Influence of fat, heat treatments and species on milk rennet clotting properties and glycomacropeptide formation

• Published in: European food research & technology 2002-03, Vol.214 (3), p.182-185
• Main Author: Calvo, Marta M
• Format: Article
• Language: English
• Subjects: Biological and medical sciences; casein; cheesemaking; ewes; Food industries; Fundamental and applied biological sciences. Psychology; goat milk; goats; heat treatment; linear models; micelles; milk; Milk and cheese industries. Ice creams; regression analysis; rennet; renneting
• ISSN: 1438-2377; 1438-2385
• DOI: 10.1007/s00217-001-0445-2

The influence of species, fat and heat treatment (70 °C for 30 min) of milk on rennet clotting time, k₂₀ value (time as the curd is firm enough to be cut) and glycomacropeptide formation was studied.Rennet clotting properties were affected by the three studied factors. The results obtained could indicate that the fat and the heat treatment have a different influence in the rennet clotting properties of cow's, ewe's and goat's milks; however, those differences, although significant, are not high and its influence in cheese manufacture perhaps have not a great importance.The slope of the glycomacropeptide formation as a function of the incubation time of milk with rennet was calculated applying a linear regression analysis. The slope decreased significantly when whole or skim cow's milk was heated indicating a slower glycomacropeptide formation. Fat and heat treatments had no significant influence on glycomacropeptide formation of ewe's and goat's milk. The results obtained indicate that the fat concentration and the fat globule membrane could influence the initial aggregation of the destabilised casein micelles.