Coconut Flour (Cocos nucifera L.) as a Partial Replacement in Wheat Flour (Triticum aestivum)-Based Tortillas and Its Effect on Dough Rheology and Tortilla Quality.

Wheat-flour (WF) tortillas are among the popular flatbreads used in northern Mexico to prepare 'burritos', which are widely accepted in the USA and other countries but have low nutritional quality. Therefore, to increase the protein and fiber contents, we replaced 10 or 20% of the WF with coconut (Cocos nucifera, variety Alto Saladita) flour (CF) and evaluated the effects on the dough rheology and quality of the composite tortillas. There were differences in the optimum mixing times among the doughs. The protein, fat, and ash contents of the tortillas increased (p < 0.05) with increasing CF content. The carbohydrate content was unchanged (p > 0.05), but the 20% CF tortillas contained more fiber than the control tortilla. Tortilla firmness increased (p < 0.05) and extensibility decreased (p < 0.05) with increasing CF content. The 80:20 blended tortillas showed the highest firmness (7.9 N), whereas the control and 90:10 blended tortillas did not differ (p > 0.05) in firmness. There were no differences (p > 0.05) in extensibility between the composite tortillas. The physicochemical properties of the tortillas indicated that the 20% CF-containing tortilla was a more nutritious option to the wheat flour tortilla due to its higher dietary fiber and protein contents, in addition to the slight reduction seen in extensibility compared to the WF tortilla.

Wheat-Free and Nutritious Bread and 'Coricos' Made with Mesoamerican Ancestral Corn, Amaranth, Sweet Potato and Chia.

People with wheat-related disorders require wheat-free and good quality baked goods. We prepared wheat-free bread and cookies (coricos) with flour blends of corn, amaranth, orange sweet potato and chia. Sweet potato flour or puree and amaranth flour were prepared and their properties evaluated. Blends were optimized for dough hardness and cohesiveness by response surface methodology, with a central composite rotatory design. Bread was prepared with optimal blends plus 1.2% chia mucilage, and alternatively used sweet potato puree. The optimized blend was 57:34:9 (corn:amaranth:sweet potato flours). Coricos were made with the blend instead of only corn as traditionally. Chemical composition, texture profile, fiber, and gluten content of the products were analyzed. The breads' crust was uniform, crunchy and golden, and the crumb was homogeneous, with 41% specific volume and 60% size of the wheat bread. Coricos presented a darker golden color than those of 100% corn. Protein content was similar (~ 12% d.w.) between the blend and wheat breads, with better chemical score for the blend one. Blend bread and coricos had 2-4% more dietary fiber and higher content of bioactive compounds than their wheat or corn counterparts. Blend bread was comparable to its counterpart in chewiness while coricos were softer. Gluten content was < 20 ppm in blend products; therefore, in addition to nutritional quality, they are safe for people with wheat-related disorders.

Phenolic Acids, Antioxidant Capacity, and Estimated Glycemic Index of Cookies Added with Brewer's Spent Grain.

Brewers' spent grain (BSG) is the major by-product of the brewing industry, with great potential as a functional ingredient due to its bioactive compounds. Thus, BSG could be suitable for improving the low nutritional quality of wheat-based snacks highly consumed by young people. The objective of this study was to substitute wheat flour with BSG (0, 10, 20, and 30%) for cookies elaboration, and evaluate the dough rheology, phenolic acids, antioxidant capacity, arabinoxylans content and proximate composition of the cookies Protein content and bioactive compounds (ferulic and p-coumaric acids, water unextractable arabinoxylans) of cookies significantly (p < 0.05) increased with the substitution level. In comparison to the wheat-alone cookies, the 20% BSG-containing cookies showed a lower hydrolysis and glycemic index (GI), and less total starch. The low cost, protein-rich BSG with antioxidant capacity improves the nutritional quality of cookies and may confer health benefits beyond basic nutrition.

Protein/arabinoxylans gels: effect of mass ratio on the rheological, microstructural and diffusional characteristics.

Wheat bran arabinoxylan (WBAX) gels entrapping standard model proteins at different mass ratios were formed. The entrapment of protein affected the gel elasticity and viscosity values, which decreased from 177 to 138 Pa. The presence of protein did not modify the covalent cross-links content of the gel. The distribution of protein through the network was investigated by confocal laser scanning microscopy. In mixed gels, protein aggregates forming clusters were detected at protein/polysaccharide ratios higher than 0.25. These clusters were not homogeneously distributed, suggesting that WBAX and protein are located in two different phases. The apparent diffusion coefficient (Dm) of proteins during release from mixed gels was investigated for mass ratios of 0.06 and 0.12. For insulin, Dm increased significantly from 2.64 × 10-7 to 3.20 × 10-7 cm2/s as the mass ratio augmented from 0.06 to 0.12. No significant difference was found for Dm values of ovalbumin and bovine serum albumin released from the mixed gels. The results indicate that homogeneous protein/WBAX gels can be formed at low mass ratios, allowing the estimation of Dm by using an analytical solution of the second Fick's law.

Structural Stability and Viability of Microencapsulated Probiotic Bacteria: A Review.

Probiotics are live microorganisms that confer a number of health benefits when consumed in adequate amounts, mostly due to improvement of intestinal microflora. Bacterial strains from the genera Lactobacillus, Bifidobacterium, and Bacillus have been widely studied and are used to prepare ready-to-eat foods. However, the physicochemical stability and bioavailability of these bacteria have represented a challenge for many years, particularly in nonrefrigerated foodstuffs. Microencapsulation (ME) helps to improve the survival of these bacteria because it protects them from harsh conditions, such as high temperature, pH, or salinity, during the preparation of a final food product and its gastrointestinal passage. The most common coating materials used in the ME of probiotics are ionic polysaccharides, microbial exopolysaccharides, and milk proteins, which exhibit different physicochemical features as well as mucoadhesion. Structurally, the survival of improved bacteria depends on the quantity and strength of the functional groups located in the bacterial cell walls, coating materials, and cross-linkers. However, studies addressing the role of these interacting groups and the resulting metabolic impacts are still scarce. The fate of new probiotic-based products for the 21st century depends on the correct selection of the bacterial strain, coating material, preparation technique, and food vehicle, which are all briefly reviewed in this article.

Effect of High-Protein and High-Fiber Breaders on Oil Absorption and Quality Attributes in Chicken Nuggets.

Consumption of fried foods is associated with a higher risk of cardiovascular and other diseases; therefore, consumers are looking to reduce fat intake. We evaluated the effect of high-protein breaders and fiber on oil absorption and quality attributes in chicken nuggets, using flour blends (wheat, chickpea, coconut, oil-quinoa-chia), soy protein concentrate, and brewers' spent grain. We evaluated the chemical composition, water and oil retention capacity (ORC), viscosity profile, and flour particle size distribution, along with the developed breaders (Formulation 1 and 2) and a commercial breader (CB), in addition to texture, color, fat, and moisture contents of the fried chicken nuggets prepared with the developed breaders and the CB. The total dietary fiber content (TDF) of the nuggets breaded with only Formulation-1 and CB was determined. Nuggets breaded with Formulation-1 showed lower (p ≤ 0.05) ORC, better moisture retention (67.6%), and more TDF (4.5% vs. 2.3%, p ≤ 0.05) compared to CB-breaded nuggets. Nuggets with Formulation-1 showed the expected texture and color characteristics for fried products. Formulation-1 has the potential to be used as a breader due to its moisture, reduced ORC, and the texture and color it imparts to the fried nuggets, providing higher amounts of nutrients and possible health benefits.

Extraction and characterization of arabinoxylans obtained from nixtamalized brewers' spent grains.

The processes to obtain value-added products from brewers' spent grain, a contaminant industrial waste, require alkaline non-ecofriendly pre-treatments. The arabinoxylans from brewers' spent grain were extracted by nixtamalization evaluating the extraction procedure, antioxidant capacity and molecular characteristics. The best arabinoxylans yields were those extracted with CaO at 100 °C and 25 °C (6.43% and 3.37%, respectively). The antioxidant capacity by 2,2-diphenyl-1-picrylhydrazyl assay of the arabinoxylans after thermal treatment and additional arabinoxylans after thermal treatment proteolysis were 434 and 118 mg TE/g, while by 2,20'-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) diammonium salt assay the value was similar (380 µmol TE/g). The intrinsic viscosities and viscosimetric molecular weights were 69 mL/g and 13 kDa for arabinoxylans after thermal treatment, and 15 mL/g and 1.6 kDa for arabinoxylans after thermal treatment proteolysis, respectively. The protein and lignin contents were 3.1% and 6.4% for arabinoxylans after thermal treatment and, 0.9% and 4.6% for arabinoxylans after thermal treatment proteolysis, while their arabinose: xylose ratios were 0.39 and 0.36, with ferulic acid contents of 0.63 and 0.14 mg/g, respectively. Both products of arabinoxylans were molecularly identical by Fourier transform infra-red. Although the purity of the extracted arabinoxylans was improved with proteolysis, their intrinsic viscosity and viscosimetric molecular weight were affected. The extraction of arabinoxylans from brewers' spent grain by CaO nixtamalization alone or after additional proteolysis was successful to obtain purity and good antioxidant capacity.

Arabinoxylans Release from Brewers' Spent Grain Using Extrusion and Solid-State Fermentation with Fusarium oxysporum and the Antioxidant Capacity of the Extracts.

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.

Highly Nutritional Bread with Partial Replacement of Wheat by Amaranth and Orange Sweet Potato.

The current dietary habits cause health problems due to foods' composition, with bread as an important example. Our aim was to formulate an optimum dough blend with flours from wheat, amaranth and orange sweet potato to obtain a physically good and highly nutritional bread. Bread was prepared with blends of wheat, amaranth and orange sweet potato flours, optimizing the technological properties of the doughs by the response surface methodology and analyzing their physical and nutritional properties. Amaranth provides protein and fiber, and sweet potatoes provide ß-carotenoids and high antioxidant activity. The prediction models were adjusted by mixing time (MT), peak dough resistance (PDR), setback (SB) and breakdown (BD). The interaction between wheat and amaranth significantly (p < 0.05) affected MT, PDR and SB, while the interaction between amaranth and sweet potato affected BD (p < 0.05); none of the components influenced PDR. The optimized blend (68.7% wheat, 22.7% amaranth and 8.6% sweet potato) produced a bread with the best crust and crumb appearance. This bread was comparable to that made with 100% wheat in specific volume and textural characteristics, but had better protein quality, higher content of fermentable fiber, pro-vitamin A, and bioactive compounds with good antioxidant capacity, and a lower glycemic index.

Enzymatic cross-linking of alkali extracted arabinoxylans: gel rheological and structural characteristics.

Ferulated arabinoxylans were alkali-extracted from wheat bran at different incubation times (0.0, 0.5, 1.0, 1.5 and 2.0 h). Wheat bran ferulated arabinoxylans (WBAX) arabinose-to-xylose ratio, ferulic acid content, intrinsic viscosity and viscosimetric molecular weight values decreased as the incubation time of extraction increased. WBAX enzymatic cross-linking capability was affected by incubation time while an increase in WBAX concentration from 5 to 6% (w/v) favored gelation. The WBAX gels formed presented a macroporous structure with mesh size ranging from 40 to 119 nm and hardness values varying from 1.7 to 5 N.

Microbial Proteases in Baked Goods: Modification of Gluten and Effects on Immunogenicity and Product Quality.

Gluten-related diseases are a range of inflammatory disorders of the small intestine, characterized by an adverse response to gluten ingestion; therefore, the treatment is a gluten withdrawal. In spite of the increased market of gluten-free products, widely available breads with high acceptability are still missing due to the technological challenge of substituting the special gluten properties. Instead of using alternative ingredients for baking, some attempts have been done to decrease gluten immunogenicity by its enzymatic degradation with microbial proteases. Although the gluten immunogenicity reduction has been reached to an acceptable level, some quality parameters of the products are affected. This review focus on the use of microbial peptidases to prepare less immunogenic baked goods and their effect on product quality.