This study assesses the association between physical properties and baking performance of dough. Sixty-six argentine wheat-breeding lines were milled using an experimental mill. Wet gluten content and physical dough properties were determined in flours; while breads, cookies and crackers were made to evaluate baking performance. Principal component analysis (PCA) was utilized to observe variations among flour samples studied. A close association was found between some farinograph parameters (development time, stability), some alveograph parameters (G, W, P), and the attributes of bread quality (specific volume and total score). Results obtained in cookies and crackers indicate that there is a close positive correlation between weak gluten content and technological attributes of quality such as specific volume and sensory evaluation (total score).

Efforts are being made to identify sources of starches with unique end-use properties, such as thermal properties, within a wide array of maize germplasm. Because redundancy may exist when evaluating these traits, it would be useful to know the pattern of correlation among traits involved to focus the expensive stage of evaluation of germplasm on traits that do not provide redundant information. The objectives of this study were to analyze the pattern of correlations between starch gelatinization and retrogradation-associated traits in a group of 12 Argentine maize inbred lines and to develop predictive models among traits when possible. Traits measured by differential scanning calorimetry included gelatinization and retrogradation properties. Pearson correlation coefficients among starch thermal properties were determined from univariate analyses, and canonical correlations were determined from multivariate analyses. Canonical correlation analyses were more sensitive in detecting associations between starch gelatinization and retrogradation parameters than univariate analyses. Multiple regression equations to estimate the change in enthalpy of starch gelatinization and retrogradation traits, especially for change in enthalpy and percentage of retrogradation, were obtained and validated with an independent data set.

Thermal properties are among the most important end-use characteristics of starch from maize (Zea mays L.). Knowledge of the contribution of genotype and environment to the total variance for starch thermal properties is needed to aid in defining a testing strategy for selecting maize with desirable thermal starch properties. Thus, the objectives of this study were 1) to characterize the thermal properties of starches from a group of recently developed Argentine maize inbred lines, and 2) to assess the variability in starch properties attributable to genetic and crop year effects. Twelve inbred lines developed by the National Institute of Agricultural Technology (INTA) in Argentina derived from a wide array of germplasm sources were evaluated. Gelatinization and retrogradation properties were measured by differential scanning calorimetry. Enthalpy means for gelatinization were below means reported in the literature, suggesting possible energy savings when using these starches. The ratio between change in enthalpy for retrogradation and gelatinization was above the mean reported in the literature, suggesting a starch that may be useful as a dietary fiber. Significant environmental effects caused by crop year were detected. Some inbred lines, with smaller observed ranges and standard deviations across environments, may be more stable for some properties.

ABSTRACTThe objective of this study was to determine the relationship between the amount and type of lipids, starch composition and structure, and storage proteins on popcorn expansion and to evaluate whether popcorns could be discriminated from other types of corn based on the protein elution parameters. Seven commercial Argentinean popcorn samples were used in the study and significant differences were observed in the popping volume of these popcorns. A significant negative correlation was observed between oleic acid and popping volume and a positive correlation was observed between linoleic acid and popping volume. Popcorn starch properties were significantly different from normal corn but no particular measured attribute of starch correlated with popping volume. α‐Zein proteins and glutelins significantly correlated with popcorn expansion volume with R2 = 0.963 and 0.744, respectively. The elution patterns of corn proteins could also be used to discriminate between different types of corn including popcorn, dent, and flint corns.

Influence of maize kernel hardness on flour hydration and cooking properties. Knowledge of the association between cooking properties and endosperm hardness may help nutritionist and processors to select raw materials for preparing maize based food products, particularly those eaten as cooked dispersions. Seven commercial maize cultivars differing in hardness were selected to evaluate endosperm hardness on the kernels and some characteristics such as composition and hydration and cooking properties on the grits obtained from those maizes. Results show that the differences in endosperm hardness (directly related to grits protein content) can explain the differences in swelling and amylographic consistencies values. Cultivars with the hardest endosperm show the lowest values at high temperature. They also show the lowest amylographic consistencies. On the other hand softer endosperms present the highest swelling power and the highest amylographic consistencies. These differences are attributed to the restriction for starch swelling caused by the protein matrix. Endosperm hardness measurements and swelling power at 95 degrees C, can be useful to select cultivars that are going to be used to prepare maize based foods like atoles, polenta, etc.

El conocimiento acerca de la asociación entre las propiedades de cocción y la dureza del endospermo del maíz puede ayudar tanto a los nutricionistas como a los procesadores a seleccionar las materias primas para elaborar productos a base de maíz, particularmente aquellos que se consumen en forma de dispersiones cocidas. Se seleccionaron siete cultivares de maíz con distinta dureza, la que fue evaluada utilizando diferentes métodos. Los granos fueron descascarados, desgerminados y reducidos a harinas para determinar la composición, el poder de hinchamiento (PH), la solubilidad y la respuesta amilográfica. Los resultados mostraron que las diferencias en dureza de endospermo (directamente relacionada con el contenido de proteína de la harina), puede explicar las diferencias observadas tanto en el poder de hinchamiento como en los valores de consistencia amilográfica. Los cultivares de endospermo más duro muestran los menores valores de PH a alta temperatura y también los menores valores de consistencia amilográfica (viscosidad). Por el contrario los endospermos más blandos presentan los mayores valores de PH y de consistencia amilográfica. Estas diferencias son atribuidas a la restricción al hinchamiento de los gránulos del almidón que provoca la estructura de la matriz proteica. Las medida de dureza del endospermo y las de PH a 95 °C pueden ser muy útiles para seleccionar cultivares que serán utilizados para lograr alimentos tales como atoles, polenta, etc.Knowledge of the association between cooking properties and endosperm hardness may help nutritionist and processors to select raw materials for preparing maize based food products, particularly those eaten as cooked dispersions. Seven commercial maize cultivars differing in hardness were selected to evaluate endosperm hardness on the kernels and some characteristics such as composition and hydration and cooking properties on the grits obtained from those maizes. Results show that the differences in endosperm hardness (directly related to grits protein content) can explain the differences in swelling and amylographic consistencies values. Cultivars with the hardest endosperm show the lowest values at high temperature. They also show the lowest amylographic consistencies. On the other hand softer endosperms present the highest swelling power and the highest amylographic consistencies. These differences are attributed to the restriction for starch swelling caused by the protein matrix. Endosperm hardness measurements and swelling power at 95 ºC, can be useful to select cultivars that are going to be used to prepare maize based foods like atoles, polenta, etc.

Understanding the association between industrial quality and biochemical and biophysical properties of commercial maize cultivars may help breeders develop cultivars best adapted to diversified processing requirements, and processors choose cultivars best for specific requirements. The suitability of cultivars for extrusion cooking is important in this regard. To supply information useful to maize breeders and processors, biophysical (endosperm texture and hardness) and biochemical (protein and starch composition) properties of kernels, grits and extruded curls of several commercial maize cultivars were determined and related to extrusion performance. Results show that extrusion alters protein hydrophobicity and degree of aggregation, though differently between cultivars. Under conditions of this study, grits from harder maize expand more, consume less energy upon extrusion, and cook more rapidly than do grits from softer maize. These behaviors appear related to differing protein compositions and endosperm textures of cultivars. Results also suggest that reversed-phase high-performance liquid chromatography of zeins (the storage prolamin proteins of maize) may be valuable for predicting end-use properties of extruded maize products, and as a quality estimator during maize breeding.

ABSTRACTScreening accessions in a germplasm bank aids in the identification of plants with unusual properties ranging from agronomic traits to functional and compositional traits of the seed itself. Results from this study confirm the presence of a wide variation in the thermal and functional properties of starch from several landraces of corn in the Argentinean germplasm. Thermal properties of starch measured using differential scanning calorimetry (DSC) identified several corn landraces with properties of potential commercial interest. The pasting and textural properties of gels obtained from starch of different corn landraces also exhibited considerable variability. The degree of variation in thermal and functional properties of corn reported in this study is comparable to the thermal properties of starch from several other crop species. These corn races show promise for further regeneration to create inbred lines with unusual traits. The potential for further improvement of corn races exists not only based on thermal properties, but directly for specific functional attributes as well. Correlation analyses suggest that the variability in thermal and functional attributes are a function of amylose content, granule size distribution and, possibly, differences in the structural makeup of amylose and amylopectin. The strong correlation observed between the thermal properties and pasting and textural properties will allow for the estimation of starch properties from small sample sizes.

ABSTRACTSamples of Argentine maize from 12 landraces were analyzed for starch and amylose content and were evaluated for hardness parameters. Amylose contents of these Argentine landraces were generally higher than for typical dent hybrids grown in the United States. Hardness, as estimated by near‐infrared reflectance; from wavelength shift of the near‐infrared transmittance spectrum absorbance maximum (λmax) in the 610–680 nm region; and by percentage of γ‐zein in zein‐2 (determined by reversed‐phase HPLC), correlated well with classical definitions of endosperm type and with amylose content. Starch content correlated negatively with hardness. Flint landraces varied substantially in amylose and starch content. The strong correlation between amylose content and maize endosperm hardness confirms and strengthens previous observations, and may provide a compositional basis for endosperm quality.

Argentinian soybean production reached almost 11 million tonnes in 1991, after a growth of 660% in 14 years. Soybean drying became a major post-harvest activity involving long drying times and high fuel consumption. Thus, production of varieties with high drying rates should be encouraged. In this work, the drying rates of 25 varieties of soybean were determined at 60°C in a laboratory dryer. Drying times required to reduce the dimensionless moisture from 1 to 0.5 were 97.3 ± 11.5 min. An analysis was then performed to explain differences in drying times. Sizes of grains, (radius squared) was a significant cause of the differences in drying time. Effective diffusion coefficients were also determined for the 25 varieties. Values found were 7.62 × 10-11 m2/s with a variation coefficient of ±9.1%. The combination of size and diffusion coefficient accounted for the 93.8% of the variations in drying times. No practical effect of oil and protein content on the drying rate was encountered. The diffusion coefficients tend to be greater for larger grains, probably due to the smaller contribution of the tegument to the grain specific resistance to water movement.