The utilization of surplus herring for the production of oil and of a protein feeding‐stuff by the process of alkali digestion

In a herring‐reduction method in which sodium hydroxide was used to dissolve minced herrings to enable most of the oil to be recovered, studies have been carried out on the recovery of the protein fraction, both in the laboratory and on a commercial scale. After digestion with 2% alkali, the protein recoverable by acidification falls by 18.6% at 70°, by 30.8% at 90° and with 3% alkali by 54.5% at 90° in 12 hours. Some practical feeding trials, giving the relationship between method of treatment and damage to protein, are discussed.