Impact dehulling oat grain to improve quality of on-farm produced feed : 2.Groat breakage and storability

Abstract

Dehulling improves markedly the feed value of oat (Avena sativa L.), but good storability of groat mass is required when large quantities of oat are dehulled at any one time. A laboratory model of an impact oat dehuller, similar to a commercial device, was used to study the effects of rotation speed and grain moisture content on groat breakage and the storage life of oat groats. Grain of oat cultivar Salo [from official variety trials, MTT Agrifood Research Finland, Jokioinen (60˚49'N), 1996-2000 was dehulled with an impact oat dehuller using rotation speeds of 200 to 500 r min -1 at 50 r min -1 intervals. In an additional experiment, grains were moistened resulting in moisture content ranging from 10% to 18%. Proportion of broken groats and size distribution of groat particles were measured. Storability was determined through analysing the evolution of pentanal, hexanal and free fatty acid content after storing groats at 10, 20 and 30˚C for two and five months. At higher rotation speeds more broken groats resulted, but dehulling did not cause any marked rancidification of the groats. Thus, impact dehulling is a practical method to increase the energy content of oat grains on-farm without such problems as groat breakage induced oxidation of fatty acids.

Predicting the Properties of Industrially Produced Oat Flours by the Characteristics of Native Oat Grains or Non-Heat-Treated Groats

“…The protein content of oats usually varies between 10 and 20% (dm), but values as high as 25% (dm) have been reported. Peltonen-Sainio et al [24] noted that the share of protein was higher after de-hulling, with an increase from 12.7% in oat grains to 15.6% in oat groats, which aligns with the current results.…”

“…The variation between the chemical composition of the different oat samples (n = 30) was expected, as the composition depends on the growth conditions, location, cultivar and variety [15,24,25]. It is important to note that although all of the samples were produced and analysed as pure cultivars, the experimental design used does not reveal linkages to the role of the cultivar, location, crop year or growth conditions; instead, we focused on revealing the factors of industrially produced oat flours in relation to the properties of the native grains.…”

Impact dehulling oat grain to improve quality of on-farm produced feed : 1.Hullability and associated changes in nutritive value and energy content

“…On the other hand, grains which did not dehull at low rotation speeds tended to have lower hull content than that of the intact grains. As the energy content of groat mass is closely associated with the amount of retaining hulls, the best rotation speed is primarily a compromise between degree of dehulling and groat breakage (Peltonen-Sainio et al 2004b). This is particularly important if there is a risk of reduced storability resulting from increased groat damage.…”

“…The small grains tended to require higher rotation speeds to be released from hulls (Peltonen-Sainio et al 2004b). Thus, for example, a large number of typically small sized tertiary grains (Palagyi 1983) in the grain mass might decrease hullability and require use of greater mechanical stress to yield groats with markedly improved metabolised energy content.…”

Characterising strengths, weaknesses, opportunities and threats in producing naked oat as a novel crop for northern growing conditions

“…Furthermore, conventional oat tended to produce higher amounts of hexanal than naked oat if differences occurred (Kirkkari et al 2004). An additional study by Peltonen-Sainio et al (2004b) with dehulled, conventional oat indicated that production of volatile compounds was not positively correlated with degree of grain damage. Even storage at high temperatures of up to 30˚C did not enhance rancidification processes in terms of production of volatile compounds when grains were stored under dry conditions.…”