Extraction of yeast cell compounds: Comparing pulsed electric fields with traditional thermal autolysis

Extracts from yeast cells (YE) are widely used in the food, nutraceutical, and pharmaceutical industries due to their rich composition of proteins, bioactive peptides, nucleotides, and free amino acids. Conventional heat-mediated autolysis is the predominant procedure to obtain YE but requires prolonged incubations at temperatures higher that 50 °C. Pulsed Electric Fields (PEF) have emerged as a promising non-thermal technology capable of enhancing intracellular compound release while preserving their bioactivity. This study evaluates the efficiency of PEF-assisted extraction compared to conventional autolysis for obtaining extracts from Saccharomyces cerevisiae. Yeast suspensions were subjected to PEF treatments (20 kV/cm, 150 μs) followed by incubation at 25, 35, and 55 °C for up to 48 h. The extraction yields of glutathione (GSH), proteins, free amino nitrogen (FAN), nucleic acids, and individual amino acids were analyzed. Results demonstrated that PEF significantly accelerated compound release, achieving over 70 % of total GSH extraction within 1 h, compared to 24 h for conventional autolysis. RNA was also released faster, reaching 80 % within 1 h at 55 °C, whereas heat-mediated autolysis required 48 h. Additionally, PEF-treated extracts exhibited enhanced proteolysis, yielding up to 10-fold higher concentrations of essential amino acids such as threonine, methionine, and leucine. Principal component analysis confirmed distinct amino acid profiles, indicating improved extraction efficiency. These findings highlight PEF as a scalable, energy-efficient alternative to conventional autolysis, enabling faster processing at lower temperatures while preserving functionality. This innovative approach could, offering a more sustainable and efficient method for obtaining extracts from yeast.