Modifications of Wheat Flour Proteins during in Vitro Digestion of Bread Dough, Crumb, and Crust:  An Electrophoretic and Immunological Study

Abstract

The proteins of wheat flour have several biological activities that can affect human health and physiology when wheat-based foods are consumed. The modifications of bread crumb and crust proteins during an in vitro peptic/pancreatic digestion process were studied by electrophoresis and immunoblotting with polyclonal antibodies specific for single proteins or groups of homologous proteins of the wheat flour, and the results were compared to those obtained for an unheated dough sample. The results show that baking affects the extent of proteolysis and the immunological and physicochemical features of the digestion products in relation to the level of the heat treatment. Therefore, the results concerning the digestion of the unheated wheat flour or dough are not representative of what happens when baked products enter the human digestive tract.

Selected Lactic Acid Bacteria Synthesize Antioxidant Peptides during Sourdough Fermentation of Cereal Flours

“…Proteolysis and heat stability of purified fractions. The purified fractions from WSE, which showed the highest antioxidant activities, were subjected to sequential protein hydrolysis by digestive enzymes according to the method described by Pasini et al (34). Briefly, freeze-dried aliquots corresponding to 10 mg of peptides were suspended in 400 l of 0.2 N HCl (pH 2.0) containing 0.05 mg/ml of pepsin (EC 3.4.23.1) (Sigma-Aldrich CO., St. Louis, MO) and homogenized in a Sterilmixer Lab (PBI International).…”

“…The highest levels of hydrophobicity were found for the sequences MAPAAVAAAEAGSK (64%), EALEAMFL (75%), LC PVHRAADL (60%), and PAEMVAAALDR (70%). The SH group of Cys (C) has a crucial antioxidant activity due to its direct interaction with radicals (34). The sequence NANGELCPNNMCCSQ WGYCGLGSEFCGNGCQSGACCPEK, which was identified in fraction 5 of rye sourdough, contains 8 cysteine residues.…”

Synthesis of γ-Aminobutyric Acid by Lactic Acid Bacteria Isolated from a Variety of Italian Cheeses

“…Simulated gastric and intestinal fluids were created (13,43). Stationary-phase-grown cells of lactic acid bacteria were harvested at 9,000 ϫ g for 15 min at 4°C, washed with physiologic solution (0.85% NaCl), and resuspended in 50 ml of simulated gastric juice (ca.…”

“…RSM (25 mg/ml), containing ca. 9 log CFU ml Ϫ1 of lactic acid bacteria, was subjected to pepsin and pancreatin digestion as described above (43). After digestion, the suspension was further incubated for 24 h at 37°C, at 100 revolutions min Ϫ1 , to mimic the synthesis of GABA by bacteria colonizing the GI tract.…”

Soybean Allergens: Presence, Detection and Methods for Mitigation

“…Heating can alter proteins by inducing denaturation (e.g., tertiary and/or secondary conformational changes), crosslinking, aggregation or rearrangements of disulfide bonds, which may cause changes in allergen reactivity (Mondoulet et al, 2005). In some cases, the changes are shown to decrease allergen reactivity (Beyer et al, 2001;Mondoulet et al, 2005), yet in other cases, the changes caused an increase in allergen bioactivity (Leszczynska et al, 2003;Simonato et al, 2001;Pasini et al, 2001), due possibly to exposing new IgE binding sites. Thermal treatments by moist heat include boiling, frying, extrusion, autoclaving and retorting, and those by dry heat include baking, roasting, and microwaving.…”