Speaker
Description
Adaptation to climate changes adjusts our views on food production and consumption. There is a shift towards reduced fertilizer use in agriculture and zero waste production systems, leading to the importance of whole grains and their complete valorization. Cereal grains contain not only starch and proteins, but also dietary fibers, such as arabinoxylan and beta-glucan, which importance in human health has been acknowledged widely. With the spread of organic farming, it has become necessary to understand how the choice of cropping system affects protein, arabinoxylan (AX), and beta-glucan (BG) contents and ratios in grains, and how it influences the baking properties of the dough. The effects of organic and mineral N fertilizers and content of AX and BG and on the protein content (PC) and their ratio (PC:AX+BG) influence on rheological properties of wheat dough were investigated.
Grain samples were collected from long-term field experiment in Tartu County (58°22′ N, 26°40′ E) in 2014‒2021. The objective of the experiment was to compare the effect of (i) cropping system (organic with cattle manure and off-season cover crop; conventional with mineral nitrogen (NH4NO3; 0, 40-50, 80-100 and 120-150 kg N ha−1) and (ii) year conditions on winter wheat Fredis and spring barley Anni wholegrain flours BG and AX content and (iii) to evaluate fiber: protein ratio impact on wheat dough rheological properties (farinograph and alveograph values).
The content of arabinoxylan and beta-glucan in wheat was 4.54 - 5.12 and 0.40 - 0.57 g 100 g−1 respectively and in barley 4.00 - 4.51 and 3.74 - 5.60 g 100 g−1 respectively. The content of fibers in grains was affected mainly by year (weather) conditions (Korge et al., 2023; Khaleghdoust et al., 2024). Higher temperatures during tillering and grain filling period increased both grains AX values, while higher precipitation during grain filling had negative effect on grains BG content. In barley and wheat, fertilization up to 150 kg N ha−1 did not have a significant effect on BG content. For AX content the effect of fertilizer treatments and cropping systems was indirect and was expressed through their effect on grain yield, 1000 kernel weight and test weight. Dietary fibers can successfully be obtained from organic or low-nutrient systems, however, as its content depends on a year, there is a need for a good prediction model.
Protein content of grains was affected by cropping system and weather conditions combined. Mean protein content of wheat grains over experimental years was 10.1-14.6%. There was a positive correlation between grain protein and AX content. Better winter wheat dough quality can be obtained with higher N treatments and lower or average yield and it depends on fiber to protein ratio, which influence dough quality indicators. Protein to fiber ratio depended more on fiber due to its higher fluctuation between years. Higher dough quality was achieved with protein to fiber ratio between 2-2.2:1. Higher fiber content gave higher dough water absorption capacity, dough development time and quality number of dough.
Figure 1. A. The arabinoxylan and B. the beta-glucan content as an average of N treatments in winter wheat and spring barley flours in different years, g 100 g-1; letters on bars refer to comparison between different cropping years of the same species; bars with the same letter are not significantly different (P <.05); C. Influence on dough quality number (FQN, mm) of PC:AX+BG ratio. PC, protein content (%); AX+BG, total amount of arabinoxylans and β-glucans (%);
Keywords: arabinoxylan, beta-glucan, conventional, organic, weather
References:
Khaleghdoust et al. (2024). Barley and wheat beta-glucan content influenced by weather, fertilization, and genotype. Frontiers in Sustainable Food Systems, 7. https://doi.org/10.3389/fsufs.2023.1326716
Korge et al. (2023). The influence of cropping system, weather conditions and genotype on arabinoxylan content in wheat and barley grains. Journal of Cereal Science, 110, 103650. https://doi.org/10.1016/j.jcs.2023.103650
| Keywords | arabinoxylan; beta-glucan; conventional; organic; weather |
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