Effect of ultrasound pretreatment and soaking time on Quinoa malting.

Abstract

In this study, malt was produced from quinoa seeds using different ultrasound treatment with different intensities (20%, 60%, and 100%), ultrasound times (5, 10, and 15 minutes), and soaking times (2, 6, and 10 hours) at a frequency of 20 kHz. The seeds were soaked in water at 25 °C during exposure to ultrasound waves. The results showed that an increase in soaking time led to a higher malting yield and percentage of soluble solids (°Brix), followed by a downward trend. This trend was intensified by longer exposure to ultrasound waves at higher intensities. The interaction effect of ultrasound wave and soaking time on physicochemical properties showed a downward trend, followed by an upward trend in cold-water and hot-water extract yields, reducing sugar, soluble nitrogen, color, and Kolbach index, with increasing levels of the variables. Finally, quinoa malt treated with an ultrasound intensity of 100% for 15 minutes and soaked for 6hours exhibited the best physicochemical characteristics.