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Titolo:
Stability against aggregation of bovine casein micelles in the presence ofacidic and alkaline gelatin
Autore:
Lefebvre, J; Antonov, Y;
Indirizzi:
Russian Acad Sci, NM Emanuel Inst Biochem Phys, Moscow 117977, Russia Russian Acad Sci Moscow Russia 117977 iochem Phys, Moscow 117977, Russia INRA, Ctr Rech Agro Alimentaires, Lab Physicochim Macromol, F-44316 Nantes03, France INRA Nantes France 03 Lab Physicochim Macromol, F-44316 Nantes03, France
Titolo Testata:
COLLOID AND POLYMER SCIENCE
fascicolo: 5, volume: 279, anno: 2001,
pagine: 434 - 441
SICI:
0303-402X(200105)279:5<434:SAAOBC>2.0.ZU;2-#
Fonte:
ISI
Lingua:
ENG
Soggetto:
COMPLEXES; POLYSACCHARIDES; COMPATIBILITY; SYSTEMS;
Keywords:
bovine casein micelles; gelatin aggregates; interactions; bridging flocculation;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
32
Recensione:
Indirizzi per estratti:
Indirizzo: Antonov, Y Russian Acad Sci, NM Emanuel Inst Biochem Phys, Kosigin Str 4,GSP-1, Moscow 117977, Russia Russian Acad Sci Kosigin Str 4,GSP-1 Moscow Russia 117977 ssia
Citazione:
J. Lefebvre e Y. Antonov, "Stability against aggregation of bovine casein micelles in the presence ofacidic and alkaline gelatin", COLLOID P S, 279(5), 2001, pp. 434-441

Abstract

The effect of the presence of colloidal dispersed and molecular dispersed acidic (type A) and alkaline (type B) gelatins with similar molecular weight and size but different isoelectric points (7.9 and 4.9) on the stability against aggregation of bovine casein micelles was investigated by turbidimetric titration and laser techniques, over a wide range of biopolymers concentrations, gelatin/casein ratio in the initial mixture (0.03-20), pH (4.9-6.7) and ionic strength (10(-3)(milk salts)-1.0 NaCl), using glucono-delta -lactone (GL) as acidifier. Aggregates of acid gelatin A interact with the oppositely charged micellar casein at an ionic strength of around 10(-3) (milk salts) and pH 6.7 resulting in the formation of an electroneutral complex by ionic bonds between the carboxyl groups of casein and the amino groupsof the gelatin molecules. The complexes obtained are polynuclear, the aggregation of which is not as sensitive to pH as that of free casein micelles. Aggregation of such complexes is the result of bridging flocculation. The "molar" ratio gelatin aggregates/casein micelles in the mixed aggregates is4/1. The complexes are formed and stabilised via electrostatic interactionrather than through hydrogen bonds or hydrophobic interaction. In the presence of an excess of gelatin molecules in the initial mixture a charged gelatin-casein complex forms and some dissociation of casein micelles occurs and, as a consequence, soluble complexes are obtained. During the addition of alkaline gelatin B aggregates to the micellar casein solution and subsequent acidification of the mixture by GL, no effect of the presence of gelatin B on the stability of micellar casein was observed.

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Documento generato il 22/10/20 alle ore 06:42:02