Pieter Dekker

Dr. Pieter Dekker

Wageningen University & Research - Food Quality and Design Group
+1
orcid

Research Focus & Metrics

Academic Career Length

8Years (2019-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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25 October 2019 in Journal of Agricultural and Food Chemistry
Verified
Journal Article
Open access
SASilvia Andini
Silvia Andini
Pieter DekkerPieter Dekker
Pieter Dekker
HGHarry Gruppen
Harry Gruppen
CACarla Araya-Cloutier
Carla Araya-Cloutier
JVJean-Paul Vincken
Jean-Paul Vincken
Glucosinolates (GSLs) are of interest for potential antimicrobial activity of their degradation products and exclusive presence in Brassicaceae. Compositional changes of aliphatic, benzenic, and indolic GSLs of Sinapis alba, Brassica napus, and B. juncea seeds by germination and fungal elicitation were studied. Rhizopus oryzae (non-pathogenic), Fusarium graminearum (non-pathogenic), and F. oxysporum (pathogenic) were employed. Thirty-one GSLs were detected by RP-UHPLC-PDA-ESI-MSn. Aromatic-acylated derivatives of 3-butenyl GSL, p-hydroxybenzyl GSL, and indol-3-ylmethyl GSL were for the first time tentatively annotated and confirmed to be not artefacts. For S. alba, germination, Rhizopus-elicitation, and F. graminearum-elicitation increased total GSL content, mainly consisting of p-hydroxybenzyl GSL, by 2-3 fold. For B. napus and B. juncea, total GSL content was unaffected by germination or elicitation. In all treatments, aliphatic GSL content was decreased (≥ 50%) in B. napus, and remained unchanged in B. juncea. Indolic GSLs were induced in all species by germination and non-pathogenic elicitation.

24 January 2023 in Food & Function
Verified
Journal Article
Open access
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TBTon Baars
Ton Baars
BEBetty van Esch
Betty van Esch
LOLuuk van Ooijen
Luuk van Ooijen
ZZZuomin Zhang
Zuomin Zhang
Pieter DekkerPieter Dekker
Pieter Dekker
RKRemco Kort
Remco Kort
This study aims to characterize the microbiota and peptidomic composition of raw milk kefir, and to address the potential anti-allergic effects of raw milk kefir using validated research models for food allergy. Raw milk kefir was produced after incubation with a defined freeze-dried starter culture. Kefir was sampled during fermentation at seven time intervals. For comparison, kefir was also prepared from heat-treated milk. Peptide compositions were determined for the raw and heated milk, and kefir end products made from these milks. In a murine food allergy model, the two kefir end products were investigated for their allergy modulating effects. In both kefirs, we identified amplicon sequence variants identical to those in the starter culture, matching the bacteria Lactococcus lactis, Streptococcus thermophilus, Leuconostoc and the yeast Debaryomyces. In raw milk kefir, additional sequence variants of Lactococcus lactis and the yeasts Pichia and Galactomyces could be identified, which were absent in heated milk kefir. Analysis of peptide compositions in both kefirs indicated that the number and intensity of peptides drastically increased after fermentation. Heating of the milk negatively affected the diversity of the peptide composition in kefir. Only raw milk kefir suppressed the acute allergic skin response to the food allergen ovalbumin in sensitised mice. These effects coincided with differences in the T-cell compartment, with lower percentages of activated Th1 cells and IFNg production after treatment with kefir made from heated milk. The results of this study indicate specific properties of raw milk kefir that may contribute to its additional health benefits.

1 March 2020 in Food Research International
Verified
Journal Article
Open access
Zhijun WangZhijun Wang
Zhijun Wang
Sara ErasmusSara Erasmus
Sara Erasmus
Pieter DekkerPieter Dekker
Pieter Dekker
BGBoli Guo
Boli Guo
JSJetse J. Stoorvogel
Jetse J. Stoorvogel
SRSaskia Van Ruth
Saskia Van Ruth
Traceability of agricultural produce is getting increasingly important for numerous reasons including marketing, certification, and food safety. Globally, banana (Musa spp.) with its high nutritional value and easy accessibility, is a popular fruit among consumers. Bananas are produced throughout the (sub-)tropics under a wide range of environmental conditions. Environmental conditions could influence the composition of bananas. Understanding the effect of these conditions on fruit composition provides a way of increasing the fruit's traceability and linking it to its origin - a crucial aspect for the increasing global supply chain. In this study, we examined the influence of growing conditions on the isotopic and elemental composition of bananas produced in 15 Costa Rican farms. A total of 88 bananas (peel and pulp) were collected from the farms and analysed for isotopic signatures (δ13C, δ15N, and δ18O) and elemental compositions. The growing conditions were characterized in terms of climate, topography and soil conditions. The isotopic ratios differed significantly between groups of farms. The δ13C and δ15N values were mainly influenced by soil types, while rainfall and temperatures related more to the δ18O values. The elemental compositions of the bananas were primarily influenced by the local rainfall and soil types, while the geographical origin could be distinguished using principal component analysis. The overall results link the growing conditions to the isotopic and elemental compositions of bananas, thereby also providing a way to trace its origin.

22 April 2020 in Nutrients
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Journal Article
Open access
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Pieter DekkerPieter Dekker
Pieter Dekker
SBSjef Boeren
Sjef Boeren
AWAlet H. Wijga
Alet H. Wijga
GKGerard H. Koppelman
Gerard H. Koppelman
JVJacques Vervoort
Jacques Vervoort
KHKasper Hettinga
Kasper Hettinga
Human milk contains proteins and/or protein fragments that originate from nonhuman organisms. These proteinaceous molecules, of which the secretion might be related to the mother’s allergy status, could be involved in the development of the immune system of the infant. This may lead, for example, to sensitization or the induction of allergen-specific tolerance. The aim of this study was to investigate the relation between maternal allergy and the levels of nonhuman proteinaceous molecules in their milk. In this study, we analysed trypsin-digested human milk serum proteins of 10 allergic mothers and 10 nonallergic mothers. A search was carried out to identify peptide sequences originating from bovine or other allergenic proteins. Several methods were applied to confirm the identification of these sequences, and the differences between both groups were investigated. Out of the 78 identified nonhuman peptide sequences, 62 sequences matched Bos taurus proteins. Eight peptide sequences of bovine β -lactoglobulin had significantly higher levels in milk from allergic mothers than in milk from nonallergic mothers. Dietary bovine β -lactoglobulin may be absorbed through the intestinal barrier and secreted into human milk. This seems to be significantly higher in allergic mothers and might have consequences for the development of the immune system of their breastfed infant.

1 February 2022 in Journal of Proteome Research
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Journal Article
Open access
Pieter DekkerPieter Dekker
Pieter Dekker
SBSjef Boeren
Sjef Boeren
JGJohannes B. van Goudoever
Johannes B. van Goudoever
JVJacques Vervoort
Jacques Vervoort
KHKasper Hettinga
Kasper Hettinga
Human milk is a dynamic biofluid, and its detailed composition receives increasing attention. While most studies focus on changes over time or differences between maternal characteristics, interindividual variation receives little attention. Nevertheless, a comprehensive insight into this can help interpret human milk studies and help human milk banks provide targeted milk for recipients. This study aimed to map interindividual variation in the human milk proteome, peptidome, and metabolome and to investigate possible explanations for this variation. A set of 286 milk samples was collected from 29 mothers in the third month postpartum. Samples were pooled per mother, and proteins, peptides, and metabolites were analyzed. A substantial coefficient of variation (>100%) was observed for 4.6% and 36.2% of the proteins and peptides, respectively. In addition, using weighted correlation network analysis (WGCNA), 5 protein and 11 peptide clusters were obtained, showing distinct characteristics. With this, several associations were found between the different data sets and with specific sample characteristics. This study provides insight into the dynamics of human milk protein, peptide, and metabolite composition. In addition, it will support future studies that evaluate the effect size of a parameter of interest by enabling a comparison with natural variability.

1 July 2020 in Food Research International
Verified
Journal Article
Open access
SRSaskia Van Ruth
Saskia Van Ruth
JVJoris van der Veeken
Joris van der Veeken
Pieter DekkerPieter Dekker
Pieter Dekker
PLPieternel A. Luning
Pieternel A. Luning
WHWim Huisman
Wim Huisman
This study examines fraud vulnerability in the food service industry; identifies underlying fraud vulnerability factors; and studies the differences in fraud vulnerability between casual dining restaurants, fine dining restaurants and mass caterers for four product groups. Vulnerability was assessed by an adapted SSAFE food fraud vulnerability assessment, tailored to the food service sector situation. The 15 food service operators rated high vulnerability for 40% of the fraud indicators. This is considerably more than food manufacturers, wholesalers and retailers did previously. In particular, more opportunities and fewer controls were noted. Overall fraud vulnerability was more determined by the type of food service operator than by the type of food product. Casual dining restaurants appeared most vulnerable, followed by fine dining restaurants. Mass caterers seemed the least vulnerable operators, because they had more adequate food fraud controls in place. Considering its high vulnerability, reinforcement of mitigation measures in the food service industry is urgently recommended.