Healthy Ready-to-Eat Expanded Snack with High Nutritional and Antioxidant Value Produced from Whole Amarantin Transgenic Maize and Black Common Bean.

Abstract

The snack foods market is currently demanding healthier products. A ready-to-eat expanded snack with high nutritional and antioxidant value was developed from a mixture (70:30) of whole amarantin transgenic maize (Zea mays L.) and black common bean (Phaseolus vulgaris L.) by optimizing the extrusion process. Extruder operation conditions were: feed moisture content (FMC, 15-25%, wet basis), barrel temperature (BT, 120-170°C), and screw speed (SS, 50-240). The desirability numeric method of the response surface methodology (RSM) was applied as the optimization technique over four response variables [expansion ratio (ER), bulk density (BD), hardness (H), antioxidant activity (AoxA)] to obtain maximum ER and AoxA, and minimum BD, and H values. The best combination of extrusion process variables for producing an optimized expanded snack (OES, healthy snack) were: FMC=15%/BT=157°C/SS=238rpm. The OES had ER=2.86, BD=0.119g/cm (3) , H=1.818N, and AoxA=13,681μmol Trolox equivalent (TE)/100g, dry weight. The extrusion conditions used to produce the OES increased the AoxA (ORAC: +18%, ABTS:+20%) respect to the unprocessed whole grains mixture. A 50g portion of OES had higher protein content (7.23 vs 2.32g), total dietary fiber (7.50 vs 1.97g), total phenolic content (122 vs 47mg GAE), and AoxA (6626 vs 763μmol TE), and lower energy (169 vs 264kcal) than an expanded commercial snack (ECS=Cheetos™). Because of its high content of quality protein, dietary fiber and phenolics, as well as high AoxA and low energy density, the OES could be used for health promotion and chronic disease prevention and as an alternative to the widely available commercial snacks with high caloric content and low nutritional/nutraceutical value.