Effect of Gamma Irradiation Treatment and Storage on Physico-chemical, Microbial and Sensory Quality of Minimally Processed Pineapple (Ananas comosus)

Aims: The aim of the study was to assess the effect of gamma irradiation dose on quality attributes of minimally processed pineapple.
Study Design: Physico-chemical quality parameters such as Total Soluble Solids (TSS), Titratable Acidity (TA), pH, Total Sugars (TS), Reducing Sugars (RS), Vitamin C, as well as Sensory and microbial quality of irradiated cut pineapples were studied over a period of 12 days at 5ºC.
Place and Duration of Study: This study was carried out at the Radiation Technology Center of Biotechnology and Nuclear Agriculture Research Institute, between May 2012 and June 2012.
Methodology: Smooth cayenne pineapples were cut into cubes and irradiated at three doses; 0 kG, 2 kGy and 3 kGy. Irradiated samples were stored at 5ºC and quality analysis carried out every 4th day of storage, for 12 days. Physicochemical analysis was also carried out according toAnalysis of the Association of Official Analytical Chemists (AOAC 1990) methods. Microbial counts including total plate count, total coliform count, total yeast and moulds count and Salmonella were assessed. Sensory attributes including sweetness, colour, flavor, texture and overall preference for the cut pineapples were assessed using 30 semi trained panelists.
Results: Results showed that irradiation treatment had no significant effect (P = 0.13) on Vitamin C, TSS, TS and RS, but significantly (P = 0.03) caused changes in pH and TA. Significant decreases (P = 0.02) in vitamin C was observed during the storage period in both control and irradiated samples. Sensory evaluation revealed that irradiation at 2kGy and 3kGy did not significantly affect (P = 0.15) the ratings of any of the sensory attributes assessed.
Conclusion: Gamma irradiation was effective in reducing the overall microbial load of minimally processed pineapple. Irradiation treatments at 2 and 3kGy and storage for about 8 days could enhance hygienic quality of minimally processed pineapple.