Abstract:
Milk proteins cross-linked with microbial transglutaminase were investigated for their potential
to improve the microbiological and physico-chemical properties of fermented tiger nut milk.
Fermented systems with cross-linked proteins did not affect S. thermophilus viable counts but
decreased that of L. delbrueckii ssp. bulgaricus compared to the untreated protein systems.
Systems with cross-linked proteins showed shorter microbial lag time and a higher pH reduction
rates during fermentation. During storage of the fermented product, viable counts of L.
delbrueckii ssp. bulgaricus decreased faster than that of S. thermophilus, and systems with cross-
linked proteins revealed a lower decrease in L. delbrueckii ssp. bulgaricus cell counts compared
to untreated proteins during 15 d. Products from cross-linked sodium caseinate or whey protein
showed 16.4 fold and 3.6 fold increase in viscosity, and approx. 30 % and 36 % decrease in
syneresis compared to their untreated counterparts, respectively. The addition of proteins to tiger
nut milk improved the lightness of the fermented product and minimized lightness decrease
during storage, and casein cross-linking further improved lightness. The enrichment of tiger nut
milk with cross-linked protein has therefore a large potential for improving the physical
characteristics of fermented tiger nut milk
