Effect of atmospheres combining high oxygen and carbon dioxide levels on microbial spoilage and sensory quality of fresh-cut pineapple

Abstract

Fresh-cut fruit such as pineapple have a very limited shelf-life. The study aims at prolonging the shelf-life of fresh-cut pineapple by means of modified atmospheres (MAs). The effect of MAs combining high O2 (21–70%) and CO2 (21–50%) levels on microbial spoilage and sensory quality of fresh-cut pineapple was therefore evaluated. In the first part of the study, the behaviour of two spoilage yeasts (Candida sake and Candida argentea) and one lactic acid bacterium (Leuconostoc citreum), which had previously been isolated from spoiled commercial fresh-cut pineapple cubes, were monitored on pineapple agar separately. In the second part of the study, the shelf-life of commercial fresh-cut pineapple cubes packaged in selected MAs was evaluated at 7°C. The results showed that MAs combining high O2 and high CO2 levels had a large inhibitory effect on the growth and volatile metabolite production of C. sake and C. argentea on pineapple agar. A MA with 50% O2 and 50% CO2 was in both cases the most inhibitive. Although MAs induced the production of ethyl acetate by the yeasts, the quantity of ethyl acetate was much lower in high O2 and high CO2 than that in air due to lower yeast population density in MAs. With regards to growth, L. citreum was not sensitive to high O2 and CO2 levels. The fresh-cut pineapple packaged in air had deteriorated and were not acceptable any more by day 7, while those packaged in 50% O2 combined with 50% CO2, which also retarded the growth of aerobes and yeasts on pineapple cubes during storage, were still acceptable. It can be concluded that a MA with 50% O2 and 50% CO2 shows the best potential for extension of the shelf-life of fresh-cut pineapple.