Microbiological quality of gluten-free meals, naturally gluten free foods, and gluten free-labelled products.

Background: The rising prevalence of gluten-related disorders such as celiac disease explains the increased consumption of gluten-free foods (GFF). However, these foods must be safe in terms of both gluten content and contamination by pathogenic microorganisms in order to avoid food poisoning. Objective: The objective of this study was to assess the microbiological quality of gluten-free meals, naturally gluten free foods, and gluten free-labelled products. Material and Methods: We collected 62 GFF samples including 20 meals (M-GF), 22 naturally gluten free (N-GFF) and 20 labelled (L-GFF) products, which were investigated for microbiological contamination according to Moroccan regulations guidelines, issued by the International Organization for Standardization (ISO). The analysis consisted of the detection of Salmonella and Listeria monocytogenes in each sample, and the quantification of the microbial load of the following six micro-organisms: total aerobic mesophilic flora, total coliforms, fecal coliforms, Staphylococcus aureus, Sulphite-Reducing Anaerobic, and yeasts and molds. Results: A total of 372 analyses were carried out, showing a microbiological contamination rate of 5.1%. This contamination concerned N-GFF in 8.3% (predominantly with yeasts and molds), and meals prepared at home in 11.7 (predominantly with Staphylococcus aureus and coliforms). Only one case (0.8%) of contamination was observed in products labelled gluten-free and no contamination was noticed in meals prepared in food services. Listeria monocytgenes and Salmonella were not detected in any samples of food analyzed. These results indicate a good compliance of L-GFP and M-GF prepared in food services, while unsatisfactory quality was observed in N-GFF and M-GF prepared at home. Conclusion: Therefore, rigorous hygienic practices and adequate corrective measures should be considered by celiac patients, especially regarding the N-GFF and M-GF prepared at home.

Evaluation of Gluten Protein Profiles in Hydrolyzed Food Products by a Multiplex-Competitive Enzyme-Linked Immunosorbent Assay.

The apparent gluten concentration profiles of 47 hydrolyzed foods (barley malt, sprouted grains, and hydrolyzed wheat proteins (HWP)) were evaluated using a multiplex-competitive ELISA that utilizes the G12, R5, 2D4, MIoBS, and Skerritt antibodies from commercial sources. Cluster analysis was conducted to evaluate similarities or differences in the gluten protein/peptide response profiles among the hydrolyzed foods and their similarities or differences with fermented foods analyzed previously by the ELISA. The gluten protein/peptide response profiles of the hydrolyzed foods mainly depended on the grain source (wheat, rye, or barley) of gluten. Some hydrolyzed foods presented profiles similar to those of certain fermented foods (e.g., barley malt and gluten reduced barley beers), whereas others presented unique profiles (e.g., HWP and sprouted wheat). Additional analysis using wheat gluten-incurred yogurts indicated that while not suitable for the barley- or rye-containing foods tested, a newly developed gluten-incurred yogurt calibrant shows promise for the possible use in the quantitation of several wheat-containing fermented and hydrolyzed foods.

Performance assessment of a new G12/A1 antibody-based rapid ELISA using commercially available and gluten-spiked food samples.

OBJECTIVE: Food products with <20 mg/kg gluten can be labeled 'gluten-free' according to international regulations. Several antibodies-based ELISAs have been develop to track gluten traces in food products. Among them, R5 and G12 antibody-based ELISAs are the frequently used methods. However, these antibodies have certain limitations. We evaluated the accuracy of G12/A1 antibody-based 'Glutentox ELISA Rapid G12' and compared the results with the current reference method i.e., R5 antibody-based 'Ridascreen R5 ELISA'. METHODS: In the first step, the performance of Glutentox ELISA Rapid G12 kit was inspected by determination of the threshold value i.e., > or <20 mg/kg gluten in different food products. In the second step, quantification accuracy was assessed by quantification of gluten in gluten-free food products spiked with gliadin reference material. RESULTS: In total 47 food products (naturally and labeled gluten-free, and food with traces of gluten) were included. Of them, 29 products were quantified with <20 mg/kg, and 18 with a low level of gluten by both the kits. Six out of 29 gluten-free products were used for the recovery test at different spike levels. Gluten concentration and mean recovery rates of individual kits showed consistency. CONCLUSION: GlutenTox Rapid G12 ELISA could be an appropriate choice for detecting gluten in food products but needs more in-house validation and collaborative tests.

Assessment of green lentil malt as a substrate for gluten-free beer brewing.

The aim of this study was to analyze whether it is possible to brew beer without using cereals so that the produced beverage could be easily accessible for the population suffering from celiac disease and other gluten-related disorders. Green lentil seeds were malted and then mashed using a congress mashing procedure to assess their advantages and disadvantages in the brewing process. Based on the congress mashing procedure, the mashing process needed to produce beer was developed, and beers were produced from the lentil malts germinated during malting for 96 h, 120 h and 144 h. It was possible to produce beers from the lentil malts; however, they were characterized by a lower alcohol content, lower degree of attenuation and some discrepancies between the concentrations of various volatiles (such as acetaldehyde, ethyl acetate, and 1-propanol) compared to the control beer produced from barley malt.

Production of the prolyl endoprotease (PEP) from Aspergillus sp. FSDE 16 by solid-state fermentation (SSF) and use for producing a gluten-free beer.

Beer is a beverage that contains gluten and cannot be consumed by people with celiac disease. In this context, the enzyme prolyl endoprotease (PEP) can be used to reduce the gluten content in beer. The present study aimed to produce the PEP from Aspergillus sp. FSDE 16 using solid-state fermentation with 5 conditions and comparing with a similar commercial enzyme produced from Aspergillus niger in the production of a gluten-free beer. The results of the performed cultures showed that during the culture, the most increased protease activity (54.46 U/mL) occurred on the 4th day. In contrast, for PEP, the highest activity (0.0356 U/mL) was obtained on the 3rd day of culture in condition. Regarding beer production, cell growth, pH, and total soluble solids showed similar behavior over the 7 days for beers produced without enzyme addition or with the addition of commercial enzyme and with the addition of the enzyme extract produced. The addition of the enzyme and the enzyme extract did not promote changes, and all the beers produced showed similar and satisfactory results, with acid pH between 4 and 5, total soluble solids ranging from 4.80 to 5.05, alcohol content ranging from 2.83% to 3.08%, and all beers having a dark character with deep amber and light copper color. Gluten removal was effectively using the commercial enzyme and the enzyme produced according to condition (v) reaching gluten concentrations equal to 17 ± 5.31 and 21.19 ± 11.28 ppm, respectively. In this way, the production of the enzyme by SSF and its application in the removal of gluten in beer was efficient.

Proteins from Blackberry Seeds: Extraction, Osborne Isolate, Characteristics, Functional Properties, and Bioactivities.

Blackberry fruit contains high levels of nutrients and phenolic compounds. Blackberry pomace accounts for 20~30% of its whole fruit during processing and is generally treated as fertilizer. Blackberry pomace has many seeds that contain carbohydrates, polyphenols, flavonoids, pectin, protein, and other bioactive nutrients. However, its functional properties and seed protein compositions have not been reported. We used a single-factor experiment, response surface, and Osborne isolate method to extract protein isolate, albumin, globulin, glutelin, and prolamin from blackberry seeds for the first time and evaluated their characteristics and functional properties. Glutelin and protein isolate showed good water-holding capacity, emulsification, and foaming capacity, while albumin and globulin showed good oil-holding capacity and thermal stability. They were found to have good antioxidant activities that might be good DPPH free radical scavengers, especially prolamin, which has the lowest IC50 value (15.76 µg/mL). Moreover, globulin had the lowest IC50 value of 5.03 µg/mL against Hela cells, 31.82 µg/mL against HepG2 cells, and 77.81 µg/mL against MCF-7 cells and a high selectivity index (SI), which suggested globulin had better anti-cervical, antihepatoma, and anti-breast activity but relatively low cytotoxicity. These seed proteins may have great prospects for the development and application of food and drugs in the future.

Consumer-Led Investigation into Potential Issues That Arise When Testing Dairy Matrixes for Gluten With the NIMA Sensor.

BACKGROUND: Some consumers with celiac disease use personal, point-of-use gluten detection devices to test food. False-positive results may occur due to sampling, matrix effects, and sensor issues. OBJECTIVE: The purpose of the present study was to determine if the positive gluten results some users were obtaining when testing cream cheese and materials of similar consistency were false positives and, if so, what might be causing them to occur. METHODS: Cream cheese, soft cheese, and yogurt were tested for gluten using the Ridascreen Gliadin R7001 sandwich R5 ELISA and the Ridascreen Gliadin R7021 competitive R5 ELISA. Two test portions were taken, extracted, and tested from each homogenized material. Materials were also analyzed for gluten using a NIMA sensor, a personal, point-of-use gluten detection device. Multiple test portion weights were tested beginning at 0.13 to 0.17 g (the ideal weight of the test portion according to the NIMA sensor development team). RESULTS: Using the sandwich R5 ELISA and the competitive R5 ELISA, all materials tested below the lower LOD for gluten. Using a NIMA sensor, as the weight of the test portion tested increased, sensor results went from no gluten found, to gluten found, to no test result. CONCLUSION: The gluten found results using the NIMA sensor are likely false positives that appear to correspond with the weight and volume of the material tested, as well as the viscosity. There is also an apparent disconnect between the gluten found result reported by the sensor and an interpretation of the lateral flow device (LFD) strip result when assessed by eye which should also be taken into account. Ideally, NIMA sensor users should be advised on the weight amount of material to analyze and test portions should be weighed before being used with the NIMA sensor. However, this is not a practical solution when testing in many environments, including restaurants. HIGHLIGHTS: Slight variations in weight and volume of test materials can result in false positive results when testing dairy matrixes for gluten using the Nima sensor.

Validation of the GlutenTox® ELISA Rapid G12 Test Kit for Determination of Gluten in Select Non-Heat-Processed Matrixes and Heat-Processed Matrixes: AOAC Performance Tested MethodSM 042301.

BACKGROUND: The GlutenTox® ELISA Rapid G12 test kit is a quantitative method designed for the determination of the immunotoxic fraction of gluten in food samples. OBJECTIVE: To obtain AOAC Performance-Tested MethodsSM certification for the method for the detection and quantification of gluten from wheat, barley, and rye flours in select foods (non-heat-processed) and incurred (heat-processed) matrixes. METHODS: The method was evaluated following the Guidelines for Validation of Quantitative Gluten Methods, with Specific Examples for ELISA Assays. The validation study was conducted at Hygiena Diagnóstica España using five food matrixes (soy flour, corn bread, seasoning mix, rolled oats, and evaporated milk) artificially contaminated with gluten from wheat, barley, or rye flour at different concentrations: 0, 5, 10, and 20 mg/kg. For each matrix and gluten contamination level, five or six individually extracted test portions were analyzed. A second bread matrix was prepared by baking a gluten-free bread mix spiked at 0, 20, and 30 mg/kg gluten from wheat, barley, or rye flour for incurred matrix testing. Ten individually extracted test portions were tested for each incurred bread and contamination level of gluten. RESULTS: The method met the AOAC performance requirements for detection and quantification of wheat gluten in the selected food matrixes, incurred bread sample, and spike levels of wheat gluten, showing an acceptable recovery. When tested with barley and rye flours, most of the results showed acceptable recoveries or a slight overestimation, depending on the matrix and gluten concentration. Method developer and independent laboratory results were comparable. CONCLUSIONS: The validation study demonstrated that the test kit is a reliable, accurate, quick, and easy-to-use method for the detection and quantification of gluten concentration in food and incurred matrixes from wheat, barley, and rye flours. HIGHLIGHTS: Most reagents provided in the kit are at ready-to-use concentrations.

Evaluation of the Usefulness of an Automatable Immunoassay for Monitoring Celiac Disease by Quantification of Immunogenic Gluten Peptides in Urine.

A gluten-free diet (GFD) is currently the only treatment available for patients with celiac disease (CD). However, adherence to a GFD can be challenging because gluten is present in many foods. A lifelong follow-up of patients with CD must be performed to promote adherence to a GFD and to identify the appearance of symptoms and the associated diseases. Therefore, the development of tools to analyze gluten exposure in these patients is important. This study proposes the development of the first automatable ELISA to monitor adherence to a GFD through the quantification of urine gluten immunogenic peptides (u-GIP). Seven healthy volunteers without suspicion of CD and 23 patients with CD were monitored as part of this study to optimize, validate, and apply this assay. Non-interference was found in the urine matrix, and the recovery percentage for spiked samples was 81-101%. The u-GIP was stable for up to 16 days when the samples were stored at different temperatures. Overall, 100% of the patients had detectable u-GIP at diagnosis (range of 0.39-2.14 ng GIP/mL), which reduced to 27% after 12 months on a GFD. Therefore, this highly sensitive immunoassay would allow the analysis of u-GIP from a large battery of samples in clinical laboratories of specialized healthcare centers.

Effect of fermentation methods on properties of dough and whole wheat bread.

BACKGROUND: Whole wheat bread is high in nutritional value but poor in technological quality; therefore, research on how to improve its technological quality has attracted extensive attention. The effects of fermentation methods, including straight dough(STD), sourdough (SOD), sponge dough (SPD), and refrigerated SPD (RSD) methods, on the dough and bread quality of whole wheat bread were investigated, focusing on pasting properties, rheological properties, thermal properties, microstructure, basic quality, and starch digestibility. RESULTS: The rapid viscosity analysis and rheological results demonstrated that SOD had the highest pasting temperature and the lowest viscosity, indicating an inhibition of starch pasting and partial protein hydrolysis, whereas the opposite trend presented by SPD and RSD indicated a greater starch hydration and a stronger gluten network. Thermal gravimetric analysis and differential scanning calorimetry results indicated reduced starch thermal degradation and increased starch pasting enthalpy in SOD and RSD. Scanning electron microscopy images revealed that the starch granules of SOD and RSD were tightly wrapped by a gluten network. SOD and RSD breads had the largest specific volume, the softest texture, and the lowest glycemic index. CONCLUSION: The effects of different fermentation methods on dough and bread structure can provide instructive information for future studies on their applications in whole wheat bread production. © 2023 Society of Chemical Industry.

Clinical utility of urinary gluten immunogenic peptides in the follow-up of patients with coeliac disease.

BACKGROUND: Gluten-free diet (GFD) is the only treatment for patients with coeliac disease (CD) and its compliance should be monitored to avoid cumulative damage. AIMS: To analyse gluten exposures of coeliac patients on GFD for at least 24 months using different monitoring tools and its impact on duodenal histology at 12-month follow-up and evaluate the interval of determination of urinary gluten immunogenic peptides (u-GIP) for the monitoring of GFD adherence. METHODS: Ninety-four patients with CD on a GFD for at least 24 months were prospectively included. Symptoms, serology, CDAT questionnaire, and u-GIP (three samples/visit) were analysed at inclusion, 3, 6, and 12 months. Duodenal biopsy was performed at inclusion and 12 months. RESULTS: At inclusion, 25.8% presented duodenal mucosal damage; at 12 months, this percentage reduced by half. This histological improvement was indicated by a reduction in u-GIP but did not correlate with the remaining tools. The determination of u-GIP detected a higher number of transgressions than serology, regardless of histological evolution type. The presence of >4 u-GIP-positive samples out of 12 collected during 12 months predicted histological lesion with a specificity of 93%. Most patients (94%) with negative u-GIP in ≥2 follow-up visits showed the absence of histological lesions (p < 0.05). CONCLUSION: This study suggests that the frequency of recurrent gluten exposures, according to serial determination of u-GIP, could be related to the persistence of villous atrophy and that a more regular follow-up every 6 months, instead of annually, provides more useful data about the adequate adherence to GFD and mucosal healing.

Evaluation of high-protein diets differing in protein source in healthy adult dogs.

Given the dynamic market for protein-based ingredients in the pet food industry, demand continues to increase for both plant- and animal-based options. Protein sources contain different amino acid (AA) profiles and vary in digestibility, affecting protein quality. The objective of this study was to evaluate the apparent total tract digestibility (ATTD) of canine diets differing in protein source and test their effects on serum metabolites and fecal characteristics, metabolites, and microbiota of healthy adult dogs consuming them. Four extruded diets were formulated to be isonitrogenous and meet the nutrient needs for adult dogs at maintenance, with the primary difference being protein source: 1) fresh deboned, dried, and spray-dried chicken (DC), 2) chicken by-product meal (CBPM), 3) wheat gluten meal (WGM), and 4) corn gluten meal (CGM). Twelve adult spayed female beagles (body weight [BW] = 9.9 ± 1.0 kg; age = 6.3 ± 1.1 yr) were used in a replicated 4 × 4 Latin square design (n = 12/treatment). Each period consisted of a 22-d adaptation phase, 5 d for fecal collection, and 1 d for blood collection. Fecal microbiota data were analyzed using QIIME 2.2020.8. All other data were analyzed using the Mixed Models procedure of SAS version 9.4. Fecal scores were higher (P < 0.05; looser stools) in dogs fed DC or CBPM than those fed WGM or CGM, but all remained within an appropriate range. Dry matter ATTD was lower (P < 0.05) in dogs fed CBPM or CGM than those fed DC or WGM. Crude protein ATTD was lower (P < 0.05) in dogs fed DC or CGM than those fed WGM. Dogs fed CBPM had lower (P < 0.05) organic matter, crude protein, and energy ATTD than those fed the other diets. Fecal indole was higher (P < 0.05) in dogs fed CBPM than those fed WGM. Fecal short-chain fatty acids were higher (P < 0.05) in dogs fed DC than those fed CGM. Fecal branched-chain fatty acids were higher (P < 0.05) in dogs fed DC or CBPM than those fed WGM. Fecal ammonia was higher (P < 0.05) in dogs fed DC or CBPM than those fed WGM or CGM. The relative abundances of three bacterial phyla and nine bacterial genera were shifted among treatment groups (P < 0.05). Considering AA profiles and digestibility data, the DC diet protein sources provided the highest quality protein without additional AA supplementation, but the animal-based protein diets resulted in higher fecal proteolytic metabolites. Further studies evaluating moderate dietary protein concentrations are needed to better compare plant- and animal-based protein sources.

Pet food trends are constantly changing. Because consumers are often focused on dietary proteins, with ingredient sources, dietary inclusion levels, and processing methods being important, they are a popular research topic. Protein sources contain different amino acid (AA) profiles and vary in digestibility, affecting protein quality. Our objective was to evaluate the apparent total tract digestibility of canine diets differing in protein source and test their effects on serum metabolites and fecal characteristics, metabolites, and microbiota of healthy adult dogs. Test diets were formulated to be similar nutritionally, but differed in protein source: fresh deboned, dried, and spray-dried chicken (DC), chicken by-product meal (CBPM), wheat gluten meal (WGM), and corn gluten meal (CGM). Fecal scores were higher in dogs fed chicken-based diets, but remained within an appropriate range. Dogs fed CBPM had lower nutrient and energy digestibilities than those fed the other diets, with protein digestibility also being lower in dogs fed DC or CGM than those fed WGM. Fecal metabolites and microbiota were shifted among diets, with animal-based protein diets increasing fecal protein metabolites. All diets were complete and balanced and performed well. When considering AA profiles and digestibility, however, the DC diet provided the highest protein quality.

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.

Simple detection of gluten in wheat-containing food samples of celiac diets with a novel fluorescent nanosensor made of folic acid-based carbon dots through molecularly imprinted technique.

A nanosensor is designed for rapid detection of the gluten content of wheat-containing samples. Gluten is a plant protein that causes allergy in individuals and leads to celiac disease. Since in a celiac diet trace amounts of gluten are able to prompt allergic reactions, a food-allergen label must be provided on foodstuffs and be seriously considered by food industries. Various analytical methods and commercial immunoassays are used for such analyses but prices per test, especially for low-income countries are high. Thus, a rapid, sensitive, simple, and inexpensive detecting tool seems essential. A solution can be designing a gluten optical nanosensor. The nanosensor is made of folic-acid-carbon dots and gluten molecularly templates embedded simultaneously in a silicate matrix. Adding gluten to the solution of this nanostructure and its adsorbing on the blank templated space on the nanostructure causes fluorescence enhancement. The concentration range of gluten detection was 0.36 to 2.20 µM.

Nutritional facts regarding commercially available gluten-free bread worldwide: Recent advances and future challenges.

Recently, there has been an increase in demand for gluten-free (GF) products due to the growing number of gluten-intolerant and healthy individuals choosing to follow a gluten-free diet. Gluten-free bread (GFB) is a staple food product; therefore, many recent studies have reported the nutritional properties of GFB. However, an overview of the current ingredients and nutritional labeling of GFB worldwide has not yet been provided. This review aimed to gather the latest information regarding the most used ingredients in GFB formulations and the nutritional quality of these products from different countries, based on studies published in the last decade (2010-2020). Our analysis showed that GFB had a lower protein and a higher fat content than gluten-containing bread, and the dietary fiber content was highly variable between countries. Some studies have revealed a high glycaemic index in most products, which is associated with the extensive use of rice flour and starch as the main ingredients in GFB formulation. Label information presented significant differences from the data obtained through the chemical analysis of fiber and other nutritional components. Micronutrient fortification is not common in the GFB. The nutritional quality of commercial GFB is a crucial issue that needs to be addressed.

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.

Characterization of rye flours and their potential as reference material for gluten analysis.

The safety of gluten-free products relies on accurate gluten analysis, most commonly using ELISA. These test kits are calibrated to gliadins or wheat gluten, because there is no reference material (RM) for rye. Our aim was to select representative samples out of 32 rye cultivars for use as RM. All cultivars were characterized by RP-HPLC, gel permeation HPLC and R5 and G12 ELISA. The protein and gluten content ranged from 5.5 to 11.2 g/100 g and 3.0 to 7.8 g/100 g, respectively. The average protein distribution was 40% albumins/globulins, 23% γ-75k-secalins, 17% γ-40k-secalins, 14% ω-secalins and 6% high-molecular-weight-secalins. The mean prolamin/glutelin ratio was 4.4 for rye and this translates to an estimated conversion factor from rye prolamins to gluten of 1.2, instead of the usual factor of 2. Seven cultivars were selected for RM production based on cluster analysis, geographical origin and availability to comprehensively cover the diversity of rye.

A chromatographic and immunoprofiling approach to optimising workflows for extraction of gluten proteins from flour.

Ingestion of gluten proteins from wheat, and related prolamin proteins from barley, rye, and oats, can cause adverse reactions in individuals with coeliac disease and IgE-mediated allergies. As there is currently no cure for these conditions, patients must practice avoidance of gluten-containing foods. In order to support patients in making safe food choices, foods making a "gluten-free" claim must contain no more than 20 mg/Kg of gluten. Mass spectrometry methods have the potential to provide an alternative method for confirmatory analysis of gluten that is complementary to analysis currently undertaken by immunoassay. As part of the development of such methodology the effectiveness of two different extraction procedures was investigated using wholemeal wheat flour before and after defatting with water-saturated butan-1-ol. A single step extraction with 50 % (v/v) propan-2-ol containing 2 M urea and reducing agent (buffer 1) was compared with a two-step extraction using 60 % (v/v) aqueous ethanol (buffer 2) followed by re-extraction of the pellet using buffer 1, using either wheel mixing under ambient conditions (19 °C) or sonication at 60 °C. The procedures were compared based on total protein extraction efficiency and the composition of the extracts determined using a combination of HPLC, SDS-PAGE and immunoblotting with a panel of four gluten-specific monoclonal antibodies. Defatting generally had a detrimental effect on extraction efficiency and sonication at 60 °C only improved extraction efficiency with buffer 2. Although the single-step and two-step procedures were equally effective at extracting protein from the samples, analysis of extracts showed that the two-step method gave a more complete extraction of gluten proteins. Future studies will compare the effectiveness of these procedures when applied in the sample workflows for mass spectrometry based methods for determination of gluten in food.

Antioxidant Properties of Gluten-Free Pasta Enriched with Vegetable By-Products.

The only therapy for coeliac disease patients is to completely avoid foods containing gluten, a protein complex common in several small-grain cereals. However, many alternative gluten-free foods available on the market present nutritional deficiencies. Therefore, the aim of this research was to evaluate the composition and the antioxidant properties of gluten-free pasta enriched with 10% or 15% of tomato waste or linseed meal, two food industry by-products. The traits analysed were protein, lipid, ash and fibre content, heat damage, tocols, carotenoids and phenolics composition (by HPLC), antioxidant capacity, and pasta fracturability. The enriched pastas contained more fibre and lipids than the control, while the protein and ash values were similar. The addition of tomato and linseed waste improved tocols concentration but had no effect on carotenoids content. The free soluble polyphenols increase was similar for both by-products and proportional to the enrichment percentage, while the bound insoluble polyphenols were higher in linseed-enriched pastas. The samples with linseed meal showed the greatest antioxidant capacity and, at 10% addition, the highest fracturability value. In conclusion, the addition of tomato and linseed by-products significantly increases the presence of bioactive compounds (particularly polyphenols), improving the nutritional value of gluten-free pasta.

Safety Assessment of Foods and Drinks Consumed by People on a Gluten-Free Diet.

Naturally gluten-free foods and processed foods that do not contain information about the potential presence of gluten in them pose a hypothetical threat to people with food allergies and celiac disease. Patients who should follow a strict gluten-free diet do not always do so. Therefore, the aim of this research was to analyze certified "gluten-free" and naturally gluten-free products without labeled "may contain gluten" information in terms of their content of gluten proteins. The enzyme immunoassay AgraQuant Gluten G12 ELISA test kit was used for the analysis. Of all the products used in the research, only 5.8% were found to contain gluten above 20 ppm. Only one product labeled "gluten-free" was contaminated with gluten at 79.3 ppm (cider cake). In addition, our research also examined the gluten content of commercial beers containing barley malt not labeled as "gluten-free". Research has shown that 60% of samples are not safe for those on a strict gluten-free diet. Our research clearly shows that many manufacturers, although they do not monitor their products for the presence of gluten in them, offer safe products, although they cannot be recommended in a gluten-free diet. Therefore, there is a strong need to increase the frequency of testing by food manufacturers for the presence of gluten in their products, so that the number of products approved for people on a gluten-free diet continues to increase.