Pineapple juice preservation by pulsed electric field treatment

Abstract

The effect of pulsed electric field (PEF) treatment on pineapple juice, applied in a batch system, was studied in terms of change in microbial community, bioactive compounds, and antioxidant capacity. Among the bioactive compounds, total phenolic content (TPC), flavonoid, ascorbic acid, and β-carotene content were evaluated. The results were monitored over a 10 days of storage at −20 oC and compared with that of untreated juice sample. A PEF device-designed and fabricated in laboratory-was used for this purpose and the applied electric field strength were 9 kV/cm, 11 kV/cm, and 13 kV/cm at a frequency of 100 Hz. Highest microbial inactivation was observed at 13 kV/cm field intensity, which was the greatest possible field strength supplied by the PEF system. During storage, microbes grew in PEF treated juice, though at a slower pace than the untreated one, since the applied field intensity was far short of critical value to inactivate them entirely.