Methods for detoxifying bran and products obtained therefrom
View Patent ↗The subject invention provides a bran composition comprising a bran component with a reduced level of inorganic arsenic, a grain product that comprises such bran composition and at least one other component and/or other ingredient, and food products that are made from such bran composition and/or such grain product. The subject invention also provides methods of detoxifying a bran and/or grain product.
1 . A method of detoxifying a bran composition, comprising the steps of:
(1) Creating a slurry by suspending the bran composition in a buffer solution, the bran composition having at least 1 mg/kg of inorganic arsenic by weight;
(2) Methylating inorganic arsenic in the slurry by treating the slurry with a methylating enzyme; and
(3) determining arsenic species and level in the treated slurry, more than 90% of the inorganic arsenic present in the bran composition being converted into dimethylarsenate (DMA).
2 . The method of claim 1 , the buffer solution being a MOPS buffer solution.
3 . The method of claim 1 , step (2) comprising mixing the slurry obtained in step (1) with the methylating enzyme.
4 . The method of claim 1 , the methylating enzyme being a heat-stable methylating enzyme.
5 . The method of claim 1 , the methylating enzyme being CmArsM.
6 . The method of claim 1 , further comprising drying the treated slurry.
7 . A method of detoxifying a grain product, comprising the steps of:
mixing the grain product with a buffer solution to create a slurry, the grain product comprising a bran composition having at least 1 mg/kg of inorganic arsenic by weight;
adding an arsenic S-adenosylmethionine methyltransferase in the slurry and incubating the slurry and the arsenic S-adenosylmethionine methyltransferase at a temperature of about 50° C.-80° C. to methylate the inorganic arsenic;
determining arsenic species and level in the mixture of the slurry and the arsenic S-adenosylmethionine methyltransferase, more than 90% of the inorganic arsenic present in the bran composition being converted into DMA, and
optionally, drying the mixture of the slurry and the arsenic S-adenosylmethionine methyltransferase.
8 . The method of claim 7 , the arsenic S-adenosylmethionine methyltransferase being CmArsM.
9 . The method of claim 7 , the buffer solution being a MOPS buffer solution.
10 . The method of claim 7 , the temperature being about 60° C.-70° C.
11 . The method of claim 1 , step (2) further comprising incubating the slurry and the methylating enzyme at a temperature of about 60° C.-70° C. for a time period from about 30 to 50 minutes.
12 . The method of claim 1 , the detoxified bran composition comprising up to 0.1 mg/kg inorganic arsenic.
13 . The method of claim 1 , further comprising:
separating supernatant from the treated slurry by centrifugation or settling of an insoluble bran component;
digesting the supernatant with a nitric acid solution and conducting arsenic species analysis to determine arsenic species and levels in the supernatant; and
recovering the insoluble bran component.
14 . The method of claim 3 , step (2) further comprising mixing a reducing chemical comprising tris(2-carboxyethyl) phosphine (TCEP) with the slurry.
15 . The method of claim 7 , further comprising, prior to the optional drying:
separating supernatant from the treated slurry by centrifugation or settling of an insoluble component;
digesting the supernatant with a nitric acid solution and conducting arsenic species analysis to determine arsenic species and levels in the supernatant; and
recovering the insoluble component.
16 . The method of claim 7 , further comprising mixing a reducing chemical comprising TCEP with the slurry.
17 . The method of claim 1 , the detoxified bran composition having inorganic arsenic up to 0.05 mg/kg by weight.
18 . The method of claim 7 , the detoxified grain product having inorganic arsenic up to 1 mg/kg by weight.
19 . The method of claim 7 , the detoxified grain product having inorganic arsenic up to 0.05 mg/kg by weight.