Thermal behavior and hydration properties of yeast proteins from Saccharomyces cerevisiae and Kluyveromyces fragilis

Thermal and surface behavior of yeast protein fractions from Saccharomyces cerevisiae

“…3a); nevertheless, the process of denaturation starts to approximately 50-55 C. Then, in a first approximation, fresh and active yeast samples are composed by two protein fractions with different thermal stability. In a previous work (Otero et al, 2000), a main peak at 66.6 C was observed in DSC thermograms of active dry Temperature ( yeast; minor peaks at temperatures lower than 60 C and higher than 70 C were also observed probably due to conformational changes during the drying process. Enthalpy value of protein denaturation in fresh yeast (20.5 J/g) was higher than those obtained in dried samples (near 14-16 J/g, Otero et al, 2000Otero et al, , 2002, indicating a lower degree of denaturation in non-dried samples.…”

“…In the present work, the clean supernatant after the second step of centrifugation was treated in mild conditions, at 40 C with the addition of NaCl for 1 h in order to activate the endogenous ribonuclease. Yeast RNases exhibit optimal temperatures very close to 50 C. Otero et al (2000) reported that in S. cerevisiae protein samples, thermal denaturation starts below 50 C. Therefore, a lower incubation temperature (40 C) was chosen to preserve native structure of proteins. Fr III, obtained by acid precipitation of this supernatant is supposed to be composed mainly by cytoplasm proteins, especially nucleoproteins, which are released to the bulk of suspension once the external structures are disrupted.…”

“…Yeast biomass, as a byproduct of food industry, is a world-spread commodity and contains about half of its dry weight as proteins and other commercially important components, as polysaccharides that could be isolated for the upgrading of yeast production (Dzeziak, 1987b;Otero, Wagner, Vasallo, García, & Añ ó n, 2000;Otero et al, 2002). The limiting factors in the utilization of yeast biomass are its high nucleic acid content, mainly ribonucleic acid (RNA) and its poor functionality (Otero et al, 2000). Therefore the isolation of yeast proteins is an attractive alternative for the utilization of yeast biomass through its use as emulsifying, gelling and foam stabilizing agents in food systems (Dzeziak, 1987b).…”

Development of innovative biodegradable films based on biomass of Saccharomyces cerevisiae

“…Meanwhile, heat treatment produces enzymatic reactions inactivation, protein denaturing and unfolding of the triple helix of β-glucan present in the cell wall (Novák et al, 2012). Protein denaturation is guaranteed at the selected temperature (90°C), as it was demonstrated in previous studies using the whole cells of S. cerevisiae and denaturation temperature peak was approximately 66°C for these cells (Otero et al, 2000).…”

“…Nowadays, there are other applications that are gaining more attention. Yeast biomass, as a by-product of food industry, contains about half of its dry weight as proteins and as polysaccharides that could be isolated for the upgrading of yeast production Añón, 2000 andOtero et al, 2002). Wagner, Sceni, and Otero Rambla (2009) explained that a yeast cell suspension can be adequately treated and that is possible to isolate individual components of interest.…”