Effect of fibre fortification of low FODMAP pasta.

Irritable bowel syndrome (IBS) is a condition affecting the digestive system and can be triggered by several different factors, including diet. To ease symptoms of IBS, a diet low in fermentable oligo-, di-, monosaccharides and polyols (FODMAPs) is often recommended. Pasta, as a staple food in the Western World, is naturally high in FODMAPs. This study investigates the impact of insoluble and soluble dietary fibre ingredients in low-FODMAPs pasta. The assessment included physicochemical, sensory, and nutritional quality. Soluble fibre strengthened gluten network, which caused a lower cooking loss and a lower release of sugars during in vitro starch digestion. Insoluble fibre interfered with the gluten network development to a higher extent causing a higher sugar release during digestion. This study reveals the most suitable fibre ingredients for the development of pasta with elevated nutritional value and sensory characteristics compared to commercial products on the market. This type of pasta has a high potential of being suitable for IBS patients.

FODMAP Content Like-by-like Comparison in Spanish Gluten-free and Gluten-containing Cereal-based Products.

Gluten-free foods (GF) availability on supermarket shelves is growing and it is expected to continue expanding in the years ahead. These foods have been linked to a lower content of fermentable oligosaccharides, disaccharides, monosaccharides and polyols (FODMAPs), molecules that trigger gastrointestinal symptoms in sensitive persons. In this study, the FODMAP content of 25 cereal-based GF foods in Spain (breakfast cereals, pasta, bread, biscuits, bakery products, and dough and puff pastry) and 25 gluten-containing equivalents (GC) available in the same supermarket were analysed and compared. Lactose, fructose, glucose, sorbitol, mannitol, raffinose, stachyose and fructans were quantified. In a like-by-like analysis, GF foods were found to generally contain fewer FODMAPs than their GC counterparts. The ingredients used in the manufacture of GF cereal-based foods may contribute to this fact. When the individually wrapped size was considered, the proportion of samples classified as high-FODMAPs in GC and GF foods showed a trend towards fewer samples in the GF. However, not all the GF samples were low-FODMAP. Altogether, our findings provide essential information for FODMAP content databases of GF products in Spain.

Selective PQQPFPQQ Gluten Epitope Chemical Sensor with a Molecularly Imprinted Polymer Recognition Unit and an Extended-Gate Field-Effect Transistor Transduction Unit.

A molecularly imprinted polymer (MIP) recognition system was devised for selective determination of an immunogenic gluten octamer epitope, PQQPFPQQ. For that, a thin MIP film was devised, guided by density functional theory calculations, and then synthesized to become the chemosensor recognition unit. Bis(bithiophene)-based cross-linking and functional monomers were used for this synthesis. An extended-gate field-effect transistor (EG-FET) was used as the transduction unit. The EG-FET gate surface was coated with the PQQPFPQQ-templated MIP film, by electropolymerization, to result in a complete chemosensor. X-ray photoelectron spectroscopy analysis confirmed the presence of the PQQPFPQQ epitope, and its removal from the MIP film. The chemosensor selectively discriminated between the octamer analyte and another peptide of the same number of amino acids but with two of them mismatched (PQQQFPPQ). The chemosensor was validated with respect to both the PQQPFPQQ analyte and a real gluten extract from semolina flour. It was capable to determine PQQPFPQQ in the concentration range of 0.5-45 ppm with the limit of detection (LOD) = 0.11 ppm. Moreover, it was capable of determining gluten in real samples in the concentration range of 4-25 ppm with LOD = 4 ppm, which is a value sufficient for discriminating between gluten-free and non-gluten-free food products. The gluten content in semolina flour determined with the chemosensor well correlated with that determined with a commercial ELISA gluten kit. The Langmuir, Freundlich, and Langmuir-Freundlich isotherms were fitted to the epitope sorption data. The sorption parameters determined from these isotherms indicated that the imprinted cavities were quite homogeneous and that the epitope analyte was chemisorbed in them.

Detection of Gluten in Gluten-Free Labeled Restaurant Food: Analysis of Crowd-Sourced Data.

INTRODUCTION: Adherence to a gluten-free (GF) diet is the mainstay of therapy for celiac disease. Until now, those wishing to avoid gluten in restaurants had to rely on menu labels, word of mouth, intuition, and restaurant workers' advice, with a relative dearth of supporting data. We used crowd-sourced data from users of a portable gluten detection device to estimate rates of, and identify risk factors for, gluten contamination of supposed GF restaurant foods. METHODS: We analyzed data from a portable gluten detection device (Nima), collected across the United States during an 18-month period by users who opted to share the results of their point-of-care tests. Data were sorted by region, time of day, median household income in the restaurant's vicinity, restaurant genre, and food items. We used the χ test for bivariate analysis and multiple logistic regression for multivariate analysis to identify predictors of gluten detection in restaurant food. RESULTS: There were 5,624 tests, performed by 804 users, in the examined period. Gluten was detected in 32% of GF labeled foods. Rates of gluten detection differed by meal, with 27.2% at breakfast and 34.0% at dinner (P = 0.0008). GF labeled pizza and pasta were most likely to test positive for gluten, with gluten detected in 53.2% of pizza and 50.8% of pasta samples. On multivariate analysis, GF labeled food was less likely to test positive for gluten in the West than in the Northeast United States (odds ratio 0.80; 95% confidence interval 0.67-0.95). CONCLUSIONS: This study of crowd-sourced data suggests that a substantial fraction of GF labeled restaurant foods contain detectable gluten. Although the highly sensitive Nima device may detect gluten at levels <20 parts per million (ppm), leading to gluten exposure of unknown clinical significance, our findings raise a potential concern. In addition, our findings of higher rates of gluten detection in pizza and pasta provide practical data when providing dining strategies for patients with celiac disease.

Contribution of Oral Hygiene and Cosmetics on Contamination of Gluten-free Diet: Do Celiac Customers Need to Worry About?

OBJECTIVES: The only available treatment for celiac disease (CD) is the gluten-free diet. It is unclear whether the presence of gluten in oral hygiene products and cosmetics that are applied on the mouth is a reason of concern for CD patients. The aim of this study was to test the level of gluten contamination in oral hygiene and cosmetic products available in the Italian market. METHODS: A total of 66 products (toothpastes = 37; dental tablets = 2; mouthwashes = 5; lip-balms = 10; lipsticks = 12) labelled gluten-free or with unknown gluten content were randomly collected from different supermarkets and pharmacies. The gluten quantification was determined by the R5 ELISA method approved by EU regulations. RESULTS: Out of 66 oral hygiene and cosmetics, 62 products (94%) were found to be gluten-free (gluten level <20 ppm), while 4 (6%) (toothpastes = 3; lipsticks = 1) showed a gluten level >20 ppm (toothpastes: 20.7, 31.4, and 35 ppm; lipstick: 27.4 ppm). None of the selected products had ingredient derived from wheat, barley, or rye. CONCLUSIONS: Gluten contamination is currently not an issue in a wide array of cosmetic and oral hygiene products that are commonly in the market.

Effect of cellulase on dough structure and quality characteristics of tough biscuits enriched with potato whole flour.

Potato whole flour is a promising way to improve the nutrition of tough biscuits, while its gluten-free characteristic was difficult to form acceptable texture properties. In this study, cellulase was used to degrade the cellulose in dough enriched with potato whole flour, so as to mitigate the interference of cellulose with the gluten network, resulting in forming the potato whole flour biscuit with great characteristics. Results indicated that cellulase within 0.2% led to the gradually reduced G' and G'' values of dough from 5.50×104 to 4.00×104 and 2.66×104 to 1.35×104, respectively. Cellulase at 0.2% resulted in the significantly increased tensile properties of the dough compared to the control. The incorporation of cellulase within 0.2% also led to the tightly ordered and intact network structure base on the results of SEM, disulfide bonds determination and FTIR. Those results indicated that cellulase was beneficial to improve the baking quality of dough, which was conductive to form tough biscuit with great characteristics. The hardness, crunchiness, crispness and specific volume analysis results confirmed that 0.2% cellulase resulted in the significantly decreased hardness by 45.25% and the significantly increased specific volume, crunchiness and crispness by 24.74%, 121.20% and 156.47%, respectively. Overall, cellulase ultimately improved the quality of the biscuits by improving the properties and structure of the dough. It was of great significance for the utilization of potato whole flour resources and the industrial production of its tough biscuits. PRACTICAL APPLICATION: The results showed that inclusion of cellulase led to the reduced hardness and increased crunchiness, crispness, and specific volume of potato whole flour tough biscuits. Cellulase could be used as a potential improver of tough biscuits. This study will provide guidance for practical uses of cellulase in improving potato whole flour dough and tough biscuit quality.

Quality and microbial diversity of homemade bread packaged in cinnamaldehyde loaded poly(lactic acid)/konjac glucomannan/wheat gluten bilayer film during storage.

The current study aimed to reveal the changes in quality and microbial diversity of bread at 25 °C, and to analyze the activity of antifungal bilayer film on maintaining the quality of bread during 10 days of storage. Antifungal bilayer film prepared with cinnamaldehyde loaded polylactic acid/konjac glucomannan/wheat gluten (PLA/KGM/WG-CIN) was used to preserve bread samples fermented at different times. The changes in the morphology, moisture state, texture properties and microbiological analysis of bread were investigated during the storage. Analysis of microbial diversity of bread samples showed a clear decrease in the abundance of the main spoilage fungi (Aspergillus and Penicillium) in samples packed with PLA/KGM/WG-CIN film. The PLA/KGM/WG-CIN film effectively prevented moisture from evaporation, maintained the texture properties, retarded the growth of fungi, and reduced the fungi diversity during the storage. Results suggest a large potential of PLA/KGM/WG-CIN film to ensure the quality and safety of bread products.

Validation of the Reveal® 3-D for Gluten Assay for Detection of Gluten in Clean-in-Place Rinses and Stainless Steel Environmental Surfaces: AOAC Performance Tested MethodSM 122201.

BACKGROUND: Reveal® 3-D for Gluten is an immunochromatographic assay for the qualitative detection of gluten in environmental samples. The test uses monoclonal antibodies reactive to prolamins in wheat. OBJECTIVE: The objective of the study was to validate the Reveal 3-D test for detection of gluten in clean-in-place rinse and swabs from a stainless steel surface. METHODS: Elements of the study included food selectivity and interference testing, matrix testing, an assay robustness study, and reagent stability/lot-to-lot consistency testing. Wheat flour was used as the spiking material for all matrixes. RESULTS: In selectivity and interference testing, nine target matrixes all tested positive and 36 of 39 non-target matrixes tested negative. Almond flour, sesame flour, and cornstarch produced positive results as 100% commodities; reactivity can be eliminated with dilution or by testing without use of food extraction buffer, which is not a standard part of the environmental testing method. With a gluten spike at 9.3 mg/kg, chestnut flour, guar gum, and xanthan gum as 100% commodities inhibited the ability of the assay to detect gluten when tested without dilution. In quaternary ammonium clean-in-place rinse and swabs from stainless steel, 100% positive results were obtained at levels of 2.8 mg/kg and 4.7 µg/100 cm2, respectively. Results of independent laboratory testing of swabs from stainless steel supported those of internal trials. Robustness testing showed that introducing variations to three operating parameters simultaneously had no adverse effect on assay performance. In the reagent stability study, data supported kit expiration dating of 11 months. CONCLUSION: Results of the current study show that the Reveal test is an accurate and reliable method for qualitative detection of gluten in select clean-in-place rinse and environmental samples. HIGHLIGHTS: The Reveal test was able to detect gluten at levels of 2.8 ppm in clean-in-place rinse and 4.7 µg/100 cm2 in swabs from stainless steel.

EZ Gluten for the qualitative detection of gluten in foods, beverages, and environmental surfaces.

The EZ Gluten assay is a rapid immunochromatographic screening method for qualitative detection of gluten in raw and cooked foods and beverages and on environmental surfaces. This AOAC Performance Tested Method study evaluated the EZ Gluten assay as an effective method for the detection of gluten in four selected matrixes: rice flour, cooked dough, beer, and dog food. In addition, the method was evaluated for its effectiveness in detecting gluten contamination of > or =1 microg/2 in.2 (25 cm2) stainless steel surface area. The EZ Gluten demonstrated 100% specificity [probability of detection (POD) 0.00, confidence interval (CI) 0.00-0.01] and 99% sensitivity (POD 0.99, CI 0.97-0.995) at the 10 ppm level for all four matrixes, and 100% specificity (POD 0.00, CI 0.00-0.11) and sensitivity (POD 1.00, CI 0.886-1.00) at the 1 microg level on the stainless steel surface. Independent laboratory testing confirmed the internal validation results in one matrix and on the stainless steel surface. Lot-to-lot, stability, and robustness studies provided evidence that the EZ Gluten is a rugged, consistent method for the detection of gluten at levels as low as 10 ppm.

Characterization of gliadin, secalin and hordein fractions using analytical techniques.

Prolamins, alcohol soluble storage proteins of the Triticeae tribe of Gramineae family, are known as gliadin, secalin and hordein in wheat, rye and barley respectively. Prolamins were extracted from fifteen cultivars using DuPont protocol to study their physiochemical, morphological and structural characteristics. SDS-PAGE of prolamins showed well resolved low molecular weight proteins with significant amount of albumin and globulin as cross-contaminant. The ß-sheet (32.72-37.41%) and ß-turn (30.36-37.91%) were found higher in gliadins, while α-helix (20.32-28.95%) and random coil (9.05-10.28%) in hordeins. The high colloidal stability as depicted by zeta-potential was observed in gliadins (23.5-27.0 mV) followed secalins (11.2-16.6 mV) and hordeins (4.1-7.8 mV). Surface morphology by SEM illustrated the globular particle arrangement in gliadins, sheet like arrangement in secalins and stacked flaky particle arrangement in hordeins fraction. TEM studies showed that secalin and hordein fractions were globular in shape while gliadins in addition to globular structure also possessed rod-shaped particle arrangement. XRD pattern of prolamin fractions showed the ordered crystalline domain at 2θ values of 44.1°, 37.8° and 10.4°. The extracted prolamins fractions showed amorphous as well as crystalline structures as revealed by XRD and TEM analysis. Space saving hexagonal molecular symmetry was also observed in TEM molecular arrangement of prolamins which has profound application in development of plant-based polymers and fibres.

Identification and characterization of high-molecular-weight secalins from triticale seeds by capillary zone electrophoresis.

A rapid and reliable method for separation and characterization of the variability of high-molecular-weight secalin subunits (HMW-SS) in hexaploid triticale (x Triticosecale Wittmack) by CZE has been developed. In this method, a mixture of two poly(ethylene oxide) polymers differing in molecular weight and a high concentration of ACN in isoelectric buffer was applied as the running electrolyte. For dynamic coating of the capillary inner wall, a low-concentration mixture of poly(vinylpyrrolidone) and hydroxypropylmethylcellulose was employed. Wide allelic variations in rye HMW-SS composition, including some novel x- and y-type HMW-SS, were detected by CZE. The CZE electropherograms of HMW-SS showed two groups of peaks in accordance with y- and x-type subunits, with migration times of 8.0-8.8 and 11.0-13.3 min, respectively. HMW-SS differed in migration times from the simultaneously resolved HMW glutenin subunits, but frequently had very similar electrophoretic mobilities during separation by SDS-PAGE. Each of the two rye subunits 2r and 6.5r detected by SDS-PAGE represents in fact two subunits (5.1r or 5.2r, and 6.4r or 6.5r, respectively). After analyzing 106 European triticale cultivars, 12 HMW-SS were identified (six x-type and six y-type). They form six allelic variants of these subunits. The simultaneous separation and identification of triticale HMW glutenin and secalin subunits by CZE is an efficient alternative to SDS-PAGE and should facilitate breeding of valuable cultivars.

Imaging and thermal studies of wheat gluten/poly(vinyl alcohol) and wheat gluten/thiolated poly(vinyl alcohol) blends.

The morphology of wheat protein (WG) blends with polyvinyl alcohol (PVA) and respectively with thiolated polyvinyl alcohol (TPVA) was investigated by atomic force (AFM) and transmission electron microscopy (TEM) as well as by modulated dynamic scanning calorimetry (MDSC). Thiolated additives based on PVA and other substrates were previously presented as effective means of improving the strength and toughness of compression molded native WG bars via disulfide-sulfhydryl exchange reactions. Consistent with our earlier results, AFM and TEM imaging clearly indicate that the addition of just a few mole percent of thiol to PVA was sufficient to dramatically change its compatibility with wheat protein. Thus, TPVA is much more compatible with WG and phase separates into much smaller domains than in the case of PVA, although there are still two phases in the blend: one WG-rich phase and another TPVA-rich phase. The WG/TPVA blend has phase domains ranging in size from 0.01 to 0.1 microm, which are roughly 10 times smaller than those of the WG/PVA blend. MDSC further illustrates the compatibilization of the protein with TPVA via the dependence of the transition temperatures on composition.

The Validation of the RIDA®QUICK Gliadin for AOAC Research Institute.

RIDA®QUICK Gliadin is an immuno-chromatographic test for the detection of gluten in foods, on surfaces, and in Cleaning-in-Place (CIP) waters. This test kit has been adopted as Final Action AOAC INTERNATIONAL Official Methods of AnalysisSM 2015.16 for gluten in corn products. The assay is based on the monoclonal antibody R5, which recognizes gluten in wheat, barley, and rye. Four different surfaces were contaminated with a gliadin material and analyzed by a direct swabbing of the surface with the dip-stick. The outcome was an LOD95% concentration of the assay between 1.6 and 3.0 µg/100 cm2 gluten. For CIP waters that contain cleansing reagents, 100% positive results were obtained for minimum gluten concentration between 50 and 100 ng/mL. If the CIP water does not contain these reagents, the minimum detectable gluten level is 10 ng/mL. The independent validation study consisted of a method comparison study of recovery from a CIP solution and from a stainless-steel surface. The test kit was evaluated at six different concentration levels for both matrices, with 20 or 30 replicates per concentration level. The probability of detection was calculated for each contamination level. Additionally, the LOD95% concentration was estimated for each matrix analyzed.

Microstructural, textural, and sensory properties of whole-wheat noodle modified by enzymes and emulsifiers.

With the utilization of enzymes including endoxylanase, glucose oxidase (GOX) and transglutaminase (TG), and emulsifiers comprising sodium stearoyl lactate (SSL) and soy lecithin, the microstructural, textural, and sensory properties of whole-wheat noodle (WWN) were modified. The development time and stability of whole-wheat dough (WWD) were enhanced by TG due to the formation of a more compact gluten network, and by SSL resulting from the enhanced gluten strength. Microstructure graphs by scanning electron microscopy (SEM) verified that TG and SSL promoted the connectivity of gluten network and the coverage of starch granules in WWN. TG increased the hardness and elasticity of cooked WWN, while two emulsifiers increased the noodle cohesiveness. Additionally, TG and SSL improved the sensory properties of noodle such as bite, springiness, and mouth-feel. The results suggest that TG and SSL are effective ingredients in enhancing the gluten strength of WWD and improving the qualities of WWN.

Composição química e aceitabilidade de pão sem glúten desenvolvido com mucilagem de quiabo / Chemical composition and acceptance of gluten-free bread developed with okra mucilage

Com objetivo de produzir pão sem glúten com composição química aprimorada e boa qualidade sensorial, foram elaboradas três formulações com diferentes quantidades de mucilagem de quiabo: (F0) 0 mL; (F1) 100 mL; (F2) 150mL. Determinou-se: rendimento da mucilagem, composição centesimal, valor calórico e atributos sensoriais dos pães por meio de escala hedônica. A mucilagem aumentou o rendimento das F1 e F2. Não houve diferença no teor de proteínas e o teor de lipídios de 7,9 g 100 g-1 (F1) e 6,0 g 100 g-1 (F2) foram inferiores ao da F0. A umidade da F1 (32,15 g 100 g-1) foi menor que nas demais formulações, enquanto cinzas (0,70 g 100 g-1), carboidrato (56,75 g 100 g-1) e valor calórico (308,1 kcal 100 g-1) foram superiores. No teste sensorial, todos os atributos foram avaliados nas categorias “gostei ligeiramente” e “gostei extremamente” pela maioria dos julgadores. A F1 obteve avaliações superiores às da F2 para textura, cor e impressão global e não diferiu em nenhum dos atributos na F0. Conclui-se que a F1 pode ser uma opção viável na busca de pão sem glúten com composição química aprimorada, por conter menor teor de lipídio e umidade, maior teor de cinzas e boa aceitação sensorial.

With the goal of producing gluten-free bread with improved chemical composition and good sensorial quality, three formulations were prepared with different amounts of okra mucilage: (F0) 0 mL; (F1) 100 mL; (F2) 150 mL. From this was determined: mucilage yield, centesimal composition, caloric value and sensory attributes of bread by hedonic scale. Mucilage increased the yield of F1 and F2. There was no difference in protein content and the lipid content of 7.9 g 100 g-1 (F1) and 6.0 g 100 g-1 (F2) were lower than that of F0. The moisture content of F1 (32.15 g 100 g-1) was lower than the other formulations, while ash (0.70 g 100 g-1), carbohydrate (56.75 g 100 g-1) and caloric value (308,1 kcal 100 g-1) were higher. In the sensory test, attributes were rated in the categories “liked slightly” and “liked extremely” by most judges. F1 scored higher than F2 for texture, color and overall impression and did not differ in any of the attributes at F0. It can be concluded that F1 may be a viable option in the search for gluten-free bread with improved chemical composition, as it contains lower lipid and moisture content, higher ash content and good sensory acceptance.

Sodium dodecyl sulfate capillary electrophoresis of wheat proteins. 1. Uncoated capillaries.

Four different polymer/buffer systems (a commercial polymer from Bio-Rad, dextran, poly(ethylene oxide) (PEO), and non-crosslinked poly(acrylamide)) were evaluated for use in sodium dodecyl sulfate capillary electrophoresis (SDS-CE) separations of wheat proteins. These polymers were chosen on the basis of published reports of their use in uncoated or dynamically coated capillaries. Each polymer was optimized (where possible) by manipulating the polymer concentration and buffer concentration, and through the use of organic modifiers such as methanol and ethylene glycol. The addition of ethylene glycol to the separation buffer was found to improve the resolution of the separations, despite dilution of the sieving polymers. When PEO was used as the sieving polymer, however, no improvement was seen when ethylene glycol was added. Despite producing similar separations of molecular mass markers, the polymers did not all produce similar wheat protein separations. The commercial reagent and dextran produced similar separations, while the poly(acrylamide) produced faster separations than either. The poly(acrylamide) displayed much lower resolution in the 40-60 kDa range than the other polymers, though this polymer was able to separate the high molecular mass glutenin subunits (HMM-GS) without the use of added organic solvent. PEO produced much different wheat protein separations than the other polymers, despite similar separations of the molecular weight markers. This may have been due to interaction between the wheat proteins and PEO. Each polymer system also predicted different molecular masses of the various wheat protein fractions separated, with the PEO and poly(acrylamide) grossly overestimating the masses for all protein classes. This could have been due to protein-polymer interactions. Further work was done with the Bio-Rad buffer modified by the addition of ethylene glycol. Several different wheat protein fractions as well as proteins extracted from several different cultivars were separated with this buffer and compared. SDS-CE separations were also compared to SDS-poly(acrylamide) gel electrophoresis (PAGE) and several differences in the migration pattern of HMM-GS were noted.

Effect of pentosanase and oxidases on the characteristics of doughs and the glutenin macropolymer (GMP).

Rheological characteristics of dough and glutenin macropolymer (GMP) extracted thereof were investigated. Three single enzymes, pentosanase (PP), glucoseoxidase (GLZ), and laccase (LAC), and their combinations were used. GLZ gave the least extensible and most resistant dough, and pentosanase/glucoseoxidase (PPGLZ) resulted in dough with improved extensibility. The enzymes improved gluten quality. The glutenin macropolymer (GMP) was characterized in terms of wet weight, protein content, pentosan association, and dynamic rheological properties. Enzymatic addition decreased the wet weight of GMP but increased the protein content. PP decreased the content of pentosans on the GMP, but single oxidases increased the content of pentosans associated with GMP. PP did not modify the elastic modulus (G') of the GMP, whereas GLZ increased G' by increasing the polymerization of proteins and LAC diminished G'. The combination PPGLZ produced a synergic increase of G'.

Physical and molecular changes during the storage of gluten-free rice and oat bread.

Gluten-free bread crumb generally firms more rapidly than regular wheat bread crumb. We here combined differential scanning calorimetry (DSC), texture analysis, and time-domain proton nuclear magnetic resonance (TD (1)H NMR) to investigate the mechanisms underlying firming of gluten-free rice and oat bread. The molecular mobility of water and biopolymers in flour/water model systems and changes thereof after heating and subsequent cooling to room temperature were investigated as a basis for underpinning the interpretation of TD (1)H NMR profiles of fresh crumb. The proton distributions of wheat and rice flour/water model systems were comparable, while that of oat flour/water samples showed less resolved peaks and an additional population at higher T2 relaxation times representing lipid protons. No significant crumb moisture loss during storage was observed for the gluten-free bread loaves. Crumb firming was mainly caused by amylopectin retrogradation and water redistribution within bread crumb. DSC, texture, and TD (1)H NMR data correlated well and showed that starch retrogradation and crumb firming are much more pronounced in rice flour bread than in oat flour bread.

Sensitive detection and quantification of gliadin contamination in gluten-free food with immunomagnetic beads based liposomal fluorescence immunoassay.

Gliadin from wheat is a common food allergen that can induce baker's asthma, wheat-dependent exercise-induced anaphylaxis, atopic dermatitis, and celiac disease. This gliadin assay focuses on rapidly screen and check for gluten contamination in raw materials and in the gluten-free food production process, not only for wheat-sensitive patients but also for the industries producing gluten-free foodstuffs. The developed assay incorporates the use of anti-gliadin antibody-conjugated immunomagnetic beads (IMBs) to capture the gliadin in samples and fluorescent dyes-loaded immunoliposomal nanovesicles (IMLNs) to produce and enhance the detection signal. Hence, a sandwich complex is formed as "IMBs-gliadin-IMLNs". Experimental results indicate that this detection platform exhibits good sensitivity for gliadin with a detection limit as low as 0.6 µg mL(-1) of gliadin; as the polyclonal antibody showed slight cross-reactions with barley and rye. Excellent recovery rates were found ranging from 83.5 to 102.6% as testing the spiked samples. Moreover, the CV (%) of intra- and inter-assay of this developed assay are 4.8-10.6% and 3.5-9.9%, respectively. Based on a parallel analysis of twenty food samples, the results of this developed assay provide a good consistency with those of an AOAC-approved ELISA kit without any false-negative results. The proposed assay method is thus a highly promising alternative method for detecting the contamination of gliadin in the food industry.

[Effects of irrigation scheme on the grain glutenin macropolymer's size distribution and the grain quality of winter wheat with strong gluten].

Taking two winter wheat (Triticum aestivum L.) cultivars (Gaocheng 8901 and Jimai 20) with high quality strong gluten as test materials, a 2-year field experiment was conducted to study the grain glutenin macropolymer (GMP)'s content and size distribution, grain quality, and grain yield under effects of different irrigation schemes. The schemes included no irrigation in whole growth period (W0), irrigation once at jointing stage (W1), irrigation two times at wintering and jointing stages (W2), respectively, and irrigation three times at wintering, jointing, and filling stages (W3), respectively, with the irrigation amount in each time being 675 m3 x hm(-2). Among the test irrigation schemes, W2 had the best effects on the dough development time, dough stability time, loaf volume, grain yield, GMP content, weighted average surface area of particle D(3,2), weighted average volume of particle D(4,3), and volume percent and surface area percent of particle size >100 microm of the two cultivars. The dough development time, dough stability time, and loaf volume were negatively correlated with the volume percent of GMP particle size <10 microm and 10-100 microm, while positively correlated with the volume percent of GMP particle size >100 microm, D(3,2), and D(4,3). It was suggested that both water deficit and water excess had detrimental effects on the grain yield and grain quality, and irrigation level could affect the wheat grain quality through altering GMP particle size distribution.