Physicochemical and pasting properties of maize as affected by storage temperature

- 35 °C promoted the highest decrease in yellowness, pH, protein solubility and breakdown viscosity.
- Protein solubility and pasting properties were related to disulfide bonds and starch interactions.
- Fat acidity and grains infected by molds were dependent of moisture content.
- The storage at 5 °C was able to maintain maize quality for up to 12 months.

Maize grains are used as raw material in various food products. In countries where the production is seasonal, the grains must be stored throughout the year in order to provide sufficient maize supply for the food industries and consumers. During storage, the environmental temperature is considered as one of the most critical variables that affects grain quality. This study aimed to evaluate the effects of various storage temperatures (5, 15, 25 and 35 °C) on the proximate composition, pH, fat acidity, percentage of grains infected by molds, grain color, protein solubility and pasting properties of maize stored for 12 months. Grains stored at 35 °C during the 12 months period showed the greatest decrease in grain yellowness, pH, protein solubility and breakdown viscosity. An increase in disulfide bonds within the protein structure and interaction between starch and non-starch components seems to be responsible for the changes in protein solubility and pasting properties determined in maize during the storage period. Fat acidity and the percentage of grains infected by visible molds were concluded to be very dependent of moisture content. The result of this study demonstrated that the minimum temperature of 5 °C was able to maintain the quality of maize stored for up 12 months.