Liisa Otama (1), Ashley Galant (2), Sari Hartikainen (1), Sheila Jensen (2), Mari Kiviluoma (1); (1) Thermo Fisher Scientific, Vantaa, Finland; (2) Busch Agricultural Resources, Inc., U.S.A.
A new automated method to measure diastatic power in malted cereal grains is presented. Traditionally, the diastatic power of malt is determined by measuring the reducing sugars produced from a controlled diastasis of starch under standardized conditions. Older manual titrimetric methods for reducing sugars have been largely replaced by automated measurements, using continuous flow analysis systems to increase sample throughput; however, these systems are expensive and require large amounts of reagents. In this novel method, diastatic power is determined by measuring the end-product formation of D-glucose using a specific enzymatic reaction through automation with the discrete analyzer Thermo Scientific Gallery Plus Beermaster. The process involves extraction of enzymes by malt infusion, followed by reaction with ASBC special starch substrate under the controlled conditions of time, temperature, pH, and substrate concentration. The resulting sugars, primarily maltose, are further hydrolyzed with alpha-glucosidase to produce D-glucose. D-Glucose is subsequently measured using the Thermo Scientific D-Glucose kit, which includes ready-to-use system reagents, including hexokinase and glucose-6-phosphate dehydrogenase. Reactions are performed at 37°C and a photometric end-point measurement at 340 nm. A method comparison study was performed by analyzing a series of malt samples with a range in diastatic power using both the novel method and ASBC Malt-6C as a reference method. The repeatability and reproducibility of the new method was also determined.
Liisa Otama earned both B.S. and M.S. degrees in analytical chemistry from the University of Helsinki, Finland. She joined Thermo Fisher Scientific in 2008 and has held several positions, ranging from process engineering to R&D. In her current role as a product manager for discrete analyzer reagents and applications, she is responsible for identifying new customer needs, as well maintaining and continuously improving the existing product portfolio. Her expertise is highly customer-focused and includes evaluating industrial product feedback and addressing inquiries, in addition to supporting customer training.