The Effect of Modified Atmosphere Packaging on ‘Ready-to-Eat’ Oranges

Abstract

The storage in modified atmospheres of oranges (Citrus sinensis), variety Salustiana, as a minimally processed product was studied. Several physical-chemical, microbiological and sensorial parameters relating to quality were investigated during a period of 11 days at a temperature of 4 °C. Two films of different permeability (A and B) and two distinct forms of preparation (manually separated segments and enzymatically peeled whole oranges) were used. For enzymatically peeled whole oranges the atmospheres created inside the bags were: for film A, the low-barrier film, 19 mL/100 mL O2and 5 mL/100 mL CO2; for film B, higher-barrier film, 14 mL/100 mL O2and 11 mL/100 mL CO2. For the segments, the atmospheres were 18 mL/100 mL O2and 10 mL/100 mL CO2for film A, and 3 mL/100 mL and 25 mL/100 mL respectively for film B. On no occasion during the first 11 days of storage were significant changes observed with regard to weight loss, acidity, °Brix and carotenoids. A greater development of mesophilic aerobic microorganisms was observed in the manually peeled oranges kept in the lower-barrier plastic (with an increase of two logarithmic cycles in 11 days). This increase was less in manually peeled oranges kept in the higher-barrier packaging and in enzymatically peeled oranges for both plastics tested. In both methods of preparation the lactic acid microorganisms grew more rapidly in the high-barrier plastic. From the point of view of sensorial quality, both the manually prepared segments and the enzymatically peeled whole oranges remained in a commercially viable condition for one week. After this, and coinciding with an increase in ethanol levels, problems with a loss of aroma and the appearance of strange tastes were noted. These effects were more pronounced in the case of manually separated segments packed in the high-barrier plastic, in which CO2content was greater.