Characterization and effects of heat treatments on antinutritional components and enzyme activities in sainfoin (Onobrychis viciifolia L.) seeds: A high-protein alternative plant-based food source.

The aim of this study was to characterize and explore the food potential of sainfoin seeds, which are primarily used in their green plant form to feed livestock. A detailed assessment of the seed's proximate composition, enzyme activity levels, and antinutrient content was performed. The seeds were then subjected to infrared, hot air, and blanching treatments to examine how these processing methods affect enzyme activities and antinutrients. In addition, optimization of processing conditions was carried out using the response surface method and central composite design to ensure low antinutrient levels, minimal color change, and total enzyme inactivation. Sainfoin seeds have a crude protein content of 42 % in dry matter, making them a promising alternative plant-based protein source. They also contain 45 % dietary fiber, 9 % crude fat, and significant levels of potassium and magnesium. The unprocessed seeds exhibited 2.01 U/g lipase activity and 10.51 U/g lipoxygenase activity, which were inactivated with infrared treatment at 2000 W IR power in 75 s. In terms of antinutrients, sainfoin seeds contain 247 mg/100 g phytic acid, 2582 TIU/g trypsin inhibitor activity, 7.9 mg catechin equivalents of tannin /100 g, and 24.97 mg/100 g hydrocyanic acid. The optimal process conditions were 2000 W IR power and 105 s for IR treatment, 150 °C and 103 min for hot air treatment, and 81 °C and 16 min for blanching. The antinutrient levels and enzyme activities in unprocessed sainfoin seeds are comparable to those found in conventional legumes, although sainfoin seeds contain a higher amount of tannins. While infrared treatment was most effective for enzyme inactivation, the impact of the different processing methods varied across the parameters studied.