Anu Kaukovirta-Norja

Germination : a means to improve the functionality of oat

The biochemical and physiological reactions of germination have long been utilised to produce barley malt for brewing and other purposes. Also some oat malt has been produced as raw-material of ale and stout production. The main goals of malting have been the degradation of grain storage components to soften the kernel structure, synthesis of amylolytic enzymes and production of nutrients for brewing yeast. Also flavour and colour attributes have been important. During the recent years interest has arisen also in the secondary metabolites produced during germination, which can have valuable health promoting properties and act as bioactive or functional compounds in foods. By using a tailored germination/malting process a desired combination of valuable properties may be obtained in germinating grains or seeds. All this requires knowledge and know-how of the germination process and the biochemistry behind it. This paper reviews the scientific knowledge about germination/malting of oat with special emphasis on changes in grain characteristics.

Oat products and their current status in the celiac diet

Publisher Summary The high content of beneficial fibers together with the bioactive copassengers make oats an attractive component both for a common and for a gluten-free diet. Oat dietary fiber is nutritionally special due to the high content of soluble, mixed linked β-D-glucan, which comprises 2–7% of the total kernel weight and is the main cell wall component of oat kernel. An adequate daily intake of β-glucan is associated with a reduced risk for heart and coronary diseases. In addition to β-glucan, oats, and especially oat bran, contain higher amount of total dietary fiber than most of the other gluten-free flours. In addition, the protein content in oats is higher than in rice or maize flour. In addition to dietary fiber and protein, oats deliver substantial amounts of unsaturated fatty acids and bioactive compounds. The total amount of lipids in oats is in the range 3–9%. The majority of the lipids are unsaturated and the most abundant fatty acids are monounsaturated oleic acid and polyunsaturated linoleic acid. Oats are known to have a high content of antioxidants and the typical tocol content is around 20–30 mg/kg. Other antioxidant compounds present in oats include phenolic acids, avenanthramides, and sterols. The distribution of the different protein classes is unique in oats, with globulins representing the largest group. In contrast, in the gluten-containing cereals wheat, rye, and barley globulins comprise at most 10% of total storage proteins, whereas the prolamins are the largest group, comprising 80% of the total storage proteins. Like most of the other cereal seed storage proteins, oat prolamins are rich in glutamine and proline.

Bio)processing as Tool to Tailor Cereal Flavour

ABSTRACT Wholegrain products are regarded beneficial for health by reducing the risk of several chronic diseases. Certain cereal types have a typical flavour, which in some cases is not regarded attractive enough for consumers. The flavour of native, untreated grain is mild and bland. Generally, the cereal flavour forms during processing, especially in heat treatments. By applying different bioprocessing techniques the flavour and texture of the products may be adjusted into desired direction. Volatile and non-volatile compounds influence the perceived flavour directly or indirectly as flavour components or flavour precursors. Descriptive profiling is used to form a general view of the sensory characteristics in the product. To understand the chemistry behind the flavour, statistical multivariate techniques are used to relate sensory characteristics and chemical compounds. In this work the impact of germination, milling fractionation, sourdough technology and enzymatic treatments on cereal flavour formation and characteristics will be discussed. Germination-drying process was found to adjust effectively the perceived flavour and increase the flavour stability of oat. Sourdough fermentation increased the perceived sourness and flavour intensity, and the following heat-treatment induced the appearance of flavours and compounds originating from Maillard reaction. The fractions of rye kernel have their characteristic flavour: between the mild tasting endospermic part and the bitter tasting outermost bran fraction, a rye-like flavour without any obvious bitterness was observed. This fraction contains significant amounts of bioactive compounds, such as alkylresorcinols, lignans and phenolic acids. Enzymes were also investigated as tools to modify rye flour. As a result of protease treatment the intensive, bitter flavour of rye was increased indicating that certain small peptides and concomitantly released phenolic compounds had a role in the bitter flavour.