Effect of high hydrostatic pressure application on the inactivation of Escherichia coli O157:H7 and the volatile profile of passion fruit (Passiflora edulis) juice

Abstract

The effect of passion fruit ( Passiflora edulis) juice treatment with high hydrostatic pressures (HHP) on the inactivation of Escherichia coli O157:H7 and some physicochemical and aromatic characteristics of the juice was determined. A 33 design was used considering pressure, temperature and treatment time (150, 200, 250 MPa; 25, 35, 45 degrees C; 0, 10, 20 min) as factors. A quadratic model was applied for the optimization of the process conditions using the response surface methodology. Escherichia coli in stored juice was estimated (72 h, 4 degrees C). The volatile profile was analyzed using the headspace solid phase microextraction (HS-SPME) technique and GC-MS. E. coli was inactivated from 150 MPa and 35 degrees C. The treatments had no effect on the total soluble solids (TSS) of the juice, suggesting acceptability by consumers. Regarding the volatile profile, the alcohols and esters responsible for the characteristic aroma of passion fruit decreased (16 \%) at 45 degrees C. The optimal conditions to obtain a microbiologically safe passion fruit juice, preserving its aromatic composition, TSS and pH were 200 MPa, 35 degrees C and 10 min.