High pressure processing and thermal pasteurization of strawberry pur,e: quality parameters and shelf life evaluation during cold storage

This study was aimed at monitoring changes in the quality of strawberry pur,e preserved by high pressure processing (HPP) and thermal pasteurization (TP) during cold storage (6 A degrees C) and determining its optimal storage period. The storage period of strawberry pur,e treated at 500 MPa, 50 A degrees C, 15 min based on microbiological changes was 12 weeks. During this period, pur,e lost 32% of polyphenols, 73% of anthocyanins and entire vitamin C. Color changes described as dE increased up to 5.05 whereas the overall sensory quality decreased by 3 points on a 9-point scale. Under similar storage conditions, TP-preserved purce lost only 28% of polyphenols and 54% of anthocyanins, and entire vitamin C. Color changes were more visible (dE = 7.21) compared to the HPP sample whereas the overall sensory quality decreased only by 2 points. Recommended cold shelf-life for the HPP product was estimated at 6 weeks, during which period HPP-preserved purce had higher content of polyphenols and colour parameters compared to TP purce.