A new or improved process of preparing a soluble food extract from brewers' yeast

摘要

A soluble food extract is produced from brewer's yeast by separating and filtering liquefied and digested yeast extract produced by peptonization of the yeast, adding a colloid adsorbing agent to remove bitter and other undesirable flavours and subjecting to the combined action of centrifugal separation and filtration to remove the residual colloid adsorbing agent. As described, the yeast is first liquefied by agitation in a mixing machine, e.g. at 65 DEG C., with addition of a small amount of common salt. It is then digested at the same temperature for a lengthy period, e.g. 72 hours, and diluted and separated in a centrifuge, from which the clear liquid and the insoluble sediments are removed separately by two collectors constructed as described in Specification 450,131, [Group II]. The extract is next fittered in a centrifugal filter constructed as described in Specification 450,130, [Group II], the filter member preferably consisting of a layer of pulp with an adsorptive constituent, e.g. 90 per cent of cellulose with 10 per cent of asbestos. The clear liquid passes to a forced circulation evaporator, after which it is brought to and maintained for a period, e.g. one hour, at about 70 DEG C. during a portion of which time activated carbon is added up to 0,75-1 per cent by volume with vigorous stirring. The bulk of the activated carbon is then removed in the plain centrifuge and the residue by subsequent filtration in the centrifugal filter which is speeded up and the filter of which may consist of a 2-inch layer of a pulp containing 60-80 per cent of cellulose and 40-20 per cent of asbestos. The extract is concentrated under vacuum to a thick paste which is redissolved in hot water and heated up to about 97,8 DEG C. to destroy proteolytic enzymes and complete the separation of insoluble phosphates, some coagulation of protein matter also occurring which encloses and removes the last traces of colloidal carbon. The heated liquid is then recentrifuged in the plain centrifuge and evaporated in a forced circulation evaporator to obtain the final pure extract.