Fate of salmonella and shiga-toxin producing Escherichia coli on wheat grain during tempering.

Outbreaks of Salmonella and Shiga-toxin producing Escherichia coli (STEC) linked to wheat flour led to increased interest in characterizing the fate of Salmonella and STEC on wheat during processing. Tempering is the stage of wheat processing where water is added to toughen the bran prior to milling, which has the potential to influence pathogen behavior on the kernels. This study aimed to quantify changes in the numbers of STEC and Salmonella inoculated onto soft red winter wheat, and to observe potential changes in the distribution of the pathogens on the surface of kernels during tempering. Lab-scale tempering experiments were conducted to quantify the water activity of and bacterial populations on wheat grain at various time points during 16 h of tempering. The highest water activity observed throughout 16 h of tempering was 0.88. There was no significant change (p > 0.05) in numbers of Salmonella, STEC, or native mesophiles. Using confocal microscopy, observation of Salmonella and STEC cells expressing mCherry on wheat kernels showed an even distribution of inoculated cells, though the localization of cells on kernels did not change significantly after tempering. Even though the environment was not favorable for pathogen replication on grain, the population remained stable, suggesting that disinfection of the kernels prior to milling could reduce food safety concerns in flour.

Wheat starch structure-function relationship in breadmaking: A review.

Bread dough and bread are dispersed systems consisting of starch polymers that interact with other flour components and added ingredients during processing. In addition to gluten proteins, starch impacts the quality characteristics of the final baked product. Wheat starch consists of amylose and amylopectin organized into alternating semicrystalline and amorphous layers in granules that vary in size and are embedded in the endosperm protein matrix. Investigation of the molecular movement of protons in the dough system provides a comprehensive insight into granular swelling and amylose leaching. Starch interacts with water, proteins, amylase, lipids, yeast, and salt during various stages of breadmaking. As a result, the starch polymers within the produced crumb and crust, together with the rate of retrogradation and staling due to structural reorganization, moisture migration, storage temperature, and relative humidity determines the final product's textural perception. This review aims to provide insight into wheat starch composition and functionality and critically review recently published research results with reference to starch structure-function relationship and factors affecting it during dough formation, fermentation, baking, cooling, and storage of bread.

Viability of Lactobacillus rhamnosus GG microencapsulated in alginate/chitosan hydrogel particles during storage and simulated gastrointestinal digestion: role of chitosan molecular weight.

Sodium alginate hydrogel particles coated with cationic biopolymers have been shown to be one of the promising means for probiotic encapsulation and protection. In this study, we aimed to systematically explore the effect of molecular weight of chitosan coating on the functional performance of sodium alginate hydrogel particles for improving the viability of Lactobacillus rhamnosus GG (LGG). We first electrostatically deposited three different molecular weights of chitosan coatings, i.e., chitosan oligosaccharide (COS), low molecular weight chitosan (LMW-chitosan) and medium molecular weight chitosan (MMW-chitosan) on sodium alginate hydrogel particles. Both SEM and FTIR results indicated that chitosan was successfully deposited onto the surface of the hydrogel particles. We then evaluated the effect of chitosan MW on the viability of LGG encapsulated in the hydrogels during long-term storage and simulated gastrointestinal digestion. Among them, the hydrogel particles coated with COS prevented the viability loss of LLG during long-term storage at different temperatures (4, 25 and 37 °C). However, we did not find any improvement in the viability of the encapsulated LGG by all three chitosan coatings during simulated digestion.

Surface Treatment of Carbon Nanotubes Using Modified Tapioca Starch for Improved Force Detection Consistency in Smart Cementitious Materials.

The remarkable mechanical properties and piezo-responses of carbon nanotubes (CNT) makes this group of nanomaterials an ideal candidate for use in smart cementitious materials to monitor forces and the corresponding structural health conditions of civil structures. However, the inconsistency in measurements is the major challenge of CNT-enabled smart cementitious materials to be widely applied for force detection. In this study, the modified tapioca starch co-polymer is introduced to surface treat the CNTs for a better dispersion of CNTs; thus, to reduce the inconsistency of force measurements of the CNTs modified smart cementitious materials. Cement mortar with bare (unmodified) CNTs (direct mixing method) and surfactant surface treated CNTs using sodium dodecyl benzenesulfonate (NaDDBS) were used as the control. The experimental results showed that when compared with samples made from bare CNTs, the samples made by modified tapioca starch co-polymer coated CNTs (CCNTs) showed higher dynamic load induced piezo-responses with significantly improved consistency and less hysteresis in the cementitious materials. When compared with the samples prepared with the surfactant method, the samples made by the developed CCNTs showed slightly increased force detection sensitivity with significantly improved consistency in piezo-response and only minor hysteresis, indicating enhanced dispersion effectiveness. The new CNT surface coating method can be scaled up easily to cater the potential industry needs for future wide application of smart cementitious materials.

Preparation and Characterization of Inclusion Complexes of ß-Cyclodextrin and Phenolics from Wheat Bran by Combination of Experimental and Computational Techniques.

Bitterness often associated with whole wheat products may be related to phenolics in the bran. Cyclodextrins (CDs) are known to form inclusion complexes. The objective was to form inclusion complexes between ß-CD and wheat phenolics. Pure phenolic acids (trans-ferulic acid (FA), caffeic acid (CA), and p-coumaric acid (CO)) and phenolic acids from wheat bran were used to investigate complex formation potential. Complexes were characterized by spectroscopy techniques, and a computational and molecular modeling study was carried out. The relative amount of complex formation between ß-CD and wheat bran extract was CA > CO > FA. The phenolic compounds formed inclusion complexes with ß-CDs by non-covalent bonds. The quantum-mechanical calculations supported the experimental results. The most stable complex was CO/ß-CD complex. The ΔH value for CO/ß-CD complex was -11.72 kcal/mol and was about 3 kcal/mol more stable than the other complexes. The QSPR model showed good correlation between binding energy and 1H NMR shift for the H5 signal. This research shows that phenolics and ß-CD inclusion complexes could be utilized to improve the perception of whole meal food products since inclusion complexes have the potential to mask the bitter flavor and enhance the stability of the phenolics in wheat bran.

Go clean label: replacement of commercial dough strengtheners with hard red spring wheat flour in bread formulations.

There is growing interest in the application of natural ingredients to replace chemical dough improvers in bread formulations in order to meet consumer demands of clean label products. The goal of this study was to evaluate the dough quality and baking quality of hard red spring (HRS) wheat flour blends to replace commercial dough improvers. Hard red winter (HRW) wheat flour is commonly used in bread and diner roll formulations. In this study, doughs were prepared by adding 10%, 20%, 30%, and 40% of HRS wheat flour to HRW wheat base-flour to compare the dough quality and baking quality relative to different levels of commercial improvers. Additional to commercial HRS flour, two commonly grown HRS wheat varieties (Glenn and Linkert) were included in the study. All of the HRS wheat flour blends had significantly (p < 0.05) higher farinograph stability and extensograph resistance at 135 min than doughs containing most of the commercial additives. Bread flour with 40% Glenn and 40% Linkert showed the highest loaf volumes of 920 cm3 and 950 cm3, respectively with the firmness of 1553.50 and 1525.50 mN, respectively. Baking quality of HRS wheat flour blends also showed significant (p < 0.05) correlation with dough rheology but commercial additives did not have the correlations. Therefore, HRS wheat flour may be used as a replacement for dough improvers, as it had better dough and bread properties compared to commercial additives and provides a great alternative for "clean-label" bread products.

Chemical composition, nutritional value and in vitro starch digestibility of roasted chickpeas.

BACKGROUND: Chickpea is considered a wholesome and nutritious food due to its nutritional properties and glycemic response. Such properties can be influenced by the thermal treatment used to cook this legume and produce a snack named leblebi. From the consumers' point of view, it is desirable to improve texture and palatability of the chickpea by the processing steps used to make leblebi. However, consumers are increasingly concerned with the nutritional value of snack foods. RESULTS: Nutritional components and digestibility properties of single and double heat-treated chickpea, single and double roasted leblebi and white leblebi were studied. High sodium, starch damage and soluble dietary fiber content were observed in white leblebi; while the other samples showed significantly (P < 0.05) higher insoluble dietary fiber content. Heat treatment and processing significantly (P < 0.05) altered the viscosity and starch properties of the samples. High resistant starch content (28.28% to 30.20%) and low estimated glycemic index (38.67 to 41.28) in heat-treated chickpeas and roasted leblebi were observed. CONCLUSION: The results indicate that heat-treated chickpea and roasted leblebi have good nutritional quality and low glycemic response. White leblebi had relatively high sodium content and glycemic response. © 2015 Society of Chemical Industry.

New QTL alleles for quality-related traits in spring wheat revealed by RIL population derived from supernumerary × non-supernumerary spikelet genotypes.

KEY MESSAGE: A population developed from an exotic line with supernumerary spikelets was genetically dissected for eight quality traits, discovering new genes/alleles with potential use in wheat breeding programs. Identifying new QTLs and alleles in exotic germplasm is paramount for further improvement of quality traits in wheat. In the present study, an RIL population developed from a cross of an elite wheat line (WCB414) and an exotic genotype with supernumerary spikelets (SS) was used to identify QTLs and new alleles for eight quality traits. Composite interval mapping for 1,000 kernels weight (TKW), kernel volume weight (KVW), grain protein content (GPC), percent of flour extraction (FE) and four mixograph-related traits identified a total of 69 QTLs including 19 stable QTLs. These QTLs were located on 18 different chromosomes (except 4D, 5D, and 6D). Thirteen of these QTLs explained more than 15% of phenotypic variation (PV) and were considered as major QTLs. In this study, we identified 11 QTLs for TKW (R (2) = 7.2-17.1 %), 10 for KVW (R (2) = 6.7-22.5%), 11 for GPC (R (2) = 4.7-16.9%), 6 for FE (R (2) = 4.8-19%) and 31 for mixograph-related traits (R (2) = 3.2-41.2%). In this population, several previously identified QTLs for SS, nine spike-related and ten agronomic traits were co-located with the quality QTLs, suggesting pleiotropic effects or close linkage among loci. The traits GPC and mixogram-related traits were positively correlated with SS. Indeed, several loci for quality traits were co-located with QTL for SS. The exotic parent contributed positive alleles that increased PV of the traits at 56% of loci demonstrating the suitability of germplasm with SS to improve quality traits in wheat.

Oxygenated fatty acids isolated from wheat bran slurries.

Oxygenated fatty acids are classified as secondary metabolites in wheat, produced by oxidation of free fatty acids (FFAs). Oxygenated fatty acids have significant impact on the organoleptic and sensory properties of food products and participate in regulation of defense and developmental processes in plants. The objective of this study was to identify oxygenated fatty acids from wheat flour slurries. Wheat bran/water slurries were incubated for 4 h and freeze dried. Total lipids were extracted in chloroform/methanol/water; and methylated and silylated FFAs were analyzed with gas chromatography/mass spectroscopy. Seven oxygenated fatty acids were identified, (A) 12,13-dihydroxy-9-octadecenoic acid, (B) 9-hydroxy-10,12-octadecadienoic acid, (C) 13-hydroxy-9cis,11trans-octadecadienoic acid, (D) 9,10,13-trihydroxy-11trans-octadecenoic acid, (E) 9,12,13-trihydroxy-10trans,15cis-octadecadienoic acid, (F) 10-oxo-13-hydroxy-11trans-octadecenoic acid and (G) 12-oxo-13-hydroxy-octadecanoic acid, in wheat bran slurries. Our results are important for whole wheat food applications since oxygenated fatty acids can result in bitter flavors in the final product.

Effect of pre-harvest sprouting on physicochemical changes of proteins in wheat.

BACKGROUND: High moisture before harvest can cause sprouting of the wheat kernel, which is termed pre-harvest sprouting (PHS). The aim of this study was to examine the variation in physicochemical properties of proteins in PHS-damaged (sprouted) hard red and white spring wheat genotypes. Specifically, protein content, enzyme activity and degradation of proteins were evaluated in sound and PHS-damaged wheat. RESULTS: Protein contents of sprouted wheat samples were lower than that of non-sprouted samples; however, their differences were not significantly (P > 0.05) correlated with sprouting score. Sodium dodecyl sulfate (SDS) buffer extractable proteins (EXP) and unextractable proteins (UNP) were analyzed by high-performance size exclusion chromatography. PHS damage elevated endoprotease activity and consequently increased the degradation of polymeric UNP and free asparagine concentration in wheat samples. Free asparagine is known to be a precursor for formation of carcinogenic acrylamide during high heat treatment, such as baking bread. Free asparagine content had significant correlations (P < 0.01) with sprouting score, endoprotease activity and protein degradation. CONCLUSIONS: Genotypes with higher endoprotease activity tend to exhibit a larger degree of degradation of UNP and higher free asparagine concentration in sprouted wheat samples.

Texturized pinto bean protein fortification in straight dough bread formulation.

Pinto beans were milled and then air-classified to obtain a raw high protein fraction (RHPF) followed by extrusion to texturize the protein fraction. The texturized high protein fraction (THPF) was then milled to obtain flour, and combined with wheat flour at 5, 10, and 15% levels to make bread. The air-classification process produced flour with high concentration of lipids and phytic acid in the protein-rich fraction. However, extrusion significantly reduced hexane extractable lipid and phytic acid. However, the reduction observed may simply indicate a reduction in recovery due to bind with other components. Total protein and lysine contents in composite flours increased significantly as THPF levels increased in composite flour. Bread made with 5% THPF had 48% more lysine than the 100 % wheat flour (control). The THPF helped to maintain dough strength by reducing mixing tolerance index (MTI), maintaining dough stability and increasing departure time on Farinograph. Bread loaf volume was significantly reduced above 5% THPF addition. THPF increased water absorption causing an increase in bread weights by up to 6%. Overall, loaf quality deteriorated at 10 and 15% THPF levels while bread with 5% THPF was not significantly different from the control. These results support the addition of 5% THPF as a means to enhance lysine content of white pan bread.

Enhancing Mechanical Properties of Corn Bran Arabinoxylan Films for Sustainable Food Packaging.

Arabinoxylan (AX)-based films can improve the mechanical characteristics of biodegradable materials when utilized for food packaging. However, the mechanical properties of AX films for food packaging applications require thorough investigation to establish their viability. In this study, AX was extracted from corn bran coproducts of dry-milling (DCB), wet-milling (WCB), and dried distiller's grains with solubles (DDGS) using an acid-alkali method. Packaging materials were produced using these AX extracts, each combined with laccase and sorbitol, forming the basis for three different films. These films were then modified by immersing the surface in a lipase-acetate solution. We evaluated their mechanical characteristics, including thickness, tensile properties, tear resistance, and puncture resistance. The thickness and tensile properties of the modified AX films derived from DCB and DDGS showed significant improvements (p < 0.05) compared to the unmodified AX films. In contrast, the modified AX films from WCB showed no significant changes (p > 0.05) in thickness and tensile properties compared to the unmodified WCB AX films. A significant increase in tear resistance (p < 0.05) was observed in all modified AX films after immersion in the lipase-acetate mixture. While puncture resistance was enhanced in the modified AX films, the improvement was not statistically significant (p > 0.05) compared to the unmodified films. The presence of hydroxyl (OH) and carbonyl (CO) groups on the surfaces of AX films from DCB and DDGS, modified by the lipase-acetate solution, suggests excellent biodegradability properties. The modification process positively affected the AX films, rendering them more bendable, flexible, and resistant to deformation when stretched, compared to the unmodified AX films.

Improving Biodegradable Films from Corn Bran Arabinoxylan for Hydrophobic Material and Green Food Packaging.

Non-biodegradable plastic materials pose environmental hazards and contribute to pollution. Arabinoxylan (AX) films have been created for applications in food packaging to replace these materials. The water interaction characteristics of biodegradable AX films were assessed following the extraction of AX from dry-milled corn bran (DCB), wet-milled corn bran (WCB), and dried distiller's grains with solubles (DDGS). Films were prepared with laccase and sorbitol before surface modification with lipase-vinyl acetate. Water solubility of the modified DCB films was significantly reduced (p < 0.05); however, the water solubility of modified WCB films decreased insignificantly (p > 0.05) compared to unmodified films. Water vapor permeability of the modified AX films from WCB and DDGS was significantly reduced (p < 0.05), unlike their unmodified counterparts. The biodegradation rates of the modified WCB AX and DDGS films increased after 63 and 99 days, respectively, compared to the unmodified films. The hydrophilic nature of AX polymers from WCB and DDGS enhances the biodegradability of the films. This study found that the modified WCB AX film was more hydrophobic, and the modified DDGS AX film was more biodegradable than the modified DCB AX film. Overall, surface modifications have potential for improving hydrophobicity of biopolymer films.

Effectiveness of Online Food-Safety Educational Programs: A Systematic Review, Random-Effects Meta-Analysis, and Thematic Synthesis.

Online food-safety educational programs are increasingly important to educate different populations as technology and culture shift to using more technology. However, the broad effectiveness of these programs has yet to be examined. A systematic review, random-effects meta-analysis, and thematic synthesis are conducted to identify the effect size of online food-safety educational programs on knowledge, attitudes, and practices of consumers, food workers, and students and their respective barriers and recommendations. Online food-safety education was found to be of moderate and low effectiveness, with attitudes being the lowest in all populations. Consumers struggled with staying focused, and it was found that messaging should focus on risk communication. Students struggled with social isolation and a lack of time, and it was recommended that videos be used. Food workers struggled with a lack of time for training and difficulty understanding the material, and future programs are recommended to implement shorter but more frequent trainings with simple language. Future online food-safety educational programs should focus on incorporating social elements, as they can remain a huge barrier to learning. They should also focus on changing the participant's attitude to risk perception and beliefs in the importance of food safety.

Dynamic changes in ferulic acid and diferulic acids in wheat flour doughs during the breadmaking process.

Ferulic acid (FA), a phytochemical concentrated in wheat bran, influences structural characteristics of arabinoxylan (AX) and rheological properties of wheat dough. This study investigates the dynamic changes in FA and diferulic acids, closely associated with AX molecular weight, during the breadmaking process. FA predominantly exists in a tightly bound state within the arabinoxylan matrix, with a substantial increase in free FA content observed during the initial fermentation phase. Furthermore, this research identified four specific wheat-derived diferulic acids: 8-5'-DFA, 5-5'-DFA, 8-O-4'-DFA, and 8-5'-DFA (benzofuran form), tracking their variations throughout breadmaking. The notable upsurge in diferulic acid levels in the early fermentation stages suggests that the cleavage of ferulic acid moieties may not be the primary factor contributing to the reduction in AX molecular weight. Future investigations into the effects of FA and diferulic acids on arabinoxylan and wheat dough properties promise to enhance understanding of the intricacies of the breadmaking process.

Phenolic Acid-ß-Cyclodextrin Complexation Study to Mask Bitterness in Wheat Bran: A Machine Learning-Based QSAR Study.

The need to solvate and encapsulate hydro-sensitive molecules drives noticeable trends in the applications of cyclodextrins in the pharmaceutical industry, in foods, polymers, materials, and in agricultural science. Among them, ß-cyclodextrin is one of the most used for the entrapment of phenolic acid compounds to mask the bitterness of wheat bran. In this regard, there is still a need for good data and especially for a robust predictive model that assesses the bitterness masking capabilities of ß-cyclodextrin for various phenolic compounds. This study uses a dataset of 20 phenolic acids docked into the ß-cyclodextrin cavity to generate three different binding constants. The data from the docking study were combined with topological, topographical, and quantum-chemical features from the ligands in a machine learning-based structure-activity relationship study. Three different models for each binding constant were computed using a combination of the genetic algorithm (GA) and multiple linear regression (MLR) approaches. The developed ML/QSAR models showed a very good performance, with high predictive ability and correlation coefficients of 0.969 and 0.984 for the training and test sets, respectively. The models revealed several factors responsible for binding with cyclodextrin, showing positive contributions toward the binding affinity values, including such features as the presence of six-membered rings in the molecule, branching, electronegativity values, and polar surface area.

Structural analysis of succinoglycan oligosaccharides from Sinorhizobium meliloti strains with different host compatibility phenotypes.

Sinorhizobium meliloti NRG247 has a Fix(+) phenotype on Medicago truncatula A20 and is Fix(-) on M. truncatula A17, and the phenotype is reversed with S. meliloti NRG185. As the succinoglycan was shown to impact host specificity, an analysis of the succinoglycan oligosaccharides produced by each strain was conducted. The symbiotically active succinoglycan trimeric oligosaccharides (STOs) from the two S. meliloti strains were compared by chromatography and mass spectrometry, and the analysis of the S. meliloti NRG247 oligosaccharides showed that this strain produces an abundance of STO trimer 1 (T1), containing no succinate (i.e., three nonsuccinylated repeats), yet the low-molecular-weight pool contained no nonsuccinylated monomers (potential repeats). This showed that STO T1 is likely to be the active signal on M. truncatula A20 and that the biosynthesis of the STOs is not a random polymerization of the monomer population. The results also suggest that the fully succinylated STO T7 is required for the infection of M. truncatula A17.

Effect of Field-applied Fungicides on Claviceps purpurea Sclerotia and Associated Toxins in Wheat.

Claviceps purpurea (Fr.) Tul is the causal organism for ergot impacting grass hosts, including wheat. The pathogen produces ergot alkaloids (EAs) during the development of mature sclerotia leading to potential wheat quality discounts or rejection at the point of sale. Cultural practices are recommended for the management of ergot in wheat, but there is limited information pertaining to the use of in-season fungicides to help reduce ergot. The objective of this research was to evaluate the efficacy of four fungicides (prothioconazole + metconazole, pydiflumetofen + propiconazole, azoxystrobin + propiconazole, and fluxapyroxad + pyraclostrobin) on sclerotia characteristics, and EAs associated with C. purpurea. A field experiment was established using a male-sterile hard red spring line with fungicide applications occurring at complete full head emergence (Feekes Growth Stage 10.5). Individual plots were harvested and cleaned, and ergot sclerotia were collected. Physical characteristics and toxin production were examined. Fungicides had a significant (p < .05) impact on total ergot body weight (EBW), with all fungicides having lower EBW than the nontreated control. The fungicide premixture of pydiflumetofen + propiconazole had the lowest EBW among all treatments. Fluxapyroxad + pyraclostrobin had the lowest levels of EAs among fungicides. Results suggest that fungicide premixtures can potentially reduce EBW and influence EA production in wheat.

Discrimination of Glutopeak Test and Mixograph Parameters for Evaluation of Wheat Flour Supplemented with Hazelnut Skin, Cross-Linked Starch, and Oxidized Starch.

Hazelnut skin is a by-product produced from hazelnut processing. It can be used as a nutritional supplement due to its high nutrient values. The purpose of this study was to evaluate the dough properties of refined flour (RF) with the addition of hazelnut skin (HS), cross-linked starch (CS), and oxidized starch (OS). Principal component analysis showed a positive correlation between maximum torque, torque after maximum, and aggregation energy. Usage of 10% HS significantly (p < 0.05) decreased the mixograph MID line peak value indicating a weaker dough. Random forest (RFT) was conducted to classify the samples and to determine the importance levels of the analysis parameters. According to the results, AE and mixograph MID line peak values were the most discriminant parameters to distinguish the samples into groups. High-level HS alone caused undesirable effects on the dough quality, yet the addition of modified starches could be used to compensate for the undesirable effects. When used together, the interaction between hazelnut skin and modified starches should be considered. Glutopeak provides a means for assessing the impacts of additives such as hazelnut skin or modified starches on flour functionality.

Inactivation of Salmonella and Shiga-toxin producing Escherichia coli on soft wheat kernels using vacuum steam pasteurization.

Wheat, the raw material for flour milling, can be contaminated with enteric pathogens, leading to outbreaks linked to flour. In previous lab-scale studies, vacuum steam treatment was able to reduce Salmonella Enteritidis PT30 and Shiga-toxin producing E. coli (STEC) O121 levels on soft wheat kernels while maintaining flour quality and gluten functionality. This study used a newly designed lab-scale vacuum steam pasteurizer (VSP) to evaluate its efficacy to inactivate multiple strains of Salmonella and STEC on soft wheat by modeling the non-isothermal time-temperature history during treatment and reduction of the microbial populations. The results demonstrated that vacuum steam treatment could effectively disinfect wheat grains inoculated with enteric pathogens. In this study, Salmonella strains were less thermally resistant than STEC strains. The D75°C of Salmonella strains were 2.8 and 3.2 min, and the D75°C of STEC ranged from 3.1 to 4.6 min. E. faecium had a D75°C of 3.3 min, which indicates that it could be used as surrogate for larger scale evaluation of vacuum steam pasteurization in the future but was not conservative compared to some of the STEC strains.