Effect of teff (Eragrostis tef) variety and storage on malt quality attributes

Abstract

Varieties of a cereal may have a considerable influence on malting qualities owing to variations in the physicochemical properties of the grains. This research was aimed at assessing the influence of five teff varieties on malt quality attributes. The teff samples were malted using previously optimized malting conditions and mashed with the congress mashing procedure. In this research, the Kuncho teff variety was malted in a one year period after harvesting, whereas the other four varieties were malted after three years of storage. Alpha-and b-amylase, and limit dextrinase activity, were in the ranges 14-68, 10-440 and 375-1072 U/kg, respectively. Extracts ranged from 54% for Dessie to 74% for Ivory teff. Free amino nitrogen, protein content, soluble nitrogen, Kolbach index, viscosity and wort colour were in the ranges 160-364 mg/L, 8.6-13.6%, 532-1048 mg/100 g, 24-50%, 1.441-1.629 mPa s and 5.9-9.0 EBC units, respectively. High-performance liquid chromatographic analysis for individual fermentable sugars revealed that the highest value in all varieties was recorded for glucose followed by maltose. The concentration of glucose ranged from 9.49 g/L in Brown teff, to 19.42 g/L in Ivory teff, whereas maltose ranged from 2.95 g/L in Dessie teff to 16.1 g/L in Kuncho teff. All of the malt quality attributes considered in this study were markedly influenced (p < 0.05) by the type of teff cultivar. It was concluded that the use of different teff varieties yielded malts with significantly different malt quality attributes. Copyright © 2013 The Institute of Brewing & Distilling Keywords: enzyme activity; malt quality; teff IntroductionTeff (Eragrostis tef) is a tropical gluten-free cereal that originated in Ethiopia, between 4000 and 1000 BC (1). It is environmentally more flexible than most other cereals. Teff is a low-risk cereal that grows over a wider ecology and can tolerate harsh environmental conditions where most other cereals are less viable, and it shows better tolerance to many diseases and pests (2,3). Among other applications, teff is mainly used in Ethiopia and Eritrea for making injera and tela. It is also gaining popularity as a health food in the Western world, notably in the Netherlands and the USA, and its flour is becoming a preferred ingredient in gluten-free diets and sport foods (4). Since teff is a gluten-free cereal with a high nutritional value, researchers are interested in studying it for utilization in different food applications. In addition to its nutritional and agricultural benefits (2,3), it has also shown promising brewing properties (5).Malt is the major raw material used in the brewing industry. The primary quality criterion for use of cereals in the brewing industry is their potential to produce malt with diastatic power (amylase activity), which is needed to hydrolyse starch molecules and produce fermentable sugars. The brewing industry is reliant on the enzymes of malted cereals in order to ensure the efficient utilization of the raw materials. Hence, the fundamental role of the ma...

Impact of process conditions on the microbial community dynamics and metabolite production kinetics of teff sourdough fermentations under bakery and laboratory conditions

“…Its presence may reflect the lower ambient temperature and higher carbohydrate content, in particular fructose, of the backslopped bakery sourdoughs (De Vuyst et al, 2002). Furthermore, the high glucose concentrations, owing to the lack of β-amylase activity in teff flour, could have contributed to the occurrence of Weissella species, as these species preferably grow on glucose (Galle, Schwab, Arendt, & Gänzle, 2010;Gänzle, 2014;Gebremariam, Zarnkow, & Becker, 2013;Gebremariam et al, 2014;Moroni et al, 2011). Additionally, degradation of phenolic compounds has been demonstrated for L. brevis, pediococci, and weissellas (Filannino, Gobbetti, De Angelis, & Di Cagno, 2014).…”

Studies on the mashing conditions of teff (Eragrostis tef) malt as a raw material for lactic acid‐fermented gluten‐free beverage

“…Based on the gelatinisation temperature of teff malt (Gebremariam et al ., ) and results from thermal stability studies on the amylolytic enzymes (Gebremariam et al ., ), temperatures ranging between 65 and 74 °C were tested to identify the conversion rest temperature that results in the highest possible extract and FAN as well as pH in the range of 5–6 (Bohak et al ., ; Muralikrishna & Nirmala, ). The pH range designed to be achieved in this experiment was the optimal range for most of starch‐degrading enzymes although the values towards the lower end are usually preferred.…”

Teff (Eragrostis tef) processing, utilization and future opportunities: a review

“…The crop's high malt quality and germinate energy, lack of gluten and high carbohydrate content make it a feasible raw material for brewing gluten-free beverages (Gebremariam et al, 2014) and gluten-free lactic acid-fermented beverages (Gebremariam et al, 2015). However, different teff varieties yield different malt quality attributes (Gebremariam et al, 2013). Yizgaw et al (2004) cited that fermentation improves mineral bioavailability and increases protein content; hence, when teff is fermented, its protein content further increases.…”