of dairy phospholipids (PLs). Total PL recovery by F2 proved to be 1.8- and 2.5-fold greater than RG and F1, respectively. Alteration of the HPLC elution program maximised peak separation and reduced co-elution of individual PLs detected by CAD. Two-fold reduction in retention time variability was achieved, <0.15 min, compared with the original method. Improved PL recovery was reflected in the higher PL values obtained from different dairy streams using the optimised protocol, 35.32 ± 0.01% and 46.09 ± 0.01% total PL, for buttermilk and butter serum respectively. Phosphatidylinositol and phosphatidylserine, in particular, demonstrated increases of between 2% and 7%, of total PL, compared with previous studies.