Butterfat, fractionated

At the 2 lowest doses, significant depression from day 2 through day 14 blood cholinesterase normal at day 21. At 60.75 mg/kg, blood cholinesterase decreased for entire 49-day posttreatment. No outward signs of organophosphate intoxication and normal food intake and demeanor At 24 h, whole milk had 0.24 mg famphur/L of which 76% was in the butterfat fraction after 72 h, residues in milk were <0.008 mg/L... 

Gillespie AM, Walters SM. 1986. HPLC silica column fractionation of pesticides and PCB from butterfat. J Liq Chromatogr 9 2111-2142. 

Usually, mobile phases of acetonitrile and acetone have been used in the analysis of TG from milk fat, most often in isocratic elution (114,115) and in gradient eiution, and they provide a resolution of 50 chromatographic peaks (Numela). One of the main difficulties in the analysis of TG is the identification of the chromatographic peaks, because of the small number of mixed TGs in a pure state. Bornaz et al. (115) and Dotson et al. (114) identified butterfat chromatographic peaks from the relationship between the retention time and the theoretical carbon number according to the model proposed by El-Hamdy and Perkins (87). An alternative method is the fractionation of total TG in milk fat by reversed-phase HPLC and analysis of the fatty acids in each fraction (116,117). 

Kaufmann et al. (1982) used a pressure of 20 MPa at 80°C for fractionation of butterfat into two fractions. The short-chain fatty acids C4—C10 were concentrated into the lower melting fraction, which had a melting point of 20°C compared to 37°C for the original milk fat. 

FAs are subjected to Ag-TLC usually in the form of methyl esters. The methods for methylation and transmethylation are simple, easy to perform, and with practically 100% yield. Methyl esters are particularly suitable when Ag-TLC is used as a complementary method with GC. Butyl and isopropyl esters were employed for the fractionation of butterfat FAs by Ag-TLC because these derivatives provided better resolution in GC. Conversion of positionally isomeric 18 1 and 20 1 FAs into phenacyl esters ensured complete resolution of the components by Ag-TLC however, this is not possible when using methyl esters. 

A Romano cheese-like aroma was produced from a butter-fat emulsion by treating it with a crude enzyme mixture isolated from Candida rugosa. The emulsion consisted of 20% butterfat and 1.5% Tween 80 in a buffer solution. The treated emulsion was held at 37°C for three hours and then aged at room temperature for three days to develop the cheese-like flavor. The volatile flavor components were isolated from both the enzyme modified butterfat (EMB) and a commercial sample of Romano cheese. The flavor isolates were separated into acidic and nonacidic fractions and analyzed by gas chromatography-mass spectrometry. The results showed good correlation between the acidic fractions of the two samples. The acidic fractions contained similar relative concentrations of eight short-chain fatty acids (C2 - Cj q). Methyl ketones and esters were major components in the nonacidic fraction of the EMB. 

Table I. Volatile Flavor Compounds Identified in the Acidic Fractions of Enzyme Modified Butterfat (EMB),...

Figure 1. Total Ion Chromatograms of the Nonacidic Fractions from the Enzyme Modified Butterfat (EMB) and Romano Cheese.

Biernoth, G. and W. Merk, Fractionation of butterfat using a liquefied gas or a... 

There is increasing commercial interest in the fractionation of butterfat to obtain a wider range of applications, e.g. soft butters from the olein. The characteristics of the three major glyceride fractions obtained by solvent fractionation have been characterized (Timms, 1980b). 

The genuine butterfat content may be determined by GC or by determining the Reichert, Polenske, and Kirschner values for volatile fatty acids in butter. These are obtained by titration of various distillation fractions against O.lmoll sodium hydroxide. 

The number of applications for Ag-HPLC continues to increase. Laakso and co-workers (64) utilized a combination of Ag-HPLC and RP-HPLC to the analysis of two solid and two liquid TAG fractions obtained from butterfat by an industrial melt process. Ag-HPLC was used to separate the TAG by unsaturation into six... 

Laakso, P.H., Nurmela, K.V.V. and Homer, D.R. (1992) Composition of the triacylglycerols of butterfat and its fractions obtained by an industrial melt crystallization process. /. Agric. Food Chem. 40, 2472-2482. 

Ice-cream is an O/W emulsion that is aerated to form a foam. The disperse phase consists of butterfat (cream) or vegetable fat, partially crystallised fat. The volume fraction of air in the foam is approximately 50%. The continuous phase consists of water and ice crystals, milk protein and carbohydrates, e.g. sucrose or corn syrup. Approximately 85% of the water content is frozen at —20 °C. The foam structure is stabilized by agglomerated fat globules that form the surface of air cells in the foam. Added surfactants act as destabilizers , controlling the agglomeration of the fat globules. The continuous phase is semi-solid and its structure is complex. 

Fractionated butterfat. The butter is separated by fractional crystallization into high- and low-melting fractions, and is utilized for various purposes (e. g. consistency improvement of whipping creams and butters). 

Thus, at refrigerator temperature, butterfat was composed of all three fractions, whereas at room temperature the solid butterfat contained mainly the MMTAG and HMTAG fractions. The same analysis could apply to CIEBF. 

Kalo et al. (1986b) studied the changes in TAG composition and melting properties of butterfat and butterfat solid fat fraction-rapeseed oil mixtures interesterified by Candida cylindracae lipase. They found that the proportion of trisa-turated TAGs with 42-52 carbons was distinctly lower in the interesterified product. They also noticed that DAGs were responsible for the changes in acyl species with 30-38 carbons. Kalo et al. (1987b) subjected butterfat to Candida cylindra-... 

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