Abstract
Three types of whey viz., paneer whey, cow milk cheddar cheese whey and buffalo milk cheddar cheese whey were concentrated through reverse osmosis to 20% TS, followed by further concentration to 40, 45, 50 and 55% TS in a vacuum evaporator. Pre-crystallization of whey concentrates was carried out at 30℃ for a period of 6 h by adding alpha-monohydrate lactose as seeding material at concentration ranging from 0.01 to 0.07%, in order to standardize the technique to produce nonhygroscopic whey powder. Results of the investigation revealed that in case of paneer whey concentrate (PWC) a maximum of 67% crystallization could be achieved at 50% TS within a period of 4 h with a seeding material of 0.03% and the crystals being below 20 μm size. Similarly, cow milk cheddar cheese whey concentrate (CWC) and buffalo milk cheddar cheese whey concentrate (BWC) yielded a maximum of 63% and 58% lactose crystallization, respectively at 0.05% seeding material at 50% TS within a period 4 h and almost all the crystals being below 20 μm size. Further increase in duration of seeding or seeding material did not improve either lactose cristallization or size distribution of lactose crystals. Further cooling of concentrates to 10% at the rate of 3℃ per h with agitation increased the crystallization to 70, 75 and 73%, respectively in case of PWC, CWC and BWC. When such pre-crystallized concentrate were spray dried resulted in free flowing whey powder free of hygroscopicity and caking problems.
