Evaluation of the structural and functional composition of South African triticale cultivars (X Triticosecale Wittmack)
Date
2009-03
Authors
Du Pisani, Frances
Journal Title
Journal ISSN
Volume Title
Publisher
Stellenbosch : University of Stellenbosch
Abstract
Triticale (X Triticosecale Whittmack), a cross between durum wheat (Triticum sp.) and rye,
is a crop with an increasing agronomic and economic potential Though studies on the
functional and compositional quality of triticale have been conducted in other parts of the
world, little is known regarding cultivars developed in South Africa in terms of these
aspects. South African triticale cultivars from various localities in the Western Cape,
obtained for two subsequent harvest seasons, were analysed for moisture, protein and ash
contents, as well as falling number (an indication of α-amylase activity), hardness (particle
size index), 1000-kernel mass and baking potential (SDS sedimentation). These triticale
samples were derived from a breeding program that was not focused on baking quality.
The results obtained were found to compare well with those reported on in previous
studies.
Significant differences were observed between both cultivars and localities within
years, illustrating the effect of genetic as well as environmental factors. Significant
differences were also observed between localities when comparing the two harvest
seasons, whereas differences between the cultivars for the two seasons were in most
cases not significant; illustrating the effect of environment. Interactions between cultivars
and localities were found to be significant for all parameters, and trends were observed
between protein content and both particle size index (PSI) (negative) as well as SDS
sedimentation (positive) results for both years.
Near infrared (NIR) spectroscopy is a rapid method of analysis and is widely used for
the quality evaluation of wheat. Limited research has been reported on calibration models
for the quality evaluation of triticale, and thus NIR spectroscopy was applied to develop
models for the prediction of moisture, protein and ash contents, as well as hardness and
baking potential for South African cultivars. Spectra were collected in diffuse reflectance
mode and partial least squares (PLS) models developed for both triticale flour and
wholegrain using two different instruments (Büchi NIRFlex N-500 and Bruker MPA Fourier
transform NIR spectrophometers) and software packages (The Unscrambler and OPUS).
Full cross-validations were performed, after which the best prediction models obtained (R2
> 0.66) were validated using an independent test set (n = 50). The best prediction results
were obtained with flour for moisture (Bruker: SEP = 0.08%; R2 = 0.95; RPD = 4.65) and
protein (Büchi: SEP = 0.44%; R2 = 0.96; RPD = 5.23 and Bruker: SEP = 0.32%; R2 = 0.96;
RPD = 4.88). For whole grain, acceptable results were obtained for protein (Büchi: SEP =
0.55%; R2 = 0.94; RPD = 4.18 and Bruker: SEP = 0.70%; R2 = 0.90; RPD = 3.23). Though results for ash content, PSI and SDS sedimentation prediction did not yield models that
can be applied as yet, these models form a good basis for further calibration model
development and possibly use in early generation screening.
The current limited ranges could be expanded by adding samples from subsequent
harvest seasons. By adding more data, a better quality profile for South African triticale
can be obtained, which will facilitate better interpretation in terms of the effect of genetic
and environmental factors. It would also enable the development of improved NIR
prediction models.
Description
Thesis (Msc Food Sc (Food Science))--University of Stellenbosch, 2009.
Keywords
Dissertations -- Food science, Theses -- Food science