Patent ID: 6190715
Filing Date: 2001-02-20
Classification: C11B

Abstract:
A method for producing edible quality refined fish oil from cooked, pressed fish comprising the steps of:extracting press liquor from said cooked fish, wherein said press liquor consists essentially of fish oil and water that is inherent in the cooked fish flesh;lowering the pH of said press liquor by adding an acid to said press liquor;separating said press liquor into a fish oil component and a water component, wherein said fish oil component contains of a homogenous mixture of stearine and olein;monitoring the pH of said water component;adjusting the flow of said acid to said press liquor to maintain a pH of less than 2 of said water component,wherein said acid addition deactivates enzymes present in said fish oil that encourage unsavory taste and smell of said fish oil;filtering moisture and insoluble impurities from said fish oil;chilling said fish oil component, without agitation, to crystallize said stearine, then filtering said olein from said stearine to produce a cold filtered fish oil;removing free fatty acids from said cold filtered fish oil including the steps of:mixing an aqueous alkali solution with said cold filtered fish oil to produce water soluble soaps from said fatty acids in the cold filtered fish oil;extracting said water soluble soaps from said cold filtered fish oil;injecting further water into said cold filtered fish oil to create a water and cold filtered fish oil mixture, wherein the temperature of said water is above the temperature of said cold filtered fish oil;mixing gently said water and cold filtered fish oil mixture in a mixing/retention loop, wherein said fatty acids that remain in said cold filtered fish oil are dissolved in the water constituent of said water and cold filtered fish oil mixture; andseparating said water constituent from said water and cold filtered fish oil mixture, thereby removing most of the fatty acids from said cold filtered fish oil;bleaching said cold filtered fish oil in a vacuum vessel to produce a bleached fish oil including the steps of:producing vacuum conditions inside of said vacuum vessel;heating said cold filtered fish oil to a first elevated temperature;mixing amorphous silica with said cold filtered fish oil;mixing diatomaceous earth with said cold filtered fish oil;heating said cold filtered fish oil to a second elevated temperature;ceasing said vacuum conditions inside of said vacuum vessel by introducing an inert gas into the head space of said vacuum vessel; andfiltering and cooling said now bleached fish oil; anddeodorizing said bleached fish oil under vacuum conditions in a steam distillation batch deodorizer to produce an edible quality refined fish oil including the steps of:heating said bleached fish oil to a first temperature increase then injecting steam into said steam distillation batch deodorizer at a low flow rate;heating said bleached fish oil to a second temperature increase then increasing said steam flow rate into said steam distillation batch deodorizer to a rated flow rate, then heating said bleached fish oil to a third temperature increase;monitoring said bleached fish oil for residual impurities;determining when said residual impurities are at an acceptable level such that a deodorized fish oil has been produced, then cooling said deodorized fish oil to a first temperature decrease;adding a chelating agent to said deodorized fish oil then cooling said deodorized fish oil to a second temperature decrease;adding one or more anti-oxidants to said deodorized fish oil; andceasing vacuum conditions in said steam distillation batch deodorizer by introducing an inert gas into said steam distillation batch deodorizer thereby producing an edible quality refined fish oil.