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Oat kernel size uniformity is of interest to the oat milling industry because kernel size is important in the dehulling process. Previous studies indicated that oat kernel size distributions are bimodal. In this study oat spikelets were dissected into primary, secondary, and tertiary kernels and kernel size distributions were determined for each of these kernel orders by digital image analysis. Spikelets with two kernels are the most abundant, and their primary and secondary kernels have distinctly different size distributions. These two kernel spikelets appear to be responsible for the bimodal distribution observed among oat kernels. Primary kernels from single kernel spikelets and primary, secondary, and tertiary kernels from triple kernel spikelets all had different mean sizes and distributions. These kernels appeared to contribute to deviations from bimodal distributions. Thus, data presented provide direct definitive evidence that the non-Gaussian distributions observed for oat kernel sizes are derived from the combination of subpopulations from each of the different orders of kernels from within the spikelet. Sieving analysis of kernel types indicated that for the samples analyzed here, secondary kernels from two kernel spikelets and tertiary kernels from three kernel spikelets appear to contribute equally to undersized kernels under 2 mm in width. Thus, from a kernel size prospective, no advantage can be attributed to the elimination of three kernel spikelets by selective breeding.

Kernel size in naked oat (Arena sativa L.) is of interest because of the importance of groat size in determining flake size in 'old fashioned' style oat flakes. Here we compared naked oat kernel size distributions with those of hulled oat (Arena sativa L.). Most hulled oat spikelets have two kernels, where the primary kernel is distinctly larger than the secondary kernel. Although naked oat panicle architecture was similar to that of hulled oat, naked oat had a distinctive multi-florous spikelet architecture that contained from one to six kernels. Because single and double-kernel spikelets were most abundant in naked oat, the mean kernel number per spikelet did not differ between hulled oat and most naked genotypes. Like hulled oat, naked oat kernel size decreased with increasing kernel order. All hulled oat and most naked genotypes had size distributions departing from normality, but some naked genotypes had normal kernel size distributions. Variances of naked oat kernel size were much smaller than those of hulled genotypes, indicating a greater degree of kernel sizes uniformity in naked genotypes. However, the increased variation in the hulled oat kernel size appeared to be due to the presence of the hull and hulled oat groats had about the same size variation as did naked oat groats., NAKED OAT, also called hull-less oat, are oat that can thresh free of the hulls during harvest. The spikelets of naked oat are distinctively different morphologically from hulled oat and [...]

Oat (Arena sativa L.) kernel size uniformity is important to the oat milling industry because oat-processing mills separate oats according to size to optimize dehulling efficiency. In this study, we compared two different approaches for analyzing oat kernel size uniformity, namely the sequential sieving of oat samples with a gradient of slotted sieve sizes and digital image analysis. Image analysis of size fractions provided evidence that sieving separated oat kernels according to their depth, whereas, digital image analysis measured kernel length and width, and derived a measure of the area of the oat kernel image. Samples identified by sieving with superior uniformity were those with greater proportions of large kernels. Histograms of oat kernel sizes derived from digital image analysis suggested oat kernel sizes were (within a genotype and location) composed of bimodal populations. A new statistical analysis allowed for the derivation of means and variances of each of these subpopulations, the numerical balance between the two subpopulations, and the extent of bimodality. Oat samples with lower levels of bimodality tended to be of higher test weight and groat percentage and thus, of better milling quality. Both methods appear satisfactory for evaluating oat kernel size uniformity, although the sequential sieving method is likely to be more useful to breeding programs because of its relative technical ease and simplicity., OAT KERNEL SIZE UNIFORMITY is important to the oat milling industry because the processing of oats for human food generally involves size separation of kernels into different streams before dehulling [...]

The presence of Β-glucan from oat (Avena sativa L.) or barley (Hordeum vulgare L.) products in the human diet can lower serum cholesterol. The selection of new oat or barley cultivars with higher Β-glucan concentration in the grain is usually limited by the efficiency of the analytical procedure required to measure this component. The utility of flour slurry viscosity as an indirect means of estimating flour Β-glucan concentration was investigated. Water at 25 ° C was added to enzyme-inactivated whole-grain oat flour to form a 23% dry matter mixture, and stirred to form a uniform slurry. Viscosity, as measured with a rotational spindle-type viscometer, increased hyperbolically with time. Viscosity measured 3 h after water addition was exponentially dependent on flour content and was linearly correlated with Β-glucan concentration in the flour. The procedure was useful as a screening method for the estimation of Β-glucan concentration in preliminary breeding lines of oat and barley. The procedure is effective with enzyme-inactivated (steam-treated) whole or dehulled grain, but the presence of endo-Β-glucanases in hulls of oats and barley prevent the application of this procedure with flours of raw whole oats and barleys., A important quality characteristic of oat and barley is their mixed linkage (1 → 3), (1 → 4)-Β-D-glucan (Β-glucan) concentration. A number of studies have suggested that this carbohydrate is [...]

The grain yield and quality determine much of the value of an oat (Avena sativa L.) crop to the producer. This study investigated effects of genotype and environment on grain yield and quality. Twelve oat genotypes were grown during 3 yr at four locations in North Dakota where detailed environmental data were being collected. Grain yield, test weight, groat percentage, groat weight, and groat composition (protein, oil, Β-glucan, and starch concentrations) were evaluated. Results were subjected to analysis of variance and influences of environmental factors were evaluated by correlation analysis. Analysis of variance suggested that grain yield, groat starch, and ash concentrations were more strongly affected by environment than by genotype. Test weight, groat percentage, groat weight, protein, and Β-glucan were about equally influenced by environment and by genotype, whereas groat lipid was more strongly influenced by genotype. Significant environment x genotype interactions for all characteristics were attributed to differential resistance of genotypes to crown rust (caused by Puccinia coronata Corda var. aveneae W.P. Fraser & Ledingham) infection. Environments severely affected by crown rust produced grain with lower test weight, groat weight, and groat percentage in susceptible genotypes. Correlation analyses suggested that warm, bright (high solar radiation) spring weather, and cooler summer weather without excessive rains during grain filling generated the best oat yields with high quality grain., CHARACTERISTICS most commonly used to describe oat quality include test weight, groat percentage, groat weight, and groat composition. The major groat compositional characteristics relating to quality include the protein, oil, [...]

The groat percentage represents an important quality characteristic of oat (Avena sativa L.). Our objectives were to characterize mechanical factors of the oat dehulling process and the physical characteristics of the oat grain that affect groat percentage. Mechanical factors were determined with a compressed air dehuller. Physical characteristics of oat grain were evaluated from 10 genotypes grown at three locations with digital image analysis. Groat percentage as determined by hand dehulling was compared with mechanical dehulling. The strength and duration of mechanical stress required to separate the hull from the groat and the strength of the aspiration required to remove free hulls from the groats had significant effects on groat percentage results. Insufficient mechanical stress resulted in ineffective dehulling, but excessive stress resulted in groat breakage. Excessive aspiration removed groats as well as hulls, but insufficient aspiration left excessive hulls with groats. Groat percentage values obtained by hand dehulling or by mechanical means correlated well. Hand sorting of mechanically dehulled groats to remove hulls remaining after dehulling improved their correlation, indicating the importance of hand-sorting mechanically dehulled oats. Test weight and oat size uniformity were highly correlated with groat percentage. Negative correlation between hulls remaining after dehulling with groat percentage suggested that heavier hulls, associated with lower groat percentage, were more difficult to remove by aspiration. Positive correlations between groat breakage during dehulling and groat percentage suggest that thin hulls provide less protection to the groat during dehulling, resulting in higher levels of breakage., THE OAT GROAT OR CARYOPSIS is typically covered with a lemma and palea, or hull after harvest. This hull must be removed before the groat can be processed for food [...]

The article discusses the variation in the fine structure, extractability and flour slurry viscosity of beta-glucan in oats due to genotype and environment. The analysis of fine structure analyzed both genotypic and environmental variation. The genotypic variation in oat flour slurry viscosity depends upon the beta-glucan concentration in the flour.

The article focuses on extraction of beta-glucan from oats for soluble dietary fiber quality analysis. The consumption of adequate amounts of beta-glucan in the diet can lead to reduction of serum cholesterol and reduce the risk for heart disease. Efforts are made to improve the nutritional quality of oat as the solubility, viscosity and molecular weight of the beta-glucan are also important for health.