Potatoes contain a lot of proteins. Up to two percent. Moreover, the potato contains its proteins in a special way, i.e. in an aqueous solution. AVEBE, the Dutch potato starch producer, recovers those proteins in a cold process; it separates them quickly in order to avoid coagulation. AVEBE is the world’s largest producer of potato starch, but we are talking about potato proteins here. Both the process and its applications are special. AVEBE directly separates the proteins into two fractions, and applies them as such, without any further separation. Proteins from potatoes, recovered from the waste stream as a high-value product. Marco Giuseppin, R&D director of Solanic, the protein daughter to AVEBE, tells us more about it.
‘Back in the fifties and sixties, we did not separate proteins from waste streams; this resulted in canals carrying a thick froth in our part of Groningen province. Nowadays, we remove the protein fraction by heating the potato process waste stream; we then recover the coagulated proteins. We sell this product for use in high-quality animal feed. Although we recycle a large part of the energy, protein recovery is an expensive part of our process. From 2007 onwards we apply cold processing in a pilot factory. We grate the potatoes, and then recover 90% of proteins within ten minutes, using advanced absorption technology. We developed the entire (well-patented) process in-house.’
‘In potatoes, proteins are stored in vacuoles, a kind of holes around two separate protein fractions, which the plant stores separately in aqueous solutions, because they coagulate when mixed. We absorb the entire protein fraction at a low temperature in a ‘simulated moving bed adsorption column system’, in which we use an adsorbent granulate made heavier by addition of tungsten carbide; much heavier because otherwise the entire bed would flow out of the reactor. We separate the two protein fractions by changing pH conditions; one fraction we recover in a slightly acid environment, the other in a neutral environment. We have to execute the process quickly in order to extract a maximum yield of proteins from the potatoes.’
‘The knack is that we do not subsequently separate these two fractions to produce pure proteins and enzymes, but use them as such in food and feed. It is a holistic approach not to separate those two fractions into their components, but use them as a whole. In doing so, we valorize them to the maximum, at the least cost. Our customers use the acid fraction in sport drinks and beverages for instance, in which our protein mixture is quite soluble. Others use our proteins as an additive to whipped cream, where they perform certain functions, and for improvement of the structure of sorbet ice cream. And we sell our protein mixtures for use in gluton free and lactose free food products.’
‘AVEBE is one of the minor players on the market of high-value proteins for human consumption, compared to animal protein producers, but we are the only one in the top segment to produce vegetal proteins.’ Says Marco Giuseppin.