168 Measurement of Total Starch Content of Cereal Grains, Food and Feed Products using α-Amylase/ Amyloglucosidase Method

Print
Methods Type: Generic Methods
Key data
Number: 168
Analyte: Starch Content
Matrix: Cereal Grains, Food and Feed Products
Year of Approval: 2017
Scope: This text describes a method for determination of the total starch content of cereal grains and a range of cereal food products based on the use of thermostable α-amylase and amyloglucosidase. For samples which are difficult to gelatinise (such as high amylose maize starch) solvents such as dimethyl sulphoxide (DMSO) are employed. Most starch assay procedures underestimate starch in samples containing resistant starch. This problem has become more pronounced with the introduction of high-amylose starches and the development of processing conditions which increase the levels of enzyme resistant starch.

This method is applicable to all cereal grains, food and feed products and vegetable products. With appropriate sample preparation, it is also applicable to all starch containing products.

Principle: In the current procedure, starch granules are hydrated and hydrolysed to maltosaccharides with thermostable a-amylase at 95-100°C. After cooling and pH adjustment, maltodextrins are hydrolysed to glucose with a highly purified amyloglucosidase. Then glucose is quantified using a glucose oxidase plus peroxidase and 4-aminoantipyrine containing reagent. Samples containing high-amylose starches or resistant starch are pre-treated with dimethyl sulphoxide (DMSO) (at 95°C) before treatment with a-amylase. Values are presented as starch as a percentage of sample weight.

Definition

Starch is a carbohydrate consisting of a large number of glucose units joined by chemically different glycosidic bonds. It is a major component in cereals and is present in varying amounts in a range of food products as an important functional component.

Resistant starch is defined as the portion of starch that cannot be digested by amylases in the human small intestine and passes to the colon to be fermented by microbiota.

Thermostable α-amylase is an enzyme that hydrolyses starch into soluble branched and unbranched maltodextrins.

Amyloglucosidase (AMG) quantitatively hydrolyses maltodextrins to D-glucose.

 

Purchase this ICC Standard Method now and download it immediately!