Validation of the Test Method - Determination of Available Carbohydrates in Cereal and Cereal Products, Dairy Products, Vegetables, Fruit and Related Food Products and Animal Feeds: Collaborative Study, Final Action 2020.07.

BACKGROUND: A simple, accurate, and reliable method to measure available carbohydrate components of food products, including cereal and dairy products, fruits, vegetables, processed food, food ingredients and animal foods, was developed by Megazyme (product K-AVCHO, Bray, Ireland). A single-laboratory validation of the enzymatic method resulted in First Action status as Official Method of Analysis (OMA) 2020.07.

OBJECTIVE: A collaborative study was conducted to evaluate the repeatability and reproducibility of OMA 2020.07 for the measurement of available carbohydrates, including digestible starch, lactose, sucrose, isomaltose, maltose, glucose, fructose, and galactose in a broad range of food and feed products.

METHOD: Samples are defatted if containing > 10% fat content, and incubated with pancreatic α-amylase and amyloglucosidase under conditions that simulate those in the small intestine (pH 6, 37 °C, 4 h). The reaction solution is clarified and diluted, and an aliquot is incubated with sucrase, maltase, oligo-1,6-α-glucosidase and β-galactosidase to hydrolyse sucrose, maltose, isomaltose and lactose to glucose, fructose and galactose, which are then measured enzymatically. The multilaboratory validation (MLV) matrixes included cereal, animal feeds, fruit, vegetables, infant formula, powdered milk drink, a dessert product and mushrooms. Additional materials were analysed by collaborators as "practice samples".

RESULTS: : All MLV matrixes resulted in repeatability relative standard deviations (RSDr) < 3.91% and reproducibility relative standard deviations (RSDR) ranging from 3.51 to 11.58% with 9 of the 10 matrixes having RSDR of < 6.19%. For the practice samples, the RSDR ranged from 2.7 to 11.4% with 7 of the 8 samples having RSDR of < 4.4%.

CONCLUSIONS: OMA 2020.07 meets the AOAC requirements for repeatability and reproducibility and the data support Final Action status.

HIGHLIGHTS: OMA 2020.07 is a robust, simple to use, and reproducible method for the analysis of available carbohydrates in a wide range of matrixes.