Saponins are an important group found in Chenopodium quinoa. They represent an obstacle for the use of quinoa as food for humans and animal feeds because of their bitter taste and toxic effects, which necessitates their elimination. Several saponins elimination methods have been examined to leach the saponins from the quinoa seeds; the wet technique remains the most used at both laboratory and industrial levels. Dry methods (heat treatment, extrusion, roasting, or mechanical abrasion) and genetic methods have also been evaluated. The extraction of quinoa saponins can be carried out by several methods; conventional technologies such as maceration and Soxhlet are the most utilized methods. However, recent research has focused on technologies to improve the efficiency of extraction. At least 40 saponin structures from quinoa have been isolated in the past 30 years, the derived molecular entities essentially being phytolaccagenic, oleanolic and serjanic acids, hederagenin, 3β,23,30 trihydroxy olean-12-en-28-oic acid, 3β-hydroxy-27-oxo-olean-12en-28-oic acid, and 3β,23,30 trihydroxy olean-12-en-28-oic acid. These metabolites exhibit a wide range of biological activities, such as molluscicidal, antifungal, anti-inflammatory, hemolytic, and cytotoxic properties.

Quinoa (Chenopodium quinoa Willd.) is a grain of great nutritional interest that gained international importance during the last decade. Before its consumption, this grain goes through many processes that can alter its nutritional value. Here we report the effect of processing (polishing and milling) and cooking (boiling and steaming) on the saponin content, mineral profile of 14 elements using Inductively Coupled Plasma-Optical Emission Spectrometry (ICP-OES), protein content, and total phenolic compound. The polishing caused an average drop in the saponin content from 1.7% to 0.46% but induced important losses in mineral content (K, Mg, Ca, Zn, Co, Cu, Fe, Mn, and Ni), and phenolic compounds. However, the greatest nutritional degradation happened after milling due to the elimination of seed teguments and embryos, where over 50% of many minerals, 60% of protein content, and almost the totality of phenolic compounds, were lost. Cooking effect was less important than processing, but some significant losses were attested. Boiling caused a loss of up to 40% for some minerals like K, B, and Mo because of their hydrosolubility, and 88% of the polyphenols, while steaming allowed a better retention of those nutrients. Consuming polished quinoa instead of semolina and using steaming instead of boiling are trade-offs consumer needs to make to get optimal benefits from quinoa virtues.

Introduction: Quinoa (Chenopodium quinoa Willd.) is internationally recognized for its exceptional nutritional profile, yet its incorporation into traditional cereal-based foods remains limited. Methods: This study developed and optimized a gluten-free couscous from quinoa and rice using D-optimal response surface methodology, evaluating the effects of quinoa fortification level (0-100%), steaming time (10-30min), and water volume (350-450 ml/kg) on techno-functional properties, proximate composition, mineral profile, bioactive compounds, and color. Results: Quinoa fortification percentage was the dominant factor across the response set, while steaming time and water volume acted as secondary modulators. The nutritional optimum converged on 100% quinoa, with processing parameters of 20min steaming and 400 ml/kg water. Compared with commercial wheat couscous and rice-only couscous, quinoa couscous showed enhanced water-holding and oil-holding capacity, up to five-fold higher potassium, three-fold higher iron, and three-fold higher total phenolic content. LC-MS/MS amino acid putative profiling detected 18-19 of 20 amino acids in quinoa couscous versus 14 in wheat and 11 in rice couscous, with enrichment in branched-chain amino acids and detection of lysine, the limiting amino acid of cereal proteins, which was undetected in rice couscous and present only at trace levels in wheat couscous. Quinoa couscous exhibited around five-fold greater polyphenol diversity than wheat couscous, including flavan-3-ols, chalcones, and hydroxycinnamic acids exclusive to quinoa formulations. Higher quinoa levels darkened the product, with color stabilizing at fortification levels above 75%. Discussion: Unlike previous work on alternative-grain couscous, this study combines process optimization with LC-MS profiling of amino acid and polyphenol composition, providing an integrated framework for gluten-free quinoa-rice couscous development. The results demonstrate that quinoa-based couscous provides a nutritionally superior, gluten-free alternative to conventional wheat couscous, with processing conditions that preserve the raw material's nutritional attributes.