Seasonal variations in the composition and thermal properties of New Zealand milk fat: I. Fatty-acid composition

Gray, I. K.

doi:10.1017/s0022029900014527

Cited by 49 publications

(14 citation statements)

References 17 publications

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“…The seasonal variations which change the proportions of these acids, especially in spring (Decaen and Journet, 1966;Gray, 1973;Masson et al, 1978), affect the Swisstype cheese ripening. Poor eye formation and lower levels of propionic and acetic acids in the curd suggest a poor propionic acid bacteria activity.…”

Section: Introductionmentioning

confidence: 99%

Effects of free fatty acids on propionic acid bacteria

Boyaval

Corre

Dupuis

et al. 1995

Lait

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Summary -The seasonal variations in milk fat composition, especially du ring the grazing period, often lead to poor eye formation in Swiss-type cheese. The influence of free fatty acids on the grow1h and metabolism of the dairy propionibacteria has been studied in this work. Linoleic (C 1B : 2 ), laurie (C 12 : 0 ), myristic (C14:0) and oleic acids (C1B:1) inhibited the growth and acid production of P treudenreichii subsp shermanii in the reference medium. The antibacterial activity of Iinoleic acid can be overcome by additions of cholesterol and soya lecithin to the medium. The four species and !WO subspecies of dairy Propionibacterium could be divided into !WO groups according to their high susceptibility to unsaturated fatty acids (P freudenreichii subsp shermanii and subsp freudenreichit) or low susceptibility (P acidipropionici, P jensenii and P thoeniJ). Nevertheless, this inhibitory action of free fatty acids was not observed in milk, retentate media or lactic curd. A total extraction of the milk lipids led to the recovery of this inhibitory effect on Propionibacterium. The possible modes of action of these molecules are discussed on the basis of the observed potassium effluxes and disturbances in the cell membranes.

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Section: Introductionmentioning

confidence: 99%

Effects of free fatty acids on propionic acid bacteria

Boyaval

Corre

Dupuis

et al. 1995

Lait

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“…Superimposed to potential variations of natural origin are nonnegligible and erratic variations that are frequently linked to uncontrolled analytical procedures, and it is seldom an easy matter to evaluate which part is attributable to each kind of variation. For example, depending on the authors, the content of butyric acid in cow milk fat would vary between 0.8-6.8% (3)(4)(5).…”

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confidence: 99%

“…However, this study was limited to the analysis of two sets of butters collected in spring and fall (totalling 24 samples). Seasonal variations of the fatty acid composition of milk fat have been recognized for a long time, and several attempts were made to follow the fatty acid composition of milk fat throughout the year (5,(7)(8)(9)(10)(11)(12). Unfortunately, and because the experiments were frequently limited to one herd or two, results were sometimes erratic, and conflicting conclusions were reached.…”

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confidence: 99%

Evaluation of sequential methods for the determination of butterfat fatty acid composition with emphasis ontrans‐18:1 acids. Application to the study of seasonal variations in french butters

Wolff¹,

Bayard²,

Fabien³

1995

J Americ Oil Chem Soc

184

119

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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 Na2SO4, filtration of aliquots of the suspension through a microfiltration unit, subsequent preparation of fatty acid isopropyl esters (FAIPE) with H2SO 4 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. FA1PE 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

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“…On the other hand, the summer milkfat had higher levels of saturated fatty acids, and short chain fatty acids, than the one found in the pattern of winter milkfat. However, this discrepancy between both fats in their fatty acid levels was due to the effect of the season of the year and consequently the plan of nutrition (14) (15) (16). From the same table, the iodine value was found to be higher in winter milkfat than that found in the summer milkfat.…”

Section: Resultsmentioning

confidence: 98%

Adulteration of butterfat: validity of Reichert-Meissl, Polenske and iodine values

Youness¹

1991

Grasas y Aceites

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RESUMEN Adulteración de grasa de manteca: validez de los índices de Reichert-Meissl, Polenske e iodo.Durante las estaciones de invierno y verano se obtuvo grasa de ieciie de búfalo. Sebo de vaca (grasa del corazón) se adquirió del mercado local. El sebo de vaca se añadió a la grasa de leche de verano en las relaciones 5%, 10%, 15% y 50% w/w. Se aplicó la cronnatografia en capa fina para obtener la fracción de triglicéridos de cada nnuestra obtenida. La cromatografía gaseosa se usó para identificar el contenido en ácidos grasos de la grasa de leche de invierno, verano y las mezclas. También se determinaron para cada muestra los índices de ReichertMeissl (RM), Polenske (P) e lodo. Se concluyó que los (RM) de la grasa de leche de invierno y de verano fueron 25.52±0.511 y 28.7410.568 respectivamente. Los índices (P) y de iodo fueron 1.94±0.162, 2.53±0.146 y 42.1±0.85, 30.33±0.839 en los mismos aspectos. La adición de sebo de vaca a la grasa de leche en las relaciones 5% y 10% no afectó los índices (RM) y (P) de las mezclas resultantes. La presencia del 15% de sebo de vaca en la grasa de leche afectó ligeramente los índices (RM), (P) e iodo. La adición del 50% de sebo de vaca a la grasa de leche sacó los valores de (RM) y (P) del rango normal, permaneciendo dentro del mismo el índice de iodo. Se observó también que la adición de sebo de vaca en las relaciones 5%, 10% y 15% a la grasa de leche de verano, mejoró el comportamiento de los ácidos grasos de la grasa de leche, mientras que el 50% de sebo de vaca en la grasa de leche, disminuyó todos los ácidos grasos de cadena corta. La determinación de los índices (RM), (P) e iodo para detectar sebo de vaca como adulterante en grasa de leche pura no es suficiente al 5% y 10% de sebo de vaca en la grasa de leche. PALABRAS-CLAVE: Adulteración (detección) -Grasa de leche -Sebo de vaca. SUMMARY Adulteration of butterfat: validity of Reichert-Meissl, Polenske and iodine values.Buffaloe's milkfat was obtained during the winter and the summer seasons. The beef tallow (Heart fat) was purchased from the local market. Beef tallow was added to the summer milkfat in the ratios 5%, 10%, 15% and 50% w/w. Thin layer chromatography was applied to obtain the triglycerides fraction of each sample obtained. Gas chromatography was used to identify the fatty acid content of the winter, summer and the admixtures. Reichert-Meissl (RM), Polenske (F^) and Iodine values were also determined for each sample. It was concluded that the (RM) of the winter and the summer milkfat were 25.52±0.511 and 28.74±0.568, respectively. The (P) and iodine values were 1. 94±0.162, 2.53±0.146 and 42.1±0.85, 30.3310.839 in the same respect. The addition of beef tallow to the milkfat in the ratios 5% and 10% did not affect the (RM) and (P) values of the resultant admixtures. The presence of 15% beef tallow in milkfat slightly affected the (RM), (P) and iodine values. The addition of 50% beef tallow to the milkfat got the values of (RM) and (P) out of the normal range. The iodine values was still within the normal ran...

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Seasonal variations in the composition and thermal properties of New Zealand milk fat: I. Fatty-acid composition

Cited by 49 publications

References 17 publications

Effects of free fatty acids on propionic acid bacteria

Effects of free fatty acids on propionic acid bacteria

Evaluation of sequential methods for the determination of butterfat fatty acid composition with emphasis ontrans‐18:1 acids. Application to the study of seasonal variations in french butters

Adulteration of butterfat: validity of Reichert-Meissl, Polenske and iodine values

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