Cited by 143
Max Rubner Institut
Publishes on Proteins in Food Systems, Protein Hydrolysis and Bioactive Peptides, Probiotics and Fermented Foods. 47 papers and 469 citations.
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Extended shelf life (ESL) milk was processed with integrated microfiltration (pore size 1.4 µm). The germ‐enriched retentate was not used for the final whole milk. Microfiltration led only to a negligible change in the content of the main components of the ESL product compared with the source milk. The total protein was only slightly decreased (0.02–0.03%) and the ratio of the protein fractions was unchanged within the measurement accuracy. The furosine content of the isolated fat globuline membrane fraction could be used as a diagnostic to prove cream had been subjected to high‐temperature treatment. The shelf life of the ESL milk was distinctly prolonged compared to HTST‐pasteurized milk.
The present paper describes a comparative study of the gelation properties of whey protein concentrate (WPC) and whey protein isolate (WPI). Penetration measurements as well as rheological studies revealed that the strength of heat-induced gels prepared with WPI was higher than with WPC. In addition, gels with WPI were clearly more elastic than WPC gels. The storage modulus of WPI and the storage and loss moduli of WPC increased with increasing frequency, while the loss modulus of WPI revealed no clear dependence on the frequency, resulting in a greater decrease in the loss angle of WPI with increasing frequency. The superior gelation properties of WPI were mainly due to the higher -lactoglobulin content as well as to lower fat, lactose and phospholipid contents. However, in this paper it is also discussed whether the low contents of glycomacropeptide, non-protein-nitrogen and proteose peptone in WPI may partly explain the superior gelation properties of these protein products. WPI were more sensible to an increase in the ionic strength (0.1-0.3% NaCl) than WPC, resulting in clearly stronger gels with WPI than with WPC. In the pH ranges of 2-3 and 7-8, elastic and translucent gels could be prepared using WPI, while their gel-forming properties were low between pH 4 and 5. The strongest gels, turbid, but still elastic, were prepared with WPI at pH 6. whey protein concentrate / whey protein isolate / gelation properties - (WPC) (WPI) WPI WPC
La formation de liaisons entre des proteines alimentaires et la transglutaminase provoque les modifications desirees des proprietes technologiques. Pour verifier si la formation de liaisons mene a une digestibilite reduite des proteines dans le tract gastro-intestinal, la proteolyse in vitro et la digestibilite prececale de caseinate traite a la transglutaminase (TgC) ont ete analysees sur le porcelet miniature Gottingen par rapport au caseinate natif (C). Les analyses in vitro ont ete realisees avec de la pepsine et de la pancreatine. L'augmentation en amino nitrogene etait a peu pres egale et n'a pas fourni d'informations sur une difference dans la capacite de proteolyse. Pour les examens in vivo, 30 g de caseinate reticule ou de caseinate natif, enrichis par l'isotope stable 15 N, etaient administres dans une ration semi-synthetique par une canule T- ileum a quatre verrats. La digestibilite proteique a ete detectee moyennant 15 N recouvert dans le chyme de l'ileum. Les impulsions de marquage indigestibles chromoxide et polyethylene glycol-4000 etaient ajoutees aux rations pour corriger les pertes de chyme et pour detecter le taux de flux. Ni les quantites (C: 623 ± 61 g; TgC, 549 ± 35 g), ni la matiere seche du chyme (C: 8,9 ± 0,4%; TgC: 9,3 ± 0,4%) indiquaient des differences signifiantes pendant la periode de collection de 33 heures. De meme, les cinetiques du flux digestif revelaient un trace concordant. Pour la caseine non-traitee, 7,7 ± 0,6% etaient recouverts a l'extremite de l'intestin grele apres avoir administre du nitrogene, et 8,1 ± 0,6% apres l'administration de caseinate traite a la transglutaminase. Cela correspond a une digestibilite proteique de 92,3% (C), respectivement de 91,9% (TgC). Ces valeurs ne revelent pas de differences signifiantes. De meme, les quantites de nitrogene endogene, c'est-a-dire le nitrogene secrete dans l'intestin au cours de la digestion, ne revelaient pas de difference signifiante. Les resultats de cette etude indiquent qu'une formation de liaisons avec la transglutaminase ne change rien au processus de digestion et a la digestibilite du caseinate.