Chemical characterization of yeast autolysate and assessment of the acceptability of cheese buns containing dried autolysate

Abstract

Objective
This study aimed to study the properties of yeast (Saccharomyces cerevisiae) autolysate obtained from pot still rum, including centesimal composition, amino acid profile and microbiological analysis, and perform a sensory analysis of cheese buns (also known as Brazilian cheese bread or rolls) enriched with dried autolysate.
Methods
Autolysate was obtained by rinsing and autolyzing the biomass and dried on a tray dryer at 70º. Its composition was then determined (fat, protein, total fiber, soluble fiber, insoluble fiber, ash and amino acid contents) followed by microbiological analysis. Finally, cheese buns enriched with dried autolysate were submitted to sensory analysis using the hedonic scale and attitude test.
Results
Dried autolysate contained 1.2% fats; 24.7% proteins; 51.3% total fiber, where 2.4% was soluble and 48.9% was insoluble; and 6.2% ash. According to microbiological analysis, the product complied with the microbiological limits established by the Agência Nacional de Vigilância Sanitária. Amino acid profile showed that histidine and methionine-cystine levels were low. Sensory analysis indicated good acceptance of the cheese buns. Only their color and appearance received low scores. Most participants reported liking the cheese buns and willingness to buy them on occasion.
Conclusion
The protein and amino acid levels found in pot still rum were lower than those reported in the literature for breweries and ethanol distilleries. Dried yeast was microbiologically suitable for human consumption. The low grades given to the appearance of the cheese buns were probably due to their unappealing dark color, as opposed to the usual pale yellow color. Future studies could suggest the addition of dried yeast to products whose visual appeal will not be as affected.