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- Emek, Sinan C, et al.
(author)
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A large scale method for preparation of plant thylakoids for use in body weight regulation.
- 2010
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In: Preparative biochemistry & biotechnology. - : Informa UK Limited. - 1532-2297 .- 1082-6068. ; 40:1, s. 13-27
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Journal article (peer-reviewed)abstract
- A method for preparation of thylakoids from plant leaves on a large scale is described. The method involves: 1) disruption of the cells with a blender followed by filtration to remove large cell debris and non disrupted cells. 2) precipitation of the thylakoids by adjusting the pH to the isoelectric point, pH 4.7. 3) a washing step by dilution of the precipitate in water followed by precipitation at the same pH. 4) concentration of the precipitate by freeze- thawing or freeze -drying to get the final product. The product is characterized, with respect to protein composition, by SDS-PAGE and mass-spectroscopy, the content of carotenoids, particularly the xanthophylls violaxanthin, antheraxanthin, and zeaxanthin. The thylakoid preparation has about the same capacity to inhibit pancreatic lipase/colipase activity as thylakoids prepared by standard laboratory methods using sucrose in the medium and centrifugation. In a study with mice, it was found that, when the thylakoids were added to the food over 32 days, they significantly reduced the body weight gain and the percentage body fat. The large scale method described here allows studies on the effect of thylakoids in appetite regulation on experimental animals in a longer lasting time and also on humans.
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| 2. |
- Rayner, Marilyn, et al.
(author)
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Chloroplast thylakoid membrane-stabilised emulsions.
- 2011
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In: Journal of the Science of Food and Agriculture. - : Wiley. - 1097-0010 .- 0022-5142. ; 91:2, s. 315-321
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Journal article (peer-reviewed)abstract
- BACKGROUND: Thylakoid-stabilised emulsions have been reported to possess satiety-promoting effects and inhibit pancreatic lipase-colipase activity in vitro, which prompted the investigation of their interfacial properties.RESULTS: Thylakoid membranes isolated from spinach were used as an emulsifier/stabiliser in oil (triglyceride)-in-water emulsions. Emulsions were characterised with respect to droplet size, interfacial tension, creaming, surface load and electron microscopy. The effects of pH and thylakoid concentration were also considered. Droplet size decreased with increasing thylakoid concentration, reaching a plateau around 15 microm beyond concentrations of 2 mg protein mL(-1) oil. The resulting emulsions were stable against coalescence but were subject to creaming. The surface pressure (air/water interface) of the thylakoid isolate was 44 mN m(-1) and the surface load 13 mg m(-2) at 10 mg protein mL(-1) oil. Electron micrographs showed thylakoids adsorbed as bunched vesicles on the drop surfaces. The stabilisation mechanism can be described as a combined effect of surface-active molecules, mainly membrane proteins but also membrane lipids, exposed on surfaces of thylakoid membrane vesicles adsorbed as particles.CONCLUSION: Thylakoid membranes effectively stabilise oil-in-water emulsions, which should facilitate their incorporation in food with satiety-promoting effects. To the authors' knowledge, this is the first study on the emulsifying properties of an isolated biological membrane as a functional ingredient.
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