Influence of Processing Techniques on the Saponin Content and Nutritional Quality of Quinoa (<i>Chenopodium quinoa</i>)

Abstract

Quinoa cultivated primarily for its edible seeds is renowned for its nutritional richness. The study highlights how each method affects quinoa’s nutritional composition and saponin content by comparing different processing techniques. This information is valuable for food processors and manufacturers seeking to optimise their production processes to enhance their nutritional value. The soaking process involved immersing the seeds in sodium bicarbonate and citric acid solution (1% and 2%, respectively) for 6 hours at room temperature then roasting at 800C for 10 min. These pretreated quinoa grains were analyzed for their saponin content and nutritional composition. In raw quinoa grains, the saponin content was measured at 0.64%. After soaking the grains in a 2% citric acid solution, a significant reduction in saponin content to 0.09%. However, roasting the quinoa grains results in a decreased saponin content slightly to 0.62%. The results indicate that soaking in a 2% citric acid solution was particularly effective in reducing the saponin content of quinoa seeds to a desirable level while also eliminating bitterness. Consequently, quinoa seeds treated with a 2% citric acid solution were selected for further nutritional analysis. Significant alterations in the nutritional composition of quinoa were observed as a result of processing. In terms of proximate composition, soaking increased moisture, protein, and ash while decreasing other parameters. Soaking causes an increase in protein content from 15.6% to 16.2%. Conversely, roasting decreased moisture and protein levels while increasing other parameters. The moisture and protein content of roasted quinoa grains were reduced to 6.8% and 14.8%, respectively. Both soaking and roasting processes resulted in elevated mineral content in quinoa seeds. Consequently, soaked and roasted quinoa grains were found to be rich in nutrients, positioning them as valuable sources for enhancing food commercialization.