Optimization of synbiotic yogurts with yacon pulp (Smallanthus sonchifolius) and assessment of the viability of lactic acid bacteria
Abstract The aim of this study was check the effects of sugar, yacon pulp and skimmed milk powder in the aroma, flavour, texture, appearance, overall impression and intent to purchase on synbiotic yogurts to optimize the formulation using Response Surface Methodology. The most accepted formulations were subjected to viability tests during 21 days by counting traditional and probiotic bacteria. Were constructed a complete 2 3 factorial design, totalling 17 experiments, and considered independent variables (percentage of ingredients) and dependent variables (sensory attributes). All attributes were graded using an acceptability assessment, for this balanced incomplete block was applied. The number of viable cells was determined using specific culture medium for each species. The percentage of yacon pulp had a pronounced negative influence on flavour, texture, appearance, overall impression and intent to purchase. Model predictions adjusted to the variables aroma, flavour, texture, appearance, overall impression and intent to purchase exhibited good predictive ability and hence could be used as tools for process control. Traditional bacterial strains and probiotic remained viable throughout the storage period. The counts of probiotic bacterial in the formulations were above 6 log CFU/g. The addition of