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A graduate exam seminar is a presentation of the student’s final research project for their degree.
This is an ALES MSc Final Exam Seminar by Luis Rojas Tovar. This seminar is open to the general public to attend.
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Conference ID: 806676827
Thesis Topic: Degradation of Wheat Germ Agglutinin and Amylase-Trypsin Inhibitors During Sourdough Fermentation
MSc with Dr. Michael Gaenzle.
Non Celiac Wheat Sensitivity (NCWS), an intolerance to the ingestion of wheat products, has increased considerably during the past few years. In sensitive individuals, NCWS manifests by intestinal and extra intestinal symptoms in different ways. Two wheat protein fractions have been linked to NCWS, amylase-trypsin inhibitors (ATI) and wheat germ agglutinin (WGA). Physicians recommend that individuals with NCWS adhere to a gluten free diet. However, gluten free diets are often associated with a reduced diversity of products, a higher price and lower sensory and nutritional quality. Thus, it was the objective of this study to explore the possibility of using sourdough fermentation to reduce the bioactivity of these two proteins linked to NCWS in wheat bread.
White pastry flour was used to analyze ATI and whole wheat flour for WGA experiments. The analytical techniques used to determine the fate of ATIs and WGA through the fermentation were size exclusion high performance liquid chromatography (SEC-HPLC), and enzyme-linked immunosorbent assay (ELISA). During fermentation, the pH of the dough decreased to 3.9 ± 0.2, which promoted the degradation of ATI from oligomers into monomers; ATI monomers are less harmful when consumed. WGA is also modified during sourdough fermentation depending on the reducing capabilities of the strains used. Initially, commercial whole wheat flour contained 6.6 μg ± 0.7 of WGA per gram. After 24 h fermentation, doughs fermented with Latilactobacillus sakei TMW 1.22 contained 2.7 μg ± 0.4 of WGA per gram of flour, while the doughs fermented with Fructilactobacillus sanfranciscensis DSM20451 and F. sanfranciscensis DSM20451 ΔgshR contained 4.3 μg ± 0.3 and 6.5 ± 1.8 μg, respectively. The WGA-SEC chromatograms show 3 peaks for doughs fermented with F. sanfranciscensis DSM20451 ΔgshR while the chromatograms with the isogenic strain F. sanfranciscensis DSM20451 show a more complex profile with 5 peaks, one of them from a very large molecular size molecule. The concentration of WGA is lower after fermentation with lactobacilli that have high reducing capacity. Clinical studies are required to determine the safety of consumption and the possible reduction in adverse symptoms, but this is a step towards finding new options to incorporate into the diet of NCWS individuals.