A kinetic model for the formation of acrylamide in a glucose-asparagine reaction system is proposed. Equimolar solutions (0.2 M) of glucose and asparagine were heated at different temperatures (120-200°C) at pH 6.8. Besides the reactants, acrylamide, fructose, and melanoidins were quantified after predetermined heating times (0-45 min). Multiresponse modeling by use of nonlinear regression with the determinant criterion was used to estimate model parameters. The proposed model resulted in a reasonable estimation for the formation of acrylamide in an aqueous model system, although the behavior of glucose, fructose, and asparagine was slightly underestimated. The formation of acrylamide reached its maximum when the concentration of sugars was reduced to about 0. This supported previous research, showing that a carbonyl source is needed for the formation of acrylamide from asparagine. Furthermore, it is observed that acrylamide is an intermediate of the Maillard reaction rather than an end product, which implies that it is also subject to a degradation reaction.
DOCUMENT
A kinetic model for the formation of acrylamide in a fructose-asparagine reaction system at initial pH 5.5 is proposed, based on an approach called multiresponse kinetic modelling. The formation of acetic acid and formic acid from the degradation of fructose and its isomer glucose was included in the proposed kinetic model. The kinetic model suggests that the effect of temperature on acrylamide formation with fructose is more due to the preceding steps with the formation of the Schiff base. The use of fructose and lower pH resulted in a higher yield of acrylamide (3%), suggesting that both can play an important role in acrylamide mitigation. Furthermore, these models have shown that, at high temperatures (120-200 °C), the Maillard reaction rapidly goes into the advanced stages, forming high amounts of organic acids and high molecular weight melanoidins. Overall, these mechanistic models provide more insight of the formation of acrylamide in a quantitative way.
DOCUMENT
Understanding taste is key for optimizing the palatability of seaweeds and other non-animal-based foods rich in protein. The lingual papillae in the mouth hold taste buds with taste receptors for the five gustatory taste qualities. Each taste bud contains three distinct cell types, of which Type II cells carry various G protein-coupled receptors that can detect sweet, bitter, or umami tastants, while type III cells detect sour, and likely salty stimuli. Upon ligand binding, receptor-linked intracellular heterotrimeric G proteins initiate a cascade of downstream events which activate the afferent nerve fibers for taste perception in the brain. The taste of amino acids depends on the hydrophobicity, size, charge, isoelectric point, chirality of the alpha carbon, and the functional groups on their side chains. The principal umami ingredient monosodium l-glutamate, broadly known as MSG, loses umami taste upon acetylation, esterification, or methylation, but is able to form flat configurations that bind well to the umami taste receptor. Ribonucleotides such as guanosine monophosphate and inosine monophosphate strongly enhance umami taste when l-glutamate is present. Ribonucleotides bind to the outer section of the venus flytrap domain of the receptor dimer and stabilize the closed conformation. Concentrations of glutamate, aspartate, arginate, and other compounds in food products may enhance saltiness and overall flavor. Umami ingredients may help to reduce the consumption of salts and fats in the general population and increase food consumption in the elderly.
MULTIFILE
Verduurzaming van de land- en tuinbouw is een actueel thema. In de zoektocht naar een economische en milieuvriendelijke manier om landbouwchemicaliën te verspreiden op het veld, zijn zaadcoatings populair. Landbouwchemicaliën zijn essentieel ter bescherming van gewassen en om opbrengsten te maximaliseren. Zaadcoatings vormen een dun film laagje om het zaad waarin groeistimulerende en ziektewerende substanties verwerkt worden. De huidige coatings zijn gemaakt uit synthetische polymeren die echter gebaseerd zijn op fossiele grondstoffen en aanleiding geven tot vervuilende microplastics bij degradatie. Biopolymeren kunnen een alternatief bieden, maar tot op heden is het niet gelukt om de synthetische polymeren te evenaren qua eigenschappen. Vooral het vinden van een juiste balans tussen stofvorming bij frictie van de zaden (“dust-off”) en het vloeivermogen van de zaden, is een uitdaging bij gebruik van biopolymeren. Het doel van het project is om een eenvoudig vernetbare vorm van poly(asparaginezuur), eventueel in aanwezigheid van cellulose fibrilen, te testen als biogebaseerde en biodegradeerbare component in watergedragen zaadcoating formulaties. Er zal onderzocht worden wat deze alternatieve materialen bieden qua toepassingsmogelijkheden in de zaadcoatingsindustrie.
