Antifungal efficacy of natural antimicrobial substances during the fermentation and storage of hardaliye

Abstract

Hardaliye is a non-alcoholic traditional fermented beverage produced using black grapes, mustard seeds, sour cherry leaves, and sodium benzoate. In this study, the effect of using plant materials (quince leaves, green tea, mulberry leaves, linden flowers, horseradish roots) as an alternative to sodium benzoate for inhibiting yeast growth to produce additive-free hardaliye was investigated. Hardaliye samples were produced using the selected test materials, microbiological and chemical analyses were performed during fermentation (20 °C for 18 days) and storage (4 °C for 2 months) periods. Additionally, the antifungal effects of test material extracts against Saccharomyces cerevisiae in grape juice and Malt Extract Broth (MEB), as well as the survival of S. cerevisiae in grape juice containing plant materials were examined. Only mustard seed extract had inhibitory and fungicidal effects at 25 mg/mL on S. cerevisiae in MEB among the tested plant material extracts and the effect increased when used in combination with grape juice. The total phenolic contents of the hardaliye samples were in the range of 2119.26–8653.33 mg gallic acid equivalents (GAE)/L, and antioxidant activities were in the range of 30.24–93.15%. The numbers of S. cerevisiae decreased below the detection limit (<1 log CFU/mL) after 1 day in grape juice containing horseradish (5%), mustard seeds (1.5%) or sodium benzoate (0.1%). This study indicated that crushed mustard seeds at increased concentrations (1.5%), mustard seeds water extract (7.5 mg/mL), or horseradish roots (5%) have the potential to be used in the production of hardaliye as an alternative to sodium benzoate.