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THE PURITY OF WATER BUFFALO MILK FAT: AN APPLICATION OF THE EU METHOD (PRECHT) BASED ON THE GAS CHROMATHOGRAPHIC DETERMINATION OF TRIGLYCERIDES Milk fat purity is presently evaluated by the gas chromatographic determination of triglycerides by the Official Method of the European Community. This method allows the detection of foreign fats, of both animal and vegetable origin, in milk fat. It is based on the determination of the triglycerides with even carbon number and on the subsequent application of formulae deriving from multiple linear regressions for the calculation of five “S” parameters. The results obtained by this calculation are compared to the limits fixed for a 99% confidence interval. The aims of this work were: a) to determine the suitability of this method to water buffalo milk fat b) to propose a modification to the method for evaluation of water buffalo milk fat purity c) to determine the sensibility of the method for the detection of non lactic foreign fats in water buffalo milk 250 samples of water buffalo milk fat were extracted from milk of guaranteed origin. The water buffalo milk was kindly supplied by a livestock breeding factory in Caserta and Salerno. In order to validate this method, 100 samples were further utilized. The results show that it is necessary to modify the limits formula of Precht method to determine the purity of water buffalo milk fat. The modified UE method allows the detection of 5% non lactic foreign fat in water buffalo milk fat.

[ITALIANO] Il settore lattiero-caseario rappresenta uno dei comparti principali del sistema agro-alimentare nazionale. Attualmente la consistenza dell’allevamento bufalino in Italia è di poco superiore ai 160000 capi ma negli ultimi anni si è registrata una crescita costante in controtendenza rispetto al continuo calo del patrimonio bovino nazionale. E’ soprattutto la produzione di latte per la trasformazione in mozzarella di bufala e sottoprodotti della lavorazione la principale opportunità di sviluppo di questo tipo di allevamento. Tale trend del mercato ha inevitabilmente accentuato la problematica delle frodi e delle metodiche analitiche per rilevarle, suscitando attenzione da parte dei produttori, consumatori ed organi di controllo. La sperimentazione ha avuto come obiettivo la caratterizzazione della componente lipidica del latte di bufala alla luce delle fonti di variabilità stagionale ed alimentare. Dai dati ottenuti utilizzando gascromatografia ad alta risoluzione (HRGC) è stato possibile ricavare dei descrittori lipidici di genuinità. / [ENGLISH] Milk sector is one of the most important fields of national agroindustrial system. Nowadays Italian buffalo breeding is above of 160000 head but, in the last year it is possible to underline a constant growth opposite to continuous decrease of national cows breeding. The main development opportunity of this breeding is the production of milk for buffalo cheese and other cheese by products. This market trend emphasize milk adulteration problems and analytical methods for evaluation, producing great attention to producers, consumers and control authority. The aim of this work were the milk fat characterization to light of seasonal and feed variability factors. The results obtain to high resolution gas chromatography analysis (HRGC), show that it is possible to outline a lipidic descriptor in order to determine milk fat genuineness.

The effect of feeding lupin seeds (Lupinus albus L.) as an alternative protein source in ewe diets was investigated. Two groups of 18 Sarda ewes were fed two different isonitrogenous diets: with lupin (L) seed, given after 12 h soaking, or soybean meal (SBM) as the main protein source. DMI, variations of body weight and milk production were unaffected by the treatment. Although not statistically significant, in the group fed L diet the production of milk fat and protein was higher. Clotting properties of milk were similar for the two treatments, probably due to the small differences in the milk protein contents. The fatty acid profile of milk was affected by treatment with a larger content of short (14.19 wt% versus 12.26 wt%)- and medium (49.37 wt% versus 47.76 wt%)-chain fatty acids in milk from ewes fed the L diet. CLA content was unaffected by treatment. Triglyceride content of fat from the two diets reflects the milk fatty acid composition. Indeed, milk from L diet showed a higher level of medium-chain triglycerides, which are of particular interest to consumers with concerns over health and heart disease. The inclusion of lupin seed in the diet of lactation ewes can be a means of achieving a more desirable triglyceride profile in milk fat. Milk with enhanced nutritive quality may promote wider market penetration of sheep dairy products. © 2005 Elsevier B.V. All rights reserved.