Technical Session 05: Malts and Grain Session
Mekonnen M Gebremariam, Institute for Brewing and Beverage Technology, Technische Universität München, Freising, Germany
Co-author(s): Martin Zarnkow and Thomas Becker, Institute for Brewing
and Beverage Technology, Technische Universität München, Freising,
Germany
ABSTRACT: Teff is a gluten free cereal with an attractive
nutritional profile, making it a suitable substitute for barley, wheat,
and other cereals in their food applications and foods for people with
celiac disease. The demand for gluten free foods is certainly
increasing. The aim of this research was to study the influence of
kilning on enzyme activities and DMS level of teff variety DZ-Cr-387 and
suggest a kilning condition that yields teff malt with low level of DMS
with no or little damage on its enzyme activities. The teff samples
were steeped for 5 hr on the first day, and 4 hr on the second day at
24°C and germinated for 4 days at 24°C in a temperature controlled
chamber with 95% relative humidity. The green malts were dried using
isothermal conditions at 30, 40, 50, 60, and 70°C for 40 hr with
sampling at certain time intervals. To set up optimum kilning
conditions, two temperature regimens were selected based on the results
of the isothermal kilning and some other trial experiments: 18 hr at
30°C + 1 hr at 60°C + (3 and 5) hr at 65°C (R1), and 18 hr at 30°C + 1
hr at 60°C + (3 and 5) hr at 80°C (R2). The results from the isothermal
kilning indicate that enzyme activities of teff malt decreased as the
kilning time and temperature increased. At lower temperatures, there was
an increase in the enzyme activities as the kilning time increased. The
DMS contents decreased with an increase in temperature and time. The
first kilning regimen (R1) with 3 hr curing at 65°C resulted in teff
malt with alpha-amylase, beta-amylase, and limit dextrinase activities
and DMS content of 68 U/g, 440 U/g, 1,072 U/kg, and 3.3 mg/kg,
respectively. The same kilning regimen (R1) with 5 hr curing at 65°C
yields teff malt with alpha-amylase, beta-amylase, and limit dextrinase
activities and DMS content of 60 U/g, 421 U/g, 780 U/kg, and 2.5 mg/kg,
respectively. Whereas the second kilning regimen (R2) with 3 hr curing
at 80°C resulted in teff malt with alpha-amylase, beta-amylase, and
limit dextrinase activities of 42 U/g, 406 U/g, and 736 U/kg,
respectively, and DMS content of 2.15 mg/kg. The same kilning regimen
(R2) with 5 hr curing at 80°C yields teff malt with alpha-amylase,
beta-amylase, and limit dextrinase activities of 37 U/g, 395 U/g, and
594 U/kg, respectively, and DMS level of 1.7 mg/kg. The results in
general show that the teff malt, which was kilned using the first
kilning regimen with shorter curing time at 65°C, contained the highest
level of amylolytic enzymes. The DMS values in all teff malts were below
the threshold level (5 mg/kg) that good quality malt should contain. It
can be concluded that the first kilning regimen (R1) with shorter
curing time is the best kilning condition that yields a good quality
teff malt. The levels of enzyme activities and DMS show that teff can be
a suitable alternative raw material for production of good quality
gluten free beer.
Mekonnen Melaku Gebremariam received his B.S.
degree in chemistry from Debub University, Ethiopia. He began
employment with the Ethiopian Ministry of Education in July 2000 as a
chemistry teacher in the South Nations and Nationality People Region. He
terminated his contract agreement with the Ministry of Education after
four years. He next was employed as a chemist in the Federal Micro and
Small Enterprises Development Authority. After 18 months with this
company, he terminated the contract agreement and joined Addis Ababa
University for further studies. He graduated from Addis Ababa
University, Ethiopia, in 2007 with an M.S. degree (with great
distinction) in food engineering. Immediately after graduation he was
employed as a lecturer and researcher by Hawassa University, Ethiopia.
After about two-and-a-half years of work at Hawassa University, he went
to Germany for his Ph.D. studies with the support of his employer,
Hawassa University. Currently he is pursuing his doctoral studies at the
Technical University of Munich, Germany.
VIEW PRESENTATION 17
