38 research outputs found
Soy protein–gum karaya conjugate: emulsifying activity and rheological behavior in aqueous system and oil in water emulsion
The main objective of this study is to investigate the effects of mixing and conjugation of soy protein isolate (SPI) with gum karaya on the characteristics of the hybrid polymer (protein–gum) in both aqueous systems and oil-in-water (O/W) emulsions. It was hypothesized that the covalent linkage of gum karaya with SPI would improve the emulsifying activity and rheological properties of both polymers. Conjugation occurred under controlled conditions (i.e., 60 °C and 75 % relative humidity, 3 days). The conjugated hybrid polymer produced smaller droplet with better uniformity, higher viscosity and stronger emulsifying activity than native gum karaya, suggesting the conjugated polymer provided a bulkier secondary layer with more efficient coverage around oil droplets, thereby inducing stronger resistance against droplet aggregation and flocculation. Emulsions containing the native gum karaya produced the largest droplet size among all prepared emulsions (D 3,2 = 8.6 μm; D 4,3 = 22.4 μm); while the emulsion containing protein–gum conjugate (1:1 g/g) had the smallest droplet size (D 3,2 = 0.2 μm; D 4,3 = 0.7 μm) with lower polydispersity. The protein–gum conjugate (1:1 g/g) also showed the highest elastic and viscous modulus, the lowest polydispersity (span) and the highest emulsifying activity among all native, mixed and conjugated polymers. Therefore, the percentage of gum karaya used for production of O/W emulsion can be decreased by partially replacing it with the conjugated gum
Can dietary fibre help provide safer food products for sufferers of gluten intolerance? A well-established biophysical probe may help towards providing an answer
A Two-Dimensional Relaxation Study of the Evolving Microstructure in a Mixed Biopolymer Gel
Kinetics of Phase Separation of Oat β-Glucan/Whey Protein Isolate Binary Mixtures
The kinetics of phase separation and microstructure
of oat β-glucan/whey protein binary mixtures varying
in concentration (4–16% w/v protein, 0.3–1.2% w/v β-
glucan) and β-glucan molecular weight (1.3×106, 640×
103, 180×103, and 120×103 g/mol) was investigated by
turbidimetry and fluorescent microscopy. The phase separation
of the mixed systems was followed at pH 7.0 and at
room temperature under quiescent conditions. Application
of first principles revealed that phase separation of the
systems follows first-order kinetics. Acceleration of the
phase-separation process was observed with increase of β-
glucan concentration for the three lowest-MW samples but\ud
the highest molecular weight (1.3×106 g/mol) exhibited the
opposite trend. Changes in the polysaccharide molecular
weight resulted in considerable differences in β-glucan
aggregate morphology in the mixed systems. The change in
the continuity of the mixed system from polysaccharide-, to
bi-, to protein-continuous was confirmed for a wide range
of mixed systems differing in biopolymer concentration,
and β-glucan molecular weigh