Obtenção de manoproteína e β-glucana de levedura descartada em cervejaria com potencial para aplicação em alimentos

Abstract

Yeasts of the genus Saccharomyces spp. are used as biotechnological tool in brewery and after five fermentative production processes; they are discarded by the beer industry. The cell wall of yeasts is mainly composed of β - glucan, which is a glucose homopolymer capable of changing the immune response in the host, and by manoproteins (MP), which have recognized emulsifying properties. The aim of the present study was to obtain these two cell wall fractions of discarded yeast employing an additional step to obtain MP in a process applicable to the extraction of β - glucan. The fractions obtained were characterized and MP was evaluated for potential for application as an emulsifier in mayonnaise formulations. From the cell wall of yeasts on dry basis, the MP and β glucan yield was 4.16% and 10 %, respectively. The residual moisture of β - glucan was 4.9 ± 0.1 % and MP was 3.9 ± 0.9 % and no changes in this parameter were observed during 28 days of storage in bi-oriented polypropylene packs (BOPP) at 10°C, 25°C or 40° C. The SDS-PAGE profile of MP showed proteins with molecular weight of 58 kDa and 64 kDa, and the highest content of constituent amino acids was observed for valine (8.9%), aspartic acid (8.2%) and leucine (6.9%). Each 100 g of mayonnaise prepared with MP at concentrations of 0.6%, 0.8 % and 1.0 % contained, on average, 25 ± 0.27 g moisture, 1.6 ± 0.10 g ash, 2.4 ± 0.04 g protein, 56 g ± 0.41 lipid and 14 ± 0.12 g carbohydrates, and no changes in attributes aroma, color, flavor and texture were observed in the study period (28 days). The results showed applicability of the method proposed for obtaining β -glucan and MP and suggest that MP has potential for application as bioemulsifier in foods, particularly in mayonnaise formulations.