proteins to influence the emulsion stability.
It is likely that time-dependent, disulfide-mediated polymerisation
took place at the fat-serum interface. The polymerisation
was probably inhibited by a-la but the inhibition
affected creaming rate only when the disulfide bond formation
occurred between neighbouring molecules adsorbed on
the same fat globule. In that case, surface viscosity
increased during storage especially in emulsions made
with b-LGI, giving it enhanced stability against aggregation
by partial coalescence. The polymerisation between neighbouring
molecules on different fat globules was probably
initiated after flocculation by noncovalent bonding (e.g. van
der Waals attractions, hydrogen and ionic bonding and
hydrophobic interactions) or bridging flocculation (i.e. sharing
of individual protein molecules by two or more fat
globules). Disulfide bonds then reinforced the flocs. This
hypothesis was advanced by McClements et al. (1993).
Thus, the rate of flocculation is not determined by interglobule,
disulfide-mediated polymerisation but the reversibility
of the process is.
The aggregation of fat globules by flocculation and/or
partial coalescence was monitored regularly during storage
by particle size measurements. During storage for up to one
week at 48C, no aggregation was observed. However, when
the storage temperature was subsequently increased to room
temperature for an extended period of time, fat globules
aggregated. This finding is illustrated in Fig. 5(a) for
emulsions prepared with WPF and b-LGI at 0.30%
protein. Particle size increased with time, the rate of
increase influenced by the whey protein material used in
the system.
proteins to influence the emulsion stability.It is likely that time-dependent, disulfide-mediated polymerisationtook place at the fat-serum interface. The polymerisationwas probably inhibited by a-la but the inhibitionaffected creaming rate only when the disulfide bond formationoccurred between neighbouring molecules adsorbed onthe same fat globule. In that case, surface viscosityincreased during storage especially in emulsions madewith b-LGI, giving it enhanced stability against aggregationby partial coalescence. The polymerisation between neighbouringmolecules on different fat globules was probablyinitiated after flocculation by noncovalent bonding (e.g. vander Waals attractions, hydrogen and ionic bonding andhydrophobic interactions) or bridging flocculation (i.e. sharingof individual protein molecules by two or more fatglobules). Disulfide bonds then reinforced the flocs. Thishypothesis was advanced by McClements et al. (1993).Thus, the rate of flocculation is not determined by interglobule,disulfide-mediated polymerisation but the reversibilityof the process is.The aggregation of fat globules by flocculation and/orpartial coalescence was monitored regularly during storageby particle size measurements. During storage for up to oneweek at 48C, no aggregation was observed. However, whenthe storage temperature was subsequently increased to roomtemperature for an extended period of time, fat globulesรวม ค้นหานี้จะแสดงใน 5(a) Fig. สำหรับemulsions ด้วย WPF และบี-LGI 0.30%โปรตีน ขนาดของอนุภาคที่เพิ่มขึ้นกับเวลา อัตราเพิ่มที่รับอิทธิพลจากเวย์โปรตีนวัสดุที่ใช้ในระบบ
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