S.E. Fayle

Maillard crosslinking of food proteins II: the reactions of glutaraldehyde, formaldehyde and glyceraldehyde with wheat proteins in vitro and in situ

As part of a study of the effects of the Maillard reaction on food texture, we have established, in the preceding paper, the capacities of formaldehyde, glyceraldehyde and glutaraldehyde to crosslink a model protein. In this paper, we validate our model study using wheat proteins, both in vitro and in situ. All three molecules were found to crosslink all fractions of wheat proteins (albumins and globulins, gliadins, SDS-soluble glutenins and SDS-insoluble glutenins) in vitro, with glutaraldehyde being the most reactive. Of the four fractions of wheat proteins, gliadins proved the least susceptible to Maillard crosslinking. Crosslinking was accompanied by a loss of lysine residues in all cases. In situ, only glutaraldehyde underwent protein crosslinking, and the reaction was specific to the albumin and globulin fraction. In the following paper, we explore the effects that this specific crosslinking of albumins and globulins in dough has on the texture of bread and croissants.

Novel approaches to the analysis of the Maillard reaction of proteins

The Maillard reaction comprises a complex network of reactions which has proven to be of great importance in both food science and medicine. The majority of methods developed for studying the Maillard reaction in food have focused on model systems containing amino acids and monosaccharides. In this study, a number of electrophoretic techniques, including two‐dimensional gel electrophoresis and capillary electrophoresis, are presented. These have been developed specifically for the analysis of the Maillard reaction of food proteins, and are giving important insights into this complex process.

Maillard crosslinking of food proteins I: the reaction of glutaraldehyde, formaldehyde and glyceraldehyde with ribonuclease

Abstract The Maillard reaction influences not only the colour and flavour of foods, but also their texture, via protein crosslinking. In this, the first of a series of three papers to assess the potential of the Maillard reaction to alter food properties in situ, the capacities of three molecules—formaldehyde, glyceraldehyde and glutaraldehyde—to crosslink a model protein—RNAse—were compared. All three molecules crosslinked RNAse in vitro, with glutaraldehyde reacting at a much greater rate than either glyceraldehyde or formaldehyde, whose rates were comparable. Crosslinking correlated well with loss of lysine in the proteins for glutaraldehyde and glyceraldehyde, with some anomalies for formaldehyde. The differences in reactivity are explained by the proposed mechanisms of crosslinking for each of the three molecules. An understanding of the range of reactivity of crosslinking molecules, and how this relates to their molecular structure, may help us understand how to harness the Maillard reaction during food processing.

Maillard crosslinking of food proteins III: the effects of glutaraldehyde, formaldehyde and glyceraldehyde upon bread and croissants

The Maillard reaction influences not only the colour and flavour of foods, but also their texture. One of the mechanisms by which this occurs is via protein crosslinking. In the preceding paper, the capacities formaldehyde, glyceraldehyde and glutaraldehyde to crosslink wheat proteins were compared in vitro and in situ. All three molecules crosslinked wheat proteins in vitro, but only glutaraldehyde crosslinked the proteins when added to wheat flour dough. Here the effects of this crosslinking on dough, bread and croissants are reported. The effect of glutaraldehyde on the dough properties was marked. Upon baking, addition of glutaraldehyde was shown to alter crumb strength and texture of bread, but had no perceivable effect on croissants. A comparison to previous results, comparing enzymatic crosslinking, suggests that crosslinking of specific wheat proteins can be correlated with particular properties of cereal foods. This suggests that the Maillard reaction may be harnessed by food processors to manipulate the texture of foods.

Crosslinkage of proteins by dehydroascorbic acid and its degradation products

Abstract Protein crosslinking can have a profound effect on the structure and function of proteins in food. Dehydroascorbic acid (DHA) has been shown to be involved in Maillard type chemistry that leads to protein crosslinking. In this study, the effect of temperature on the rate of this reaction was studied. The reaction was shown to proceed rapidly at temperatures that may be encountered during food processing. In order to assess the relative reactivity of DHA and its breakdown products, five known degradation products were reacted with protein and their crosslinking ability, via Maillard chemistry, was assessed. Oxalic acid did not effect protein crosslinking. Threose, glyoxal, diacetyl and methyl glyoxal all reacted faster than DHA. The main crosslinking reaction observed was shown to involve a lysine residue. Our results suggest that these molecules may be important in determining the modification of protein functionality during food processing.

The Effect of Non‐Gluten Proteins on the Staling of Bread

As part of our studies on the mechanisms of bread staling, starch bread was used as a research tool that enables us to gain insights into the individual contributions that starch and gluten have on staling. Reconstitution experiments have demonstrated that bread of equivalent specific loaf volume stales at the same rate irrespective of protein concentration, or type of protein. However, other properties of bread, such as specific loaf volume, may be altered by specifically changing the protein component in the flour.

Cyclotene Hydrate, C6H8O2.H2O

The title compound exists as the 2-hydroxy-3-methylcyclopent-2-enone tautomer hydrogen bonded to a water molecule. All three H atoms bonded to O atoms are involved in a hydrogen-bonding network that assembles the molecules into chains along the b axis.