Gluten-Free Bread Production
Ingredients for bread includes: gluten-free flour (Buckwheat, chickpea and lentil flour), salt, gum and guar, sugar, transglutaminase, dried yeast, water, oil, sodium caseinate. In the literature, the strain of Lactobacillus buchneri is indicated for gluten-free baking products.
The process consist in mix all the ingredients, mold, ferment (30ºC for 40 minutes), bake (230°C for 43 minutes) and cool at room temperature.
Choosing the type/combination of flours to use for our gluten-free bread
Fig 1.1 Flow diagram of bread-making process
For non-gluten-free bread, wheat flour is used (10-12% of the protein is gluten). Gluten is essential in the development of bread taste and texture.
Many alternatives to wheat flour have been found and extensive studies on the properties of these alternatives have been performed over the number of years.
‘Alternative flours’ include those from gluten-free cereal flours other than rice such as oat, corn, sorghum, millet and teff, from pseudocereals such as buckwheat, amaranth and quinoa, from tubers such as cassava and potato, from legumes such as soy and chickpea and from other raw materials such as chestnut, tigernut, and chia.
Hydrocolloids were often used as improvers in bread based on rice flour, the most common one being hydroxypropyl methylcellulose (HPMC) but also carboxymethylcellulose (CMC) and methylcellulose (MC). Mohammad et al. (2015) concluded that among xanthan, carob, guar gum and tragacanth, xanthan showed the best quality in bread making.
The flour/gum combination for our gluten-free bread is as follows:
50:50 – Wholegrain Buckwheat flour: Pulse Flour
Pulse flour comprises of 50:50 - Chickpea flour: Lentil flour
Sedej et al. (2010). Buckwheat flour was chosen due to its high protein and fibre content and lower sugar content compared to wheat flour. In addition, buckwheat flour has a 2-3 fold higher phenolic content, higher DPPH scavenging activity and a significantly higher tocopherol content than wheat flour. Sensory analysis performed on a gluten-free snack product made from buckwheat flour suggests no difference in sensorial properties compared to wheat flour.
The pulse flours were chosen in order to fortify the nutritional content of our gluten-free bread mixture. Pulses contain complex carbohydrates (dietary fibres, resistant starch, and oligosaccharides), high protein with a good amino acid profile (high lysine), important vitamins and minerals (B-vitamins, folates, and iron), as well as antioxidants and polyphenols. Pulses are also gluten-free and have a low glycemic index, characteristics with benefits for people with diabetes, cardiovascular disease, and celiac disease.
Fig 1.2 Pie chart representing ratios of the ingredients making up the bread
In order to mix the dry ingredients together, as depicted by the image of the process above, a hybrid paddle ribbon mixer will be ulitised to ensure that all the dry ingredients are evenly distributed in the food system.
The hybrid paddle ribbon mixer, as shown below, has proven to be highly efficient in mixing dry, powdery ingredients of different particle sizes (In-house testing). Mixing for 5 minutes ensures that all the dry ingredients are evenly distributed, ready for the next mixing step.
After mixing the dry ingredients, the dry ingredients move onto the spiral mixer (Fig 1.4). The oil is added, and is mixed a further 5 minutes. The water is then added and the dough is mixed for a further 5 minutes under the spiral mixer. According to literature, when kneading gluten-containing dough, a spiral or a hook is sufficient for ensuring the inclusion of the entire material due to the cohesiveness of the dough. However, gluten-free dough is generally stickier, less cohesive and more batter-like. Therefore, the spiral mixer combined with dough scrapers (Fig 1.5) ensure that the ingredients are evenly mixed within the dough.
After the mixing of the dough, it is moved on to the cutter, where the dough is cut into small pieces, and molded into a convenient snack-size shape and moves on to an oven set at 30 degrees Celcius to ferment for 45 minutes.
The fermented dough, then goes into another oven to bake at 230 degrees Celcius for 45 minutes and cooled to room temperature, then sliced before packaging!
References
Elgeti, D., Jekle, M. and Becker, T. (2015). Strategies for the aeration of gluten-free bread – A review. Trends in Food Science & Technology, 46(1), pp.75-84.
Mohammadi, M., Azizi, M., Neyestani, T., Hosseini, H. and Mortazavian, A. (2015). Development of gluten-free bread using guar gum and transglutaminase. Journal of Industrial and Engineering Chemistry, 21, pp.1398-1402.
Equipment used for the bread-making process
Fig 1.3 Hybrid Paddle-Ribbon Mixer
Fig 1.4 Industrial Spiral Mixer
Fig 1.5 Dough Scraper
Fig 1.6 Dough Cutter
Fig 1.7 Oven (Fermentor)
Fig 1.8 Cooling rack for bread loaf