Production of extracellular emulsifiers from yeasts for using in dairy and food products
2009
Amer, A.E.A. | Sherif, S.A. | Moushdy, I.M. | El-Magdoub, M.N.I.
The main objective of this study was to test the ability of a number of yeast strains for production extracellular bioemulsifiers for potential use in food. An emulsifying agent was extracted from each strain of yeast tested, including 9 species of genera other than Candida utilis. From the 11 products tested, eight had emulsifying properties that were better than those of commonly used as food emulsifiers' mono-glyceride (Glycerol monoleate). Candida utilis EMCC 120 was selected for further study due to the excellent emulsification properties of its extracellular product and the food grade status of the yeast strain. Extracellular bioemulsifiers extracted emulsifier was purified by ultrafiltration. The purified product was evaluated for chemical and physical stability to establish its potential use as a natural emulsifier in processed foods. The yield of purified bioemulsifier was 3.2 gl. 1 of the original dry cell weight for Candida utilis EMCC 120, and 0.85 gI. 1 for Saccharomyces cerevisiae EMCC 69. Carbohydrate content of the purified bioemulsifier was 76%. Protein content was 23.75 for Candida utilis EMCC 120. Butter oil-in-water emulsions were stabilized over a broad range of conditions, from pH 2 to 11, with up to 5% sodium chloride or up to 15% sucrose in the aqueous phase. In the presence of a low concentration of various solutes, emulsions were stable to three cycles of freezing and thawing.
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