Abstract
Fungi are the most important microorganisms contaminating fruit and fruit products like jams. Food industry uses different synthetic food additives to prevent mold and yeast spoilage. However, consumers concern for human health have forced producers to search for more natural alternatives to control food spoilage caused by microorganisms. In this work, the antifungal activity of cinnamon bark oil-in-water emulsions against Zygosaccharomyces bailii has been evaluated in vitro and in strawberry jam as well as the effect of these emulsions on the sensory properties of jam. For this purpose, 0.06, 0.08, 0.10 and 0.12 mg/g of cinnamon bark oil and 5 mg/g of xanthan gum were used. Emulsions were prepared by High Shear Homogenization (HSH) at 20000 rpm for 3 min and/or High Pressure Homogenization (HPH) at 400 and 800 bar. Cinnamon bark oil-in-water emulsions were characterized by measuring the particle size and the ζ-potential. The results obtained in the in vitro assays and in the physicochemical analysis determined the concentration of cinnamon oil used in emulsions: 0.08 and 0.10 mg/g at 400 bar. Strawberry jams with the selected emulsions were inoculated with Zygosaccharomyces bailii and incubated at 25 °C for 28 days. Total inhibition of Zygosaccharomyces bailii on samples containing cinnamon bark oil-in-water emulsions took place during the first 7 days of storage. The panellists identified a different sensory profile in samples after emulsion incorporation and significant differences (p<0.05) were found for all the sensory attributes evaluated, except for colour and consistency. The present work evidences the promising advantages of using emulsions as natural additives in the preservation of strawberry jams.
