Development of innovative biodegradable films based on biomass of Saccharomyces cerevisiae

• Saccharomyces cerevisiae cells are able to form films when specific treatments were applied to yeast dispersions.
• Cytoplasmic components must be released from cells at high homogenisation pressure (125 MPa).
• High pressure homogenisation, a heat treatment and a final homogenisation are three steps needed to obtain a good film.
• Hydration of films was increased with the number of homogenisation processes applied to yeast dispersions.
• Yeast biomass could be a promising choice to traditional sources of biopolymers to generate new eco-friendly packaging.

Biodegradable alternatives to petroleum-based polymers are being developed for food packaging. Saccharomyces cerevisiae has been widely used for the production of fermented beverages and leavened foods. In this work, the application of high pressure homogenisation and a thermal treatment to the yeast biomass was studied to develop biodegradable films. The highest dispersibility indexes of protein (84.5 ± 3.3%), carbohydrates (24.3 ± 1.1%), RNA (40.6 ± 0.9%) and soluble solids released were found at high homogenisation pressure (125 MPa). Combinations of one or two homogenisations and a thermal treatment at 90 °C during 20 minutes were applied and dispersions were fully characterised, focusing on their film-forming capacity. The best combination was homogenisation, heat treatment and a further homogenisation, since it produced films that presented good attributes, great continuity and homogeneity without small cracks. However, hydration of films was increased from 0.31 to 0.48 gH2O/g.d.m with the number of homogenisation processes applied. Results revealed that yeast biomass is a viable source to be used in biodegradable films.Industrial relevanceSaccharomyces cerevisiae yeasts have many applications in food industry. The development of biodegradable films based on yeast biomass carries many advantages such as, the possibility of using commercial pressed baker's yeast or an industrial residue from brewing industry, the use of a low-cost sources and the application of environmentally friendly procedures. The methodologies applied for the development of the film forming dispersion, high pressure homogenisation and thermal treatment, are able to be scaled-up to an industrial level.