Abstract
The main objective of this study was to evaluate the feasibility of developing shelf stable avocado puree processed with pressure-assisted thermal sterilization (PATS). A pressure of 600 MPa and initial vessel temperature of 90 degrees C was used over 5 min processing time. Two high barrier polymeric packages were used: Film A-PE/PA6//EVOH and Film B-AlOx-coated PET//AlOx-coated PET//AlOx-coated PET//ONy//CPP. Ascorbic acid with concentration of 0.4 g/kg of avocado was added to puree to enhance its color stability (pH 6.6). Results showed that the weight loss was lower in package B (0.5%) than in package A (4-5%) over 104 days of storage at 23 degrees C. Instrumental color (greenness) of the puree in both packaging changed significantly (p > 0.05) during storage despite the addition of ascorbic acid; however, total color changes of puree in film B were lower than film A. There was no significant (p > 0.05) degradation of chlorophyll concentrations of PATS-processed avocado during storage. The dissolve oxygen concentration in avocado puree during storage was stable and the maximum normalized dissolve oxygen was less than 1%. Lipid oxidation of the fortified and plain avocado puree packaged in films A and B was stable with no significant (p > 0.05) changes during storage. Total plate count of avocado puree after PATS and during the 3 months of storage was below the detection limit. The results suggest that shelf stable avocado puree with limited shelf life could be developed using the PATS process.