Drying kinetics and thermodynamic analysis; enhancing quinoa (Chenopodium quinoa Willd.) quality profile via pre-treatments assisted germination and processing

Pre-treatments assisted germination is an efficient technique to enhance the nutritional profile of Quinoa (Chenopodium quinoa Willd.). The present study investigated the impact of pre-treatments assisted germination of quinoa nutritional, anti-nutritional, and structural properties. Quinoa grains JQ-778 were subjected to various pre-treatments including soaking, ultrasound at 28 kHz &40 kHz (US 28 kHz, US 40 kHz) for 30 min followed by germination over 96-hour at 25 °C in a Biochemical-Incubator, 12/12 h dark and light dried at temperatures 50 °C, 60 °C, 70 °C, and combined temperatures (70 °C, 60 °C, 50 °C). Among evaluated models, page and logarithmic showed the best fit, presenting the highest, R² ≥ 0.9991, X² ≤ 0.0013, RMSE ≤ 0.0022, and RSS ≤ 0.0201. Moisture diffusion varied from 3.74 × 10^-9 to 8.36 × 10^-9, with R² 0.9272 to 0.9837, and energy activation from 18.25 to 28.41 kJ/mol with R² 0.9533-0.9896. US 40 kHz significantly lowered drying time without affecting germinated quinoa grains bioactive components or other qualitative factors. Ultrasonic pre-treatment at 40 kHz and drying at 60 °C yielded the highest antioxidant potency composite index of 98.78 %. The contentof phytic acid and tannin dropped by 66.66 to 82.99 % and 31.48 to 41.60 %, respectively (p < 0.05). Each treatment significantly altered quinoa's quality attributes. Principal Component Analysis revealed significant correlations between analyses, explaining 80.37 % variability. The intensity of functional groups decreased in the infrared spectra, although the transmission of signals was greater in pretreated samples than in control. Scanning electron microscopy analysis showed extensive fragmentation and surface erosion of quinoa grains after ultrasound treatment. Our data suggests that ultrasound-treated quinoa grains may enhance their nutritional value, making them a suggested source of high-protein grains, bioactive components, with distinct structural properties.