Research In Food Technology
The structure of high-protein foods formed during heat-induced aggregation and gelation can be controlled by the addition of peptides. Depending on the need, both stronger and weaker gels can be made in this way. This is the outcome of research by NIZO scientist Hans Kosters in the framework of Top Institute Food and Nutrition and carried out at the Laboratory of Food Chemistry of Wageningen University.
High-protein foods are being developed for targeted nutrition of the elderly, who suffer from declining muscle mass, and for sports nutrition. Such foods can also play a role in combating obesity, since proteins have a similar energy level as carbohydrates but a higher satiating effect. High-protein foods tend to show defects in their structure because it is difficult to keep proteins in their native form during (heat) processing. Hans Kosters has now shown that the gel strength of these foods can be controlled by the addition of food-protein-derived peptides, as proven in model food systems. In this way, the drinkability or chewability of high-protein systems can be improved without addition of other ingredients since peptides of the same origin are used.
Kosters, who worked on the interaction of proteins with peptides for his PhD thesis, found that peptides containing a thiol group (-SH) could be employed to control the gel strength of a heat-induced whey protein system. The choice of enzymes determines which peptides are formed during hydrolysis and thereby the effect on (high-) protein structures. These results can be applied to various high-protein foods, such as muesli bars, low-fat cheese or tortillas.
Moreover, in this study, disulfide-containing peptides were found to reduce the presence of sulfurous volatiles, formed after heating β-lactoglobulin or ovalbumin solutions. Kosters:“The reduction of H2S has clear practical advantages. Adding these peptides to milk products during production before heating can help to reduce off-flavours in the final product.”
Kosters will defend his thesis on Friday 5th October at 16.00 h in the Aula of Wageningen University. Prof. Dr. Ir. Harry Gruppen and Dr. Ir. Peter Wierenga from the Laboratory of Food Chemistry at Wageningen University are the thesis supervisors.