PDF《Food Hydrocolloids》

1 h, and insoluble solids were collected on a synthetic cloth. This procedure was repeated ?ve times using

180 mL of ethanol 80% v/v until a clear extract was obtained. The residue was stirred overnight in pure acetone (250 mL), passed through a G1 glass sinter ?lter and air-dried at

45 C. Subsequently, AIR was ground to a ?ne powder using a Retsch grinder (Düsseldorf, Germany) with a 0.125 mm retention mesh. 2.4. Rheological measurements Rheological measurements of AIR in aqueous solutions at various concentrations (1e10% w/v) were performed on a Kinexus rheometer (Malvern Instruments, Worcestershire, UK) equipped with cone-plate geometry system (4 inclination angle,

40 mm diameter, 0.15 measuring gap) and a Peltier element for tempera- ture control. Material ?ow curves were measured in shear rate- controlled mode, where shear rate was varied from 0.1 to

100 s?1 . All measurements were performed in duplicate at

20 C, which was identical for the preparation of the AIR solutions. Rheological data for 1% solutions of xanthan, guar gum, locust bean gum, and the crude mucilages (CM) from Sinapis alba seeds, O. ?cus-indica stems, and Sophora japonica seeds, respectively, were calculated and illustrated according to mathematical model and corresponding parameters described by Bourbon et al. (2010), Cui, Eskin, and Biliaderis (1993), Marcotte, Taherian Hoshahili, and Ramaswamy (2001) and Medina-Torres, Brito-De La Fuente, Torrestiana- Sanchez, and Katthain (2000). 2.5. Sequential extraction of the AIR AIR samples of

800 mg were mixed with

5 mL of ethanol 96% v/ v. The mixture was suspended in

50 mL of bi-distilled water and stirred at

40 C for

30 min. After centrifugation at 6660g for

10 min (20 C), the pellet was re-suspended in

50 mL of bi-distilled water, extracted at

40 C for

1 h under stirring, and again centrifuged. The combined supernatants were pooled, and dialyzed exhaustively against water for

48 h using dialysis membranes (type 36/32, pore size 25e50 A, Medicell International London, UK). The water- soluble pectin fraction (WSP) was then freeze-dried. To extract the oxalate-soluble pectin fraction (OXP), ammonium oxalate (0.5% w/v,

50 mL) was added to the water insoluble residue at

40 C for 1.5 h. The suspension was centrifuged for

10 min at 6660g, and the obtained pellet washed twice with

50 mL of distilled water. The OXP-fraction was dialyzed for two days against water, and freeze- dried. For further extraction, the residue was suspended in

50 mL of diluted hydrochloric acid (0.05 mol/L) and stirred for

1 h at

60 C. The suspension was centri........