Effects of corn drying and storage conditions on flour, starch, feed, and ethanol production: a review.

The objective was to review the effects of the drying and storage conditions of corn on the physical-chemical quality in the processing of starch and flour, in the production of animal feed, and in the industrialization of ethanol. Initially, the review presented an overview of the post-harvest stages of corn grains, highlighting drying and storage. The main drying and storage methods used for corn grains were presented. Among the drying conditions, the air temperature was the main factor that affected the properties of starch, flour, feed, and ethanol produced from corn. It was verified that the corn grains submitted to drying at temperatures below 60 °C obtained better results in the industry. In storage, in addition to the storage time, factors such as temperature and moisture content of the grains affected the physical-chemical quality of the processed products. In this stage, the moisture content below 14% and the storage temperature below 25 °C conserved the physical-chemical quality of the grains and obtained better processing results. Further studies are needed to assess the effects of the drying and storage conditions of corn on the properties of flour, starch, animal feed, and, mainly, ethanol production.

Effects of drying temperature of corn from the center and extremities of the corncob on drying parameters, protein and starch properties, and carotenoid profile.

The corn grains from the extremities of corncob are known to have a spherical shape and the grains from the center of corncob have higher length and lower thickness. It is understood that these differences in grain dimensions can affect post-harvest processes and the properties of the grains. Therefore, the objective of this study was to evaluate the effects of drying temperature (60, 80, and 100 °C) of corn from the center and extremities of corncob on drying parameters, protein and starch properties, and carotenoid profile. At 60 °C, the drying rate and effective moisture diffusivity of corn from the center and extremities of the corncob did not differ. However, at 80 and 100 °C these parameters were higher in the corn from the center. Corncob part and separation did not significantly affect corn pasting properties. However, they caused significant changes in the properties of the grain proteins, mainly the reduction of the solubility and inactivation of the lipase enzyme, and the reduction of the lutein and ß-carotene contents in the grains from the center and separated after drying. The results of this research show the need to evaluate the effects of these drying conditions during grain storage. In addition, the implementation of an industrial separation step and/or the development of new corn cultivars with more homogeneous grains should be studied.

Mathematical modeling and multivariate analysis applied earliest soybean harvest associated drying and storage conditions and influences on physicochemical grain quality.

Anticipating the harvest period of soybean crops can impact on the post-harvest processes. This study aimed to evaluate early soybean harvest associated drying and storage conditions on the physicochemical soybean quality using of mathematical modeling and multivariate analysis. The soybeans were harvested with a moisture content of 18 and 23% (d.b.) and subjected to drying in a continuous dryer at 80, 100, and 120 °C. The drying kinetics and volumetric shrinkage modeling were evaluated. Posteriorly, the soybean was stored at different packages and temperatures for 8 months to evaluate the physicochemical properties. After standardizing the variables, the data were submitted to cluster analysis. For this, we use Euclidean distance and Ward's hierarchical method. Then defining the groups, we constructed a graph containing the dispersion of the values of the variables and their respective Pearson correlations for each group. The mathematical models proved suitable to describe the drying kinetics. Besides, the effective diffusivity obtained was 4.9 × 10-10 m2 s-1 promoting a volumetric shrinkage of the grains and influencing the reduction of physicochemical quality. It was observed that soybean harvested at 23% moisture, dried at 80 °C, and stored at a temperature below 23 °C maintained its oil content (25.89%), crude protein (35.69%), and lipid acidity (5.54 mL). In addition, it is to note that these correlations' magnitude was substantially more remarkable for the treatments allocated to the G2 group. Furthermore, the electrical conductivity was negatively correlated with all the physicochemical variables evaluated. Besides this, the correlation between crude protein and oil yield was positive and of high magnitude, regardless of the group formed. In conclusion, the early harvest of soybeans reduced losses in the field and increased the grain flow on the storage units. The low-temperature drying and the use of packaging technology close to environmental temperatures conserved the grain quality.