RESUMO
In this paper, the chemical composition, the main physicochemical properties, phase behavior and thermal stability of rambutan (Nephelium lappaceum L.) seed fat were studied. These results showed that the almond-like decorticated seed represents 6.1% of the wet weight fruit and is: 1.22% ash, 7.80% protein, 11.6% crude fiber, 46% carbohydrates, and 33.4% fat (d.b.). The main fatty acids in the drupe fat were 40.3% oleic, 34.5% arachidic, 6.1% palmitic, 7.1% stearic, 6.3% gondoic, and 2.9% behenic; the refraction, saponification and iodine values were 1.468, 186, and 47.0, respectively. The phase behavior analysis showed relatively simple crystallization and melting profiles: crystallization showed three well-differentiated groups of triglycerides around maximum peaks at +30.8, +15.6 and -18.1 degrees C; the fat-melting curve had a range between -14.5 and +51.8 degrees C with a fusion enthalpy of 124.3 J/g. The thermal stability analyzed in an inert atmosphere of N(2) and in a normal oxidizing atmosphere, showed that in the latter, fat decomposition begins at 237.3 degrees C and concludes at 529 degrees C, with three stages of decomposition. According to these results, rambutan seed fat has physicochemical and thermal characteristics that may become interesting for specific applications in several segments of the food industry.
Assuntos
Gorduras/química , Sapindaceae/embriologia , Sementes/química , Varredura Diferencial de Calorimetria , Cristalização , Cromatografia Gasosa-Espectrometria de MassasRESUMO
Four isolectins (TEL-I, TEL-II, TEL-III and TEL-IV) were isolated from seeds of Talisia esculenta by reverse-phase high-performance liquid chromatography. RP-HPLC was performed on a u-Bondapack C18 column (0.78 cm x 30 cm) (Waters 991-PDA system) at room temperature. Rechromatography of the four fractions on a C18 column under the same conditions yielded lectins with two dissimilar subunits (Mr 20 kDa and 40 kDa) bound noncovalently. The isolectins showed very similar characteristics, such as molecular masses, N-terminal sequences, and hemagglutinating activity, but differed in their isoelectric points and in inhibition by carbohydrates.