N-Glycosidase F improves gel firmness in fermented milk products

Healthier dairy products can be obtained by reducing fat content, but removal of fat from fermented milk products causes a reduction in gel firmness. To compensate, costly protein enrichment with either skim milk powder or whey protein concentrate is typically necessary. An attractive solution could be substitution of protein enrichment with a texturising enzyme. We aimed to identify such enzymes and found that after treatment with N-glycosidase-F (PNGase-F), yoghurt gel firmness increased. Highly pure PNGase-F was produced in Escherichia coli and our studies revealed that PNGase-F could substitute addition of 2% SMP used for protein enrichment in yoghurt. The effect on gel firmness of PNGase-F was stable over a period of 28 days and a sensory panel described the yoghurts as having improved thickness. Our study shows that it is indeed possible to find satisfying enzyme solutions that can replace the need for protein enrichment.