Insights into the Potential of Sourdough-Related Lactic Acid Bacteria to Degrade Proteins in Wheat.

Vera Fraberger,Martin Ladurner,Konrad J Domig,Lisa M Call,Rupert Hochegger,Clemens Grunwald-Gruber,Alexandra Nemec,Stefano D’Amico

doi:10.3390/microorganisms8111689

Abstract

Sourdough processing contributes to better digestible wheat-based bakery products, especially due to the proteolytic activity of lactic acid bacteria (LAB). Therefore, sourdough-related LAB were screened for their capacity to degrade immunogenic proteins like gluten and alpha-amylase-trypsin inhibitors (ATIs). Firstly, the growth of 87 isolates was evaluated on a gluten-based medium. Further, the breakdown capacity of selected isolates was determined for gluten with a focus on gliadins by measuring acidification parameters and MALDI-TOF MS protein profiles. ATI degradation after 72 h of incubation within an ATI-based medium was investigated by means of acidification, HPLC, and competitive ELISA. All isolates exhibited the potential to degrade ATIs to a high degree, whereas the gliadin degradation capacity varied more greatly among tested LAB, with Lacticaseibacillus paracasei Lpa4 exhibiting the strongest alterations of the gliadin pattern, followed by Lactiplantibacillus plantarum Lpl5. ATI degradation capacities ranged from 52.3% to 85.0% by HPLC and 22.2% to 70.2% by ELISA, with Lacticaseibacillus paracasei Lpa4 showing superior breakdown properties. Hence, a selection of specific starter cultures can be used in sourdough processing for wheat-based bakery products with reduced gluten and ATI content and, further, better tolerated products for patients suffering from non-celiac wheat sensitivity (NCWS).

Highlights

Wheat is a staple food worldwide, with a production of up to 760 million tons in September 2020 [1]
The a6bsoef 1n7ce of gliadins with masses above 30 kDa was evident for the amylase-trypsin inhibitors (ATIs) isolate (Figure S1b), whereas gliadins exheibxtitreadct a(sseteroFnigguraebuS1nad).anDcueeitno tthhee ifnactetrtmhaetdailalttehesxetrparcott(esienes bFeiglounrge tSo1ath).e pDruoelatmointhseufpaecrtfatmhailtya, ll thesheavpirnogtesinmsilbarelpornogpetrotieths e(mporloelcaumlairnwseuipgehrt,fahmydilryo,phhaovbiincigtys,iimmimlaurnporgoepneicrtpieoste(nmtioal)ec[3u0la],rfuwrethigerht, hydpruorpihfiocabtiicointys, eimemmsutonobgeevneircypcootmenptliiacla)te[3d0a],nfdurtitmheercpounrsiufimcaintigo.nSusememisntgoubpe, vtheerypcrodmupcleidcaetxetdraacntd timceocnotnaisnuemd ihniggh. lSyucmonmceinntgrautped, tAhTeIps rwoidthucloewd ecxontrcaecnttcraotniotanisnoefdohthiegrhplyroctoeinncse,nwtrhaictehdwAasTcIsonwfiirtmh elodw conbceyntthrraeteiodnisffeorfeontthmeretphroodtesi.ns, which was confirmed by three different methods
This study discovered a low response of ATIs to the R5 antibody commonly used for gliadin detection by competitive ELISA measurements, which is preferred for analysis of fermented foods

Summary

Introduction

Wheat is a staple food worldwide, with a production of up to 760 million tons in September 2020 [1]. The increasing consumption of wheat and wheat-based products had led to an expansion of wheat-related disorders [2]. Diseases associated with wheat are celiac disease (CD) and IgE mediated allergies, with gluten as the main causative agent. This protein cooperates two fractions, namely gliadin (prolamin) and glutenin (glutelin). The gliadin fraction is further divided into α-, γ-, and ω-gliadins; glutenins are subdivided into high molecular weight (HMW) and low molecular weight (LMW) subunits [3]. It was reported that especially the α-gliadin family contains peptides exhibiting the highest immunogenic peptides, including a 33-mer peptide, p31–p43, a DQ2-restricted epitope, and a DQ8-restricted epitope [4]

Methods

Results

Conclusion