Natural antimicrobials combined with ultrasound treatments to enhance quality parameters and safety of unpasteurized strawberry juice

BÁRBARA TOMADONI; LUCÍA CASSANI; MARÍA MOREIRA; PONCE ALEJANDRA; AGÜERO, MARÍA VICTORIA

International Journal of Fruit Science

Taylor & Francis

Año: 2019

1553-8362

The search for novel non-thermal preservation technologies iscontinuously growing, as traditional thermal processing may haveundesirable effects on sensory and nutritional properties of fruit juices.Therefore, the aims of this study were to find the ultrasound,pomegranate extract and geraniol levels that simultaneously optimizedifferent quality parameters of strawberry juice after 14 days ofrefrigerated storage (5°C) and evaluate the performance of the optimalcombination of these treatments to control a contamination withEscherichia coli O157:H7. Response surface methodology was applied foroptimization study where geraniol was applied at 0, 0.15 and 0.30μL/mL; pomegranate extract, at 0, 180 and 360 μg/mL; and ultrasoundtreatments were performed at 40 kHz during 0, 15, and 30 min. Theoptimum combination resulted in 0.15 μL/mL of geraniol, 360 μg /mL ofpomegranate extract and 30 min of ultrasound. This treatment was ableto significantly reduce microbial counts, with a low impact on sensoryattributes, while improving the antioxidant capacity of the productcompared to untreated juice sample. Also, it allows reducing thecontamination with E. coli to undetectable values. Thus, the optimizedtreatment resulted adequate for extending the shelf-life as well asincreasing the safety of strawberry juice.