Abstract:
Formulation is an important factor for the production of Active Dried Yeast (ADY).Different additives were used in this study to increase viability of S. cerevisiae during dryingprocess. Carboxy methyl cellulose, guar gum and karaya gum were used as a stabilizer atconcentrations of 0.5-5 %(w/w). Sorbitan monostearate were selected as an emulsifier atconcentration of 0.5-7.5 %(w/w). Butylated hydroxy toluene, butylated hydroxy anisole andpropyl gallate, an antioxidant were used at concentration of 0.025-0.5 %(w/w).Firstly, only one additive was used to formulate the yeast. The study shown that 1.15 %(w/w) guar gum gave the highest viability of 29 % followed by 0.23 %(w/w) propyl gallate (23% viability) and 7.5 %(w/w) sorbitan monostearate (20 % viability). The combinations of 1.15 %(w/w) guar gum and 7.5 %(w/w) sorbitan monostearate increased cell viability to 39 %. Whenguar gum or sorbitan monostearate was used in the formulation, the addition of propyl gallatecould not increase the viability of yeast cells. Moreover, the higher concentration of antioxidant,the viability of yeast cell was lower due to the toxicity of phenolic compounds of the antioxidant.The viability of dried yeast increased to 43 % when 1 %(w/w) calcium monohydrogenphosphate (CaHPO4) was added together with 1.15 %(w/w) guar gum and 7.5 %(w/w) sorbitanmonostearate. Due to the lower number of viable cells per gram of ADY, the activity (CO,production) of ADY was lower than the cream yeast. The quality of ADY in term of CO,production from this study was comparable to Instant Success but not as good as Fermipan.From the study, the best formulation for drying purpose was 1.15 %(w/w) guar gum, 7.5%(w/w) sorbitan monostearate and 1 %(w/w) calcium monohydrogen phosphate. The addition ofpropyl gallate in the formulation and the storage at low temperature could prolong the shelf lifeof the dried yeast.