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The Use of Response Surface Methodology to Optimise Malting Conditions of Tef (Eragrostis tef (Zucc.) Trotter) as a Raw Material for Gluten-free Foods and Beverages
Zarnkow, M., Almaguer, C., Burberg, F., Back, W., Arendt, E. K., Kreisz, S. and Gastl, M.

Celiac disease is a condition, in which case the person's body reacts to the prolamins of wheat, rye, barley, and oats. The only way to treat CD is a total lifelong avoidance of gluten consumption. In this study Tef (Eragrostis tef L.), which belongs to the family poaceae that is regarded as gluten free, was used as raw material. The objective of this study was to optimize the malting conditions to produce a gluten free malt of high quality for gluten free foods. Tef, with a thousand kernel weight of 0.3-0.4 g, needed special arrangements like small sieves etc. Tef has a remarkable agronomical advantage that the water requirement is probably the lowest of any major cereal. 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 tef malt. Each predictor variable was tested at three levels. Vegetation times were 4, 5 and 6 days, degrees of steeping were 46, 50 and 54 % and vegetation temperatures were 16, 20 and 24 ?C. Kilning temperatures of 65 ?C were used. The used analyses were based on methods outlined in EBC or by MEBAK. The raw material was yielded 2006 in Utah, USA. A range of malt quality parameters was determined including extract, apparent attenuation limit, gelatinisation temperature, ?-amylase activity, a-amylase activity, limitdextrinase activity, Kolbachindex, alpha amino nitrogen, viscosity, and colour. The achieved values slightly deviate from the calculated ones. The obtained attributes were 52.1?% extract, 69.1?% AAL, 84?U/g ?-amylase activity, and 187?U/g ?-amylase activity, 1062?U/kg limit dextrinase activity, 5.9?EBC colour, 285?mg/100?g FAN and 2.782?mPa x s viscosity. 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 Eragrostis tef is a crop with a potential as a raw material for malting purposes. Coeliac disease (CD) (also known as non-tropical sprue, gluten-sensitive enteropathy, celiac sprue, idiopathic steatorrhea, primary malabsorption, Gee-Herter disease, gluten-induced enteropathy, adult celiac disease) is a digestive disease that damages the small intestine and interferes with absorption of several important nutrients from food including iron, folic acid, calcium and fat-soluble vitamins [1, 2]. People who suffer from CD cannot tolerate a protein called gluten, which generally consists of prolamin and glutelin proteins. Gluten is found in wheat, rye, barley and, possibly, oats; all these cereals and their prolamins ? gliadin (wheat), hordein (barley), secalin (rye) and avenin (oats) ? are toxic to those, who suffer from Coeliac disease [3, 4]. The disease is caused by an immune-mediated response in the small intestine triggered by the ingestion of gluten in genetically susceptible individuals. The symptoms of Coeliac disease can develope at any age and include severe symptoms of malabsorption such as steatorrhea, abdominal discomfort, weight loss, tiredness, anaemia and severe diarrhoea [5, 1, 4]. The only effective treatment for CD is a strict adherence to a diet that avoids ingestion of nutritions that contain gluten throughout the patient?s lifetime [6]. The total avoidance of gluten and gluten related proteins leads to a recovery of the mucosa.Cereals not containing gluten include: rice (Oryza sativa), maize (Zea mais), sorghum (Sorghum bicolour), tef (Eragrostis tef) and millets (e.g. Panicum miliaceum, Setaria italica, Pennisetum glaucum and Eleusine coracana). Other carbohydrate rich pseudocereals without gluten are buckwheat (Fagopyrum esculentum), amaranth (Amaranthus species) and quinoa (Chenopodium quinoa). Recent studies have focussed on the production of malt for foods and beverages including beer from gluten-free cereals such as rice, maize and millets, as well as pseudo-cereals such as buckwheat, quinoa and amaranth [7, 8, 30-34].

Descriptors: tef, malt, response surface technology, gluten-free, cereal

BrewingScience - Monatsschrift fr Brauwissenschaft, 61 (May/June 2008), pp. 94-104