Effect of cooking conditions on chickpea flour functionality and its protein physicochemical properties.

Chickpea is an important food legume that usually undergoes various processing treatments to enhance nutritional value and functional properties. This study aimed to investigate the effects of different cooking conditions on physicochemical, structural, and functional properties of chickpea, especially its protein macromolecules. Kabuli chickpea seeds were processed by water cooking at different temperatures (63, 79, 88, and 96°C), followed by evaluating flour solubility, water-holding capacity (WHC), pasting property, as well as the total protein profile and fractionated protein distributions. Cooking treatments significantly decreased flour solubility (from 39.45 to 25.21 g/100 g flour) and pasting viscosity (peak and final viscosities, from 1081 to 300.5 cP and 1323 to 532 cP, respectively), while increasing WHC (from 0.862 to 1.144 g H2O/g flour) of chickpea flour (p < 0.05). These behaviors were enhanced by increasing cooking temperature. Meanwhile, cooking induced a significant change of chickpea proteins, modifying the albumin- and globulin-like fractions of chickpea protein to display glutelin-like behavior. The current study provides potential approaches for manipulating chickpea flour functionalities (e.g., solubility, viscosity, and WHC) to address the process and product challenges and favor product innovation.

Enhancing Gluten Network Formation and Bread-Making Performance of Wheat Flour Using Wheat Bran Aqueous Extract.

Wheat bran possesses diverse nutritional and functional properties. In this study, wheat bran aqueous extract (WBE) was produced and thoroughly characterized as a functional ingredient and improver for bakery application. The WBE contained 50.3% total carbohydrate, 24.5% protein, 13.0% ash, 6.7% soluble fiber, 2.9% insoluble fiber, and 0.5% ß-glucan. Notably, adding 7.5% WBE significantly increased the bread-specific volume to 4.84 cm3/g, compared with the control of 4.18 cm3/g. Adding WBE also resulted in a remarkable improvement in dough properties. The WBE-enriched dough showed increased peak, setback, breakdown, and final viscosities, along with higher storage and loss modulus. Scanning electron microscopy analysis further revealed that the WBE promoted the aggregation of protein and starch within the dough. The extractable gliadin to glutenin ratio increased with 5 and 7.5% WBE additions, compared with the control and 2.5% WBE addition. WBE did not significantly alter the starch gelatinization temperature or dough extension properties. These findings demonstrate that the inclusion of WBE in wheat flour is a promising approach for producing high-quality bread that is enriched with dietary fiber and protein.

Normal rice flours perform better in gluten-free bread than glutinous rice flours.

This study aims to determine gluten-free bread-making potential of different types of rice, particularly comparing normal rice versus glutinous rice flours. Proximate and chemical compositions, hydration, and dough mixing and pasting properties of ten rice cultivars (i.e., seven types of normal rice and three types of glutinous rice), and quality parameters (specific volume, texture profile, and crumb structure) of gluten-free bread from these flours were assessed. Significant differences were observed in flour properties among different types of rice. Significant correlations were observed between bread specific volume and rice amylose content (r = 0.91, p < 0.01), as well as pasting peak time (r = 0.86, p < 0.01) and final viscosity (r = 0.77, p < 0.01). Further, strong correlations were observed between bread resilience and properties of rice flour, such as amylose content (r = 0.91, p < 0.01), pasting peak viscosity (r = 0.83, p < 0.01), and final viscosity (r = 0.93, p < 0.01). In conclusion, the normal rice types exhibited much better gluten-free bread-making performances than glutinous flour. Important parameters of rice flour determining its gluten-free bread-making properties include amylose content, water retention capacity, and pasting properties. PRACTICAL APPLICATION: Compared with glutenous rice flour, normal rice flour leads to more viscous paste and gluten-free breads with larger volume, evener texture, and better resilience. This study provides guidance for practical uses of rice flours in improving gluten-free dough and bread quality.

Effect of environment and field management strategies on phenolic acid profiles of hard red winter wheat genotypes.

BACKGROUND: Integrated wheat management strategies can affect grain yield and flour end-use properties. However, the effect of integrated management and its interaction with environmental factors on the phenolic acid profiles of wheat has not been reported. The phenolic acid profile has become another parameter for the evaluation of wheat quality due to its potential health benefits. RESULTS: Year × location × management and year × management × genotype interactions were significant for the total phenolic content (TPC) of wheat samples. The year × location × management × genotype interaction was significant for the concentration of trans-ferulic acid and several other phenolic acids. Field management practices with no fungicide application (e.g., farmer's practice, enhanced fertility) may lead to increased accumulation of phenolic compounds, especially for WB4458, which is more susceptible to fungi infection. However, this effect was also related to growing year and location. Higher soil nitrogen content at sowing also seems to affect the TPC and phenolic acid concentration positively. CONCLUSION: Wheat phenolic acid profiles are affected by genotype, field management, environment, and their interactions. Intensified field management, in particular, may lead to decreased concentration of wheat phytochemicals. The level of naturally occurring nitrogen in the soil may also affect the accumulation of wheat phytochemicals. © 2021 Society of Chemical Industry.

Dietary N-epsilon-carboxymethyllysine as for a major glycotoxin in foods: A review.

N-epsilon-carboxymethyllysine (CML), as a potential glycotoxin and general marker for dietary advanced glycation end products (dAGEs), exists in raw food and is formed via various formation routes in food processing such as Maillard reaction between the reducing sugars and amino acids. Although comprehensive cause-effect proof is not available yet, current research suggests a potential risk of chronic diseases such as diabetes is associated with exogenous CML. Thus, CML is causing public health concerns regarding its dietary exposure, but there is a lack of explicit guidance for understanding if it is detrimental to human health. In this review, inconsistent results of dietary CML contributed to chronic disease are discussed, available concentrations of CML in consumed foods are evaluated, measurements for dietary CML and relevant analytic procedures are listed, and the possible mitigation strategies for protecting against CML formation are presented. Finally, the main challenges and future efforts are highlighted. Further studies are needed to extend the dietary CML database in a wide category of foods, apply new identifying methods, elucidate the pathogenic mechanisms, assess its detrimental role in human health, and propose standard guidelines for processed food.

Potential bioaccessibility of phenolic acids in whole wheat products during in vitro gastrointestinal digestion and probiotic fermentation.

Health benefits of whole wheat products are partially attributed by their unique phenolic compounds. This study investigated effect of simulated gastrointestinal digestion and probiotic fermentation on releasing of phenolic acids from whole wheat foods (bread, cookie, and pasta). Kinetics results showed that more phenolic acids were released within the first hour of gastric and intestinal digestions compared to the prolonged digestion. Lactobacillus rhamnosus GG, a common probiotic strain, released additional phenolic acids from the digestive residues during fermentation. Simulated digestion released more soluble trans-ferulic acid than chemical extraction in breads (17.69 to 102.71 µg/g), cookie (15.81 to 54.43 µg/g), and pasta (4.88 to 28.39 µg/g). Phenolic acid composition of whole wheat products appeared to be better estimated by digestion methods than the chemical extraction method. The unique insoluble-bound nature and fermentability of wheat phenolic acids may lead to a mechanistic understanding of whole grain consumption for potential colorectal cancer prevention.

Changes in phenolic profiles and antioxidant activities during the whole wheat bread-making process.

Health benefits of whole wheat products are partially attributed to their unique phenolic profiles. This study investigated the effect of bread-making processes on the phenolic profiles and antioxidant activities of four different varieties of hard red winter wheat. The fermentation process generally increased soluble phenolic content, flavonoid content, antioxidant activities, and soluble ferulic acid of whole wheat products. The baking process increased the soluble phenolic content and antioxidant activities. Some phenolic acids were incorporated into Maillard reaction products during baking. For the insoluble fraction, fermentation and baking slightly increased phenolic content, flavonoid content, and antioxidant activities of certain wheat varieties. Ferulic acid and isomers of di-ferulic acid (DFA) were not significantly affected by the baking process. Overall, the bread-making process demonstrated positive effects on the potential health benefits of whole wheat products.

Rapid determination of total phenolic content of whole wheat flour using near-infrared spectroscopy and chemometrics.

Phenolics in whole wheat products provide many health benefits. Wheat breeders, producers, and end-users are becoming increasingly interested in wheats with higher total phenolic content (TPC). Whole wheat flour with higher phenolics may have greater marketing value in the future. However, conventional methods determining TPC are costly and labor-intensive, which are not practical for wheat breeders to analyze several thousands of lines within a limited timeframe. We presented a novel application of near-infrared spectroscopy for TPC prediction in whole wheat flour. The optimal regression model demonstrated R2 values of 0.92 and 0.90 for the calibration and validation sets, and a residual prediction deviation value of 3.4. The NIR method avoids the tedious extraction and TPC assay procedures, making it more convenient and cost-effective. Our result also demonstrated that NIR can accurately quantify phenolics even at low concentration (less than 0.2%) in the food matrix such as whole wheat flour.

Individual effects of enzymes and vital wheat gluten on whole wheat dough and bread properties.

The objective of this research was to determine effects of five enzymes on whole wheat bread properties, particularly loaf volume, bread texture, and staling. Enzymes containing conventional α-amylase (α-amyl), cellulase (cel), glucose oxidase, maltogenic α-amylase (m amyl), and xylanase (xyl) were added at three levels. Vital wheat gluten (VWG) was added as an additional, separate treatment at 2.5% (flour weight basis). Enzymes had minimal effect on water absorption and mixing time. Each enzyme increased specific loaf volume for at least one of the usage levels tested (P < 0.01). Among the enzyme treatments, the greatest loaf volume was seen for xyl at the medium and high levels. No enzyme was as effective as VWG at increasing loaf volume. Overall, enzymes did not significantly change cell structure. The greatest reduction in fresh bread hardness was obtained for the high level of xyl. VWG, m amyl, and xyl reduced the rate of bread firming over 7 days. α-Amyl, cel, and m amyl decreased starch retrogradation at day 7 as measured by differential scanning calorimetry (P < 0.01). M amyl nearly eliminated the endothermic peak for recrystallized amylopectin. This study demonstrated the specific application of enzymes in whole wheat bread to increase loaf volume and decrease initial crumb hardness and bread staling. PRACTICAL APPLICATION: This study will provide guidance for practical uses of enzymes in improving whole wheat dough and bread quality.

Production and Characterization of Antioxidative Hydrolysates and Peptides from Corn Gluten Meal Using Papain, Ficin, and Bromelain.

There has been a growing interest in developing natural antioxidants with high efficiency and low cost. Bioactive protein hydrolysates could be a potential source of natural and safer antioxidants. The objectives of this study were to hydrolyze corn gluten meal using three plant-derived proteases, namely papain, ficin, and bromelain, to produce antioxidative hydrolysates and peptides and to characterize the antioxidant performances using both chemical assays and a ground meat model. The optimum hydrolysis time for papain was 3 h, and for ficin and bromelain was 4 h. The hydrolysates were further separated by sequential ultrafiltration to 5 hydrolysate fractions named F1 to F5 from low molecular weight (MW) (<1 kDa) to high MW range (>10 kDa), which were further characterized for TPC, free radical scavenging capacity against DPPH and ABTS, and metal chelating activity. The fraction F4 produced by papain (CH-P4), F1 produced by ficin (CH-F1), and F3 produced by bromelain (CH-B3) showed the strongest antioxidant activity and yield, respectively. These three fractions were incorporated into ground pork to determine their inhibition effects on lipid oxidation during a 16-day storage period. The inhibition effect was enhanced with the addition of higher amount of hydrolysate (e.g., 1000 vs. 500 mg/kg). The CH-P4 reduced lipid oxidation in ground meat by as much as 30.45%, and CH-B3 reduced oxidation by 27.2% at the same level, but the inhibition was only 13.83% with 1000 mg/kg of CH-F1. The study demonstrated that CGM protein hydrolysates and peptides could be used as naturally derived antioxidant in retarding lipid oxidation and improving product storage stability.

Potassium bicarbonate improves dough and cookie characteristics through influencing physicochemical and conformation properties of wheat gluten.

Baking soda (NaHCO3) has critical technological functions in cookie products. Health concern on excessive sodium consumption is increasing; therefore, it is necessary to explore NaHCO3 alternatives, such as KHCO3, for bakery products. This study investigated the impact of KHCO3 on the technological behaviors of cookie dough and end-uses in comparison with control samples prepared with NaHCO3 and explore the changes of physicochemical and conformation properties of soft wheat gluten during the process. Dough rheological measurements demonstrated that addition of KHCO3 reduced dough stickiness, and adding KHCO3 achieved similar dough and baking performances as using NaHCO3, which were partially attributed to the decrease of gliadin to glutenin ratio, changes of secondary structure, and intensive aggregation of gluten by introducing KHCO3. Cookie sensory attributes were also not adversely affected by using KHCO3. Therefore, partially replacing NaHCO3 with KHCO3 in cookie products can be an effective approach for sodium reduction.

Antioxidant Characteristics and Identification of Peptides from Sorghum Kafirin Hydrolysates.

Grain sorghum is gaining interest for various uses as a highly sustainable crop. Kafirin is the main storage protein in grain sorghum. However, the antioxidant activities of kafirin hydrolysates have not been systematically investigated. The objectives of this study were to characterize the antioxidative hydrolysates and their ultrafiltrated fractions from sorghum kafirin using chemical assays and model systems and to identify the representative peptides. Kafirin Neutrase hydrolysates displayed promising yield and antioxidant capacity among those prepared with several different proteases. The effects of critical variables including protein substrate content, enzyme-to-substrate ratio, and reaction time on antioxidant production were studied. Selected hydrolysates were further fractionated through ultrafiltration and gel filtration chromatography (GFC). Medium-sized fraction (3 to 10 kDa) revealed relatively higher total phenolic content and stronger antioxidative activities with regard to free radical scavenging activity, metal ion chelating activity, reducing power, and oxygen radical absorbance capacity. In an oil-in-water emulsion system, incorporation of selected fraction of hydrolysates inhibited the formation of primary and secondary oxidation products by 83.03% and 65.59%, respectively, by the end of a 14-day incubation period. Similar oxidation inhibition effect was also observed in a ground meat system. Peptide compositions of the most promising fraction from GFC and reversed-phase high-performance liquid chromatography were identified using matrix-assisted laser desorption ionization-time of flight/time of flight mass spectrometry. PRACTICAL APPLICATION: This study provided a feasible approach to produce peptide antioxidants from sorghum kafirin. The novel naturally derived antioxidants could be potentially used as alternatives or synergetic components to synthetic antioxidants in improving the oxidative stability of various food products.

Physicochemical properties and gluten structures of hard wheat flour doughs as affected by salt.

Hard wheat flour doughs were prepared with five different levels of sodium chloride, and rheological properties were characterized. Zeta potential, disulfide-sulfhydryl groups, surface hydrophobicity, secondary structure, and extractable gliadin and glutenin of gluten were analyzed to elucidate gluten structure changes induced by salt. Addition of higher levels of salt (2.0 and 2.4%, fwb) in doughs resulted in larger storage and loss modulus, and elongational viscosity. Starch gelatinization temperatures increased with higher amounts of salt. The presence of salt decreased the free sulfhydryl content but increased the ß-sheet structure of gluten. RP-HPLC indicated that salt enhanced the macromolecular aggregation of gluten proteins. The changes in gluten molecular conformation and network structure induced by salt significantly contributed to the improved physicochemical properties of dough. This study provides a better understanding of salt functionality in hard wheat flour dough and a valuable guide in searching for salt alternatives for bakery products.

Aggregation behavior of semolina gluten during dough production and fresh pasta cooking upon kansui treatment.

Sodium salt reduction in cereal products has been one of the top health trends. During pasta-making, kansui (an alkaline salt with reduced sodium) was added at 0, 0.5, 1.0, 1.5, and 2.0% (total flour weight basis) to modify semolina gluten aggregation reactions in dough production and pasta cooking. Adding 1.0% kansui enhanced pasta dough elasticity and strength, but cooking quality was changed barely. These consequences may be attributed to more polymeric glutenin incorporated in the network through thiol (SH)/disulfide (SS) exchange or other non-redox reactions/interactions by introducing kansui, which was confirmed by SDS-PAGE, FTIR, and HPLC results. The protein cross-linking induced by kansui (1.0%) improved the texture properties of pasta without compromising the cooking and coloration characteristics. Considering the process convenience and food safety of reducing sodium chloride with natural alkaline salt reagent in industrial pasta production, this could be a potential approach for sodium reduction.

Effect of Sodium Chloride and Sodium Bicarbonate on the Physicochemical Properties of Soft Wheat Flour Doughs and Gluten Polymerization.

Soft wheat flour doughs were prepared with different levels of salt (NaCl) or baking soda (NaHCO3). Oscillation rheology, elongational viscosity, and extensibility of doughs were tested to evaluate the effect of salt and baking soda on the physical properties of doughs. Furthermore, a series of physical-biochemical analytical techniques were used to investigate gluten polymerization in doughs, including zeta potential analyzer, Fourier transform infrared spectroscopy (FTIR), spectrophotometer, and reversed-phase high-performance liquid chromatography (RP-HPLC). The addition of high levels of NaHCO3 (1.0% fwb), either by itself or in combination with NaCl, increased dough strength, elongational viscosity, and viscoelasticity. RP-HPLC results demonstrated macromolecular aggregation of gluten proteins in the presence of NaCl or NaHCO3. The addition of NaHCO3 or NaCl also decreased both free sulfhydryl content and random-coil structure of gluten isolated from the doughs. Overall, NaCl and NaHCO3 induced the changes of molecular conformation of gluten, which impacted the physicochemical qualities of soft wheat flour dough. This study provides a better understanding of salt and baking soda functionality in the formation of soft flour dough, which will support the searching of feasible sodium reduction strategies in soft flour bakery products.

Determination of advanced glycation endproducts in cooked meat products.

Advanced glycation endproducts (AGEs), a pathogenic factor implicated in diabetes and other chronic diseases, are produced in cooked meat products. The objective of this study was to determine the AGE content, as measured by Nε-carboxymethyllysine (CML) levels, in cooked chicken, pork, beef and fish (salmon and tilapia) prepared by three common cooking methods used by U.S. consumers: frying, baking, and broiling. The CML was detected in all the cooked samples, but the levels were dependent on types of meat, cooking conditions, and the final internal temperature. Broiling and frying at higher cooking temperature produced higher levels of CML, and broiled beef contained the highest CML content (21.8µg/g). Baked salmon (8.6µg/g) and baked tilapia (9.7µg/g) contained less CML as compared to the other muscle food samples.

[Relative validity of food frequency questionnaire for estimating dietary iron intake of students with anemia].

OBJECTIVE: To assess the relative validity of food frequency questionnaire (FFQ) for estimating dietary iron and its related nutrients and food intakes of students with anemia. METHODS: FFQ and weighed dietary records combining with 24h dietary recalls (adopted as reference method) were applied respectively to investigate the diet of 156 anemic students aged 10 - 12 years. The average dietary intakes of iron, haem iron, non-haem iron, vitamin C, meat/fish/poultry and eggs were estimated. Wilcoxon matched-pairs signed-rank test, Spearman's rank correlation, cross-classification and actual values for surrogate categories were performed to assess the relative validity of FFQ. RESULTS: Compared with the reference method, dietary iron and its related nutrients and food intakes were overestimated by FFQ, and bear poor correlation with reference method. The results of cross-classification and actual values for surrogate categories indicated that the low and high intakes of all dietary components could not be clearly differentiated by FFQ. CONCLUSION: FFQ presents unsatisfactory accuracy in assessing dietary intakes of iron and related nutrients of anemic students in less developed districts.