Determination of dietary fiber in food

Dietary fiber is the edible part of plants and cannot be digested and absorbed by the human small intestine.
It is of health significance to the human body.
The sum of carbohydrates and lignin and other polymers in plant foods with a degree of polymerization of ≥3, including cellulose, hemicellulose, pectin, inulin and so on
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The unique role of dietary fiber in maintaining human health and preventing diseases has been confirmed by more and more researches, and it has become one of the indispensable and important substances in the human diet
.

The measurement methods of dietary fiber mainly include non-enzyme-weight method, enzyme-weight method and enzymatic chemical method
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1.
Principle

Of dried specimens, the a- amylase, protease, and glucosidase enzyme digestion to remove starch and protein, after hydrolysis sample solution was ethanol precipitated, filtered and the residue washed with ethanol and acetone, dried and weighed material is the Total dietary fiber (TDF) residue; another sample is directly filtered after enzymolysis with the above three enzymes, the residue is washed with hot water, dried and weighed to obtain insoluble dietary fiber residue; the filtrate is 4 times The volume of 95% ethanol is precipitated, filtered, dried and weighed to obtain soluble dietary fiber residue
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2.
Result calculation

(1) The mass of the blank is calculated as follows:

Where m _B ——the mass of the blank, mg

^m BR ₁ , ^m BR ₂ ——Residue mass of double blank determination, mg

^m p _B ——the mass of protein in the residue, mg

^m A _B ——the mass of ash in the residue, mg

(2) The content of dietary fiber in the sample is calculated as follows:

Where x——the content of dietary fiber in the sample, g/100g

^m R ₁ , ^m R ₂ ——the mass of double sample residue, mg

m _p , m _A ——respectively the mass of protein and ash in the sample residue, mg

m _B ——the mass of the blank, mg

m ₁ , m ₂ ——the mass of the sample, mg

(3) Total dietary fiber (TDF), insoluble dietary fiber (IDF), and soluble dietary fiber (SDF) are all calculated by the above formula
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3.

This method is suitable for the determination of general foods (such as cereals, vegetables, etc.