Investigation of physicochemical, microbiological, textural, and sensory properties of set-type yogurt with Mentha pulegium L. (pennyroyal) powder

Abstract

In this study, five types of yogurt samples were produced with different concentrations (0% [control group], 0.05%, 0.10%, 0.15%, and 0.20%) of Mentha pulegium L. (pennyroyal) powder (MPP) and their physicochemical, textural, sensory, and microbiological properties were investigated on the 1st, 7th, and 14th days of storage. Increasing concentrations of MPP affected the L* and a* values of yogurt considerably. About 0.05% and 0.15% MPP addition improved the textural properties of yogurt samples. The higher the MPP concentration, the lower the lactic acid bacteria counts were; however, the numbers were still over the minimum requirement for yogurt. Fibrous and filamentous structures in yogurt samples with MPP were monitored by scanning electron microscopy. Consequently, it can be stated that MPP can be successfully added to yogurt. Furthermore, considering sensory evaluations, it would be plausible to say that yogurt samples containing MPP up to 0.10% may have market potential in the future. Practical applications Currently, there is a growing trend of healthy and functional foods throughout the world. Dairy product, especially yogurt, is one of the best conveyors for the functional ingredients. Therefore, enrichment of yogurt with different herbs/spices/fruits attracts great attention among consumers. Mentha pulegium L. (MPP, pennyroyal) is a functional herb and a good candidate to be utilized in yogurt with its dense aromatic properties. This study presents the first findings of MPP incorporation into yogurt. MPP addition up to 0.10% was found acceptable considering textural and organoleptic properties. Lactic acid bacteria counts in yogurt samples slightly decreased with increasing concentrations of MPP. The results of the research showed that MPP can be utilized in yogurt up to 0.10% without any problems.