The effect of high pressure on selected properties of yoghurt

The aim of the experiment was to assess the possibility of applying the high pressure technique for yoghurt preservation. Yoghurt subjected to pressures of 200-700MPa/15min (18C) was stored at temperatures of 4 and 20C for four weeks. The scope of examination included the effect of pressurisation on the survivability of yoghurt microbiota, acidity and organoleptic features. The extent of bacteria inactivation was found to have increased with the applied pressure. Lower survivability of microflora was observed in yoghurts stored at 20C as compared with those stored at 4C. Intensive increase in acidity was observed in the non-pressurised yoghurt, whereas this feature in the pressurised product remained constant or grew slightly during the four weeks of storage. Pressures ranging from 300 to 700MPa brought about slight deterioration of the yoghurt consistency. Pressurised yoghurt kept at 4C preserved its good organoleptic quality longer than the non-pressurised product.