Process for producing a cholesterol-reduced substance

Abstract

According to the present invention, a process for producing a practical cholesterol-reduced substance by converting cholesterol contained in foods and feeds to coprostanol having very low intestinal tract absorbability by utilizing enzymatic action is provided. Cholesterol in a cholesterol-containing substance such as meat, egg, milk, seafood and cooked processed foods containing the same, or feeds for animals, poultry and pisciculture, and the like, can be treated with three kinds of enzymes which are a cholesterol dehydrogenase having an optimum pH in a neutral pH range and 4-cholesten-3-one dehydrogenase and coprostan-3-one dehydrogenase each having an optimum pH in a weak acidic range, or microbial cells containing the enzymes, for converting the cholesterol to coprostanol to reduce the amount of the cholesterol.

What is claimed is:  
     
         1 . A process for producing a cholesterol-reduced substance, comprising converting cholesterol in a cholesterol-containing substance into coprostanol via cholesten-3-one and coprostan-3-one by contacting said cholesterol-containing substance with cholesterol dehydrogenase, 4-cholesten-3-one dehydrogenase and coprostan-3-one dehydrogenase, wherein enzymatic action of said cholesterol dehydrogenase, 4-cholesten-3-dehydrogenase and coprostan-3-one dehydrogenase reduce amount of the cholesterol, and wherein the cholesterol dehydrogenase is a cholesterol dehydrogenase having a relative active value at pH=7.0 which is not less than 80% of the maximum active value.  
     
     
         2 . The process for producing a cholesterol-reduced substance according to    claim 1   , wherein the 4-cholesten-3-one dehydrogenase and the coprostan-3-one dehydrogenase are a 4-cholesten-3-one dehydrogenase and a coprostan-3-one dehydrogenase each having an optimum pH in a weak acidic pH range.  
     
     
         3 . The process for producing a cholesterol-reduced substance according to    claim 1   , wherein the cholesterol-containing substance is selected from the group consisting of meat, egg, milk, seafood and cooked processed foods containing the same, or feeds for animals, poultry and pisciculture.  
     
     
         4 . The process for producing a cholesterol-reduced substance according to    claim 1   , wherein one or more compounds selected from the group consisting of nicotinamide, phospholipase and phosphate ion are added to the cholesterol-containing substance.  
     
     
         5 . The process for producing a cholesterol-reduced substance according to    claim 1   , wherein the enzymes have been isolated from Eubacterium separated from lion feces.  
     
     
         6 . The process for producing a cholesterol-reduced substance according to    claim 1   , wherein the enzymes have been isolated from Eubacterium separated from human feces.  
     
     
         7 . The process for producing a cholesterol-reduced substance according to    claim 1   , wherein the cholesterol dehydrogenase has an optimum pH of 6.7 to 7.7.  
     
     
         8 . The process for producing a cholesterol-reduced substance according to    claim 1   , wherein the cholesterol dehydrogenase has an optimum pH of 6.5 to 7.8.  
     
     
         9 . The process for producing a cholesterol-reduced substance according to    claim 1   , wherein the enzymes are provided sequentially, in the order of cholesterol dehydrogenase, 4-cholesten-3-one dehydrogenase and coprostan-3-one dehydrogenase.  
     
     
         10 . A method for reducing the amount of cholesterol in a cholesterol-containing substance, by enzymatic action of cholesterol dehydrogenase, 4-cholesten-3-one dehydrogenase and coprostan-3-one dehydrogenase on the cholesterol-containing substance, comprising contacting the cholesterol-containing substance with the cholesterol dehydrogenase, the 4-cholesten-3-one dehydrogenase and the coprostan-3-one dehydrogenase to reduce the amount of cholesterol in the cholesterol-containing substance by converting the cholesterol to coprostanol via 4-cholesten-3-one and coprostan-3-one, wherein the cholesterol dehydrogenase is a cholesterol dehydrogenase having a relative active value at pH=7 which is not less than 80% of the maximum active value.  
     
     
         11 . The method for reducing the amount of cholesterol according to    claim 10   , wherein the 4-cholesten-3-one dehydrogenase and the coprostan-3-one dehydrogenase are a 4-cholesten-3-one dehydrogenase and a coprostan-3-one dehydrogenase each having an optimum pH in a weak acidic pH range.  
     
     
         12 . The method for reducing the amount of cholesterol according to    claim 10   , wherein the cholesterol-containing substance is selected from the group consisting of meat, egg, milk, seafood and cooked processed foods containing the same, or feeds for animals, poultry and pisciculture.