Gluten-free foods could benefit from highly fibrous fruit flours developed from the by-product of juice and cider production, according to a senior researcher.
Amid snowballing gluten-free demands and some research suggesting that gluten-free products lack nutrition (vitamin B, iron and fibres), manufacturers are scrambling to find alternatives that are structurally sound yet nutritionally valuable.
Popular choices have been ancient grains such as buckwheat, quinoa and amaranth but new research underway at Dublin-based Food Research Centre, Teagasc, is looking into apple and orange fruit by-product flours.
“Creating gluten-free bread of equal nutritional and physical quality to its wheat counterpart creates difficult problems for the cereal technologist. Food scientists have shown fruit and vegetable by-products to be untapped sources of nutrients such as dietary fibre and phytochemicals,” the researchers said.
The research, funded by the Irish Department of Agriculture and Food under its wider research consortium FIRM (Food Institutional Research Measure), commenced in January 2011 and will run until 2013.
Researchers are using the pomace (core, pips and skin) of apples and oranges processed at Bulmers, The Apple Farm and Wild Orchard facilities in Ireland.
Speaking to BakeryandSnacks.com, Eimear Gallagher, senior research officer overseeing the project at Teagasc, revealed that initial findings are “extremely promising in terms of structure and nutrition”.
“These by-product flours are high in dietary fibre,” Gallagher said.
Further nutritional studies will be conducted over the next few months once formulations are optimised as “we are also anticipating that the flours will have high antioxidant properties,” she added.
“We are currently doing structural studies on the fruit flours for dough and bread to ascertain how structurally strong they are,” she said.
Initial studies are focused on bread, biscuit and extruded, aerated snacks applications.
“We are taking the by-product to dry and mill into flour. It is then incorporated into gluten-free applications as a novel, functional ingredient,” Gallagher said.
There are flavour implications when using these ingredients, Gallagher detailed, and so the team will conduct volatile and sensory flavour analysis to better understand these impacts.
“The apple flour for example has a sweeter taste so would likely be better suited to types of confectionery, biscuits and scones,” she said.
Bland and neutral flours will need to be blended in to balance the taste impacts as well as provide key structural requirements needed for gluten-free bakery and snacks products, she said.
For the gluten-free bread, rice flour and potato starch is blended with the fruit flour and for extruded snacks it is mixed with maize flour.
The researchers are using 10-15% fruit flour in the formulations for technical and taste purposes, she noted.
However current findings using orange pomace flour suggest a much lower percentage (5.5%) is ideal for gluten-free bread as at this level it ensures increased fibre content while maintaining texture and volume.
Sustainability brownie points
The pomace collected from the juice and cider processors is usually just disposed of to landfill, Gallagher said.
The researchers said that in the fruit and vegetable industry, “the preparation and processing procedures can lead to one third of the product being discarded. This can be costly for the manufacturer and also may have a negative impact on the environment”.
The sustainability value of using these flours therefore would be an “ideal selling point among other things”, Gallagher noted.
“We can see commercial end-points…We would hope as the project progresses and it nears the end, we can collaborate with bakery, snacks and juice firms to up-scale this to a commercial level,” she said.
Findings of the research will be published as and when sufficient data is compiled, she said.