Anti-stress effect and functionality of yeast hydrolysate SCP-20

SCP-20, an SCP-carbon which is a treated SCP-20 with active carbon, and extracts of St John's wort (St-wort) were tested to compare their anti-stress effects. When the SCP-20, SCP-carbon and St-wort were ingested by the rats for 8 days prior to being subjected to a 48 h stress period, they showed anti-stress effects on their changes of weight for the adrenal glands, spleen, thymus and thyroid in comparison with the stressed control. The levels of epinephrine and norepinephrine in plasma were increased by immobilized stress. St-wort, SCP-20, and SCP-carbon lowered the elevated levels of epinephrine and norepinephrine to near control levels. Emulsifying and foaming properties of the SCP-20 and SCP-carbon were measured in the range pH 3-8. The emulsifying activities of yeast hydrolysates increased to a high level near neutral pH, but decreased in acidic conditions. The emulsifying activity in SCP-carbon was higher in the acidic pHs than that in SCP-20. The patterns of the emulsion stabilities for SCP-20 and SCP-carbon were similar to those of the emulsifying activities. SCP-20 and SCP-carbon showed poor foaming capacity from pH 4.0 to 7.0. In particular, SCP-carbon showed lower foaming capacity and foam stability than SCP-20.