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Changes in pasta protein networks induced by drying and their relationship to protein digestibility and allergenicity

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HAL Id: hal-02818282

https://hal.inrae.fr/hal-02818282

Submitted on 6 Jun 2020

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Changes in pasta protein networks induced by drying

and their relationship to protein digestibility and

allergenicity

Chantal Brossard, Maud Petitot, Cecile Barron, Marie-Anne Legoux, Evelyne

Paty, Sandra Denery-Papini, Valérie Micard

To cite this version:

Chantal Brossard, Maud Petitot, Cecile Barron, Marie-Anne Legoux, Evelyne Paty, et al.. Changes in pasta protein networks induced by drying and their relationship to protein digestibility and aller-genicity. 4. International Symposium on Molecular Allergology, Oct 2010, Munich, Germany. 2010. �hal-02818282�

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A

Pasta is a popular food which possesses interesting nutritional quality but may trigger allergic reaction in sensitized people. Many questions remain open for research area, including the relationship between pasta processing, pasta structure and resulting nutritional properties. The purpose of this study was to characterise the structure of pasta dried at different conditions and to relate it to the in vitro digestibility and allergenicity of proteins. Four drying profiles were studied: Low Temperature 55°C (LT), High Temperature 70°C(HT), Very High Temperature 90°C applied either from the beginning of the cycle, when the moisture content of spaghetti was high (20%) (VHT) or at the end of the drying cycle, when the moisture content of pasta was low (12%) (VHT_LM).

BROSSARD C. 1 *, PETITOT M.2,3 , BARRON C 2 , LEGOUX M.A. 1, PATY E., 4, DENERY S.1**and MICARD V.2

1. UR 1268 Biopolymères, Interactions, Assemblages, INRA, F-44316 NANTES

2.UMR1208 Ingénierie des Agropolymères et Technologies Emergentes, INRA – UMII – SupAgro – CIRAD, F-34060 MONTPELLIER 3.Crecerpal, Panzani, F-13013 MARSEILLE

4. CHU Necker. Pneumo Allergologie Infantile - 149 Rue de Sèvres – F-75015 PARIS **: presenting author * e-mail: brossard@nantes.inra.fr

Changes in pasta protein network induced by drying and

their relationship to protein digestibility and allergenicity

Protein Solubility a a b b 0 10 20 30 40 50 60 70 80 90 % o f to ta l p ro te in c o n te n t (d b ) a b c d e a b c d e a b c c

Cooked pasta are similar

Cooking led to an increased

protein aggregation, especially for LT and HT pasta

Dried pasta are different but

Increasing drying temperatures

led to increased protein aggregation (lower protein solubility in SDS).

Cooked pasta

Fig. 1:Peak surfaces of SE-HPLC elution profiles of SDS-soluble, DTE-soluble and calculated unextractable protein fractions in semolina and dried pasta (A) and in cooked pasta (B)

Aggregation during cooking

probably occurred through disulphide

bonds (increase in DTE-soluble

fraction) and other covalent bonds (increase in insoluble fraction) Distinct letters by parameter (SDS, DTE or Insoluble) within a graph (A or B) indicate

significant difference between mean values (p<0.05).

A B

Aggregation probably occurred

through disulphide bonds (increased DTE-soluble fraction) and through other covalent bonds (presence of insoluble proteins) with VHT drying profiles.

HT Semolina LT VHT_LM VHT Semolina & dried pasta

SDS DTE INSOLUBLE SDS DTE INSOLUBLE

a a a a

a a a a c

Methods

Proteins:Size Exclusion HPLC (SE-HPLC) after protein extraction with SDS (detergent), then with DTE (reducer) in dried and cooked pasta (Fig.1)

Microstructure:Confocal Laser Scanning Microscope of cross sectioned cooked pasta after protein staining with fuchsine acid (Fig. 2).

Protein digestibility :In vitro digestion of cooked pasta composed of a buccal phase (α-amylase, pH7), a gastric phase (pepsin, PH2) and an intestinal phase (pancreatin, pH7). Protein hydrolysis was evaluated by measuring the increase in free amine groups in protein extracts (Fig. 3).

Protein allergenicity :Juices from in vitro bucco-gastric or pancreatic digests were used to inhibit recognition of wheat proteins by IgE from a pool of allergic patients (table 1).

Acknowledgement: PASTALEG was carried out within the framework of Programme National de la Recherche and financially supported by the Agence Nationale de la Recherche.

VHT_LM decreased significantly protein digestibility (by 10 %) and increased allergenicity of intestinal digests. This could not be explained by a different protein spatial distribution at a microscopic level. VHT_LM cooked pasta presented a higher proportion a high molecular weight protein aggregates (data not shown) which may have contributed to this lower digestibility and higher allergenicity. Both gluten and soluble proteins seemed to be involved. It appears that applying VHT at the end of the drying cycle led to the formation of specific protein aggregates.

50µm

50µm 50µm

Bucco-gastric phase no significant effect of the drying profile (data not shown) ⇒Intestinal phase

VHT_LM drying profile

significantly decreased protein digestibility (by 10%) compared to other drying processes.

50 60 70 LT HT VHT _LM VHT % P ro te in H y d ro ly s is b a a a

Distinct letters indicate significant difference between mean values (p<0.05)

Fig.3:Mean degree of protein hydrolysis after 3 hours of intestinal phase.

Protein digestibility in Cooked PastaLocalisation effect:External zone: looser protein network with

swollen starch granules: creation of a moisture gradient during cooking ⇒Drying profile: LTother drying profiles

Fig.2:Example of CLSM images of LT cooked pasta at the central (A), intermediate (B) and external (C) zones of pasta strand.

A B C

50µm 50µm 50µm

Microstructure of cooked Pasta

Digestion juice from

the end of LT HT VHT VHT_LM

gastric phase 66 a 64 a 44 b 40 b αααα-gliadin

intestinal phase 16 cd 14 cd 10 d 19 c gastric phase 88 a 79bc 80 abc 81 ab γγγγ-gliadin

intestinal phase 78 bc 75bc 72 c 77 bc gastric phase 93 a 91 ab 90 ab 87 b

Low MW

glutenins intestinal phase 51 d

66c 46 d 63 c gastric phase 28a 26ab 24 ab 24 ab

Albumin/ globulin

fraction intestinal phase 14c 16 c 14c 21 b

Wheat fractionIgE reactive peptides from different wheat fractions are present in all tested digestion juices.

Digestion step: digests from gastric phase are richer in IgE reactive peptides than those from intestinal phase, difference depends on wheat fraction.

Drying process:compared to LT process, increasing the drying temperature led to a reduction in gastric digests and an increase in intestinal digests of IgE reactive peptides, specially for VHT_LM.

Allergenicity of Digests from Cooked Pasta

Table 1.Competitive ELISA with digestion juices from cooked pasta and a pool of sera from allergic patients to wheat. Percentage of inhibition obtained with digestion juices at the end of the gastric phase (5 minutes by α-amylase and 3 hours by pepsin) and at the end of the intestinal phase (end of gastric phase + 3 hours by pancreatin) are presented.

Distinct letters by protein indicate significant difference between mean values(p<0.05)

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Diapositive 1

d3 remplacer 20 ppm gluten par 20 ppm

Figure

Table 1. Competitive ELISA with digestion juices from cooked pasta and a pool of sera  from allergic patients to wheat

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