Optimization of modified atmosphere packaging with respect to physicochemical characteristics of Requeijão

The effects of modified atmosphere packaging on physicochemical and sensorial characteristics (contents of free fatty acids, lactose, lactic acid and moisture, as well as pH and rigidity) in Portuguese whey cheese (Requeijão) were studied following a response surface methodology using storage time, storage temperature and fraction of CO2 in the flushing gas as manipulated variables. Inspection of the sensorial optima in terms of the different parameters indicated that it is convenient to set the storage temperature equal to 4°C because no significant lipolysis takes place, irrespective of overhead atmosphere. Plain CO2 as flushing gas will in general ensure more constant composition until 15 days and will provide protection against extensive lipolysis. In terms of overall visual aspect, all packaged cheeses were preferred to their unpackaged counterparts; however, in terms of acidic smell, only whey cheeses stored at 4°C exhibited significant differences relative to those stored at higher temperatures.