The EEC wet milling industry, after having the USA as its sole supplier for a long time, now uses about 5 million tonnes of EEC maize every year, amounting to 20% of the European total. Maize has been provided by South West France and Italy for about 10 years, and by Spain, Greece and Northern France for 3 or 4 years. This new orientation as far as supply sources are concerned has given rise to several problems concerning the techniques of transformation.
In this research project it is intended to compare the extraction aptitude of different components of grain maize with the industrial properties of extracted starch transformation, using experimental and representative maize samples from different European Community countries. The variety, the type of grain (flint, flint x dent, dent), the area of production (Spain, Greece, France, Belgium) and cultivation practices will also be varied and compared.
European maize production and the properties of the extracted starch by a damp starch process are being evaluated. The principal factors studied were: maize varieties; place of production; levels of nitrogen fertilisation; and feed and water. Starch was extracted in a pilot starch extraction process capable of treating small experimental batches of around 15 kg. The experimental starch samples were analyzed.
It was found that, under certain stressful water irrigation situations, yields were extremely reduced to about 3 tons per hectare. Stress situations concerning nitrogen fertilisation or water gave grains which, on average, were lighter and weaker in character. The total nitrogen content was affected in those trials where no nitrogen fertiliser was given. Conversely the situations where irrigation was improved tended to dilute the total nitrogen.
Primary repeatability studies were performed and these allowed the determination of confidence intervals at 1.5% and 0.15% on total starch recuperation and the residual composition of the proteins in the starch coming from the first passage of the pilot process. The amylases were found in trace state in the perricarpel and equally distributed between the embryo and the albumen. The globulin and albumin proteins have crossed their composition in the grain before decreasing at the end of the grain. The residual proteins in the starch after extraction were essentially functional. This was detected by a tryptophan dosage whose presence reveals the protein type. Amino acid analysis is currently being performed.
Analysis will be performed on grain samples and extracted products (starch, gluten, germ, fibre, etc). Extractions will be conducted on a wet milling pilot plant, the results of which (starch and gluten yield, starch purity, etc) can be extrapolated for the industry in general. Results of this research should influence maize breeding and permit the most appropriate choice of hybrids and cultivation techniques in order to supply the EEC starch industry with the best quality of maize.
Funding SchemeCSC - Cost-sharing contracts