Strawberry polyphenols with antihypertensive and antioxidant activities as natural antifungal in strawberry-orange juice

Abstract

Tucumán is the leading producer of strawberries in Argentinaand consumption of strawberry juice is high. The contaminatingmicrobiota that can be present in strawberry juice is mainly constitutedof yeasts extraordinarily resistant to chemical preservativescommonly used in the juice industry. On the other hand, there isa high amount of damaged strawberries which is discarded duringharvest, so that their reutilization as source of polyphenols withantifungal activity could be a good alternative.The aim of this work was the recovery and identification ofphenolic compounds present in strawberries and the investigationof their beneficial properties, such as antimicrobial, antihypertensiveand antioxidant activities. Orange-strawberry juice was usedas food model system. Our results demonstrated that strawberrypolyphenols possess antioxidant and antihypertensive activities upto 60%. Microbiological and sensorial analysis of juices enrichedwith polyphenols and inoculated with yeasts were performedthroughout two weeks of storage at 4, 20 and 28 ◦C. The addition ofphenolic compounds significantly increased antioxidant and antihypertensivecapacity of strawberry-orange juice when comparedto fresh control. Polyphenols treatments, alone or combined withmetabisulfite, completely killedspoilage yeasts in juice samples,at all conditions tested. Thus, polyphenols from strawberry couldbe feasible alternatives to improve microbiological quality withlow impact on the organoleptic properties of polyphenols-enrichedstrawberry-orange juice.