Process for producing edible quality refined fish oil from menhaden, and other similar fish containing omega-3 long chain fatty acids

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;
• and
• separating 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;
• and
• filtering and cooling said now bleached fish oil;
• and
• deodorizing 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;
• and
• ceasing 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.