Search

Increasing population and wealth brings increasing demand for dairy products, so sustainable growth of dairy production will be needed. We explore the possible contribution of oilseed waste, in particular rapeseed meal, to improved milk yields and quality. Addition of 500 g of rapeseed meal to the daily feed of Holstein dairy cattle contributed to a 12.7% increase in the gross milk yield compared to the control group of dairy cows, as well as increase in the milk's butterfat, protein and lactose content. The norm for adding rapeseed meal to the basic diet of dairy cattle is justified. [ABSTRACT FROM AUTHOR]

Ghee, a nutritional dairy product in Iranian culture, can be easily produced on a small scale. This study was undertaken to analyze fatty acids and volatile compounds of collected ghee samples from different ghee production sites of Iran (Ilam, Kermanshah and Hamedan) using HeadSpace Solid Phase MicroExtraction (HS-SPME) technique. According to the results, palmitic and oleic acids were the dominant fatty acids in all the samples investigated. Further, it might be concluded that compounds such as dodecane, acetone, butyric acid, hexanoic acid, 2-pentanone, 2-heptanone, and 2-undecanone, which are present and might have accumulated as the results of oxidative, hydrolytic, or microbial activities, contribute to the flavor of ghee. Lactones, which are produced at high temperatures, were not collected in any sample except the Hamedan sample (< 1%). Low thermal processing in the ghee production prevented the formation of off-flavor volatile compounds. The qualitative and quantitative parameters determined in this study might be useful in assessing the quality of the ghee and may help the industry to improve its commercial production. [ABSTRACT FROM AUTHOR]

Phytonutrients retained palm olein (PRPOL) was prepared and blended into butterfat at different ratios. The physicochemical characteristics and the phytonutrient composition of blends, as well as its utilization in the preparation of functional chocolate spread were evaluated. The results showed that the redness, yellowness, slip melting point, free fatty acids, peroxide value, iodine value, unsaponifiable matter, diacylglycerol and monoacylglycerol increased while lightness, saponification value, and triacylglycerol significantly decreased upon incorporation of increased quantities of PRPOL into butterfat. The incorporation affected short chain, medium chain and long chain fatty acids content along with variation in the palmitic, stearic, oleic acids content of the blends as compared to butterfat alone. Improvement in carotenoids (6-27 fold), phytotosterols (3-15 fold), tocopherols and tocotrienols (4-17 fold), and squalene (1-6 fold) in blends was observed upon incorporation of PRPOL. Cholesterol level in the blends was reduced (10-50 %) as compared to the butterfat. The blends showed an intermediate solid fat content of PRPOL and butterfat. Moreover, radical scavenging activity of the blends increased with increase in PRPOL quantity. Prepared chocolate spreads showed similar fat, moisture, colour components ( L*, a* and b*) and better emulsion stability. The hardness of the spreads was increased upon increasing quantity of PRPOL. The sensory evaluation showed that chocolate prepared by replacing butterfat with 20 % PRPOL had acceptable sensory attributes. [ABSTRACT FROM AUTHOR]

The impact of the amount of dietary α-linolenic acid (ALA) on its own tissue accumulation and conversion to longer n-3 polyunsaturated fatty acids (PUFAs) remains controversial and may depend on the other dietary fatty acids mixed with ALA. Whereas linoleic acid (LA) is well known to compete with ALA for its conversion to longer n-3 PUFAs, the concomitant presence of dietary ALA with dairy saturated fatty acids (C4:0-C14:0) that are highly susceptible to β-oxidation may inversely lead to its increased cellular storage and better conversion to long-chain n-3 PUFAs. The present study was therefore aimed at investigating further the putative beneficial effect of dietary dairy fat on n-3 PUFA tissue levels in the rat. Firstly, we showed that when combined with a well-defined dietary level of ALA (0.6% energy), substitution of olive oil for butterfat improved ALA storage in adipose tissue and liver, and had moderate effects on its conversion to n-3 long-chain PUFAs. Secondly, we showed that, when mixed with dairy fat, a small increase in dietary ALA (from 0.6 to 0.8% of energy) enhanced the ALA storage in adipose tissue only but conversely significantly increased its conversion to highly unsaturated n-3 PUFAs in the liver. Practical applications: α-linolenic acid (ALA) is the most accessible source of n-3 PUFAs in the global diet. However, the intake of ALA is currently lower than dietary guidelines and the rate of ALA conversion to longer chain n-3 PUFAs is low. The results from this study showed that a small enrichment in dietary ALA combined with dairy fat increased adipose tissue ALA storage, which represents a slow releasable pool that may be utilized over time by other tissues and greatly increased the conversion of ALA to highly unsaturated n-3 PUFAs in the liver. This knowledge may possibly result in the development of new dietary strategies to increase the cellular level of n-3 PUFAs in animals and humans. When mixed with dairy fat, a small increase in dietary α-linolenic acid (from 0.6 to 0.8% of energy) enhances the α-linolenic acid storage in adipose tissue and significantly increases its conversion to highly unsaturated n-3 polyunsaturated fatty acids in the liver. [ABSTRACT FROM AUTHOR]

Two substrate blends (8:6:6 and 6:6:9, by weight) of anhydrous butterfat (ABF), palm stearin (PS), and flaxseed oil (FSO) were interesterified by immobilized lipases. The reaction was carried out in the absence of solvent at 60 °C for 24 h in a 1-L tank stirred-batch type reactor. In terms of equivalent carbon number (ECN) of triacylglycerol (TAG), the areas of ECN 36-38 (from FSO) and ECN 48-50 (from PS) decreased during the interesterification while ECN 42–46 increased with increasing reaction time. As interesterification time increased, the decreased enthalpy (∆ H), peak temperature ( TP) and transition range were observed. After short path distillation, interesterified fat (IF) was produced in which α-linolenic acid contents (ALn, mol%) of the 8:6:6 and 6:6:9 IF were 15.7 and 21.7%, respectively. Tocopherol, cholesterol and phytosterol contents in each IF were significantly reduced after short path distillation. In this study, hardness of 6:6:9 IF and 8:6:6 IF were 217 and 800 g/cm2, respectively. After interesterification, short spacing at 4.6 Å disappeared or weakened, indicating that the predominant polymorphic form had changed from the β form to the desirable crystalline structure of the β′ form. [ABSTRACT FROM AUTHOR]

The high dry matter yield of kikuyu (Pennisetum clandestinum) under favourable conditions supports high stocking rates and milk production per hectare. However, the quality of kikuyu is generally low and consequently the milk production per cow is also low. The aim of the study was to determine the grazing capacity, milk production and milk composition from kikuyu, kikuyu over-sown with annual ryegrass (Lolium multiflorum var. westerwoldicum), kikuyu over-sown with a mixture of perennial ryegrass (L. perenne), white clover (Trifolium repens) and red clover (T. pratense), and kikuyu over-sown with a mixture of white and red clovers. Milk production per cow was highest on pasture with high clover content and the grazing capacity of pasture increased as the grass component increased. The milk produced from kikuyu during spring (15 kg cow-1 d-1) and summer (14.4 kg cow-1 d-1) was higher than during the autumn (12.1 kg cow-1 d-1). The total milk production from kikuyu during spring (3 876 kg milk ha-1) increased when kikuyu was over-sown with annual ryegrass (8 133 kg milk ha-1) or with clover (7 370 kg milk ha-1). The summer and autumn grazing capacity of kikuyu and kikuyu-annual ryegrass fertilised with nitrogen was higher than the kikuyu-clover pastures not receiving nitrogen. The clover content of the pastures did not affect the milk protein or butterfat content. The mean annual grazing capacity of kikuyu (6.7 cows ha-1) and kikuyu-annual ryegrass (8 cows ha-1) pasture was higher than the kikuyu-clover (5.3 cows ha-1) pasture. The grazing capacity and milk production per cow from kikuyu over-sown with ryegrass varied less than from kikuyu or kikuyu-clover pastures. This resulted in a similar or higher milk production per hectare from kikuyu-ryegrass compared to that of kikuyu or kikuyu-clover pastures. [ABSTRACT FROM AUTHOR]

Objective:To estimate the intake of ruminant trans fatty acids (TFA) in the Danish population aged 1–80 years.Design:Descriptive study.Subjects:A sex- and age-stratified random sample drawn from the Danish Civil Registration System. A total of 3098 participants (51% female) aged 1–80 years were included. The participation was 66%.Dietary information:A 7-day dietary record.Results:The estimated median intake of ruminant TFA was 1.4 g/day with the 80% central range being from 0.9 to 2.1 among children aged 1–6 years and 1.6 g/day (1.0–2.4) among children aged 7–14 years. The median TFA intake was 1.8 g/day (0.9–2.9) among adults aged 15–29 years and among adults aged 30–80 years. The intake expressed as percentage of energy intake was 0.8, 0.6, 0.7, and 0.7, respectively. Dairy products were the main source of ruminant TFA.Conclusions:The median intake of ruminant TFA in the Danish population aged 1–80 years is estimated to be 1.7 g/day (0.9–2.7), corresponding to 0.7% of energy intake (0.5–1.0), with dairy products being the main source of ruminant TFA.Sponsorship:The Danish Heart Foundation (Grants 02-2-9-8-22010 and 03-2-9-4-22087) and the Female Researchers in Joint Action (FREJA) programme from the Danish Medical Research Council.European Journal of Clinical Nutrition (2006) 60, 312–318. doi:10.1038/sj.ejcn.1602316; published online 19 October 2005 [ABSTRACT FROM AUTHOR]

The aim of this paper was to develop a process for the production of DAG from butterfat through glycerolysis and short-path distillation and to evaluate the physical properties of the DAG in comparison with the original butterfat. Chemical glycerolysis produced a mixture of acylglycerols containing DAG together with MAG and TAG. From the mixture of glycerolysis products, MAG were removed through three consecutive distillations (vacuum < 0.001 mbar) at 150°C. TAG were separated from DAG by distillation at 210°C, which gave a product with more than 80% DAG in the distillates. Distillation temperatures had significant effects on acyl migration. The formation of desirable 1,3-DAG was favored at higher temperatures. Under 210°C distillation, the equilibrium ratio of 6:4 was obtained between 1,3-DAG and 1,2(2,3)-DAG. The FA profile of the DAG product was relatively similar to the original butterfat. The total DAG recovery was around 77% in the pilot-scale production. The different patterns of m.p. were observed between butterfat and the DAG fraction produced as well as the MAG fraction collected. Solid fat content profiles of the DAG fraction and its mixtures with rapeseed oil possessed trends similar to those of the corresponding butterfat and its mixtures with rapeseed oil. Compared with butterfat, the DAG fraction behaved differently in its thermal profiles, crystallization patterns, and rheological properties; for example, the dropping point was 13°C higher for the latter than for the former, and the crystal pattern was mostly β form for the latter, whereas the former was the β' form. [ABSTRACT FROM AUTHOR]

Copyright of Zeitschrift für Ernäehrungswissenschaft is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The temperature dependency of the solid-fat content of a fat is important for predicting the consistency of the final product and for process control. Two direct analytical methods for determining the solid-fat content and the melting characteristics of milk-fat fractions have been developed. The fractions are analyzed during crystallization, and the results give reproducible information about the thermal behavior of the fractions and the actual crystal amount in the suspensions. The results are obtained within minutes, and no separation of the fractions before the measurement is necessary. New ways of reducing process time are proposed. It is possible to adapt crystallization time to seasonal variations of the initial milk fat and to the required properties of the final product. Partially crystallized milk fat was directly measured in a calorimeter and a pulsed nuclear magnetic resonance spectrometer. The data showed good correlations and even more accurate results than the conventional methods. The calorimetric method makes it possible to detect polymorphic changes and co-crystallization in the crystals so that the influence of processing parameters, such as energy input, on crystallization behavior can be investigated. [ABSTRACT FROM AUTHOR]

Chemical interesterification of butterfat-canola oil blends, ranging from 100% butterfat to 100% canola oil in 10% increments, decreased solid fat content (SFC) of all blends in a nonlinear fashion in the temperature range of 5 to 40°C except for butterfat and the 90∶10 butterfat/canola oil blend, whose SFC increased between 20 and 40°C. The sharp melting associated with butterfat at 15-20°C disappeared upon interesterification. Heats of fusion for butterfat to the 60∶40 butterfat/canola oil blend decreased from 75 to 60 J/g. Blends with >50% canola oil displayed a much sharper drop in enthalpy. Heats of fusion were 30-50% lower on average for interesterified blends than for their noninteresterified counterparts. Both noninteresterified and interesterified blends deviated substantially from ideal solubility, with greater deviation as the proportion of canola oil increased. The change in the entropy of melting was consistently higher for noninteresterified blends than for interesterified blends. Chemical interesterification generated statistically significant differences for all triacylglycerol carbon species (C) from C to C except for C and in SFC at most temperatures for all blends. [ABSTRACT FROM AUTHOR]

Milkfat was separated into major chainlength fractions by solid-phase extraction. The effect on thermal behavior and texture of replacing both saturated and monounsaturated long-chain triglycerides from milkfat by long-chain monounsaturated triglycerides with an unsaturated fatty acid in the sn-2 position is reported. Increasing proportions of cocoa butter were added to fractions of short-to medium-chain triglycerides (C−C) and medium- to long-chain triglycerides (C−C) isolated from milkfat. Thermal behavior and texture of the mixtures were measured. Results indicated that long-chain monounsaturated triglycerides from cocoa butter enhanced co-crystallization and co-operative melting and did not induce polymorphic transitions upon crystallization and melting of the fractions. At 4°C, they acted as texture builder if present in proportions of more than 30%, whereas below this level, they acted as texture softeners. The effect of the long-chain monounsaturated triglycerides on the texture of fractions that melt at low temperature could not be predicted from the proportion of solid fat at that temperature. [ABSTRACT FROM AUTHOR]

The successive steps of an integrated analytical procedure aimed at the accurate determination of butterfat fatty acid composition, including trans-18:1 acid content and profile, have been carefully checked. This sequential procedure includes: dispersion of a portion of butter in hexane/isopropanol (2:1, vol/vol) with anhydrous NaSO, filtration of aliquots of the suspension through a microfiltration unit, subsequent preparation of fatty acid isopropyl esters (FAIPE) with HSO as a catalyst, and analysis of total FAIPE by capillary gas-liquid chromatography (GLC). Isolation of trans-18:1 isomers was by silver-ion thin-layer chromatography (Ag-TLC), followed by extraction from the gel of combined saturated and trans-monoenoic acids with a biphasic solvent system. Analysis of these fractions by GLC allows the accurate quantitation of trans-18:1 acids with saturated acids (14:0, 16:0, and 18:0) as internal standards. A partial insight in the distribution of trans-18:1 isomers can be obtained by GLC on a CP Sil 88 capillary column (Chrompack, Middelburg, The Netherlands). All steps of the procedure are quite reproducible, part of the coefficients of variation (generally less than 3%, mainly limited to butyric and stearic acids) being associated with GLC analysis (injection, integration of peaks) and, to a lesser extent, to FAIPE preparation. FAIPE appear to be of greater practical interest than any other fatty acid esters, including fatty acid methyl esters (FAME), for the quantitation of short-chain fatty acids, because peak area percentages, calculated by the integrator coupled to the flame-ionization detector, are almost equal (theoretically and experimentally) to fatty acid weight percentages and do not require correction factors. With this set of procedures, we have followed in detail the seasonal variations of fatty acids in butterfat, with sixty commercial samples of French butter collected at five different periods of the year. Important variations occur around mid-April, when cows are shifted from forage and concentrates during winters spent in their stalls to fresh grass in pastures. At this period, there is a decrease of 4:0-14:0 acids and of 16:0 (−2 and −6%, respectively), while 18:0 and cis- plus trans-18:1 acids rise suddenly (2 and 5%, respectively). These modifications then progressively disappear until late fall or early winter. Other variations are of minor quantitative importance. Although influenced by the season, the content of 18:2n-6 acid lies in the narrow range of 1.2-1.5%. Trans-18:1 acids, quantitated by GLC after Ag-TLC fractionation, are at their highest level in May-June (4.3% of total fatty acids), and at their lowest level between January and the end of March (2.4%), with a mean annual value of 3.3%. The proportion of vaccenic ( trans-11 18:1) acid, relative to total trans-18:1 isomers, is higher in spring than in winter, with intermediate decreasing values in summer and fall, which supports the hypothesis that the level of this isomer is linked to the feed of the cattle, and probably to the amount of grass in the feed. [ABSTRACT FROM AUTHOR]

Doubling the length of a CP-Sil 88 capillary column (Chrompack, Middelburg, The Netherlands) from 50 to 100 m remarkably improves the resolution of individual trans-18:1 isomers from either ruminant fats or partially hydrogenated oils. Although the use of a 50-m column gives interesting results, it does not allow sufficient resolution of the trans-10 and trans-11 18:1 isomers. Moreover, the trans-6 to trans-9 18:1 isomers emerge as a single group of peaks, whereas the trans-12 isomer is only partly resolved from the adjacent trans-11 and trans-13 plus trans-14 isomers. With the 100-m column, the trans-9, trans-10, and trans-12 18:1 isomers are almost base-line resolved from other isomers. However, with both columns, it is not possible to separate the critical pair of trans-13 and trans-14 18:1 acids which co-elute under a single peak. Despite this minor drawback, the 100-m CP-Sil 88 column appears to be of great interest for the separation and the quantitation of most individual trans-18:1 acids. Except for the use of argentation thin-layer chromatography, there is no need for complementary techniques, such as ozonolysis. This simple and powerful tool may be applied to ruminant fats, partially hydrogenated oils, and human tissue lipids. [ABSTRACT FROM AUTHOR]

Lipase-catalyzed interesterification of butterfat was carried out in a cosurfactant-free microemulsion system containing mixtures of Span 60 and Tween 60 (ICI Specialty Chemicals Altemix Inc., Brantford, Ontario, Canada) as surfactants. Four commercial lipases were used-Lipozyme 10,000L (Novo Nordisk, Copenhagen, Denmark) and N, D and MPA (Amano Pharmaceutical Co. Ltd., Nagoya, Japan). Stereospecific analyses of fractionated selected high-molecular weight triacylglycerols were performed by enzymatic deacylation with commercial pancreatic lipase, random generation of rac-1,2-diacylglycerols by Grignard degradation, synthesis of rac-phosphatidylcholines and a stereospecific release of sn-1,2 diacylglycerols by phospholipase A. The results showed that the hydrolytic affinity of commercial lipases demonstrated an acyl-group specificity toward lower-molecular weight fatty acids C4-C14∶0. Stereospecific analyses of fatty acids of interesterified selected triacylglycerols of butterfat catalyzed by lipase N demonstrated a 46% increase in the proportion of C18∶1 cis Δ at the sn-2 position, whereas those catalyzed by lipases MAP, D and Lipozyme 10,000L were enriched with C16∶0 at the same position by 21, 35 and 41%, respectively. [ABSTRACT FROM AUTHOR]

The positional distribution of acetic and butyric acids in bovine milk fat triacylglycerols was determined by chiral-phase high-performance liquid chromatography (HPLC) of the derived diacylglycerols. Enriched fractions of acetic and butyric acid-containing triacylglycerols were isolated by normal-phase thin-layer chromatography (TLC) from a molecular distillate of butter oil, and they were fully hydrogenated. Mixed sn-1,2(2,3)- and X-1,3-diacylglycerols of short- and long-chainlength, which were generated by partial Grignard degradation of the hydrogenated triacylglycerols, were isolated by borate-TLC. The enantiomeric sn-1,2-and sn-2,3-diacylglycerols and the X-1,3-diacylglycerols as their 3,5-dinitrophenylurethanes were resolved by HPLC on chiral columns. Both acetic and butyric acids were exclusively associated with the sn- 2,3- and X-1,3-diacylglycerols of short and long chainlength. These results establish the presence of acetic and butyric acids in the sn-3-position of bovine milk fat triacylglycerols. Other short-and medium-chainlength acids were found in progressively increasing proportions also in the sn-1- and sn-2-positions. [ABSTRACT FROM AUTHOR]

Triacylglycerols of Finnish winter butterfat containing one saturated and two monoenoic fatty acyl residues were studied. With silver ion high-performance liquid chromatography (HPLC), molecules were separated according to the difference in the configuration of one fatty acyl moiety. The distribution of the saturated cis,trans-dimonoenoic and saturated cis,cis-dimonoenoic triacylglycerols according to their acyl carbon numbers was compared by means of reversed-phase HPLC and tandem mass spectrometry. Furthermore, two examples of the fatty acid composition of a specified molecular weight species were shown. The fatty acid compositions of corresponding saturated cis,trans-dimonoenoic and saturated cis,cis-dimonoenoic triacylglycerols were similar; however, there may be differences in the proportions of different fatty acid combinations or in the distribution of fatty acids between primary and secondary glycerol positions. [ABSTRACT FROM AUTHOR]

The triacylglycerols of winter butterfat were fractionated according to the type and degree of unsaturation into six fractions by silver ion high-performance liquid chromatography (Ag-HPLC). The acyl carbon number distribution of the triacylglycerols in each fraction was elucidated by reversed-phase HPLC and mass spectrometry (MS). The MS analysis of each fraction gave deprotonated triacylglycerol [M - H] ions which were produced by chemical ionization with ammonia. The daughter spectrum of each of the [M - H] ions provided information on its fatty acid constituents. Successful fractionation of triacylglycerols differing in the configuration of one fatty acyl residue by Ag-HPLC was important because geometrical isomers could not be distinguished by the MS system used. In addition to the fatty acid compositions, reversed-phase HPLC analysis demonstrated the purity of the collected fractions: molecules having a cis-trans difference were separated nearly to the baseline. Triacylglycerols differing in the configuration of one fatty acyl residue were not equally distributed in relation to their acyl carbon numbers. This indicates that during the biosynthesis of triacylglycerols, cis- and trans-fatty acids are processed differently. Although the fatty acid compositions of the corresponding molecular weight species of disaturated trans- and disaturated cis-monoenoic triacylglycerols were similar, there may be differences in the amounts of different fatty acid combinations or in the distribution of fatty acids between the primary and secondary glycerol positions. In addition to the main components, it was possible to analyze minor triacylglycerols, such as molecules containing one odd-chain fatty acid, by the MS system used. [ABSTRACT FROM AUTHOR]

The effect of composition on butter texture usually has been treated via the iodine value or the fatty acid content. The development of a new analytical technique allowed accurate determination of triglyceride composition of five different types of butters collected in winter and summer periods. The firmness of these samples has been measured in parallel, by using an Instron® universal testing machine and a cone penetrometer. As expected, a regional and seasonal variation of butter firmness was found. The correlation between firmness at 15°C and triglyceride composition allows the selection of four triglyceride fractions (TG1, TG2, TG3 and TG4) mainly represented by: TG1, POO; TG2, MyOO; TG3, CLaO + CyMyO + CoPO + BuSO and TG4, BuPO + CoMyO + CoPL (P, palmitic acid; O, oleic acid; My, myristic acid; C, capric acid; La, lauric acid; Cy, caprylic acid; Co, caproic acid; Bu, butryic acid; S, stearic acid; L, linoleic acid). The proportions of TG1 and TG2 are negatively correlated with firmness (r=0.89 and r=0.95, respectively). The level of the two other groups runs parallel to firmness (r=0.95 and r=0.91, respectively). The high correlation coefficients of these prevalent triglyceride fractions could be a better representative indication than iodine value or fatty acid content on the variation of this physical property of butter. [ABSTRACT FROM AUTHOR]

Based on the interpretation of the high-resolutionC nuclear magnetic resonance spectra of 15 spreading fats, baking fats, vegetable creams and an infant formula, it is possible to decide whether the sample contains butterfat, lauric oils, partially hydrogenated fat, linoleic acid or linolenic acid. The data have been interpreted in a semiquantitative manner, and this provides an insight into the nature of the material present in each sample. [ABSTRACT FROM AUTHOR]

In the present study, high-performance liquid chromatography analysis of butterfat allowed separation of 46 peaks at 32°C. Knowing the theoretical carbon number value of each triglyceride (TG), 32 peaks of the butterfat chromatogram were identified. These TGs were determined by extrapolation of their capacity factor values, and their identifications were confirmed with some standard TGs. Analysis of winter and summer butterfat from five different French areas showed significant seasonal and regional variation in the TG composition. However, the most important contribution to this variation was provided by TG groups represented by only four peaks. To approximately select the predominant TGs in these four peaks, a random distribution hypothesis was used to predict the amount of each TG. This hypothesis allowed the prediction of the TG components that seem to provide the most important contribution to both seasonal and regional variation. [ABSTRACT FROM AUTHOR]

A new method was developed to obtain lactones from butterfat. The application of lipases and capillary gas-liquid chromatography with chiral phases for the separation of γ-lactone enantiomers resulted in elucidation of the racemic composition of γ-lactones from butterfat. The seasonal distribution of lactones in butterfat was determined. [ABSTRACT FROM AUTHOR]

Fractionation of butterfat by melt crystallization is a commercial process in many countries for making butter fractions with varying melting, textural and flavor properties for use as food ingredients. However, the crystallization phenomena in this complex system are poorly understood and difficult to optimize and control. In this study, the crystallization kinetics of anhydrous butterfat were determined by cooling a melted sample to the final crystallization temperature in either a lab-scale (2 L) batch crystallizer or a pilot-scale (20 L) crystallization vessel. The butterfat was cooled sequentially from an initial temperature of 60°C to final temperatures of 30, 20 and 15°C at a constant cooling rate. Crystals formed at each temperature were separated by vacuum filtration, with the liquid cooled to the next crystallization temperature. Nucleation rates were determined by counting the number of crystals in a given volume of suspension during the course of crystallization. Crystal growth rates were obtained from image analysis of optical photomicrographs. Changes in viscosity, turbidity and mass of crystals also were determined. Effects of impeller velocity (75, 100 or 125 rpm) on the crystallization kinetics were determined. Nucleation and mass deposition rates increased while crystallization lag times decreased with increasing agitator velocities. Growth rates increased with agitator rpm at 20 and 15°C, but decreased with agitator rpm at 30°C, indicating different growth mechanisms. At 20 and 30°C, aggregation was the primary mechanism of crystal growth, whereas little aggregation was observed at 15°C. Crystallization at the larger scale, 20 L, showed only minor differences. [ABSTRACT FROM AUTHOR]