Abstract

In this research, the protective culture (Lactobacillus rhamnosus LC705 andPropionibacterium freudenreichii JS) and biopreservatives as Nisin (Nisaplin), Delvocid^®(natamycin) or Nipasol M (propyl paraben) on the physical, chemical and sensory properties of strained yoghurt were studied in relation to its viability of undesirable yeasts-moulds during storage at 4±1°C for 28 days. Based on chemical and physical characteristics studied, there were no effective or negative effect originated from these preservatives. Moreover control samples had lower scores especially at the end of storage. The preservative supplemented strained yoghurts were protected from yeast and mould growth. The inhibitory action of protective culture against yeast and moulds  depended on type of preservatives. Also, use of protective culture or bio preservatives did not affect sensory properties of strained yoghurt.

Key words: Biopreservatives, fermented milks, protective cultures, strained yoghurt, yoghurt.