IN VITRO GROWTH INHIBITION OF PATHOGENIC AND FOOD SPOILAGE YEASTS AND FUNGI BY PEPPERMINT (MENTHA PIPERITA) ESSENTIAL OIL AND SURVIVAL OF SACCHAROMYCES CEREVISIAE IN FRUIT JUICES

Abstract

In the present research, the antifungal and antioxidant activities of Mentha piperita essential oil (MPEO) were investigated, and its potential as a natural food preservative in Orangina juices was evaluated. The major component was menthol (54.47%). The percentage inhibitions of MPEO were dose dependent with IC₅₀ values of 2.53±1.77 mg/mL in DPPH test and 8.24±1.16 mg/mL in metal complexing ability. The microbial inhibition of MPEO was assessed against different food spoiling strains. The MPEO strongly inhibited the growth of Rhodotorula sp. and Saccharomyces cerevisiae with a diameter of the inhibitory zone (DIZ) ranging from 17–85 mm at the lower dose (20 µL), and from 35-85 mm at the higher quantity (60 µL). The minimum inhibitory concentration varied from 0.0078 to 0.5% (v/v) for yeasts. In addition, the anti-yeast effectiveness of MPEO alone and in association with moderate heat treatment was investigated in Orangina juices. The juices treated with association of MPEO at different doses (1, 2 and 6 µL/mL) and medium heat treatment (80 °C for 2 min) improved the reduction of Saccharomyces cerevisiae viability cells. Present data confirmed the superior performance of integrated thermal treatment over individual use of peppermint oil for Orangina juices preservation.