Study of Essential Amino Acids’ Bioaccessibility in a Quinoa (Chenopodium quinoa Willd.) and Amaranth (Amaranthus caudatus) Supplements for Ecuadorian Adolescents

The consumption of food supplements in Latin America represents 7% of the world’s consumption, as reported by the Latin American Alliance of Responsible Nutrition (ALANUR) in 2021. Developing high-quality Andean-grain supplements could be interesting for enhancing the country’s food security. A supplement has been developed that contains high-quality protein and carbohydrates sourced from a blend of precooked quinoa and amaranth flours. Additionally, it includes omega-3 and omega-6 fatty acids derived from microencapsulated sacha inchi and chia oils, along with vitamins and minerals. The process for obtaining the precooked flours involved cooking at 75 ◦C for 12 min, followed by drying in a tray dryer at 70 ◦C for 8–9 h, grinding in a disk mill, and sieving to achieve a particle size of 150 µm. Pasta tests were conducted using RVA and DSC to check their gelatinization. The supplement’s composition adheres to the mandatory nutrient requirements specified by the Ecuadorian standard NTE INEN1334-2, 2011. Moreover, the supplement satisfies the sensory criteria related to taste and consistency. To evaluate the impact of the processing on the nutrients’ attributes, assessing their bioaccessibility becomes significant. To accomplish this, the static in vitro digestion method was employed, both before and after the digestion process. The digestion protocol involves the following steps: an oral phase with amylase, a gastric phase with pepsin, and an intestinal phase with pancreatin. The resulting digest was subsequently centrifuged and filtered. The apparatus utilized consisted of a reactor equipped with precise controls for temperature, pH, and agitation. The in vitro digestibility percent for the supplement shake was determined to be 96.7% (IVD). Essential amino acids were quantified through HPLC analysis with a fluorescence detector. As a result, lysine and histidine exhibited the highest bioaccessibility values of 97% and 79%, respectively, while methionine had the lowest value of 32%. The remaining amino acids showed intermediate value