No abstract

An increased consumption of healthy foods to reduce chronic diseases risks is needed. We developed and evaluated a multigrain snack as a nutritive alternative to the highly consumed corn tortilla chips. Corn, wheat, and chickpea grains were boiled in 1% calcium oxide solution, steeped, washed, and ground before being mixed with soy protein isolate and oat flour to prepare the multigrain masa. Multigrain tortillas were moulded, baked, dried, and fried. Proximate composition, dietary fiber, protein quality, sensorial, and textural properties were evaluated. A commercial tortilla chip was used as control. The multigrain snack contained 153% more protein, 53% more dietary fiber, and 43 % less fat than commercial tortilla chips. Its lysine and isoleucine contents helped to increase the corrected-net protein utilization by 10%, while digestibility increased from 83.5 to 91.8% as compared to commercial tortilla chips. The mean breaking force was 6,082 g for the multigrain snack and 4,780 g for the commercial tortilla chips. The mean acceptability score for the multigrain snack was 12.1 (unstructured line scale 0-15 cm), and 82% of the panelists rated the snack as acceptable. In conclusion, a nutritionally enhanced multigrain tortilla snack was developed which provides significantly more dietary fiber and protein and less fat than traditional commercial corn tortilla chips, but with comparable appearance and high acceptability.

Propiedades reológicas y composición proteica: parámetros de calidad en harinas de líneas experimentales de trigo

Rheological studies in food have shown chemical changes during their preparation process. In bread making, dough viscoelasticity studies reflect the chemical changes produced by the baking process, which in turn modifies bread volume. The aim of this research was to study the effect of the freezing rate, part-baking and storage time on the viscoelastic properties and specific volume of part-baked bread and the specific volume of bread completely baked. We prepared water-flour dough for viscoelastic evaluations. Formulated dough for part-baked bread was baked for 0, 3 or 6 min, frozen at two freezing rates: slow (0.15°C/min) or fast (1.45°C/min) and stored for 56 days. Every 14 days, par-baked bread frozen samples were thawed for rheological evaluations including: elastic moduli (G´), viscous moduli (G¨) and Tan δ. Another part of the thawed samples was re-baked (complete baked) to complete 10 min and the specific volume of bread was measured. We used a 3x2x5 factorial design experiment. An analysis of variance was carried out with 95% confidence level. The elastic moduli (G’) increased with part-baking time. Part-baking time decreased Tan δ, increasing the elasticity in dough and part-baked bread. Part-baking time decreased gelatinization temperature peak in all frozen storage time. A longer storage time resulted in an increase in the elasticity of dough and part-baked bread. The specific volume of bread increased with part-baking time, however, this parameter decreased with storage time.

Brewers’ spent grain (BSG) is the most abundant byproduct generated from the beer-brewing process. BSG is a material rich in hemicellulose, composed of arabinoxylans (AX). However, the high crosslinking of this material causes low availability of AX, for which it is necessary to apply different treatments. The objective of this research is to increase the release of arabinoxylans through solid-state fermentation with Fusarium oxysporum f. sp. lycopersici using extruded brewery spent grain. First, the BSG is subjected to two types of physical treatments: extrusion at 20% moisture, 200 rpm and 50 °C (BSGe), and blade milling (BSGm). The chemical composition is determined for each sample (BSG, BSGe and BSGm). Subsequently, the solid-state fermentation process (SSF) is carried out on each sample. The fermentation kinetics at 30 °C are monitored for 7 days. Once the SSF concludes, AX are extracted, and the purity of AX is determined by the phloroglucinol colorimetric assay. Finally, the total phenolic compounds, phenolic acids and antioxidant capacity by DPPH are quantified. No significant differences (p ≥ 0.05) in the protein, lipid, ash or total dietary fiber contents are found among the samples. No significant difference (p ≥ 0.05) in the content of soluble fiber is found, although BSGe and BSGm have higher values than BSG. On the other hand, the yields of soluble AX exhibit significant differences (p ≤ 0.05) among nonfermented samples (BSG, 0.03%; BSGm, 0.53%; BSGe, 0.70%) and with SSF (BSG, 2.95%; BSGm, 6.24%; and BSGe, 9.58%). In addition, the contents of free phenolic compounds and free phenolic acids and the percent inhibition of free extracts by 2,2-diphenyl-1-picrylhydrazyl (DPPH) differ significantly (p ≤ 0.05) between samples subjected to SSF and nonfermented samples. Therefore, extrusion and SSF treatment increase AX release from BSG as well as the antioxidant capacity of the extracts.