Iron-polyphenol complexes cause blackening upon grinding Hermetia illucens (black soldier fly) larvae

Research output: Contribution to journalArticleAcademicpeer-review

Abstract

Insects are a promising alternative protein source. One of the bottlenecks in applying insects in food is the fast darkening initiated during grinding. Besides enzymatic browning, non-enzymatic factors can cause off-colour formation, which differs between species. This study investigates the impact of iron, phenoloxidase, and polyphenols on off-colour formation in insect larvae. Hermetia illucens showed a blackish colour, whereas Tenebrio molitor turned brown and Alphitobius diaperinus remained the lightest. This off-colour formation appeared correlated with the iron content in the larvae, which was 61 ± 9.71, 54 ± 1.72 and 221 ± 6.07 mg/kg dw for T. molitor, A. diaperinus and H. illucens, respectively. In model systems, the formation of iron-L-3,4-dihydroxyphenylalanine (L-DOPA) bis- and tris-complexes were evidenced by direct injection into ESI-TOF-MS, based on their charges combined with iron isotope patterns. The reversibility of the binding of iron to phenolics, and thereby loss of blackening, was confirmed by EDTA addition. Besides complex formation, oxidation of L-DOPA by redox reactions with iron occurred mainly at low pH, whereas auto-oxidation of L-DOPA mainly occurred at pH 10. Tyrosinase (i.e. phenoloxidase) activity did not change complex formation. The similarity in off-colour formation between the model system and insects indicated an important role for iron-phenolic complexation in blackening.

Original languageEnglish
Article number2967
JournalScientific Reports
Volume9
DOIs
Publication statusPublished - 27 Feb 2019

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Simuliidae
Military Personnel
Polyphenols
Larva
Iron
Insects
Monophenol Monooxygenase
Levodopa
Iron Isotopes
Tenebrio
Fast Foods
Edetic Acid
Oxidation-Reduction
Color
Injections

Cite this

@article{35cc21289c264c2a824591feca0a9dff,
title = "Iron-polyphenol complexes cause blackening upon grinding Hermetia illucens (black soldier fly) larvae",
abstract = "Insects are a promising alternative protein source. One of the bottlenecks in applying insects in food is the fast darkening initiated during grinding. Besides enzymatic browning, non-enzymatic factors can cause off-colour formation, which differs between species. This study investigates the impact of iron, phenoloxidase, and polyphenols on off-colour formation in insect larvae. Hermetia illucens showed a blackish colour, whereas Tenebrio molitor turned brown and Alphitobius diaperinus remained the lightest. This off-colour formation appeared correlated with the iron content in the larvae, which was 61 ± 9.71, 54 ± 1.72 and 221 ± 6.07 mg/kg dw for T. molitor, A. diaperinus and H. illucens, respectively. In model systems, the formation of iron-L-3,4-dihydroxyphenylalanine (L-DOPA) bis- and tris-complexes were evidenced by direct injection into ESI-TOF-MS, based on their charges combined with iron isotope patterns. The reversibility of the binding of iron to phenolics, and thereby loss of blackening, was confirmed by EDTA addition. Besides complex formation, oxidation of L-DOPA by redox reactions with iron occurred mainly at low pH, whereas auto-oxidation of L-DOPA mainly occurred at pH 10. Tyrosinase (i.e. phenoloxidase) activity did not change complex formation. The similarity in off-colour formation between the model system and insects indicated an important role for iron-phenolic complexation in blackening.",
author = "Janssen, {Renske H.} and Greta Canelli and Sanders, {Mark G.} and Bakx, {Edwin J.} and Lakemond, {Catriona M.M.} and Vincenzo Fogliano and Vincken, {Jean Paul}",
year = "2019",
month = "2",
day = "27",
doi = "10.1038/s41598-019-38923-x",
language = "English",
volume = "9",
journal = "Scientific Reports",
issn = "2045-2322",
publisher = "Nature Publishing Group",

}

Iron-polyphenol complexes cause blackening upon grinding Hermetia illucens (black soldier fly) larvae. / Janssen, Renske H.; Canelli, Greta; Sanders, Mark G.; Bakx, Edwin J.; Lakemond, Catriona M.M.; Fogliano, Vincenzo; Vincken, Jean Paul.

In: Scientific Reports, Vol. 9, 2967, 27.02.2019.

Research output: Contribution to journalArticleAcademicpeer-review

TY - JOUR

T1 - Iron-polyphenol complexes cause blackening upon grinding Hermetia illucens (black soldier fly) larvae

AU - Janssen, Renske H.

AU - Canelli, Greta

AU - Sanders, Mark G.

AU - Bakx, Edwin J.

AU - Lakemond, Catriona M.M.

AU - Fogliano, Vincenzo

AU - Vincken, Jean Paul

PY - 2019/2/27

Y1 - 2019/2/27

N2 - Insects are a promising alternative protein source. One of the bottlenecks in applying insects in food is the fast darkening initiated during grinding. Besides enzymatic browning, non-enzymatic factors can cause off-colour formation, which differs between species. This study investigates the impact of iron, phenoloxidase, and polyphenols on off-colour formation in insect larvae. Hermetia illucens showed a blackish colour, whereas Tenebrio molitor turned brown and Alphitobius diaperinus remained the lightest. This off-colour formation appeared correlated with the iron content in the larvae, which was 61 ± 9.71, 54 ± 1.72 and 221 ± 6.07 mg/kg dw for T. molitor, A. diaperinus and H. illucens, respectively. In model systems, the formation of iron-L-3,4-dihydroxyphenylalanine (L-DOPA) bis- and tris-complexes were evidenced by direct injection into ESI-TOF-MS, based on their charges combined with iron isotope patterns. The reversibility of the binding of iron to phenolics, and thereby loss of blackening, was confirmed by EDTA addition. Besides complex formation, oxidation of L-DOPA by redox reactions with iron occurred mainly at low pH, whereas auto-oxidation of L-DOPA mainly occurred at pH 10. Tyrosinase (i.e. phenoloxidase) activity did not change complex formation. The similarity in off-colour formation between the model system and insects indicated an important role for iron-phenolic complexation in blackening.

AB - Insects are a promising alternative protein source. One of the bottlenecks in applying insects in food is the fast darkening initiated during grinding. Besides enzymatic browning, non-enzymatic factors can cause off-colour formation, which differs between species. This study investigates the impact of iron, phenoloxidase, and polyphenols on off-colour formation in insect larvae. Hermetia illucens showed a blackish colour, whereas Tenebrio molitor turned brown and Alphitobius diaperinus remained the lightest. This off-colour formation appeared correlated with the iron content in the larvae, which was 61 ± 9.71, 54 ± 1.72 and 221 ± 6.07 mg/kg dw for T. molitor, A. diaperinus and H. illucens, respectively. In model systems, the formation of iron-L-3,4-dihydroxyphenylalanine (L-DOPA) bis- and tris-complexes were evidenced by direct injection into ESI-TOF-MS, based on their charges combined with iron isotope patterns. The reversibility of the binding of iron to phenolics, and thereby loss of blackening, was confirmed by EDTA addition. Besides complex formation, oxidation of L-DOPA by redox reactions with iron occurred mainly at low pH, whereas auto-oxidation of L-DOPA mainly occurred at pH 10. Tyrosinase (i.e. phenoloxidase) activity did not change complex formation. The similarity in off-colour formation between the model system and insects indicated an important role for iron-phenolic complexation in blackening.

U2 - 10.1038/s41598-019-38923-x

DO - 10.1038/s41598-019-38923-x

M3 - Article

VL - 9

JO - Scientific Reports

JF - Scientific Reports

SN - 2045-2322

M1 - 2967

ER -