A Preliminary Study on the Effect of the Instant Controlled Pressure Drop Technology (DIC) on Drying and Rehydration Kinetics of Maize Kernels (Zea mays L.)

Abstract

Maize is one of the three worldwide cereal crops with the most outstanding production; however, its postharvest losses range from 2 to 40% due to inadequate harvesting, drying, and storage technologies. This study focuses on the Instant Controlled Pressure Drop technology (DIC) effect on maize kernels’ drying and rehydration kinetics. In total, 19 different DIC treatments were carried out on maize kernels (~25% d.b.). The DIC parameters studied were steam pressure (0.1 to 0.4 MPa) and treatment time (10 to 90 s). After DIC treatment, drying kinetics were carried out by Convective Air Drying (CAD) at 50 °C and 0.4 ms−1 airflow. Rehydration kinetics and Water Holding Capacity (WHC) were evaluated at 20 °C. In comparison to CAD samples, DIC (0.4 MPa and 90 s) reduced the drying time from 180 min to ~108 min. Additionally, regarding the rehydration and WHC results, DIC achieved the same moisture content in only 3.5 min that controls achieved after 1 h of rehydration (0.40 g H2O/g dry matter). Moreover, DIC (0.4 MPa and nine cycles of 10 s) increased the WHC 2.3 times compared to the control. In this way, DIC could be a postharvest technology to improve maize kernels’ drying operations and functional properties.

Factors, Harms, and Control of Corn Kernel Breakage: A Review

“…Moisture content acts on the heat and mass transfer process during kernel drying, and is related to kernel drying effectiveness and breakage rate, and kernels of corn with high moisture content undergo greater volume changes during drying, and are more susceptible to breakage due to water dissipation and kernel crumpling [103,104]. In addition, the components of the corn kernel, such as the pericarp, hard endosperm, soft endosperm, and germ, have different water dissipation efficiencies, and it has been found that differences in changes in the moisture content of the internal structure of the corn kernel under the same drying conditions can trigger a moisture gradient and create stresses that can crack when the destructive strength of the corn kernel is exceeded [105][106][107]. The effect of temperature gradients during drying can also lead to corn kernel breakage, and temperature gradients caused by non-uniform drying environments or non-consistent drying rates can cause kernel cracking during drying [97], with temperature gradients typically arising within approximately 20 seconds after the start of drying and disappearing after 2 to 3 minutes [97,108].…”

Estudio de la cinética de secado del maíz suave (Zea mays L) variedad Guagal (INIAP 111)

“…El contenido de humedad para la cinética de secado de maíz inicial fue de 22,13%, cada muestra finalizo con un contenido de humedad de 0,53%; 0,7%; 0,61%. Según Cardador-Martínez et al, 13 realiza la cinética de secado por un lapso de 24 h con la diferencia que el peso se registra cada 5 min durante los primeros 30 min, luego a los 45, 60, 90, 120, 150 y 180 min. Hasta lograr que el contenido de agua de equilibrio.…”

Multivariate Interaction Analysis of Zea mays L. Genotypes Growth Productivity in Different Environmental Conditions

“…Maize (Zea mays L.) is a significant cereal crop and has the most abundant worldwide production, supplying human nutrition, animal feed, and feedstock for many industrial products and biofuels [1]. In addition to outstanding progress in the selection of new maize genotypes, the potential of maize yield is largely affected by abiotic and biotic factors, themselves determined by a certain combination of different factors, such as soil and climatic conditions, solar radiation, quality of seed, genetic performance, the potential for hybrids, and field management practices [2][3][4].…”