Microencapsulated oregano essential oil in grated Parmesan cheese conservation

Abstract

The objective of this study was to produce particles containing oregano essential oil by spray drying applying whey protein isolate as wall material, and to evaluate its antimicrobial effect on inhibiting growth of fungi in grated Parmesan cheese. The microcapsules contained 18% (w/w) of oregano essential oil and a 90% microencapsulation efficiency was found. Carvacrol, cymene, γ-terpinene, thymol and β-caryophyllene were the main components identified in free oregano essential oil and in the oil extracted from the microcapsules. Application of microencapsulated oregano oil was effective inhibiting the growth of fungi and yeast during 45 days of grated cheese storage. Only the treatment containing 0.5% of microencapsulated oil still remained with undetectable counting, being considered the most effective treatment in the control of filamentous fungi and yeast growth in grated parmesan cheese. The study confirms the antimicrobial effect of oregano oil and the maintenance of the microcapsules antimicrobial activity over the storage time.