With a protein content significantly below that of soya, beans can struggle to find a foothold in feeds where protein requirement is high
More economical processing methods are needed before faba beans could compete with soya and fishmeal as a protein source for the rapidly expanding farmed fish feed market.
Presenting results from the four-year Beans4Feed £2.6m industry and Innovate UK co-funded project at a review meeting near Peterborough, Dr Viv Crampton, principal scientist at the Cargill Innovation Centre - Cargill being a major supplier of fish feed - described how the research separated bean protein from bean starch using an air classification system.
“Beans need to be cleaned, dehulled, finely ground and put through a cyclone to separate protein and starch concentrates. You end up with a wonderfully rich starch source and a wonderfully rich protein source.”
While the product was successful nutritionally and could be used at up to 21% in fish diets, costs of cleaning, dehulling, lower-than-expected protein yield and grinding to the required fineness, made production prohibitively expensive, said Dr Crampton. “It is a lot of work for little benefit.”
A wet processing method of extracting bean protein normally used for separating potato starch was also trialled but the resulting concentrate was unpalatable to salmon. One delegate at the meeting suggested approaching a manufacturer producing pea concentrate based in Germany to see whether progress could be made.
While the fish feed market appears to offer little prospect for bean growers at present, the brewing and distilling industry might. Dr Pete Iannetta, researcher at the James Hutton Institute, Dundee, described how he’d worked with a local brewer to develop beer from a mix of 60% barley malt and 40% beans. “Barley is needed to drive the process. Beans don’t malt well but malting ability could be bred into them, he said.”
The process also produces a potentially high protein by-product with the combination of beans and yeast, however, with a moisture content of 30% for distillery spent grains and 90% from brewing, Dr Iannetta is investigating ways of making drying of the by-product affordable. “We are working with companies in Europe and particularly Belgium to see what cost efficiencies are possible.”
Dr Iannetta’s work also encompasses bean agronomy and he believes that if beans were treated as a cash crop, significantly higher yields are possible. “In Brazil they match the variety of soya to the rhizobia which has allowed them to become very efficient at what they do.”
Field trials including beans inoculated with elite lines of rhizobia, the bacteria involved in nitrogen fixing, are currently underway following research trials carried out by Dr Iannetta which he said saw yield improvements of up to 20%. Results are expected for peas in September and beans in October/November.
Dr Pete Iannetta, researcher at the James Hutton Institute, believes there is significant scope to boost bean yield and protein content. Here are a few of the research areas he is working on: