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Measurement of lipoprotein lipase activity (as free fatty acid change or accumulation) is accepted as indicative of milkfat globule membrane (MFGM) disruption. However, measurement is confounded by variables unrelated to the MFGM, e.g., microbial quality. To resolve this, a modified approach to using lipase activity to probe MFGM was developed. Methanol (1%, w/w) and lipoprotein lipase (2%, w/w, raw milk) were added to pasteurised milk samples resulting in formation of methyl esters that therefore served as a new and unique signal for lipase gaining access to interfacial fat. Analysis conditions minimised product formation to minimise sample perturbation. The method could detect 1% (w/w) of homogenised milkfat globules blended with native globules, with linear response to 10% (w/w) and saturation above 20% (w/w). The approach was applied to assess MFGM in samples subjected to disruptive treatments (shear, aeration) under different conditions; findings were consistent with previous research, but with greater sensitivity.

Protection efficiency of polyethylene terephthalate (PET) packaging comprising light protective additives (LPA) was investigated for ultra-high temperature (UHT) 2% milk over 26 weeks in refrigerated LED-lighted retail case storage. For the first time, synergistic efficacy of titanium dioxide (TiO2) and carbon black (CB) pigments in PET packaging in protecting milk nutrients and flavor was evaluated in this study. Combination of TiO2 (6.8 wt%) and CB (23 ppm) pigments in PET packaging (S-PET) protected milk quality as effectively as light-proof packaging up to 13 weeks of storage, as demonstrated by improved riboflavin retention, lower TBARS value, and reduced production of volatiles associated with off-flavor including aldehydes compounds and dimethyl disulfide. Photolysis of riboflavin in milk packaged with S-PET packaging was limited to 7.0% within 13 weeks of storage under exposure of high intensity of LED light. The study demonstrated that selection of appropriate LPA combined with PET packaging provided a cost-effective solution for light protection of 2% milkfat UHT milk stored in refrigerated LED-lighted retail conditions for up to 26 weeks.

Recombined whole milk was prepared by heating skim milk before homogenising with milkfat (HEHO milk) or by homogenising milkfat with unheated skim milk and heating the recombined milk (HOHE milk). Heat treatment caused whey protein denaturation, more at higher temperatures and slightly more in HEHO milk than in HOHE milk. Less protein was adsorbed to the fat globules of the HEHO milk than the HOHE milk; the former had a higher proportion of αS-casein and β-casein and a lower proportion of κ-casein and denatured whey proteins at the interface, indicating a different interaction mechanism. Gelation pH and gelation time were similar for acidified HEHO and HOHE samples and correlated to the denaturation of whey proteins. The final G’ and yield stresses were lower for the HEHO than the HOHE milk. The differences in gelation behaviour were related to the compositions and interactions of the proteins adsorbed to the fat globules.

Grazing rotation length is one of the most important tools that dairy farmers possess to control pre-grazing herbage mass (HM), pasture characteristics and utilization. An experiment was carried out in the INIA Remehue dairy farm during summer, from 29 December, 2014, to 28 March, 2015, in which two grazing rotation lengths (GRL): 30 vs. 45 days were compared. The experiment was carried out with 48 Holstein Friesian cows in mid lactation (130 days in milk), which were producing an average of 25.9 kg/d of milk with concentrations of 33.6 and 33.2 g/kg of milkfat and protein, respectively. Body condition score was 2.9 and body weight was 521 kg. At the beginning of the experiment, herbage allowance was fixed at 22 kg DM/d > 3 cm. Due to dry conditions and reduced pasture growth during summer, herbage allowance was then reduced to 18 kg DM/d, and supplementation was included: 4.4 kg DM/d of concentrate (from 28 January) and 4.6 kg DM/d of herbage silage (from 1 March). Pre-grazing HM above 3 cm was lower with 30 than 45 days GRL (2077 vs. 2656 kg DM/ha). On average, pre-grazing platemeter sward height was 8.4 cm and was not affected by treatments. Due to dry conditions, herbage presented low quality with high NDF content and low digestibility (565 g/kg and 0.69 (in vitro), respectively). Post-grazing herbage characteristics were similar between treatments. Post-grazing platemeter sward height and herbage mass > 3 cm averaged 4.7 cm and 660 kg DM/ha, respectively. On average, milk production was 14.9 kg/day and body condition score was 2.83. Productions per ha of 4% fat corrected milk (1430 vs. 1985 kg/ha) and milk solids (106 vs. 142 kg/ha) were lower with 30 than 45 d GRL. Overall, the effect of GRL during summer was null for animal performance. This may be related to similar herbage characteristics between treatments, even if significant differences in pre-grazing HM were generated. The fact of including relatively high supplementation may also have reduced the effect of GRL. On the other hand, under these grazing conditions, a longer GRL results in greater production per ha.

The adulteration of cheeses is a problem that has increased due to the high value of butterfat. Analytical methods for identifying adulteration are costly and time-consuming. Differential scanning calorimetry (DSC) has been effective for studying the thermal properties of milk fat. The aim of this study was to determine the thermal properties of cheese with added vegetable fat, relate them to the lipid profile and couple the DSC data with cluster analysis to identify adulterated samples. Two endothermic peaks (11.1 and 47.2 °C) in cheeses were found; the first peak could be related to saturated fatty acids and the second to unsaturated fatty acids. It was possible to discriminate 100% of genuine cheeses from adulterated cheeses with a vegetable fat minimum content of 5 g/L using DSC results coupled with cluster analysis; therefore, DSC coupled with cluster analysis can be a tool to determine the authenticity of fresh cheeses.

Lipid oxidation remains a major problem faced by the dairy industry. The bio-active ingredient (oil/milkfat) can be shielded by encapsulation within a secondary material. Emulsion stability is one of the main requirements for the production of oil/fat microcapsules with low levels of free surface fat and better encapsulation efficiency. This study focused on the use of sodium caseinate (NaCas)-lactose complex; conjugated via the Maillard reaction, as encapsulating materials, and investigated the effect of pH on the stability of protein-polysaccharide oil-in-water (O/W) emulsions. Subsequently, the properties of spray dried oil microcapsules, including encapsulation efficiency, insolubility, wettability, and microstructure, were analysed. The results demonstrated that better NaCas-lactose interactions were achieved at pH 11, with enhanced adsorption of the conjugates at the oil droplet particles and subsequently better emulsifying properties and stability. Additionally, a better oil entrapment (95.2 ± 3.7%) by the cross-linked protein and lactose was achieved when the pH of NaCas-lactose mixture was adjusted to 11 as compared to a pH of 7.5 (73.1 ± 2%). The outcome showed that it was possible to achieve stable microcapsules with oil loading as high as 80%, and with similar functional properties as those with 40% oil loading.

The crystallisation and melting behaviour, fat polymorphs, microstructure and texture of anhydrous milk fat (AMF) was investigated in the presence of dissolved CO2 (0-2000ppm) under two crystallising conditions (non-isothermal versus isothermal). CO2 was found to induce higher onset crystallisation temperature during cooling from 35 to 5°C at 0.5°Cmin-1. X-ray scattering analysis showed that, in the presence of dissolved CO2, this rapid crystallisation caused the formation of unstable, α polymorph fat crystals. For milk fat crystallised under isothermal condition at 25°C for 48h, dissolved CO2 improved solid fat content, slightly depressed melting temperature and exhibited a sharper melting peak. Microstructure of AMF visualised by Polarised light microscopy of crystallised AMF showed that increasing dissolved CO2 concentration was associated with smaller crystal size and greater crystal number. The bulk properties of the fat appeared to mirror the microstructural differences, in that the texture of CO2-treated AMF was harder under isothermal condition but became softer than untreated AMF under cooling condition. The results of this study are of significance in understanding how CO2 treatment might be used to modulate the crystallisation behaviour of milkfat and thereby the structural development and physical functionality of fat-containing dairy products.

Two low-pressure columns (Bio-Beads SX-3) and three high-pressure GPC columns were compared for clean-up of a wide range of pesticides in fatty matrices of vegetable or animal origin. The GPC fractions were analyzed by GC-MS/MS and LC-MS/MS without additional clean-up. The performance of the GPC clean-up on the five column types was compared in terms of solvent consumption, lipid removal, pesticide recovery and repeatability. It was found that for fatty matrices, mainly consisting of high molecular weight triglycerides i.e. most vegetable oils and animal fats, good fractionation is obtained for the majority of the pesticides. On the other hand, for fats and oils containing relatively high amounts of low molecular weight triglycerides, i.e. butter fat and palm kernel oil, none of the columns provided sufficient clean-up and cause interferences and system contamination, especially in the case of GC-MS/MS analysis. For the latter case, best results in terms of lipid removal and pesticide recovery were obtained on a set (2×300mmlength) of narrow bore (7.5mm ID) columns packed with 5µm PL Gel material. Column loadability is, however, much lower on that set of columns compared the other evaluated GPC columns, impairing overall method sensitivity.

Phenolic compounds, including propyl gallate, 1-o-galloylglycerol, ferulic, gallic, caffeic, rosmarinic, and carnosic acids, tocopherols, and butylated hydroxytoluene (BHT), were investigated as antioxidants to improve the oxidative stability of a structured lipid (SL) produced by the enzymatic acidolysis of menhaden oil with caprylic and stearic acids. SL had similar physical properties to butterfat but was more susceptible to oxidation. The above phenolic compounds were each added to SL as antioxidants. SL with 1-o-galloylglycerol, rosmarinic acid, or BHT showed the highest oxidative stability during an accelerated oxidation test with the total oxidation (TOTOX) value around 250 after 18 days. Oxidation induction time (OIT) using differential scanning calorimetry showed a good correlation with the accelerated oxidation test. A mixture of 1-o-galloylglycerol and tocopherols at 50:50 ppm had the strongest protective effect on SL (OIT = 115.1 min) compared to the other tested compounds or combinations at the same concentration (OIT 100 min).

Butters are considered as “natural products” by many consumers, once they are obtained from milkfat without adding of any additive, except sodium chloride, starter cultures and natural dyes. The main goals of this study were to extend the scope of a previously developed method, including a new analyte (benzoic acid) and new matrices (butter and margarine), and thus evaluate the content of preservatives in national and imported butters traded in Brazil. Samples (n = 51) from inspected establishments in Argentina (n = 2), Brazil (n = 40), France (n = 7) and Uruguay (n = 2) were assessed by liquid chromatography-tandem mass spectrometry. Two screening inspection rounds were carried out between November, 2015 and January, 2016. Non-compliance rates were 36.4% in 2015 and 22.2% in 2016 for Brazilian butters. It was shown that preservatives are irregularly added to butters by many factories, contrary to regulation, and without proper declaration on labeling. The limits of quantitation (LOQ) were set to 25.00 mg kg−1 (benzoic acid), 1.25 mg kg−1 (natamycin), 3.13 mg kg−1 (nisin) and 2.50 mg kg−1 (sorbic acid). Except nisin, any of the researched preservatives was detected in a total of 12 samples, in concentrations that ranged from

The blend of fish oil with a high percentage of long chain poly-unsaturated fatty acids, and milkfat with a high percentage of saturated fatty acids, could potentially demonstrate desirable characteristics from both components, such as increased omega-3 fatty acids and melting point, as well as improved crystallization and oxidative stability. In this study, the effect of various milkfat concentrations on thermal properties and crystalline structure of these blends were analysed to understand parameters determining the overall characteristics of the blend. Blends with different ratios of fish oil: milkfat (9:1, 7:3, 5:5, 3:7, 1:9), as well as pure fish oil and pure milkfat, were investigated at different cooling conditions. The crystallization behaviour in all samples shifted to lower temperature ranges, by increasing the cooling rate from 1 to 32 °C/min. However, the changes in cooling rate did not have significant effect on the melting profile of the samples. Whereas changes in milkfat ratio affect both the crystallization and melting behaviour. New crystallization peaks were observed on DSC spectra between the range of −4 to −13 °C in the blends. Moreover, new melting peaks appeared in two ranges of −1 to −8 °C and 8–9 °C, in the blends. The crystallization and melting behaviour of the blends were similar to those of milkfat when >30% milkfat was used. This was further confirmed via XRD where milkfat demonstrated the dominant polymorphic behaviour. Regarding shape of the crystals, fractal dimension analysis showed a similarity between clusters in blends containing 50% milkfat or higher. Increasing the ratio of milkfat led to an increase in fractal dimension which indicates higher mass-spatial distribution of the crystal networks in the blends. The data showed that adding 30% or more milkfat to pure fish oil resulted in blends demonstrating similar characteristics to milkfat, including thermal, structural, and oxidative stability. This shows the potential of blending a high percentage of docosahexaenoic acid in milk fat to improve their overall stability.

Background Absolute dietary fat intake but even more so fatty acid pattern is discussed to be critical in the development of non-alcoholic fatty liver disease (NAFLD). Here, we determined if switching a butterfat enriched diet to a rapeseed oil (RO) enriched diet affects progression of an existing NAFLD and glucose intolerance in mice. Methods For eight weeks, female C57Bl/6J mice were either fed a liquid control (C) or a butterfat-, fructose- and cholesterol-rich diet (BFC, 25E% butterfat) to induce early signs of steatohepatitis and glucose intolerance in mice. For additional five weeks mice received either BFC or C or a fat-, fructose- and cholesterol-rich and control diet, in which butterfat was replaced with RO (ROFC and CRO). Markers of glucose metabolism, liver damage and intestinal barrier were assessed. Results Exchanging butterfat with RO attenuated the progression of BFC diet-induced NAFLD and glucose intolerance. Beneficial effects of RO were associated with lower portal endotoxin levels and an attenuation of the induction of the toll-like receptor-4-dependent signaling cascades in liver. Peroxisome proliferator-activated receptor γ activity was induced in small intestine of ROFC-fed mice. Conclusion Taken together, exchanging butterfat with RO attenuated the progression of diet-induced steatohepatitis and glucose intolerance in mice.

Cheese ripening is often associated with lipolysis of milkfat, an essential element of the development of cheese aroma. Because of the asymmetric molecular structure of milkfat, the partial breakdown of triacylglycerols (TAGs) to free fatty acids (FFAs) leads to noticeable changes in the composition of TAGs and fatty acids (FAs) that were bound to TAGs. Methods for authenticating milkfat purity are primarily based on the genuineness of FA or TAG composition. To investigate the impact of cheese ripening on foreign fat detection, 29 samples of differently ripened cheeses available on the German market were examined. The highest lipolysis occurred in mould-ripened and long-ripened cheeses, which often impaired authentication using butyric acid (C4). Authentication using TAG equations was less susceptible to increased fat acidity, but still had the potential to yield false positives. Strong correlations were found between the contents of FFAs, C4 and the analysed TAG C24 comprising certain diacylglycerols.

The experiment was carried out to determine effects of different fatty acids (FA) mixtures on milk FA composition and milk fat oxidation change. Thirty-six dairy cows were used in a completed design experiment for 8 weeks. Cows were fed one of three lipid supplements (1) short- and medium-chain fatty acids (SMCFA), (2) butterfat, and (3) long-chain fatty acids (LCFA). Data were analyzed using MIXED procedure of SAS. Daily dry matter intake (DMI), milk yield, and milk protein, total solids (TS), lactose, free fatty acids (FFA) content were unaffected among 3 treatments, whereas milk fat concentration was decreased (P

The current concern for cocoa butter fat as major ingredients of chocolate intake in the World has raised the question of the high price of cocoa butter among all other vegetable fats. Productions of natural cocoa butter fats are decreasing day by day due to the decrease of cocoa cultivation worldwide; moreover, cocoa fruit contains only a little amount of cocoa butter. Therefore, the food industries are keen to find the alternatives to cocoa butter fat and this issue has been contemplated among food manufacturers. This review offers an update of scientific research conducted in relation to the alternative fats of cocoa butter from natural sources. The findings highlights how these cocoa butter alternatives are being produced either by blending, modifying the natural oils or fats from palm oil, palm kernel oil, mango seed kernel fats, kokum butter fat, sal fat, shea butter, and illipe fat.

Postprandial lipemia, low-grade systemic inflammation, and endothelial activity are related to metabolic disorders. It is well known that dietary fatty acid composition modulates postprandial lipemia, but information on the other metabolic risk markers is limited. We therefore studied the acute effects of a meal rich in SFA compared with those of a meal rich in (n-6) PUFA on postprandial responses in overweight men who are at an increased risk to develop the metabolic syndrome and its comorbidities. In a crossover design, the effects of 50 g butter (rich in SFA) on lipemia and markers for inflammation and endothelial activity were compared with those of 50 g sunflower oil [rich in (n-6) PUFA] during an 8-h postprandial mixed meal tolerance test in 13 overweight men. Postprandial changes in serum TG were comparable between the meals (P = 0.38), except for a reduction in the incremental area under the curve (P = 0.046) in the late postprandial phase after (n-6) PUFA (125 +/- 96 mmol.min.L(-1)) compared with SFA (148 +/- 98 mmol.min.L(-1)). Compared with the SFA meal, the (n-6) PUFA meal decreased plasma IL-6 (P = 0.003), TNFalpha (P = 0.005), soluble TNF receptors I and II (sTNFr; P = 0.024 and P < 0.001, respectively), and soluble vascular cell adhesion molecule-1 (sVCAM-1; P = 0.030) concentrations. These results indicate that exchanging SFA from butterfat for (n-6) PUFA in a mixed meal may decrease postprandial lipemia and concentrations of IL-6, TNFalpha, sTNFr-I and -II, and sVCAM-1 in overweight men.

Milkfat–soybean oil blends were enzymatically interesterified (EIE) by Aspergillus niger lipase immobilized on SiO2–PVA hybrid composite in a solvent free system. An experimental mixture design was used to study the effects of binary blends of milkfat–soybean oil (MF:SBO) at different proportions (0:100; 25:75; 33:67; 50:50; 67:33; 75:25; 100:0) on the compositional and textural properties of the EIE products, considering, as response variables, the interesterification yield (IY), consistency and hardness. Lipase-catalysed interesterification reactions increased the relative proportion of TAGs’ C46–C52 and decreased the TAGs’ C40–C42 and C54 concentrations. The highest IY was attained (10.8%) for EIE blend of MF:SBO 67:33 resulting in a more spreadable material at refrigerator temperature in comparison with butter, milkfat or non-interesterified (NIE) blend. In this case, consistency and hardness values were at least 32% lower than values measured for butter. Thus, using A. niger lipase immobilized on SiO2–PVA improves the textural properties of milkfat and has potential for development of a product incorporating unsaturated and essential fatty acids from soybean oil.

Novel functional chocolate spreads were formulated by replacing butter fat in conventional chocolate spread by red palm olein at 20%, 40%, 60%, 80% and 100% levels. Sensory evaluation revealed that chocolate spread made from 20% red palm olein (RPOL) and 80% butter fat was accepted as the conventional chocolate spread (100% butter fat). Hence, the former two chocolate spreads were selected for further study. Samples were stored at room temperature and fridge for 6 months and monitored for their physical properties, fat stability, fatty acid composition and natural antioxidants. The data revealed that the replacement of butter fat in functional chocolate spread led to a significant increment in tocopherols and tocotrienols (3.7 folds) and carotenes (19.8 folds), as compared to the control. The functional chocolate spreads could be stored at room temperature for 6 months without any deteriorative effects on their quality.

Gangliosides are thought to play a role in modifying the intestinal microflora and promoting neural development in the neonate. Milk is a good source of gangliosides, which are localised in the milkfat globule membrane. Robust quantitative analysis is required to underpin any claims made on ganglioside content in milk products. We have modified and validated our previously published method to quantify the amounts of the two predominant gangliosides classes, GD 3 and GM 3 , in a range of bovine dairy products. After extraction and separation using hydrophilic high-performance liquid chromatography, an LTQ-Orbitrap™ mass spectrometer was used to extract and sum the major species of GD 3 and GM 3 , generating fully resolved extracted ion current peaks for both standards and samples. The method had good repeatability (coefficient of variation 2–8%) and its results compared favourably with thin layer chromatography, a method that has been used extensively in the literature for the quantification of gangliosides in various sample matrices.

There is a continual need for development of rapid methods that meet or exceed the detection levels of currently available analytical methods for authentication of food products. The objective of this study was to evaluate temperature-controlled attenuated total reflectance-mid-infrared (ATR-MIR) spectroscopy combined with multivariate analysis as a simple and rapid method for the determination of butter adulteration as a dairy food system. Commercial samples of butter fat were adulterated with margarine fat at levels ranging from 0% to 100% (v/v). Partial least square regression (PLSR) models gave standard error of cross-validation (SECV) of r ) > 0.99. Excellent predicting capabilities were obtained using an external validation set consisting of butter adulterated with margarines at ratios of 2.5%, 13%, and 45%. We have demonstrated the feasibility of a temperature-controlled ATR-MIR spectroscopy technique that would allow for rapid analysis of dairy products.

Milkfat (MF)/soybean oil (SBO) blends ranging from 50% to 100% of milkfat (w/w) were enzymatically interesterified with a sn-1,3 specific lipase from Rhizopus oryzae immobilized on polysiloxane-polyvinyl alcohol matrix, in a solvent free medium. Interesterification progress was monitored by following the changes in the relative proportions of 50-carbon triacylglycerols (TAGs) to 44-carbon TAGs (50/44 ratio) in the reaction. The starting materials and products were also analyzed in terms of consistency measured in a texturometer. All reactions gave interesterified (IE) products with lower consistency than non-interesterified (NIE) MF:SBO blends and interesterification degree varied from 0.54 to 2.60 in 48 h reaction. The highest interesterification degree was achieved for 65:35 MF:SBO blends, which gave 76% reduction in the consistency. These results showed the potential of the immobilized lipase to change the TAGs profile of the MF:SBO blend allowing to obtain cold-spreadable milkfat.

Lipase-catalysed interesterification was performed to produce low- trans spreadable fat (LTSF) with anhydrous butterfat (ABF), flaxseed oil (FSO), and palm stearin (PS) using biocatalysts (Lipozyme RM IM and Novozym SP435). The reaction was carried out for 24 h at 60 °C in a shaking water bath (180 rpm). Seven substrate blends for the production of LTSF were prepared: 12:6:2, 10:6:4, 9:6:6, 8:6:6, 6:6:8, 6:6:9, and 4:6:10 (ABF/PS/FSO, by weight). After 24-h interesterification, decreased saturated fatty acid (SFA) contents in LTSFs were observed with ranges from 67% to 41%. LTSFs exhibited low atherogenic index (AI) with ranges from 2.8 to 0.8, compared with 3.3–4.7 AI of butter fat. Equivalent carbon number (ECN) 42–46 in the newly produced triacylglycerol (TAG) increased according to rearrangement of FAs on TAG backbone. The α-linolenic acid contents (mol%) of each LTSF were 5.6% (12:6:2), 10.7% (10:6:4), 15.1% (9:6:6), 15.8% (8:6:6), 20.8% (6:6:8), 22.4% (6:6:9) and 26% (4:6:10). The trans fatty acids in the LTSFs was not more than 2%. Melting point ranges of LTSF were from 37 (9:6:6) to 32 °C (4:6:10).

A new human milk fat substitute (HMFS) was produced from butterfat. A 2-week’s feeding experiment was performed using three groups of rats with 10 wt.% fat in their feed; the fat was either (1) butterfat-based HMFS + long-chain polyunsaturated fatty acids (LCPUFA), (2) the reference oil + LCPUFA, or (3) the reference oil without LCPUFA. The apparent fat absorption after intake of butterfat-based HMFS (95.9% ± 1.8%) was significantly higher than the other two groups, indicating that much less calcium soap was formed after feeding butterfat-based HMFS. Calcium contents in urines and faeces from the two groups fed LCPUFA in their diet were lower than those without supplementation of LCPUFA, suggesting that LCPUFA could improve calcium absorption by reducing the calcium excretion. It can thus be concluded that the butterfat-based HMFS improves fat absorption, and supplementation of LCPUFA in the formula improves calcium absorption.

This study determined the sensory characteristics of ultrapasteurized (UP) lactose-free milk of different fat contents, and compared them with regular milk. Nine milk samples (six UP lactose-free and three regular) containing 0, 2 or 3 g milkfat/100 mL were tested by a descriptive panel. A consumer test with three UP lactose-free milk and three regular samples was also conducted. The skim milks were found to be lacking in freshness and the dairy notes were lower compared to the higher-fat-content milks. The UP lactose-free milks were different from the regular milk because of higher intensities of cooked, processed, and sweet attributes. UP lactose-free milks tended to score higher than the regular milks at the same fat content for dairy-related attributes, but this difference was not significant for the reduced-fat milks. Although majority of the consumers in the present study were aware that UP lactose-free milks existed in the market, only few had tasted them before. The higher intensities of cooked and sweet flavor attributes in the UP lactose-free milks might be a hindrance to their consumption by the lactose-intolerant population. More efforts are needed from the dairy industry to develop better lactose-free products and to educate consumers about lactose-free dairy products.

Ethnopharmacological relevance The experimental finding of Asian traditional medicine revealed the pharmacological effect of the local application of ghee which was taken from cow butterfat and the rhizomes of Curcuma longa. These materials significantly improved the healing process of the wound. In addition, ancient physicians of Middle East discovered that the powdered rhizomes of Curcuma longa (common turmeric) also had impressive medicinal qualities. Over the centuries, this spice has been used as a pain relieving, anti-inflammatory agent to relieve pain and inflammation in the skin and muscles. Aim of the study We decided to mix ghee which was taken from sheep butterfat with the powdered rhizomes of Curcuma longa to formulate a novel cost-benefit material and then, evaluate its potential therapeutic effect on acceleration of surgical wound healing; moreover, this present study was performed to compare the effects of Curcuma longa–ghee formulation and hyaluronic acid on gingival wound healing following surgery. Materials and methods Five healthy 3-year-old male beagle dogs were used in this study. They had intact teeth and the clinical and radiographic examination revealed no periodontal disease. Ghee was obtained from the refined sheep butterfat heated to 70 °C mixed with the powdered rhizomes of Curcuma longa and was applied with two different ratios including materials A and B. Randomly, these three materials including hyaluronic acid, materials A and B were applied topically in test regions and then covered with periodontal pack. Histological changes were monitored in days 4 and 7 after operation to evaluate the inflammatory and repair stage of healing process. Results We observed significant difference in the inflammatory and repair parameters of the healing process between cases treated with this new formulation and cases of hyaluronic acid application. Conclusion The results suggested a positive potential therapeutic effect on surgical wound healing particularly improvement of periodontal treatment consequences after surgery.

Ultrasound combined with heat treatment has yielded favorable results in the inactivation of microorganisms; however, the composition of food influences the rate of microbial inactivation. The objective of this research was to study the effect of butter fat content in milk on the inactivation of Listeria innocua and compositional parameters after thermo-sonication. Four butter fat contents in milk were evaluated at 63 °C for 30 min of sonication (Hielscher® UP400S, 400 W, 24 kHz, 120 μm amplitude). Results showed that inactivation of Listeria cells occurs first in fat free milk, and that the rate of inactivation decreases with increasing fat content. No degradation of protein content or color variation was observed after the treatments. The pH dropped to 6.22, and lactic acid content showed an increase of 0.015% after the treatment; solids-non-fat, density and freezing point decreased. During storage life, growth of mesophiles was retarded with sonication. Industrial relevance Ultrasound is an emerging technology that has shown positive effects in milk processing. Listeria monocytogenes represent one of the main foodborne pathogenic microorganisms in the food industry. Results of this research show that thermo-sonication is a viable technology capable of inactivating Listeria cells in milk and extending shelf-life without significant nutritional or physicochemical changes.

An animal experiment was undertaken to examine the effects of Gouda-type cheese produced using Lactobacillus helveticus on some biological markers of the metabolic syndrome. The study revealed a significantly lower weight of the mesenteric adipose tissue in cheese-fed rats on a 20% fat diet compared with rats fed a similar high fat diet containing casein and butterfat. The amount of cholesterol in very low-density lipoprotein and the serum level of low-density lipoprotein were lower in the rats receiving the cheese diet, for all molecular categories of lipoproteins. While the serum adiponectin concentrations were significantly lower in the control group, there were no significant changes in the cheese diet group during the experimental period. Thus, the results of this study suggest that cheese consumption might have a beneficial suppressive effect on abdominal adipose accumulation and prevent the development of metabolic syndrome.

The effect of the addition of the total proteose-peptone (TPP) fraction on some physico-chemical properties of recombined cream was studied. Oil-in-water emulsions, 30% or 20% (w/w) fat, were prepared using only the dairy components buttermilk, milkfat and TPP. The effect of different concentrations of TPP on droplet size, creaming stability, flow behaviour, viscosity and whippability of recombined creams was tested. Of the different creams, those containing 2% (w/w) or more TPP were more viscous, showed different flow behaviour, and had improved stability and whippability compared with the other creams. The modifications in physico-chemical properties appeared to be driven by changes in particle size distribution caused by droplet aggregation. The percentage of fat also influenced the properties of the final product. It may therefore be possible to obtain desirable modifications in recombined cream using only dairy ingredients.

Over the past few decades, consumption of butter has declined due to its high content of saturated fatty acids and cholesterol. Opposingly, phytosterol esters (PE) have been used as a food ingredient for their effectiveness in lowering plasma cholesterol levels. The objective of this work was to evaluate the effects of the addition of PE on the physical and chemical properties of milkfat (MF). The fatty acid and sterol compositions were determined by gas chromatography (GC). A constant speed texture analyser was used to evaluate consistency. Solid fat content (SFC) was determined by nuclear magnetic resonance (NMR) and crystal structure was observed with polarized light microscopy. Results showed that β-sitosterol (33.5%), campesterol (23.6%), and stigmasterol (14.9%) were the most abundant sterols in the PE blend. Blends containing MF and PE presented a softer consistency than pure MF at low temperatures. Despite the higher SFC, PE caused a decrease in the SFC of MF. The images of MF, PE, and their blends obtained by polarized light microscopy showed the influence of temperature on crystal size and number. This method revealed the particular crystalline structure of PE, formed by a solid, dense crystal network, with amorphous crystals of varied sizes, different from crystal structures generally observed in fats. The high SFC and low consistency of PE may indicate a weak crystal network, probably due to the presence of different molecular structures.

In order to obtain a rapid method that can detect adulteration of butter fats with cheaper vegetable fats, the use of NIR spectroscopy and multivariate modelling was explored. For model building and validation, an extensive set of samples was collected, consisting of 152 butter samples, 42 oils and 200 blends thereof. Variations in butter fat composition are reflected in distinct NIR spectral regions. Principal components analysis and partial least square discriminant analysis was used to inspect the variation within the sample set. As reference values for training partial least squares models, butter fat levels as declared by suppliers were taken, as well as C4:0 fatty acid levels as measured directly by GC. All samples were used for training, except for 100 blends, which were used later for validation. Different pre-processing and PLS approaches were explored, resulting in models that had a RMSEPs for butter fat and C4:0 fatty acid level in the range of 4.3–8.2 and 0.33–0.38%(w/w), respectively. The performance of NIR in assessment of C4:0 fatty acid levels is lower as for GC, but this disadvantage is outweighed by shorter measurement times and the lower skill levels required. Furthermore NIR is able to assess overall levels of butter fat, in addition to the indirect indicator provided by the C4:0 fatty acid level.

Relationships between genetic merit for milk production and animal parameters and various parameters of reproductive performance were examined using multilevel binary response analysis in a study of 19 dairy herds for three successive years, representing approximately 2500 cows per year. The proportion of cows intended for rebreeding that were back in-calf again within 100 days of calving (ICR-100) and the proportion of cows that reappeared again with 365 (RR-365) and 400 days (RR-400) of a previous calving were considered in addition to the traditional measures of reproductive performance. Each 100-kg increase in genetic merit for milk yield was associated with an increased interval to first service (IFS) and calving index (CI) of 1.4 ( P

A quantitative electron impact GC-MS method using molar correction factors (MCFs) for [M-RCOO]+ ions has been developed for determination of molecular species of triacylglycerols (TAGs). MCFs were determined by linear calibration for 226 ions of 104 TAG species with good reproducibility: on the average, coefficient of determination was 0.975 +/- 0.043 and 0.963 +/- 0.115 for saturated and unsaturated TAGs, respectively. The MCFs of the sn-1(3) regioisomers of short-chain TAGs were lower than those of sn-2 isomers indicating ca. 2-3-fold higher cleavage of butyroyl and caproyl groups from the primary positions than from the secondary position. The method enabled quantification of 139 and 135 individual TAG species of butterfat (BF) and interesterified butterfat, respectively, including several regioisomers of short-chain TAGs. The most abundant molecular species of the even-numbered TAGs in BF were butyroylpalmitoyloleoylglycerol (5.05 mol%), butyroyldipalmitoylglycerol (4.75 mol%), and palmitoyldioleoylglycerol (3.32 mol%). The method provides an alternative for elucidation of nutritional and technological properties of relatively saturated TAG mixtures.

Detection of foreign fat in milk fat can be performed by analyzing triacylglycerols (TAGs) by gas–liquid chromatography (GLC) using the standardized methodology. The standard methodology recommends the use of a packed column, which allows the separation of milk TAGs according to their chain length (total carbon number). This procedure is not widely applied because these columns are not commercially available. This study describes a fast methodology by using a short apolar open-tubular capillary column. The developed experimental conditions can be used to obtain the chromatographic resolution required in the standardized procedure, and the separation of milk fat TAGs (C24 to C54) is achieved in less than 4 min. As indicated by the standardized method, the quantification was performed by calibration using the certified reference material CRM-519 butterfat as standard substance. The methodology was fully validated and relative repeatability values were compared with the values provided in the standardized procedure. The developed method was applied to detect adulteration of milk fat with partially hydrogenated vegetable oils (PHVOs). PHVOs contain variable amount of trans-18:1 acids and two different PHVOs having different trans-18:1 acid levels (13 and 38%) were added to milk fat at levels ranging from 5 to 30%. The obtained mixtures were analyzed by GLC and formulas established by the European Union were applied. Calculated S values indicated that PHVOs in milk fat could be analyzed at these levels. Approximate amounts of PHVOs added to the composite samples could be calculated using the standardized formula. The impact of adulteration of milk fat with PHVOs, which contains an important amount of trans-9 and trans-10 18:1 acid isomers, was investigated as a complementary analytical criteria. We showed in composite samples, that the trans-18:1 acid isomeric distributions are distinct when referenced to the original milk fat profile and that trans-9 18:1 acid isomer is a good indicator of the occurrence of PHVOs in milk fat. Our results showed clearly that a short apolar capillary column can be used instead of a packed-column and that the mathematical model developed for the detection of foreign fat was suitable to detect adulteration of milk fat with PHVOs.

The aim was to develop a simple and rapid method for determination of fat and protein content in milk. Based on the laser light scattering theory, the ratio of the scattered light (at 90±0.05° scattering angles) intensity to the transmitted light intensity, which is called scattered–transmitted-ratio method, is adopted as the optical parameter representing the milk fat content and the protein content. In this way, the influence of the fluctuation of the power of the light source is eliminated and the accuracy of determination is improved accordingly. The system we use is real-time and can satisfy the challenging requirements of dairy farming. Results of this study indicate the feasibility of using this technology for fresh milk fat and protein analysis. The fat contents and protein contents of 50 milk samples determined by this method were consistent with the values obtained by the reference methods based on Rose-Gottlieb method and Kjeldahl determination of N method. In this paper, the operating principle of the instrument is introduced and the influence of the environmental conditions, such as the homogenization pressure and homogenization temperature, etc. on the result of the test is analyzed. Through data analysis, the concrete schemes for testing the fat using the curve fitting and testing the protein using the surface fitting technique are determined. Finally, the difference from the reference values of the test is discussed.

Bovine milk contains a lipoprotein lipase that accounts for most, if not all, of its lipolytic activity. The total lipase activity in raw milk is sufficient to cause rapid hydrolysis of a large proportion of the fat. However, in reality this does not happen, because the lipase is prevented from accessing the fat by the milkfat globule membrane. Physical damage to this membrane in raw milk initiates lipolysis. Furthermore, simply cooling certain individual milks soon after secretion can initiate the so-called spontaneous lipolysis. The biochemical basis of spontaneous lipolysis is still poorly understood, but it appears to be related to a balance between activating and inhibiting factors in the milk. Lipolysis in milk and milk products causes rancid off-flavours and other problems, and is a constant concern in the dairy industry. A thorough understanding of the mechanism of lipolysis and constant vigilance by operatives is required to minimize lipase-related problems.

This contribution reviews the global importance of goat farming in subsistence-based, market-based and high-input production systems and discusses performance recording and performance testing of meat and dairy goats with special reference to the South African environment. Environmental effects, genetic parameters and breeding strategies are considered. Marked progress has been made with performance testing and recording of meat and dairy goats in South Africa, but there is still ample scope for further improvements in the national improvement programmes.

Milk composition varies between herds and cows within herds, enabling its segregation on farm, rather than during processing, for the manufacture of specific dairy products. Benefits may include increased product yields, reduced processing costs and greater suitability of differentiated milk for the production of high value niche market products. However, costs are also likely to be greater. An integrated spreadsheet model was developed to determine the break-even premium required for a farmer with a seasonal calving herd to be economically no worse off producing segregated than conventional milk. The model incorporated breeding (quantitative and qualitative traits), cow requirements and feeding, transport, and economic sub-models. Cows were segregated within herd and milk composition was altered over time by genetic selection. Four quantitative trait (“white” milk colour) scenarios and two qualitative trait (BB β-lactoglobulin milk) scenarios were considered. The model suggested that “white” milkfat would need to earn 38.4% more at the farm gate than conventional milkfat for the two systems to break even. “White” milk cows produced less than their status quo counterparts due to the reduced selection pressure on production milk traits and this had a considerable impact on the premium, as did the low initial volumes of white milkfat. The difference in production between the B β-lactoglobulin cows and their status quo counterparts was less than for selection on white milkfat only. The high risk to farmers of discontinuing a differentiated milk policy could be moderated by changing the structure of premium payments over time. Hence, processing companies and farmers will need to work together to facilitate the uptake of milk segregation. This research model could be applied by dairy companies and farmers considering milk segregation policies.

Temperature dependent vapor pressures of the methyl esters of fourteen fatty acids that are commonly present in biodiesel fuels were predicted by the Antoine equation and a group contribution method. The predicted boiling points of these esters up to a pressure of 100 mmHg were within ±1.0% of reported data for these two methods. Normal boiling points were determined from both the predicted vapor pressure and a correlation equation and the prediction errors were less than 5 K comparing to available published data. The vapor pressure and normal boiling points of 19 real-world biodiesel fuels were predicted and compared with reported data where available. The prediction errors of normal boiling points were less than 1.0%, and the predicted vapor pressures were also observed to closely match the reported data among the methyl esters of soybean oil, rapeseed oil and tallow. The predicted results showed that, except for coconut and butterfat, most of the methyl esters of the vegetable oils and animal fats had a normal boiling point in the range of 620–630 K. A sensitivity analysis indicated that the variation of fatty acid composition and the uncertainty of the normal boiling point of C18:2 were the main factors that affected the predicted normal boiling points of the biodiesel fuels.

The effect of fat on the antibotulinal activity of 11 food preservatives, 12 free fatty acids, and nine lots of enzyme-modified cheese (EMC) was evaluated in a media system. Anhydrous milkfat or soybean oil was added to tubes of Trypticase–peptone–glucose–yeast extract medium (TPGY) supplemented with the additives (final pH adjusted to 5.9). Treatments were inoculated with 3-log10 proteolytic Clostridium botulinum spores/ml (10-strain mixture of serotypes A and B) and incubated anaerobically at 30°C for up to 14 days. For the preservative and fatty acids studies, growth of C. botulinum was determined by measuring optical changes at OD640 nm. Botulinal toxin production was determined in EMC-treatments using the mouse bioassay. Data revealed that the antibotulinal effects of nisin, and free fatty acids caprylic, capric, lauric, myristic, oleic, and linoleic acids were each significantly reduced in treatments supplemented with 20% fat (P

Milk harvesting and subsequent milk handling and treatment effect changes to the milkfat globule membrane (MFGM) and the fat globule as a whole. These phenomena are generally termed “MFG(M) damage”. Various measurement techniques have been reported in the literature to measure MFG(M) damage. These are reviewed and evaluated for their potential use in future research on the causes and prevention of damage during commercial milk handling.

Changes in the composition and structure of the milkfat globule membrane of bovine fat globules post secretion by the mammary secretory cell are reviewed. These changes occur while the milk is still within the mammary gland and also during and after milk harvesting. The effects of a selected number of factors (gas bubbles, agitation, temperature, ageing, bacteriological quality, mastitis, stage of lactation and season) on the stability of the fat globules are considered. Areas for future research are highlighted.

Gamma-irradiating barley grains with doses of 10–100 kGy, a dose dependent isomerization of the naturally occurring cis -unsaturated fatty acids such as oleic, cis -vaccenic, linoleic and also of linolenic acid was found. Whereas the effect was negligible up to 10 kGy, at 50 kGy the trans -fatty acid level became comparable to that of other natural products like butter fat which means that there is no essential nutrition danger. The cis–trans- isomerization found in barley grains is explained mainly by a thiyl radical driven process rather than direct isomerization.

Blending and chemical interesterification of fats have been used to modify physical and chemical properties of natural fats. The objective of this study was to produce binary mixtures of butterfat and corn oil that serve as a base for a tablespread, keeping the desirable organoleptic qualities of butter, yet with higher contents of ω-6 fatty acids. Chemical interesterification was performed to improve butter’s physical properties, such as better spreadability. Liquefied butterfat and corn oil were mixed in different proportions and then chemically interesterified. Butterfat consisted of 66.5% saturated fatty acids, with palmitic acid being predominant. Corn oil had more than 50% of linoleic acid in its composition. Interesterification significantly reduced trisaturated and triunsaturated triacylglycerol contents and increased softening points in all blends. The negative coefficients of the blends from multiple regression of the solid fat content revealed a monotectic interaction between butterfat and corn oil in temperatures ranging from 10 to 35 °C, before and after interesterification.

The purpose of the study was to measure platelet aggregation and fatty acid composition for pigs fed diets containing different fats/oils, and to compare platelet aggregation with empirical indices calculated from the fatty acid compositions of the diets and platelet phospholipids, and the index of thrombogenicity of Ulbricht and Southgate [1]. Four groups of 16 pigs were fed for 70 days on diets containing one of three test fats/oils; anhydrous milkfat (AMF), fish oil (MaxEPA TM ) or hydrogenated coconut oil (HCO) at a level of 100 g/kg, or a basal diet containing starch at the expense of the test fat/oil. Blood samples were collected from each pig at 56 and 70 days. ADP- and collagen-induced platelet aggregation were measured by the turbidometric method at 56 days, intra-platelet cGMP response to sodium nitroprusside activator was measured by radioimmunoassay at 56 days, and the fatty acid composition of platelet phospholipids was measured at 70 days. There was a significant effect of diet on collagen-induced platelet aggregation (%) (AMF 76.0, MaxEPA 70.8, HCO 81.3, basal 86.8) which was lower in the MaxEPA group compared to the hydrogenated coconut oil and basal groups, and on the proportions (% total fatty acids) of the major monounsaturated (18:1 n -9, AMF 16.6, MaxEPA 13.1, HCO 14.6, basal 15.9; 18:1 n -7, AMF 0.9, MaxEPA 3.3, HCO 1.1, basal 1.2) and polyunsaturated (18:2 n -6, AMF 7.6, MaxEPA 7.4, HCO 8.7, basal 7.6; 20:4 n -6, AMF 13.3, MaxEPA 4.8, HCO 16.2, basal 15.6; 20:5 n -3, AMF 0.9, MaxEPA 10.3) fatty acids in platelet phospholipids. There were no significant effects of diet on ADP-induced platelet aggregation or platelet cGMP. The relative pattern of platelet aggregation across dietary treatments was consistent with empirical indices based on the ratios of the n -6/ n -3 fatty acids in the diets and platelet phospholipids, but did not match the pattern based on the index of thrombogenicity [1]. The data suggest that useful factors for predicting platelet aggregation are the proportions of the fatty acids 18:2 n -6 + 20:4 n -6 / 18:3 n -3 + 20:5 n -3 + 22:6 n -3 in the diets and platelet phospholipids.

Economic values in Irish pounds (IR£) were calculated for milk, fat and protein yields (IR£ cow−1 year−1 kg−1), survival (IR£ cow−1 year−1 % survival−1), and calving interval (IR£ cow−1 year−1 day−1) using a farm model for pasture-based systems in Ireland. Economic values for yield were calculated by changing one of these traits whilst keeping the other traits at the default level, i.e. the economic value for calving interval does not include the costs of higher culling due to a longer calving interval. Herd parameters (e.g. number of milking cows, replacements, youngstock and calving pattern), milk production, energy requirements, feeding ration, land use and labour requirements were re-adjusted to calculate economic performance. Three scenarios were simulated as follows: (S1) milk and fat% quota with a fixed number of cows per farm and quota leasing; (S2) non-quota scenario with a fixed number of cows per farm; and (S3) milk and fat% quota with a fixed output per farm. Sensitivity analysis showed that, with high quota costs and/or lower fat prices, the weighting of fat yield was close to becoming negative in the quota leasing scenario (S1). There was major re-rankings among the top 1000 bulls due to a negative weighting on fat. The results for S1 suggested that the economic values in profit per cow per year are −IR£0.06 per kg milk, IR£0.68 per kg butterfat, IR£4.49 per kg protein, IR£8.98 per % survival, and −IR£1.63 per day calving interval, and the corresponding values in additive genetic standard deviation units were −0.47, 0.19, 1.00, 0.56 and −0.21, respectively.

Studies on the kinetic characteristics of calf pregastric lipase (EC 3.1.1.3) have shown that it preferentially releases short chain fatty acids (SCFAs) from bovine milkfat. The released fatty acids form mixed micelle structures. The aim of this investigation has been to test whether hydrolysed milkfat is antimicrobial, and how the state of the emulsion alters the bactericidal or bacteriostatic effects. Partial hydrolysis of milkfat by pregastric lipase was carried out in two types of emulsion systems, containing either Triton X-100 or casein/lecithin, plus milkfat in citrate/phosphate buffer (pH 5.0-6.0). The concentrations and compositions of fatty acids were determined by gas chromatography. The minimum percentages of hydrolysed milkfat which affected growth and survival of selected Gram-positive and Gram-negative bacteria were measured. The bacterial experiments were repeated using pure fatty acids at similar concentrations. Lauric acid (C12:0) was found to be the most potent bactericidal fatty acid against Enterococcae (Gram-positive), and caprylic acid (C8:0) was the most potent against coliforms (Gram-negative). Use of Triton X-100 for milkfat emulsification provided a more compatible medium for studying bacterial growth in the hydrolysed milkfat than did use of casein/lecithin. The results also show that the antimicrobial effects of individual fatty acids released from hydrolysed milkfat were at least additive and suggest that hydrolysis of milkfat may be a significant factor in controlling growth of organisms imbibed with food in pre-weaned animals. The amount of pregastric catalyzed triglyceride hydrolysis in the digestive tract is sufficient to produce an antibacterial concentration of fatty acids and monoglycerides.

Bovine milk fat may protect against gastrointestinal infections by means of its antimicrobial constituents. This paper summarises our studies performed to test the bactericidal activities of milk fat. In vitro, the fatty acids C 10:0 . C 12:0 and unsaturated C18 fatty acids together with digestion products of sphingolipids were effective bactericidal agents. Listeria monocytogenes and Campylobacter jejuni were very sensitive, whereas E. coli O157:H7 and Salmonella enteritidis were less vulnerable. In rats, high intake of milk fat triglycerides protected against orally administered L. monocytogenes but not against S. enteritidis. The enhanced resistance to L. monocytogenes was related to an increased release of gastric bactericidal saturated fatty acids. Since gastric bactericidal activity is predictive for butter fat-mediated resistance to L. monocytogenes in vivo, C. jejuni and E. coli O157:H7 were incubated with gastric contents of rats fed high or low butter fat diets. Ex vivo killing of E. coli was not affected whereas bactericidal activity towards C. jejuni was enhanced in gastric chyme of rats fed high butter fat diets, implying that milk fat triglycerides may also protect against campylobacter infections. Since unsaturated C 18 fatty acids were listericidal in vitro, the efficacy of these agents was tested in rats. High corn oil intake did not protect against listeria infection, suggesting that the protective effect of fatty acids in vivo may be limited to C 10:0 and C 12:0 . The effectiveness of membrane lipids was also tested in rats. Colonisation of L. monocytogenes was decreased in rats fed diets based on sweet butter milk powder (membrane lipid rich) compared with rats fed skim milk-based diets (low content of membrane lipids). In conclusion, bovine milk fat triglycerides containing C 10: and C 12:0 , and sphingolipids may enhance the resistance to certain types of food-borne gastrointestinal infections.

Eight-week-old pigs (6 pigs per group) were fed diets containing either fish oil, milkfat, coconut oil, olive oil or cornstarch at an inclusion rate of 4% (w/w) for 3 weeks. Serum total cholesterol concentration was significantly higher in pigs fed coconut oil than in pigs fed cornstarch or fish oil (p < 0.05). Pigs fed coconut oil, olive oil and milkfat had a significantly higher HDL cholesterol concentration than those fed cornstarch or fish oil. There were no significant differences in LDL cholesterol concentrations between groups. The serum triglyceride concentrations were higher in pigs receiving coconut oil and milkfat. This study showed that dietary fats that have a hypercholesterolaemic effect in humans tended to raise HDL cholesterol rather than LDL cholesterol concentrations in pigs. These findings suggest differences in lipoprotein metabolism between humans and pigs and caution is warranted when making inferences about human lipoprotein metabolism from porcine studies.

Six commercial lipases, in either free or immobilized forms, were screened for their ability to catalyze acyl exchange between the triacylglycerols of butteroil (milkfat) and conjugated linoleic acid (CLA) in an organic solvent-free medium. Immobilized lipase preparations from Candida antarctica and Mucor miehei demonstrated the ability to increase the CLA content of the milk fat acylglycerols from the native value of 0.6 g/100 g fat to values which were at least an order of magnitude higher. Comparable increases were also obtained with a free enzyme from Candida rugosa . In addition to the screening studies, the effects of the weight ratio of milkfat to CLA on the product distribution and of the water content on the kinetics and maximum extent of this acidolysis reaction were systematically investigated in a batch reactor: The fatty acids liberated from the butteroil triacylglycerols were primarily short chain fatty acids, especially butyric and caproic acids. Modified butteroils were also produced via acidolysis of butteroil with CLA in a packed bed reactor containing an immobilized lipase preparation from C. antarctica. Significant enrichment of the butteroil in CLA residues was accomplished at reactor space times (fluid residence times) of 2–4 h at 40–60°C. Under these conditions, approximately 80–90% of the free CLA fed to the reactor is (inter)esterified.

A study was conducted using a randomized complete block design to determine feed intake, live-weight changes, milk yield and cost of milk production in Friesian cows fed napier grass (NG) at 10 weeks (MNG) or 15 weeks (ONG) of maturity. The MNG or ONG was supplemented with equal amounts of sunflower (SFBC) or poultry litter (PLBC) based concentrates in experiment 1, while in experiment 2, the MNG was supplemented with graded levels of the PLBC. In 0.75 experiment 1, the intakes of total organic matter (TOMI) was lower (135.9 vs. 137.7 g kg W ) while intake of total crude 0.75 protein (TCPI) was greater (16.6 vs. 12.0 g kg W ) for MNG than ONG diets (P , 0.001). The TOMI (137.8 vs. 135.8 0.75 0.75 W ) and TCPI (14.3 vs. 14.2 W ) were higher for SFBC than PLBC diets (P , 0.05). The yield of milk corrected for 21 21 butter fat (FCM) was higher (11.0 vs. 5.7 kg cow day ) for MNG than ONG diets (P , 0.001). In experiment 2, the 0.75 0.75 TOMI (112.8 vs. 130.6 g kg W ) and the TCPI (12.2 vs. 16.1 g kg W ) were lower for MNG only diet than the mean of 21 21 the supplemented MNG (P , 0.001). The MNG only diet supported lower yields of FCM (7.7 vs. 10.7 kg cow day ) than the mean of the supplemented MNG (P , 0.001). Although supplemented cows fed MNG diets gained weight, those fed supplemented ONG diets or MNG only diet lost weight. Feeding of supplemented ONG resulted in loss of revenue while supplementing with PLBC had higher profits than SFBC. We concluded that use of the PLBC would lower costs and improve milk production in dairy cows fed NG-based diets. © 2000 Elsevier Science B.V. All rights reserved.