THE EFFECT OF DIFFERENT HEAT STERILIZATION REGIMES ON THE QUALITY OF CANNED PROCESSED CHEESE

The impact of four different regimes of heat sterilization (110C for 100 min, 115C for 32 min, 120C for 10 min and 125C for 3.2 min) on the properties of processed cheeses was evaluated. Also, nonsterilized samples were analyzed. Samples without and with the addition of lactose (0.5–2.0% w/w) were studied because lactose might be present in raw materials at various concentrations and might significantly affect processed cheese quality. All the sterilization regimes ensured inactivation of microflora. When the sterilization temperature was reduced (with simultaneously prolonged exposure time) the samples showed worse sensory properties. Significant hydrolytic changes of proteins and larger amino acid losses were also detected. The smallest changes were noted in products treated at 125C for 3.2 min. The heat treatment at 120C for 10 min caused acceptable modification of cheese properties. Addition of lactose higher than 1.0% w/w was found unsuitable for the production of sterilized processed cheeses. PRACTICAL APPLICATIONS Processed cheese is a natural cheese-based foodstuff manufactured using heat treatment (especially at 80–100C). Sterilized processed cheese is a specific product with prolonged shelf life, which could be used either in everyday life or for military and rescue team boarding during operations (Buňka et al. 2004). This product is manufactured in many countries but only limited scientific information about its quality and properties is available. Powdered skim milk and whey (used mainly for cutting the costs of the ingredients), which contain high amounts of lactose, are widely used in production of processed cheese. Lactose can show a deteriorating effect on the quality of processed cheeses, especially after application of severe heat treatment. Results of this study could be useful for setting sterilization time and temperature in order to manufacture products with high nutritive and sensory value. Moreover, a comparative study exploring acceptable lactose concentration value was carried out.