The Effect of Microbial Transglutaminase on the Viscosity and Protein Network of Kefir Made from Cow, Goat, or Donkey Milk
Lívia Darnay,
Adrienn Tóth,
Barbara Csehi,
Anna Szepessy,
Martin Horváth,
Klára Pásztor-Huszár,
Péter Laczay
Affiliations
Lívia Darnay
Department of Food Hygiene, University of Veterinary Medicine Budapest, István u. 2, H-1078 Budapest, Hungary
Adrienn Tóth
Department of Livestocks Product and Food Preservation Technology, Institute of Food Science and Technology, Hungarian University of Agriculture and Life Sciences, Ménesi út 43-45, H-1118 Budapest, Hungary
Barbara Csehi
Department of Livestocks Product and Food Preservation Technology, Institute of Food Science and Technology, Hungarian University of Agriculture and Life Sciences, Ménesi út 43-45, H-1118 Budapest, Hungary
Anna Szepessy
Department of Food Hygiene, University of Veterinary Medicine Budapest, István u. 2, H-1078 Budapest, Hungary
Martin Horváth
Department of Livestocks Product and Food Preservation Technology, Institute of Food Science and Technology, Hungarian University of Agriculture and Life Sciences, Ménesi út 43-45, H-1118 Budapest, Hungary
Klára Pásztor-Huszár
Department of Livestocks Product and Food Preservation Technology, Institute of Food Science and Technology, Hungarian University of Agriculture and Life Sciences, Ménesi út 43-45, H-1118 Budapest, Hungary
Péter Laczay
Department of Food Hygiene, University of Veterinary Medicine Budapest, István u. 2, H-1078 Budapest, Hungary
In this study, we aim to decrease the fermentation time and to produce low-fat set-type kefir with adequate textural properties using microbial transglutaminase without inactivation. In addition, we reveal the effect of microbial transglutaminase, during and after fermentation, on kefir made with cow, goat, or donkey milk, which is a novel approach. Fermentation is followed by continuous pH and viscosity measurements; the final product is characterized by dry matter content, whey separation, protein pattern, and viscosity parameters, as well as gel firmness. The results show that already 0.5 U/g protein dosage of MTGase decreases pH levels independent of milk type, but MTGase does not influence the kinetics of fermentation. Apparent viscosity could be measured from different stages of fermentation depending on milk type (cow milk, 6 h; goat milk, 8 h; and donkey milk, 9 h). The final product characteristics show that the higher the casein ratio of the applied milk, the better the viscosity and gel firmness of the kefir due to the high reaction affinity of MTGase.
