Improving functional properties of “Piel de Sapo” melon juice by addition of a Lippia citriodora natural extract and probiotic-type lactic acid bacteria

Six selected lactic-acid probiotic-type (PT-LAB) bacteria were screened for sensitivity towards a Lippia citrodora extract with reported functional properties (PLX®). The effect of pH (6.7 and 5.5) and temperature (35 °C and 4 °C) on the minimum inhibitory concentrations (MICs) was determined by the microdilution broth assay. PLX® MIC values at 4 °C were lower than those at 35 °C, and at pH 5.5 were generally higher than those at pH 6.7. After storage at 4 ºC-4 days, both plain “Piel de Sapo” melon juice (MJ) and fortified with PLX® (PLX®FMJ) at 2500 μg/mL (maximum sensorial acceptable limit in MJ), maintained the viability of the six PT-LAB bacteria. Additionally, four of these bacteria showed growth potential (δ > 0.5) in MJ and only one of them (Lactobacillus rhamnosus GG) in PLX®FMJ. PLX® synergistically increased the antioxidant activity of MJ. PLX® and PT-LAB are promising ingredients to increase the functional properties of “Piel de Sapo” MJ.