Manufacture of yoghurt from stored frozen sheep’s milk
The effects of long-term deep-frozen storage of sheep’s milk on its physicochemical, microbiological and physical stability characteristics,as well as on the corresponding characteristics and the sensory attributes of the yoghurt manufactured from the storedfrozen milk after thawing were examined. Bulk whole sheep’s milk, after clarification and pasteurisation (72 C for 15 s), wassampled for analysis and then poured into plastic bags, frozen in a moving-air freezer at 25 C in thin blocks (21 cm long, 21 cmhigh and 2.7 cm thick) weighing about 1.2 kg, and stored at 20 C for up to 6 months. At 2, 4 and 6 months of storage, sampleswere removed, thawed and analysed. Moreover, set type yoghurts were manufactured from these samples and examined. The resultsindicated that there were no significant (P>0.05) differences between fresh (control) and stored frozen milk samples in pH, acidity,acid degree value, peroxide value, protein sediment, apparent viscosity or coliform counts. The frozen samples had significantly(P0.05) differences in pH, acidity, lactose,appearanceand colour, body and texture, flavour, overall acceptability, consistency, apparent viscosity or syneresis were observed between thecontrol milk yoghurt and the yoghurts made from milk stored frozen for up to 6 months. # 2002 Elsevier Science Ltd. All rights reserved.