This review of literature provides an overview on the compositional data of Rambutan (Nephelium lappaceum Linn.) and rambutan seed fat for usage in chocolate product. It is a seasonal fruit native of west Malaysia and Sumatra. It is harvested when the fruit have reached optimum visual and organoleptic quality. Rambutans rapidly deteriorate unless proper handling techniques are employed. The rambutan fruits are deseeded during processing and these seeds (~ 4-9 g/100 g) are a waste by-product of the canning industry. And some studies was showed that rambutan seed possesses a relatively high amount of fat and these fats are similar to those of cocoa fat, although have some different physical properties. In the present research about rambutan seed fat continued increasing due to from previous research was found that this fat can use as substitute in cocoa butter for chocolate products. Therefore, the extracted fat from rambutan seed not only could be used for manufacturing candles, soaps, and fuels, but it also has a possible to be a source of natural edible fat with feasible industry use.
The study was conducted to investigate fatty acid composition, rheological properties and crystal formation of rambutan fat and cocoa butter. The results showed that lauric acid, palmitic acid, and stearic fatty acid in rambutan fat were less than cocoa butter, but oleic acid found almost the same. The crystal formation of cocoa butter was not complex at 25oC, while rambutan fat and their mixture shown complicated network of crystal form. The Newton, Bingham and Casson plastic rheological models was used to describe fat flow in this experiment and the result showed that rambutan fat had higher viscosity than cocoa fat. Based on the results the study recommended that mixture proportion up to 30% rambutan seed fat can be used as a cocoa butter substitute whereas higher proportion completely alters original cocoa butter properties. Therefore, there is feasibility of using the rambutan fat to substitute cocoa butter and the mixtures of the two fats in suitable proportion in chocolate manufacturing.
Fat content and macroscopic properties of fat network formulation result in final products in chocolate industry. The knowledge of physical properties is required in regard to stability of final food products resulting to quality. The study was carried out to investigate the thermal behavior, solid fat content and hardness of Rambutan fat (RF), cocoa butter and mixtures between two fats. The results found that the mixtures can be compatibility; the cocoa butter indicated the higher of solid fat content at room temperature more than RF and other mixtures. The RF had the highest melting point in both non-stabilized and stabilized form among cocoa butter and their mixtures. The hardness behavior showed lower in the mixture 1 and RF. For the phase behavior of crystallization exhibited the similar for all samples whereas the time of crystallization and temperatures were different. Therefore, the RF might be possible source of cocoa butter substitute with suitable proportion in the manufacturing chocolate and confectionery products.