The aim of this study was to optimize the germination conditions of amaranth seeds that would maximize the antioxidant activity (AoxA), total phenolic (TPC), and flavonoid (TFC) contents. To optimize the germination bioprocess, response surface methodology was applied over three response variables (AoxA, TPC, TFC). A central composite rotable experimental design with two factors [germination temperature (GT), 20-45 ºC; germination time (Gt), 14-120 h] in five levels was used; 13 treatments were generated. The amaranth seeds were soaked in distilled water (25 °C/6 h) before germination. The sprouts from each treatment were dried (50 °C/8 h), cooled, and ground to obtain germinated amaranth flours (GAF). The best combination of germination bioprocess variables for producing optimized GAF with the highest AoxA [21.56 mmol trolox equivalent (TE)/100 g sample, dw], TPC [247.63 mg gallic acid equivalent (GAE)/100 g sample, dw], and TFC [81.39 mg catechin equivalent (CAE)/100 g sample, dw] was GT = 30 ºC/Gt = 78 h. The germination bioprocess increased AoxA, TPC, and TFC in 300-470, 829, and 213%, respectively. The germination is an effective strategy to increase the TPC and TFC of amaranth seeds for enhancing functionality with improved antioxidant activity.

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In this work the objectives were: (1) To optimize the extrusion conditions of defatted chia seeds maximizing antioxidant activity (AoxA), total phenolic content (TPC) and in vitro protein digestibility (IVPD), and (2) To evaluate the nutritional, nutraceutical, and sensory (acceptability) properties of tortillas formulated with commercial nixtamalized maize flour (MASECAMR) and optimized extruded defatted chia flour. Response surface methodology was applied as an optimization tool. A central composite rotatable design with two factors [Extrusion temperature (ET=50-160°C), screw speed (SS=50-240 rpm)] in five levels were used. The extruded from each treatment (13) were dried and ground to obtain extruded defatted chia flours (EDCF). The desirability function was applied as optimization technique. The prediction models for each response variable were adequate and reproducible. The optimal extrusion conditions to obtain optimized extruded defatted chia flour (OEDCF) were ET=147°C/SS=237 rpm; a high global desirability (D=0.815) was associated with these optimal conditions. The tortillas elaborated with MASECATM flour + OEDCF had higher IVPD, C-PER, TPC and AoxA, and better antihypertensive potential than elaborated with only MASECATM flour. The addition of OEDCF to MASECATM flour increased the nutritional and nutraceutical value of the tortillas.

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The aims of this research were to develop functional beverages from amaranth and chia flours, processed by germination and extrusion, and evaluate its nutritional, antioxidant and antihypertensive properties. Optimal conditions, previously obtained, to produce extruded (Extrusion temperature= 141 °C/screw speed = 81 rpm) and germinated (Germination temperature= 30 °C/germination time= 78 h.) amaranth flours (EAF, GAF) were applied. Optimal conditions of germination temperature (29 °C) and germination time (197 h) to elaborate germinated chia flour (GCF), with maximum values of antioxidant activity, total phenolic and protein contents, were obtained. A 200 mL portion of the functional beverages, elaborated with 25 g of 70 % EAF+ 30% GCF or 70 % GAF + 30 % GCF mixtures, had 3.90-4.53 g protein, 5.04-6.81 g dietary fiber, 95-96 kcal of energy, calculated protein efficiency ratio = 2.52-2.69, antioxidant activity= 4,009-6,495 μmol TE, antihypertensive potential (IC50) = 0.43-0.47 μg extract/mL, and sensorial acceptability between “I like it very much” and “I like it extremely”. These functional beverages, due to its high nutritional value, and antioxidant and antihypertensive potential, can be used for health promotion of consumers.