The physico-chemical properties of chia seed polysaccharide and its microgel dispersion rheology.
The polysaccharide gel layer surrounding hydrated chia seeds was extracted using water and isolated by ethanol precipitation. The freeze-dried sample consisted of ∼95% non-starch polysaccharides (35% w/w neutral soluble fraction and 65% w/w negatively charged insoluble fraction). The soluble polysaccharide fraction has molar mass, root-mean square radius and intrinsic viscosity of ∼5×10(5)g/mol, 39nm and 719mL/g, respectively. The whole polysaccharide (included soluble and insoluble fractions) when dispersed in water showed presence of irregular shape, fibrous microgel particles with an average size (D4,3) of ∼700μm. Rheological measurements indicated a 'weak' viscoelastic gel and strong shear dependent properties even at low concentration (0.05% w/w). The viscosity of the dispersion was fairly resistant to variations in temperatures (20-80°C), pH (4-12), ionic strengths (0.01-0.5M NaCl) and cation types (MgCl2, CaCl2, NaCl and KCl). The swollen microgel particles dispersed in soluble polysaccharide continuous phase provided complex and potentially useful rheological properties in food systems.
Massey Institute of Food Science & Technology, School of Food & Nutrition, Massey University, Private Bag 11-222, Palmerston North, New Zealand. Electronic address: k.t.goh@massey.ac.nz.
Kelvin Kim Tha
KK
Goh
Massey Institute of Food Science & Technology, School of Food & Nutrition, Massey University, Private Bag 11-222, Palmerston North, New Zealand.
Lara
L
Matia-Merino
Massey Institute of Food Science & Technology, School of Food & Nutrition, Massey University, Private Bag 11-222, Palmerston North, New Zealand.
Jie Hong
JH
Chiang
Massey Institute of Food Science & Technology, School of Food & Nutrition, Massey University, Private Bag 11-222, Palmerston North, New Zealand.
Ruisong
R
Quek
Massey Institute of Food Science & Technology, School of Food & Nutrition, Massey University, Private Bag 11-222, Palmerston North, New Zealand.
Stephanie Jun Bing
SJ
Soh
Massey Institute of Food Science & Technology, School of Food & Nutrition, Massey University, Private Bag 11-222, Palmerston North, New Zealand.
Roger G
RG
Lentle
D002240:Carbohydrate Sequence; D055598:Chemical Phenomena; D005782:Gels; D006863:Hydrogen-Ion Concentration; D009005:Monosaccharides / Q000032:analysis; D011134:Polysaccharides / Q000737:chemistry*; D012212:Rheology; D027544:Salvia / Q000737:chemistry*; D012639:Seeds / Q000737:chemistry*; D012965:Sodium Chloride / Q000737:chemistry; D012995:Solubility
D005782:Gels; D009005:Monosaccharides; D011134:Polysaccharides; D012965:Sodium Chloride
Chia seed; Microgel dispersion; Molecular characteristics; Monosaccharide composition; Rheology; Viscoelasticity