Extraction and analysis of prebiotics from selected plants from southern Thailand.

Thirteen plants and their parts acquired from southern Thailand were investigated for their polysaccharide contents and prebiotic properties. The fresh, ground samples were extracted with 50% and 95% ethanol and water at ambient and boiling temperatures. The extracts were freeze-dried, digested with HCl buffer and -amylase, and indigestible polysaccharide contents were determined. Base on extract yields and indigestible polysaccharide contents, ten samples were chosen as potential sources of prebiotics. These included embryo, flesh and pericarp of palm fruit (Borrassus flabellifer L.), skin, flesh and seed of jackfruit (Artocarpus heterophyllus Lam.), flesh of rambutan (Nephelium lappaceum L.), jampadah (Artocarpus integer Merr.), and young coconut (Cocos nucifera Linn.), and okra pod (Hibiscus esculentus Linn.). Their extract yields (% dry wt) were 26.54, 44.94, 51.69, 71.54, 59.43, 16.00, 55.73, 34.11, 22.66, and 12.39, respectively, and indigestible polysaccharide contents (mg/g dry extract) were 409.85, 334.87, 705.80, 689.08, 605.76, 403.44, 566.83, 542.56, 513.87, and 460.73, respectively. The amounts of oligosaccharide were 33.69, 47.20, 14.13, 0.00, 98.05, 29.35, 9.43, 2.40, 0.00, and 49.15 mg/g dry extract, respectively. Subsequently, five samples were chosen for further studies and possible commercial development based on their extract yield, the amount and type of oligosaccharides, i.e. palm flesh, palm embryo, jackfruit flesh, jackfruit seed, and okra pod. Molecular weights of the polysaccharides from the five samples were 190-1,600 Daltons with a degree of polymerization of 5-6.