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Different pigmented corn and sorghum types were evaluated to characterize their biophysical, nutraceutical, and technofunctional properties for the first time. Commercially pigmented (blue, purple, red, black, and yellow) popcorn (Zea mays var. everta) and sorghum (Sorghum bicolor L.) of yellow and red colors were analyzed. Biophysical and proximal analyses were performed using official methods. The nutraceutical profile included the total phenolic and anthocyanin content. In addition, rheological, structural, and morphological studies were conducted. The results demonstrated significant differences between the popcorn samples and grain types, especially in terms of their biophysical and proximate features. The nutraceutical profile revealed that these specialty grains contained higher concentrations of antioxidant compounds (up to 3-fold when compared with the other grains). The rheological analysis demonstrated that sorghum grains developed higher peak viscosities than popcorn. According to the structural assessments, the type A pattern displayed peaks at the interplanar spaces corresponding to the crystalline and amorphous regions in all the samples. The data obtained in this study provides a base to further investigate the products obtained using these biomaterials.

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The viscoelastic properties of cereal kernels are strongly related to their quality, which can be applied to the development of a more selective and objective classification process. In this study, the association between the biophysical and viscoelastic properties of wheat, rye, and triticale kernels was investigated at different moisture contents (12% and 16%). A uniaxial compression test was performed under a small strain (5%), and the increase in viscoelasticity at 16% moisture content corresponded to proportional increases in biophysical properties such as the appearance and geometry. The biophysical and viscoelastic behaviors of triticale were between those of wheat and rye. A multivariate analysis showed that the appearance and geometric properties significantly influenced kernel features. The maximum force showed strong correlations with all viscoelastic properties, and it can be used to distinguish between cereal types and moisture contents. A principal component analysis was performed to discriminate the effect of the moisture content on different types of cereals and to evaluate the biophysical and viscoelastic properties. The uniaxial compression test under a small strain and the multivariate analysis can be considered a simple and non-destructive tool for assessing the quality of intact cereal kernels.

Vermicompost was used for humic acid (HA) preparation, and the adsorption of aflatoxin B1 (AFB1) was investigated. Two forms of HA were evaluated, natural HA and sodium-free HA (SFHA). As a reference, a non-commercial zeolitic material was employed. The adsorbents were characterized by attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR), energy-dispersive X-ray spectroscopy (EDS), zeta potential (ζ-potential), scanning electron microscopy (SEM), and point of zero charge (pHpzc). The adsorbent capacity of the materials when added to an AFB1-contaminated diet (100 µg AFB1/kg) was evaluated using an in vitro model that simulates the digestive tract of chickens. Characterization results revealed the primary functional groups in HA and SFHA were carboxyl and phenol. Furthermore, adsorbents have a highly negative ζ-potential at the three simulated pH values. Therefore, it appears the main influencing factors for AFB1 adsorption are electrostatic interactions and hydrogen bonding. Moreover, the bioavailability of AFB1 in the intestinal section was dramatically decreased when sorbents were added to the diet (0.2%, w/w). The highest AFB1 adsorption percentages using HA and SFHA were 97.6% and 99.7%, respectively. The zeolitic material had a considerable adsorption (81.5%). From these results, it can be concluded that HA and SFHA from vermicompost could be used as potential adsorbents to remove AFB1 from contaminated feeds.

Microwave heating may affect some non-starch polysaccharides of cereal kernels. This microwave effect can be positive for functional properties and the final product. Therefore, the purpose of this work was to explore the effects of microwave heating on mechanical properties, malt extract yield, wort viscosity,beta;-glucan of wort, and soluble, insoluble, and total dietary fiber in malting and feed barley.The barley kernels were microwave heated for 4 and 8 s and compared with a control (0 s) with no microwave irradiation treatment. The mechanical properties were measured by compressive loadings; an Environmental Scanning Electron Microscopy was used for kernel layers.beta;-glucan content in the barley kernel and wort was measured with a Mixed Linkage beta-glucan (K-BGLU Megazyme International; Wicklow, Ireland). Insoluble, soluble, and total dietary fiber was determined using 32-07 of AACC method.The thickness of barley kernel bran layers was related to the mechanical properties. The modulus of elasticity decreased after 4 s of heating but increased after 8 s. Irradiation affected non-starch polysaccharides, such asbeta;-glucan and fiber.beta;-glucan decreased after 4 s as did wort viscosity. The insoluble and total dietary fiber followed the same trend asbeta;-glucan, but the soluble fiber content increased with prolonged microwave heating.A few seconds of microwave heating is enough to increase barleyrsquo;s value in the brewing industry and improve health benefits due to minor changes in the biochemical grain components.

The use of sourdough for bread production involves fermentation, which is dominated by lactic acid bacteria (LAB) and yeast. Sourdough can be inoculated with a starter culture or through a food matrix containing microorganisms to initiate sourdough fermentation. Sourdough is used as leavening agent for bread making, and metabolites produced by LAB and yeast confer a specific aroma and flavor profile to bread, thus improving its sensory attributes. However, few publications report the effect of microorganisms from different food products and by-products on sourdough fermentation. This review focuses on using different starter cultures from various food sources, from wheat flour to starter cultures. Additionally, included are the types of sourdough, the sourdough fermentation process, and the biochemical transformations that take place during the sourdough fermentation process.

El desarrollo de métodos predictivos para determinar la calidad y el uso final del trigo ha sido una necesidad para fitomejoradores y para productores, molineros y panaderos. En este estudio se investigó el uso de granos individuales de trigo (Triticum spp.) con la técnica de ultrasonido como método predictivo para la caracterización de la calidad. Se evaluaron 45 muestras de trigos mexicanos de la cosecha 2003. La señal ultrasónica viajó más rápido en el grano de trigo duro o cristalino, seguida por el trigo panadero y por último el trigo suave. La ecuación polinomial de mejor ajuste de los parámetros del grano del trigo (contenido de cenizas, número de caída, microsedimentación y contenido de proteína) con la velocidad ultrasónica, fue una polinomial de segundo grado, excepto para peso hectolítrico que fue lineal. Las variables de la harina como rendimiento harinero, número de caída, sedimentación y temperatura de pastificado, se relacionaron linealmente con la velocidad ultrasónica. También la mayoría de los datos reológicos del alveógrafo y farinógrafo se relacionaron linealmente con la velocidad ultrasónica. Para una misma clase de trigo la tendencia es que a mayor dureza del grano la velocidad ultrasónica se incrementa y así representa mejor calidad. Entonces, las mediciones de velocidad ultrasónica en granos individuales pueden ser utilizadas para predecir el volumen del pan, así como para la evaluación no destructiva y rápida de la calidad del trigo.

Pulque is a Mexican alcoholic, probiotic beverage with shelf life of 3 days. The physicochemical, probiotic, and sensory properties of pulque depend on its content of lactic acid bacteria (LAB) and yeasts. The aim of this study was to apply ohmic heating (OH) in order to extend the shelf life of pulque without altering its properties. Pulque processed by conventional pasteurization (63 °C, 30 min) was used as control. Parameters such as electrical conductivity (0.22 S/m) and optimal pasteurization conditions by OH (65 °C, 5 and 7 min; 70 °C, 3 and 5 min) were determined. Shelf life was evaluated with these parameters during 22 days of storage at 4 ± 1 °C. A higher content of LAB (6.68 and 5.96 log10 CFU/mL) was obtained at 65 °C for 5 and 7 min, respectively, compared with conventional pasteurization (3.54 log10 CFU/mL). After 22 days, physicochemical properties (pH, color, and alcohol content) were stable for both methods of pasteurization. However, the pulque treated with OH had greater sensory acceptance. For the first time, OH was used to process pulque, and results revealed that is an effective technology for extending the shelf life until 22 days, preserving microbiological and physicochemical properties. Microorganisms as surviving the OH treatments were identified as Lactobacillus acidophilus, Lactobacillus kefiri, and Saccharomyces cerevisiae.

Chapalote is a Mexican ancient maize landrace with popping characteristics that have not been studied. This work aimed to study the kernel physicochemical properties and their relationship with popping properties of 10 Chapalote accessions. Two popping methods, cooking pan and hot-air popping, were tested. A commercial popcorn sample was used for comparison purposes. Hot-air popping led to higher expansion volume, less unpopped kernels, and bigger popped kernels than traditional popping. Among Chapalote samples, one accession (612) had the best popping properties, but none of them popped similarly to the commercial popcorn. This behavior may be related to the non-breeding origin of Chapalote accessions contrasting with the improved hybrids. Smaller kernels containing more pedicel, pericarp, and vitreous endosperm led to higher expansion volume and lower unpopped kernels. In air-popping, higher α-zein content, and bigger starch granules with less crystallinity influenced positively the popping properties, mainly the air bubbles and popped kernel size. Pericarp thickness was not a crucial factor in popping performance. Some Chapalote accessions with good popping quality could be an important source of germplasm in breeding programs for the development of modern popcorn varieties with distinct properties, which may help to avoid the extinction of this landrace.

Background: Extraction techniques of phenolic compounds (PC), such as conventional maceration (CM) has been associated with high consumption of organic solvents and time. Objective: The objective of this study was to evaluate the effects and interactions of the variables involved in the aqueous extraction of phenolic compounds from Psidium guajava leaves by CM and ultrasound-assisted extraction (UAE). Methods: A split-plot design was developed according to the extraction variables of interest. For CM was time, temperature, and dilution were considered and for UAE the wave amplitude was included. Response variables were considered the following parameters: yield, total phenolic compounds, total flavonoid compounds, antioxidant capacity measured as radical uptake by ABTS and DPPH.Results: The results show that for UAE, the treatment of 1 g/ 50 mL, 50ºC temperature, 30% amplitude, and 20 min of extraction was associated with a higher extraction yield, reporting 125.84 mg of acid gallic equivalents/ g for PC, 381.18 mg quercetin equivalents/g for total flavonoids and 85.28% ABTS and DPPH 40.2% expressed as radical scavenging activity. On the other hand, the maceration method reported best extraction yield, using the treatment of 1 g/ 50 mL of dilution, 50ºC temperature and 10h of extraction time, achieving a total of 62.04 mg of gallic equivalents/ g for PC, 289 mg quercetin equivalents/g for total flavonoids, and 95.9% ABTS and DPPH 48% regarding radical scavenging activity.Conclusion: The ultrasound process was more effective in extracting phenolic compounds, flavonoid compounds, and their extracts had the highest antioxidant capacity. Keywords: Psidium guajava, phenolic compounds, extraction, ultrasound.

Introduction: A diet high in calories and saturated fats has been associated with health problems that have been increasing worldwide. Therefore, it is required to increase the number of formulated foods that generate well-being to health. Yogurt is a widely consumed food by all sectors of the population and it can be used as a vehicle to incorporate bioactive compounds. The phenolic compounds present in forest residues, such as those from oak bark, can be used and incorporated into yogurt, to increase its benefits as a functional food.Objective: The objective of this study was to develop a multifunctional yogurt enriched with vegetable oil (2.3% w/w) as a source of omega 6 and 3 and adding nanocapsules (24.5% w/w) of an extract of oak bark from Quercus crassifolia, rich in in phenolic compounds and high antioxidant capacity.Methods: Three yogurt formulations were prepared: F1: yogurt was made with non-fat milk, used as a control, F2: yogurt was prepared with non-fat milk and added with vegetable palm oil, and F3: non-fat yogurt was added with vegetable oil and nanoencapsulated oak bark phenolic extract. The yogurts were characterized in their chemical composition, microbiological analysis, and sensory analysis. Results: The multifunctional product F3 and product F2 presented lactic acid bacteria in concentration of 3.01X106 and 4.73x106, respectively, preserving characteristics of probiotic food. Product F3 presented low levels of syneresis (7.34%) and it was significantly different from the control yogurt (9.01%). The viscosity increased from 150 cP in the control yogurt to 341 cP in F3, due to the increase in the concentrations of solids by nanoencapsulating the phenolic. The wall material used for nanoencapsulation was sodium caseinate and mantodextrin. However, this increase in viscosity did not affect the sensory evaluation of the product. There were no significant differences between the control yogurt and the F2 and F3 products.Conclusion: A yogurt added with vegetable oil and nanoencapsulated oak bark phenolic extract was obtained. It was enhanced by the presence of probiotics, bioactive compounds, and essential fatty acids, and then evaluated and accepted by a sensory panel. Nanoencapsulation is a viable alternative to mask the characteristic astringent taste of phenolic compounds because it was not detected by the panelists. Keywords: waste recovery; functional dairy foods; essential fatty acids; probiotics; antioxidants; sensory.

Chia (Salvia hispanica L.) seeds contain antioxidants with great benefits for health and are widely used in the food industry. Antioxidants can be degraded by environmental factors, decreasing their biological activity. Their encapsulation in chitosan (CH) particles represents an alternative to protect them and increases their application. The encapsulation efficiency (%EE) of the antioxidants in the CH particles depends on the synthesis conditions. In this study, two methods for encapsulation of chia extract in chitosan particles were evaluated: method A, 0.05% CH in 1% acetic acid was mixed with 0.07% of tripolyphosphate (TPP) and method B, 0.3% CH in 2% acetic acid was mixed with 1% TPP. The results showed that the %EE decreased with the concentration of the extract, and the FTIR analysis suggested that the compounds of the extract were adsorbed on the surface of the particles. Dynamic light scattering and zeta potential analysis showed that the particles of method A are unstable and with a tendency to agglomerate, and the particles of method B are stable. The highest %EE was obtained with 0.2 mg·mL−1 (method A) and 1.0 mg·mL−1 (method B) of the extract. The higher loading capacity (%LC) (16–72%) was exhibited by the particles of method A. The best particle yield (62–69%) was observed for method B. The particles with the extract adsorbed showed antioxidant activity (5–60%) at 25°C; however, in the particles with the extract encapsulated, the activity increased after subjecting to acidic conditions at 40°C due to the breakdown of the particles. The results obtained will allow choosing the appropriate conditions for the synthesis of chitosan particles loaded with chia extracts with specific characteristics (%EE, %LC, size, and type) according to their future applications. The particles could be used in food and pharmaceutical industries and even in edible films for food packaging.

Chia (Salvia hispanica L.) seeds contain antioxidants with great benefits for health and are widely used in the food industry. Antioxidants can be degraded by environmental factors, decreasing their biological activity. Their encapsulation in chitosan (CH) particles represents an alternative to protect them and increases their application. The encapsulation efficiency (%EE) of the antioxidants in the CH particles depends on the synthesis conditions. In this study, two methods for encapsulation of chia extract in chitosan particles were evaluated: method A, 0.05% CH in 1% acetic acid was mixed with 0.07% of tripolyphosphate (TPP) and method B, 0.3% CH in 2% acetic acid was mixed with 1% TPP. The results showed that the %EE decreased with the concentration of the extract, and the FTIR analysis suggested that the compounds of the extract were adsorbed on the surface of the particles. Dynamic light scattering and zeta potential analysis showed that the particles of method A are unstable and with a tendency to agglomerate, and the particles of method B are stable. The highest %EE was obtained with 0.2 mg·mL−1 (method A) and 1.0 mg·mL−1 (method B) of the extract. The higher loading capacity (%LC) (16–72%) was exhibited by the particles of method A. The best particle yield (62–69%) was observed for method B. The particles with the extract adsorbed showed antioxidant activity (5–60%) at 25°C; however, in the particles with the extract encapsulated, the activity increased after subjecting to acidic conditions at 40°C due to the breakdown of the particles. The results obtained will allow choosing the appropriate conditions for the synthesis of chitosan particles loaded with chia extracts with specific characteristics (%EE, %LC, size, and type) according to their future applications. The particles could be used in food and pharmaceutical industries and even in edible films for food packaging.

Highlights • Conventional pasteurization drastically decreases Lactobacillus sp. • Thermosonication (TS) for less 9 min is sufficient for processing pulque. • Physicochemical properties of pulque were not modified by the use of TS. • Thermosonication extending shelf life of pulque up to 24 days. • TS is a viable technology for processing pulque., The aim of this study was to evaluate thermosonication as an alternative method for the pasteurization of pulque in order to improve its shelf life and retain its quality parameters. Thermosonication was carried out at 50 °C using amplitudes of 75% (for 6 and for 9 min), 85% (for 4 and for 6 min), and 95% (for 3 and for 5 min). These were the optimal conditions found for processing pulque by thermosonication. Physicochemical (acidity, color, alcohol content, and sensory analysis) and microbiological (lactic acid bacteria and yeasts) parameters were determined during 30 days for storage at 4 ± 1 °C. Conventional pasteurization (63 °C, 30 min) and raw pulque were used as controls. According to the results, the shelf life of pulque was extended up to 24 days storage at 4 °C. After this time, the quality of beverage decreased, due that the microbial load increases. Thermosonication treatments at 75% and 85% showed a higher content of LAB (6.58–6.77 log CFU/mL) and yeasts (7.08–7.27 log CFU/mL) than conventional pasteurization (3.64 log CFU/mL of LAB and 3.97 log CFU/mL of yeasts) at 24 days of storage. Raw pulque demonstrated up to 7.77 log CFU/mL of yeasts and 7.51 log CFU/mL of LAB. Pulque processed by thermosonication exhibited greater lightness, sensory acceptance, a maximal acidity of 0.83 g/lactic acid, and an alcohol content of 4.48–4.95% v/v. The thermosonication process preserves sensory and physicochemical properties better than conventional pasteurization. Lactic acid bacteria such as Lactobacillus kefiri, Lactobacillus acidophilus, and Lactobacillus hilgardii and yeasts such as Saccharomyces cereviasiae were identified in thermosonicated pulque.

The impact of addition of palmitic acid (PA) on the amylose‐lipid complexes formation and their influence on amylopectin retrogradation were studied. Tortillas prepared with 0.0%, 1.0% and 1.5% (w/w) of PA were stored for 0, 7, and 14 days at 4 °C. Tortillas with 1.0% and 1.5% of PA were softer than tortillas without PA during storage time; this change can be associated with reduction in starch retrogradation. Texture evaluation suggests that retrogradation reduction, influences directly tortilla texture (r = 0.82; P

The objective of this work was to evaluate changes in the fatty acids profile and starch properties during nixtamalization and tortilla-making processes of high-oil maize (HOM) hybrids. HOM grains had more linoleic acid than normal maize, and it decreased significantly from raw maize to tortilla, probably due to saponification and by its participation in the amylose-lipid complexes formation. After nixtamalization and milling, native type I amylose-lipid complexes were transformed into type IIa and IIb complexes. Tortillas from HOM showed similar retrogradation degree after 48 h of storage as revealed by thermal analysis, and this was reflected in the texture as reflected by the tensile strength and elongation values. The total relative crystallinity and the infrared 1047/1022 cm−1 spectral ratio increased on retrogradation however they behave in a complex manner in HOM samples. High-oil maize hybrids can be used for nixtamalization and tortilla preparation, but the higher oil content could not give an advantage for reducing tortilla staling.

Nixtamalization is the cooking of corn grains, traditionally in water with wood ashes or alkaline compounds. However, due to the pollution caused, the use of other calcium salts or weak acids, as well as alternative processes, has been explored. The pericarp and endosperm comprise 80.5–92.9% of the total weight of the grain and therefore have great effects on handling during processing and the quality of nixtamalized corn-based products. An introduction to nixtamalization processing conditions is followed by reviews of the microstructure and composition of the pericarp and endosperm, and the effects of nixtamalization on the structures and compositions of these tissues. In particular, the processing of raw corn into masa (dough) affects the gelatinization of starch, the interactions of starch with calcium and amylose-lipid complexes, with impacts on pasting properties and digestibility. Finally, the research required to underpin the development of new processing alternatives is discussed.

Teosinte is the wild ancestor of modern maize. It has served as a study model of evolutionary processes and even more as a potential source of genomic variation to introgress maize varieties suitable for both food and feed. Although some metabolites have been studied in teosinte, little is known about its secondary metabolites like phenolic compounds. To evaluate the diversity present in teosinte, 22 different teosinte varieties were used to extract and quantify soluble and bound total and specific phenolic compounds by HPLC-PDA, respectively. Also, their antioxidant bioactivities were evaluated. Kernel biophysical parameters showed significant differences among the different teosinte varieties. Teosinte's phenolic profile showed that p -coumaric acid was the predominant phenolic acid form with soluble concentrations around 17 μg/gdw to 31 μg/gdw whereas concentrations of bound ranged from 215 to 238 μg/gdw in all varieties. Teosinte's antioxidant capacities were higher for bound phenolics with values ranging from 50 to 82 mmolTE/100gdw compared to only 7 to 17 mmolTE/100gdw observed in commercial maize. The diversity found in phenolic content and potential bioactivity of teosinte could serve as a platform for the development of new breeding programs into high performance modern maize with distinct nutraceutical potential.

The objective of this study was to ascertain the optimal additive conditions to develop a film from an alternative source of modified starch, using the response surface methodology. The central composite design + points used factors to evaluate the effect of the independent variables (glycerol concentration: 0.3, 0.35, and 0.40 g g−1 starch; carboxymethylcellulose: 0.5, 0.75 and 1 g/5 g starch; stearic acid 0.025, 0.05, and 0.075 g/5 g starch) on the response variables (solubility, swelling, opacity, luminosity, tensile strength, elongation, water vapor permeability, and water activity). A simultaneous optimization was achieved using concentrations of glycerol 0.30 g g−1 starch, CMC 0.32 g/5 g starch, and stearic acid 0.007 g/5 g starch, which generated interesting properties validated through experimentation. Therefore, an ecological film was obtained that can be considered for food coating because it presented a low permeability to water vapor (0.0055 g ms−1MPa−1), a high percentage of elongation (91%), and a decrease in solubility (23%). This will also allow the incorporation of other compounds such as antioxidants, reinforcements, and sensors with favorable results, and with a positive perspective on the use of alternative sources of starch.

The objective of this study was to examine the physicochemical composition, thermal properties, quality, and sensorial characteristics of bread with substitution of wheat flour with ayocote bean (Phaseolus coccineus) or black bean (Phaseolus vulgaris) flours at 10, 20, and 30%. Ayocote and black bean contain 21.06 and 23.94% of protein, 3.06 and 5.21% of crude fiber, and 3.1 and 5.21% of ash, respectively, directly influencing bread composition. Bread with ayocote and black bean presented higher values in those components in contrast with control bread. The protein content increased in a range of 14–34%, ash increased by 10% to double, and crude fiber also increased. In vitro protein digestibility was similar for bread with 10% of substitution and control, and it decreased in samples with 30% of wheat substitution. Thermal analysis by DSC denoted that the addition of those legumes reduces retrogradation, as seen in 45.33–65.65 °C endotherm, producing higher endotherms of amylose-lipid complexes and protein denaturalization. Finally, the addition of black bean and ayocote bean decreased specific volume when the replacement percentage was 30% black bean and 20 and 30% for ayocote. An increase in nutrient content without sensorial properties affectation could be observed in substitution around 10 and 20%.

The objective of this study was to investigate the variation in physical, chemical, and sensory properties of tortillas when using two nixtamalization cooking times for three native corn landraces with different kernel hardness levels. When Oloton and Comiteco races are cooked with lime for 60 min, tortillas were softer and rolled better. In contrast, when Tuxpeno was nixtamalized for 30 min tortillas were less prone to breaking. Starch gelatinization is the main factor responsible for textural changes, although retrogradation may also be involved. Structural composition of grains affects thermal and rheological properties and, consequently, the texture of tortillas. Textural properties (tension, rollability, and elasticity) of tortillas are affected by the type of endosperm (hard and soft), whereas kernel hardness correlated only with tortilla tension. Chemical composition correlated well with kernel shape, starch thermal (enthalpy) and rheological properties. Protein affected tortilla elasticity, firmness, and smoothness. Fat and carbohydrate were negatively correlated with nixtamal aroma but protein was positively correlated. Crude fiber correlated negatively with tortilla smoothness, and corn-aroma. Even though the perception of aroma, flavor, smoothness was related to corn landrace, cooking time also exerted an effect. A longer nixtamalization cooking time usually reduces the intensity of tortilla sensory properties like corn and nixtamal aromas.

The effect of dough formation using dynamic rheology, thixotropy, zeta-potential, and FT-IR properties of soft wheat dough as a function of Ca(OH)2, and Ca-salts contents (0.3%, 0.7%, and 1.1%) was investigated. Physical data were further supplemented by measurements of dough texture profile analysis, wet gluten, and pH. Additional information provided by structure-sensitive properties, such as the zeta-potential, thixotropic index, and slopes of rheo-destroyed and complex viscosity curves using Cox–Merz rule, can comprise complementary instances of evidence of the ability of dough self-regeneration or build-up after rheodestruction to certain limits. There is a different behavior of the dough properties above and below pH 7.0. Above pI ≈ 5.2, dough (pH 5.5–7.0) has zeta-potential with negative charge from ionizing hydroxyl groups of starch and proteins that favor protein unfolding and that increase α-helix, wet gluten, and functionality. Weak non-covalent bonds and electrostatic forces induce strong entanglement and interaction with water, increase swelling, and preserve the chemical structure. However, at pH > 7.0, Ca(OH)2 treatment changed to negative charge tendency of the dough system, specifically of starch. The effects provided by nixtamalization are essential for its application in improvement of wheat flour with limited functionality, such as soft wheat flour and other grains or materials.

Little attention has been given to the influence of non-gluten components on the viscoelastic properties of wheat flour dough, bread making process and their products. The aim of this study was to evaluate by creep tests the viscoelastic properties of tablets manufactured from Osborne solubility fractions (globulins, gliadins, glutenins, albumins and residue), pentosans, flour and bread. Hard and soft wheat cultivars were used to prepare the reconstituted tablets. Sintered tablets (except flour and bread) showed similar values to those obtained from the sum of the regression coefficients of the fractions. Gliadins and albumins accounted for about 54% of the total elasticity. Gliadins contributed with almost half of the total viscosity (45.7%), and showed the highest value for the viscosity coefficient of the viscous element. When the effect of dilution was evaluated, the residue showed the highest instantaneous elastic modulus (788.2 MPa). Retardation times of the first element (λ1~ 3.5 s) were about 10 times lower than the second element (λ2~ 39.3 s). The analysis of compliance of data corrected by protein content in flour showed that the residue fraction presented the highest values. An important contribution of non-gluten components (starch, albumins and globulins) on the viscoelastic performance of sintered tablets from Osborne fractions, flour and bread was found.

Biodiversity contributes to nutrient production and, together with processing, is a critical factor in product quality. Physicochemical and nutritional properties of toasted tortillas (totopos) were evaluated in 1) maize samples from Oaxaca communities and 2) maize races of different endosperm texture. Texture profiles show that totopos elaborated from Zapalote Chico maize race showed the best performance (low breaking force) and higher crunchability, similar to commercial totopos. Quality of Zapalote Chico totopos was explained by flotation index (FI) and starch viscosity as well as thermal properties. FI was negatively correlated with texture that may related to end use. Zapalote Chico maize gelatinizes at higher (P 0.05) peak viscosity (3,093–4,723 cP), suggesting a more organized starch structure. In hybrid and Tuxpeno samples, most of the starch granules (90%) were gelatinized and increased the hardness in totopos. The totopo samples in...

Tamales were prepared with 3 nixtamalization processes (traditional, ecological, and classic) and evaluated for chemical composition, starch properties, and glycemic index. Resistant starch (RS) in tamales increased 1.6 to 3.7 times compared to raw maize. This increment was due to the starch retrogradation (RS3) and amylose-lipid complexes (RS5) formation. Tamales elaborated with classic and ecological nixtamalization processes exhibited the highest total, soluble and insoluble dietary fiber content, and the highest RS content and lower in vivo glycemic index compared to tamales elaborated with traditional nixtamalization process. Thermal properties of tamales showed 3 endotherms: amylopectin retrogradation (42.7 to 66.6 °C), melting of amylose lipid complex type I (78.8 to 105.4), and melting of amylose-lipid complex type II (110.7 to 129.7). Raw maize exhibited X-ray diffraction pattern type A, after nixtamalization and cooking of tamales it changed to V-type polymorph structure, due to amylose-lipid complexes formation. Tamales from ecological nixtamalization processes could represent potential health benefits associated with the reduction on blood glucose response after consumption.

Extrusion was used for obtaining corn masa. Particle size, Ca(OH)2 concentration, and tempering time had significant effects on the viscosity of extruded flours. Ground corn tempered for different periods of time (0.016–10 h) increased viscosity without application of heat. This behavior can be explained by the release of starches from the protein matrix. Viscoelastic properties of masas showed storage modulus (G′) > loss modulus (G″) for all samples. G′ and G″ increased as a function of tempering time, indicating higher water absorption capacity (WAC). The same behavior was found for Ca(OH)2 concentration, suggesting formation of cross-links between starch and polymers. Viscosity of masas modeled by the power law showed a value of n close to 0.1, suggesting that the dispersed solid phase was greater than the liquid phase. Index n and consistency coefficient K were associated with water absorption and viscosity, respectively. Regarding Ca(OH)2, the higher the Ca(OH)2 concentration, the lower the index n; ...

The objective of this work was to evaluate the changes in the thermal and structural properties of maize starch during nixtamalization and the tortilla-making process and their relationship with grain hardness. Three maize types with varying hardness (hard, intermediate, soft) were processed by three nixtamalization processes (classic, traditional and ecological). Starch from the three maize types showed an A-type pattern and two endotherms corresponding to gelatinization and melting of the Type I amylose-lipid complexes. After cooking and steeping, in intermediate and soft grains the partial gelatinization and the annealing affected the starch properties and promoted the formation of amylose-lipid complexes. These effects were not observe in hard grains. The increase in melting enthalpy and the intensity of the peak 2θ∼20° from nixtamal to tortillas demonstrated the formation of amylose-lipid complexes. A third endotherm above 114 °C in some treatments of nixtamal and tortilla starch demonstrated the transformation of some amylose-lipid complexes in a most ordered structures (Type II complexes). The V-type polymorph structure found in native starch, nixtamal, and tortilla corresponds to a coexistence of Type I and Type II complexes. Formation of amylose-lipid complexes in tortillas had a partial effect on decreasing starch retrogradation (r = −0.47, P

Effects of high-molecular-weight glutenin subunits on viscoelasticity of wet gluten, and its relationships with mixing, extensibility, and breadmaking parameters, were investigated by creep recovery using the Kelvin–Voigt model on 19 hard red winter wheat flours. Gluten samples with Glu-A1 1 and 2* showed significant differences in retardation time (λ2), whereas subunit 17+18 in Glu-B1 showed higher elastic moduli (G0, G1, and G2) and viscosity coefficients (η0, η1, and η2) compared with subunits 7+8 and 7+9. Wheats with Glu-D1 5+10 had higher values of G0, G1, G2, η0, η1, and η2 compared with Glu-D1 2+12. Gluten samples were on average 5.5, 3.1, and 1.6 times less stiff than dough when comparing G0, G1, and G2, respectively; these differences suggest that the nongluten components have high influence in the instantaneous and first Kelvin–Voigt elements of the model, and they are manifested more quickly compared with gluten components. Higher explanation of variance of loaf volume was found in parameters η...

This research aimed to evaluate the effect of different calcium compounds and their concentration on the viscoelastic parameters of flours and tortillas obtained with traditional and ecological nixtamalization. Specimens (tablets) of nixtamalized flours and tortillas (14% moisture) prepared with three different calcium sources and four concentrations were sintered using a die and a hydraulic press and were evaluated by stress-relaxation tests with a texturometer. Data collected from the stress-relaxation curve were fitted into a three-element generalized Maxwell model (r2 = 0.9999), allowing the detection of significant differences in the estimated viscoelastic parameters. When flours are processed into tortillas, the most notable change was the increase of +88.44% and +73.44%, respectively, in the summation of the elastic modulus, and the compressional viscosity in samples produced with CaCO3. On the contrary, tablets from samples with Ca(OH)2 presented a sharp diminishing (loss) in both of the evaluated viscoelastic parameters, accounting a decrease of -39.82% and -46.28% for the elastic modulus and compressional viscosity summations, respectively. Highly significant correlations were found among viscoelastic parameters when a slight proportional increase was observed in the specific elastic moduli, meaning that the energy was stored by each elastic element in the tablets, while the compressional viscosity coefficients varied as a function of time. Finally, it was found that the residual spring due to the pure elastic component (E0 ) stored energy during the entire test. PRACTICAL APPLICATION: There is no published information about a simple methodology for the evaluation of the viscoelastic properties of dry nixtamalized flours (powder) with a texturometer. The method proposed was sensitive and accurate, since it was capable of detecting differences among samples processed under distinct processing factors conditions. The study of viscoelastic properties of grain foods contributes to the construction of molecular theories occurring in their chemical compounds, which is strongly related to food texture. Those theories are handy to improve nutritional and textural properties of grain foods and are essential to powder handling, processing, and transportation, which allows the processing factors optimization.

Background: The aim of this research was to evaluate the visco-elastic properties of conditioned wheat kernels and their doughs by applying the compression test under a small strain. Conditioned wheat kernels and their doughs, from soft and hard wheat classes were evaluated for total work (Wt ), elastic work (We ) and plastic work (Wp ).; Results: Soft wheat kernels showed lower We than Wp , while the hard wheat kernels had a We that was higher than Wp . Regarding dough visco-elasticity, cultivars from soft and hard wheat showed higher Wp than We . The degree of elasticity (DE%) of the conditioned wheat kernel related to its dough decreased ∼46% in both wheat classes. The Wt , We and Wp from the soft wheat kernel and dough correlated with physico-chemical and farinographic flour tests. The Wt , Wp and the maximum compression force (Fmax ) of the dough from hard wheat class presented highly significant negative correlations with wet gluten.; Conclusion: The visco-elasticity parameters from compression test presented significant differences among conditioned wheat classes and their doughs. © 2016 Society of Chemical Industry.; © 2016 Society of Chemical Industry.

Tamales were produced using a traditional nixtamalization process. The nixtamal was milled into masa, mixed with shortening, and boiled to prepare tamales. Enzymatic methods and DSC enthalpies were used to investigate resistant starch (RS) and starch–lipid complexes (resistant starch 5; RS5). The addition of shortening to masa showed an endotherm of lipid melting with To(m), Tp(m), and Tf(m) of approximately 40, 44, and 50°C, respectively. Processing masa by boiling at >90°C for 2 h to make tamales showed three endotherms: one related to amylopectin retrogradation (RS3), one to starch gelatinization (G), and one to Type I complex (RS5). The retrograded amylopectin presented temperatures of 49, 55, and 60°C for To(RS3), Tp(RS3), and Tf(RS3), respectively. The X-ray diffraction pattern showed that during processing starch Type A complexed with lipids to form a Type V (RS5) amylose–lipid starch complex. The RS5 in tamales estimated by DSC affected blood glucose levels from in vivo tests.

There is no previously published data covering the viscoelasticity of Osborne protein solubility fractions. Therefore, the objective of this study was to compare the viscoelastic properties of Osborne fractions, water soluble pentosans, flour and bread using relaxation tests. Sintered tablets from glutenins presented similar elasticity as gliadins but almost twice the viscosity. However, most of the wheat viscoelasticity performance in tablets was given by the sum of the non-gluten components (albumins, globulins, residue and especially water soluble pentosans). The residue was 86.1% w/w in flour and contained 4% protein while its estimated viscoelastic effect was higher compared to all the other flour components. Regarding the estimated viscosity in flour due to protein from specific fractions, it was higher in gliadins compared to glutenins. The residue although has low protein in flour (4.0%), the large amount of residue in flour had significant viscoelastic effect. The viscoelasticity of water soluble pentosans corrected by weight was similar to the Osborne protein fractions. The results indicate that the starch, pentosans, and non-gluten components may not be considered merely as inert filler and play a major role in determining the viscoelastic nature of flour and bread.