Session II – Cereal Science, Whole Grain Foods and Processing –Talk: Zarnkow

The Use of Response Surface Methodology to Optimise Malting Conditions of Oat (Avena sativa L.) as a Raw Material for Alternate Fermented Beverages with High Content of β-Glucan

Martin Zarnkow1,2,3, Alicia Munoz1, Felix Burberg1, Werner Back1, Elke K. Arendt2, Martina Gastl1

1Lehrstuhl für Technologie der Brauerei I, Technische Universität München-Weihenstephan, Weihenstephaner Steig 20, 85354 Freising

2Department of Food and Nutritional Sciences, National University of Ireland, University College Cork, College Road, Cork, Ireland.

3Corresponding author, Email:

Abstract

Oats (Avena sativa) are one of the most popular cereals for human consumption. In the middle ages oats were the brewing cereal par excellence. Over the centuries they were substituted by other cereals and their brewing properties were nearly forgotten. Today oats are popular once more because of their excellent health-related properties. For people who suffer with celiac disease oats are also of interest. Based on their historical use in brewing and their health-related properties pilot malting trials were carried out with different cultivars, followed by brewing trials with a selected cultivar. The results obtained showed that oat malt is an appropriate choice for brewing.

Response surface methodology was used to investigate the influence of the three malting parameters, vegetation time, degree of steeping and temperature on the quality of oat malt. Each predictor variable was tested at three levels. Vegetation times were 6, 7 and 8 days, degrees of steeping were 42, 45 and 48 % and vegetation temperatures were 12, 15 and 18°C. Kilning temperatures of 80°C were used. The used analyses were based on methods outlined in EBC or by MEBAK. The raw material was yielded 2007 in Granskevitz, Germany.

A range of malt quality parameters was determined including extract, apparent attenuation limit, gelatinization temperature, α-amylase activity, β-amylase activity, limitdextrinase activity, Kolbachindex, alpha amino nitrogen, viscosity, colour, and most important β-Glucan.

This publication shows clearly that on the one hand RSM is a prove method for testing the malting conditions of unknown cereals and on the other hand Avena sativa is a crop with a potential as a raw material for malting purposes and alternate fermented beverages.

This work was completed at the Lehrstuhl für Technologie der Brauerei I, Technische Universität München-Weihenstephan.