Effect of milk pasteurization and curd scalding temperature on proteolysis in Malatya, a Halloumi-type cheese

Abstract

-The effect of pasteurization of cheese milk and cooking temperature of the curd on proteolysis of Malatya cheese was examined during ripening. The cheeses that were characterized by the scalding of curd in hot whey were manufactured from raw or pasteurized milk and the curds were scalded in hot whey at 60, 70, 80 or 90°C. Differences in the levels of pH 4.6-soluble nitrogen between cheeses were significant (P < 0.05) after 30 days of ripening. Urea-polyacrylamide gel electrophoresis of the pH 4.6-insoluble fractions showed that both α s1 -and β-caseins were not extensively degraded, especially after 30 days of ripening, but β-casein was less degraded than α s1 -casein. Analysis of peptide profiles of the pH 4.6-soluble fractions by RP-HPLC showed significant differences in the concentrations of some peptides between the cheeses. Principal component analysis distinguished the cheeses made from raw or pasteurized milk based on their peptide profiles. The results suggest that the pasteurization of cheese milk had a greater effect on peptide profiles of cheese than scalding temperature of the curd.Malatya cheese / proteolysis / scalding / raw milk / pasteurizationRésumé -Effet de la pasteurisation du lait et de la température de chauffage du caillé sur la protéolyse du Malatya, un fromage de type Halloumi. Les effets de la pasteurisation du lait de fabrication et de la température de cuisson du caillé sur la protéolyse du fromage Malatya ont été examinés pendant l'affinage. Les fromages qui sont caractérisés par la cuisson du caillé dans du *Corresponding author (通讯作者): ahayaloglu@inonu.edu.tr Dairy Sci. Technol. 90 (2010) Article published by EDP Sciences lactosérum chaud ont été fabriqués à partir de lait cru ou pasteurisé et les caillés ont été traités dans du lactosérum chauffé à 60, 70, 80 ou 90°C. Les différences de teneur en azote soluble à pH 4,6 entre fromages étaient significatives (P < 0,05) après 30 jours d'affinage. L'électrophorèse sur gel de polyacrylamide en milieu urée des fractions insolubles à pH 4,6 a montré que les deux caséines β et α s1 n'étaient pas beaucoup dégradées, en particulier après 30 jours d'affinage, mais la caséine β était moins dégradée que la caséine α s1 . L'analyse du profil peptidique par chromatographie RP-HPLC des fractions solubles à pH 4,6 a montré des différences significatives dans les concentrations de quelques peptides entre fromages. L'analyse en composante principale différenciait les fromages au lait cru de ceux au lait pasteurisé à partir de leur profil peptidique. Les résultats suggèrent que la pasteurisation du lait de fabrication a un effet plus grand sur les profils peptidiques des fromages que la température de chauffage du caillé.fromage Malatya / protéolyse / chauffage / lait cru / pasteurisation

Formation and Degradation of Beta-casomorphins in Dairy Processing

“…Major steps in cheese manufacture include Tyr-Pro-Phe-Pro-Gly-Pro-Ile-Pro-Asn-Ser-Leu Kaminski et al (2007) FORMATION, DEGRADATION OF BETA-CASOMORPHINS IN DAIRY PROCESSING heat treatment of milk, coagulation with rennet and starter culture, separation of curd from whey, and ripening of curd to produce the final cheese. Heat treatment of milk is commonly done by pasteurization at 72 C for 15 seconds (Hayaloglu et al, 2010). Cheese studies that used milk heated at above 72 C involving peptide profiles (Hougaard et al, 2010) showed denaturation of whey protein, leading to the interaction between whey protein and casein.…”

“…However, the endogenous protease plasmin has been shown not to release BCMs (Gaucher et al, 2008) and similarly the rennet enzymes used to coagulate milk protein also do not liberate bioactive peptides (McSweeney, 2004); excluding these enzymes activities as sources of BCMs. Hayaloglu et al (2010) investigated the peptide profile of Malatya cheese made from raw milk without addition of starter culture. The authors demonstrated considerably higher concentration of peptides but did not measure BCMs, although they may have been present in this cheese.…”

“…The authors demonstrated considerably higher concentration of peptides but did not measure BCMs, although they may have been present in this cheese. Hayaloglu et al (2010) compared to raw milk cheese to cheese made from pasteurized milk with added L. lactis ssp. lactis and S. Thermophilus and suggested that the resultant peptides were as a result of nonstarter culture derived enzyme-activity.…”

“…Hayaloglu et al (2010) investigated the peptide profile of Malatya cheese made from raw milk and from milk pasteurized at 72 C for 30 seconds. The authors suggested that pasteurization of milk results in a decrease in peptide content during ripening, with considerably higher concentration of peptides being reported in cheese made from raw milk than from pasteurized milk; however, the actual peptides produced were not identified.…”

“…The action of plasmin which is more active in milk that has been pasteurized than in unheated milk may be the reason for the contrast in results (Mendia et al, 2000;Benfeldt and Sørensen, 2001), although plasmin will be inactivated upon severe heat treatment of milk. Although a number of studies have investigated the effect of thermal treatment of milk on proteolysis (Rynne et al, 2004;Hayaloglu et al, 2010;Hougaard et al, 2010), its effect on modification of protein, leading to formation of BCMs in the final fermented dairy product is still unknown.…”