The Effect of Essential Oils on the Survival of Bifidobacterium in In Vitro Conditions and in Fermented Cream

Mariola Kozłowska,Jolanta Małajowicz,Magdalena Rudzińska,Małgorzata Majcher,Karolina Michewicz,Małgorzata Ziarno

doi:10.3390/app12031067

Mariola Kozłowska, Jolanta Małajowicz + Show 4 more

Open Access

https://doi.org/10.3390/app12031067

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Abstract

Essential oils derived from plant materials are a mixture of compounds that exhibit antibacterial properties. Due to their distinct aroma, they also serve as a desirable natural additive for various food products, including dairy products. In this study, the essential oils of lemon peels, clove buds, and juniper berries were obtained by steam distillation and characterized using gas chromatography–mass spectrometry to determine their chemical compositions and effects on the viability of seven Bifidobacterium strains. Furthermore, the effect of essential oils on the viability of Bifidobacterium animalis subsp. lactis Bb-12 was investigated in cream samples during fermentation and after storage for 21 days at 6 °C. The fatty acid composition of fat extracted from essential oils containing sour cream samples and the volatile aroma compound profile of the sour cream samples were also determined chromatographically. Among the 120 compounds identified, monoterpene hydrocarbons were dominant in the essential oils of lemon peels (limonene and γ-terpinene) and juniper berries (sabinene and β-myrcene), while eugenol and eugenol acetate were abundant in the essential oil of clove buds. In addition to these compounds, butanoic and acetic acids were found in the tested sour cream samples. In turn, fat extracted from these samples was rich in saturated fatty acids, mainly palmitic acid. Among the tested strains of the genus Bifidobacterium, B. animalis subsp. lactis Bb-12 was the most sensitive to the essential oils of clove and juniper, as indicated by the larger growth inhibition zones. However, both the concentration and type of essential oils used had no effect on the number of cells of this strain present in the cream samples immediately after fermentation and after its 21-day storage, which suggests that the tested essential oils could be a natural additive to dairy products.

Highlights

Among the 120 identified components representing 96.59–99.54% of the total oils, 34, 47, and 72 belonged to the etheric oil obtained from clove buds, lemon peels, and juniper berries, respectively
The essential oils obtained from lemon peels, clove buds, and juniper berries by the steam distillation method showed antimicrobial activity against the tested strains of Bifidobacterium in in vitro conditions
Neither the type of essential oil nor its concentration had any influence on the number of B. animalis subsp. lactis Bb-12 cells in the samples of cream directly fermented with this strain and those stored for 21 days at 6 ◦ C

Summary

Introduction

They hydrolyze sugars and produce lactic and acetic acids, which are metabolic end products. They reduce the pH of the contents in the large intestine and, the levels of various harmful substances, including ammonia [2]. Bifidobacteria can utilize ammonia as a source of nitrogen. Due to their low pH, they exert an antibacterial effect, inhibiting the growth of pathogenic microorganisms such as Shigella, Salmonella, and Staphylococcus, as well as enteropathogenic Escherichia coli strains. Bifidobacteria-containing formulations used to treat constipation promote the production of organic acids by these bacteria, which stimulate normal intestinal peristalsis [4]. Studies confirm that some of the bifidobacteria strains have excellent probiotic potential and, can be included in formulas used for infants who cannot be fed with their mother’s milk [5]

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