Development of a process scheme for the production of high value functional products from DDGS

Abstracts are not currently available in GtR for all funded research. This is normally because the abstract was not required at the time of proposal submission, but may be because it included sensitive information such as personal details.

The aim of the proposed work is to develop a process for the transformation of DDGS, produced by distillers and bioethanol factories into arabinoxylooligosaccharides (AXOS) with prebiotic activities, gluten for biodegradable film packaging, nutritional supplements betaine and choline, and crude dietary fibre. The focus of the research will be to use a combination of thermal and alkali treatment followed by physical separation methods, such as absorption and/or ethanol precipitation, to separate DDGS into a soluble stream and then fractionate it into gluten and arabinoxylan (AX) and separate out the betaine and choline. The target is to achieve high recovery yields and purities for each type of product in their respective process streams. The gluten fraction will be characterised by SDS PAGE and HPLC and will be used to produce film packaging. The microstructure, morphology and oxygen and moisture permeability of the films will be studied aiming to produce a product with potential for commercial applications. Betaine and choline will be separated by anion exchange chromatography. AX will be hydrolysed in a control manner by commercial or novel endo-beta-1,4 xylanases to produce AXOS fractions, which will be collected by size exclusion preparative chromatography, and their prebiotic activity evaluated in vitro using the gut model systems at UoR. On the basis of the data from the prebiotic testing, the enzymatic process will be subsequently re-visited targeting the production of a mixture of AXOS with a specific molecular weight range, at high yields, and following that a scalable membrane filtration process will be developed to separate the AXOS from small molecular weight components. The proposed work is innovative as it offers a completely novel approach to the utilisation and upgrade of DDGS, and is technically challenging as the aim is to develop a process that is efficient, scalable and cost effective, which can be transferred into commercial scale.

The research will have a socioeconomic impact to various beneficiaries including: (i) the commercial private sector, mainly companies involved in the production of DDGS by distillers and bioethanol factories, functional food ingredients, nutritional supplements and biodegradable packaging materials, (ii) the UK economy and (iii) the general public.

The transformation of DDGS, which is currently sold as animal feed, into medium and high value products will open up new markets for DDGS producers, more specifically for prebiotics, nutraceuticals and bioplastics.

In 2010, the total European food and beverage prebiotics market was valued at Euro316 million, coresponding to a volume of approximately 100 kt. By 2015, the market is estimated to be valued at about Euro767 million, with a unit volume of 205 kt and an annual growth rate of 13.7 % (Frost and Sullivan, 2010 report). The market value in the US for prebiotics is currently about $110 million and is expected to double over the next 5 years, whereas in Asia, it was approximately $141 million in 2009 and is estimated to reach $232 by 2014. The market share of arabinoxylans and arabinoxylooligosaccharides is at the moment much smaller than that of the established inulin, fructooligosaccharides and galactooligosaccharides, but they are the most investigated compounds out of the emerging prebiotics and have attracted commercial interest over the last five years.

Bioplastics make up about 0.1% of the global market in plastics, which currently stands at about 260 million tonnes per annum, and is predicted that by the end of 2011 this will reach over 1500 kt (HGCA report). Among these, the bioplastics that are used as food packaging materials are mainly starches (~60% of market), cellulose acetate (~15% of market), and polylactic acid (PLA) (~15% of market) (HGCA report). Providing that the production costs are low, gluten-based bioplastics could eventually replace cellulose-based bioplastics as gluten has unique viscoelastic properties and can form films which are good oxygen barriers at low relative humidities.

Betaine has an established market within the nutritional supplements sector, which primarily includes sports nutrition; it is estimated that the betaine market is between 300-400 kt and is growing fast. Choline is mainly used as an animal health ingredient but has promising human applications as a nutritional supplement, as it has been associated with brain and memory health.

Considering the above market volume data and taking also into account the fact that in 2012 800 to 1000 kt of DDGS are expected to be produced annually in the UK, it can be deduced that a significant market potential exists for producing the above components from DDGS. In terms of the economics, currently the cost of DDGS is around £60-100 per tonne whereas the cost of a prebiotic is around £2000-4000 per tonne and the cost of betaine and choline are about £300 to 500 per tonne. The cost of gluten film packaging is likely to be considerably high; for comparative purposes the cost of biodegradable cellulose films is between £1,000-4,000 per tonne. The above figures indicate a potentially large economic impact to the UK economy by the transformation of DDGS through investment and product sales. The success of the project will also increase the possibility for attracting further funding to the UK academia from industry, the UK research councils, or the EU.

The societal and environmental impact of the project will also be significant. DDGS derived gluten plastics are sustainable products that can offer an alternative to synthetic petrochemical plastics, and are also fully biodegradable, which can help reduce waste and pollution. Moreover, the project's outcomes will result in an improvement in the quality of life and the health of consumers, through the development of functional health ingredients that can be incorporated into daily consumed food products or nutritional supplements