Multiplex-Competitive ELISA for Detection and Characterization of Gluten during Yogurt Fermentation: Effects of Changes in Certain Fermentation Conditions on Gluten Protein Profiles and Method Reproducibility Assessment.

The protein/peptide profiles of gluten during yogurt fermentation were evaluated using an optimized multiplex-competitive ELISA by preparing yogurts incurred with gluten at different concentrations and by varying certain fermentation conditions. Analysis indicated that epitope-specific responses with antibody binding to glutenin epitopes decreased less during longer fermentation times or at higher starter culture concentrations relative to gliadins. Incomplete proteolysis was observed after 24 h of fermentation, which became more efficient as fermentation time was increased. Western blot confirmed the results of ELISA. Cluster analysis indicated that out of the investigated parameters, fermentation time is the only parameter that could affect the overall gluten protein/peptide profiles during yogurt fermentation. This parameter needs consideration in evaluating the suitability of calibrant(s) to be used with the multiplex-competitive ELISA or any other methods to ensure accurate quantitation of gluten in yogurts and potentially in other foods with similar fermentation chemistry. A small-scale multilaboratory evaluation indicated that the multiplex-competitive ELISA has good analytical reproducibility (average interlaboratory % CV of 28-41%).

Multi-criteria assessment of pea protein quality in rats: a comparison between casein, gluten and pea protein alone or supplemented with methionine.

The objective of this study was to assess the nutritional quality of pea protein isolate in rats and to evaluate the impact of methionine (Met) supplementation. Several protein diets were studied: pea protein, casein, gluten, pea protein-gluten combination and pea protein supplemented with Met. Study 1: Young male Wistar rats (n 8/group) were fed the test diets ad libitum for 28 d. The protein efficiency ratio (PER) was measured. Study 2: Adult male Wistar rats (n 9/group) were fed the test diets for 10 d. A protein-free diet group was used to determine endogenous losses of N. The rats were placed in metabolism cages for 3 d to assess N balance, true faecal N digestibility and to calculate the Protein Digestible-Corrected Amino Acid Score (PDCAAS). They were then given a calibrated meal and euthanised 6 h later for collection of digestive contents. The true caecal amino acid (AA) digestibility was determined, and the Digestible Indispensable Amino Acid Score (DIAAS) was calculated. Met supplementation increased the PER of pea protein (2·52 v. 1·14, P < 0·001) up to the PER of casein (2·55). Mean true caecal AA digestibility was 94 % for pea protein. The DIAAS was 0·88 for pea protein and 1·10 with Met supplementation, 1·29 for casein and 0·25 for gluten. Pea protein was highly digestible in rats under our experimental conditions, and Met supplementation enabled generation of a mixture that had a protein quality that was not different from that of casein.

Wheat flour based propionic acid fermentation: an economic approach.

A process for the fermentative production of propionic acid from whole wheat flour using starch and gluten as nutrients is presented. Hydrolysis of wheat flour starch using amylases was optimized. A batch fermentation of hydrolysate supplemented with various nitrogen sources using Propionibacterium acidipropionici NRRL B 3569 was performed. The maximum production of 48.61, 9.40, and 11.06 g of propionic acid, acetic acid and succinic acid, respectively, was found with wheat flour hydrolysate equivalent to 90 g/l glucose and supplemented with 15 g/l yeast extract. Further, replacement of yeast extract with wheat gluten hydrolysate showed utilization of gluten hydrolysate without compromising the yields and also improving the economics of the process. The process so developed could be useful for production of animal feed from whole wheat with in situ production of preservatives, and also suggest utilization of sprouted or germinated wheat for the production of organic acids.

Celiac disease: epidemiology, pathogenesis, diagnosis, and nutritional management.

Celiac disease (CD) is an inflammatory small intestinal disorder that can lead to severe villous atrophy, malabsorption, and malignancy. It is triggered by the gluten proteins of wheat, barley, and rye. All patients express the antigen-presenting molecules human leukocyte antigen-DQ2 (HLA-DQ2) and/or HLA-DQ8, which bind gluten peptides and thus activate destructive intestinal T cells. Patients with untreated CD have circulating IgA autoantibodies to the enzyme tissue transglutaminase (tTG), a component of endomysium. Testing for serum IgA tTG has a high predictive value. Therapy of CD is a lifelong gluten-free diet. Counseling by an expert dietitian and association with a celiac support group are important in helping the patient embark on a healthy gluten-free diet. Current research focuses on non-dietary therapies and treatment of refractory (diet-unresponsive) CD.

In vitro assessment of acetic-acid-soluble proteins (glutenin) toxicity in celiac disease.

Acetic-acid-soluble storage proteins from gluten of the bread wheat cv. Sprint 3 were fractionated by adsorption chromatography on 2000 A controlled-pore glass (CPG) beads, and glutenin polymers with molecular mass higher than 10(7) Da and free from monomeric gliadins were recovered. The glutenin polymers were found to consist of high-molecular-weight (HMW) and low-molecular-weight (LMW) glutenin subunits. Peptic-tryptic (PT) digests of glutenins were examined for their agglutination activity on human myelogenous leukemia K 562(S) cells, agglutination being strongly correlated with toxicity for the celiac intestine. The peptide fraction at a concentration of 1 g/L of culture medium was able to agglutinate 30% of K 562(S) cells, suggesting a moderate toxic effect. This toxicity may be accounted for by homologies in amino acid sequences between glutenin subunits and alpha/beta- and gamma-gliadins.