Our habit! Crack rambutan open. Suck in the mouth watering flesh, then threw away the seeds and peels.
Imagine it on industry level, canning. They are simply discarded as waste and treated as of no economic value. What a huge waste of resource! Of course, dumped organic materials eventually decay and become fertilizer. However, we want something more than that. Something we can sell for more profit.
Jirawat Eiamwat et. al. (2014) conducted a study on possible toxicity of rambutan seeds. Why?
Taken from their manuscript:
It is a potential source of edible fat, 4-9% of the whole fruit and 14 to 41% of the seed.
Rambutan seed fat is semi-solid at room temperature (25-27°C) and characterized by high levels of oleic acid between 36.8 and 42.0% and arachidic acid between 34.3 and 36.4% (Harahap et al., 2011; Sirisompong et al., 2011; Solís-Fuentes et al., 2010; Yanty et al., 2013). Due to the physical and chemical characteristics, rambutan seed fat may provide an economic advantage with possible utilization in food and cosmetics.
Arachidic acid is for production of detergents, photographic materials and lubricants. Oleic acid is a healthy oil known to lower cholesterol levels. It maybe used as salad dressings, on baking and as replacement of animal fat.
The fear of toxicity fear us from using any unproven commodity, especially if it is not a common food for the man. Rambutan is delicious, perfectly edible and safe but we are unsure about the seeds. The usual practice is outright throw. Another example is the guyabano fruit. The flesh is perfectly safe but the seeds in known to have toxic substances. Thanks to its hard shell. I never affects us on accidental ingestion.
Is rambutan seed toxic?
According to their study results, fat and oils are not lethal to rats at levels of 5,000 mg/kg body weight.
Food technologists and Chemists! Grab the opportunity before somebody else do.
Toxicity studies on rambutan (Nephelium lappaceum) seed fat and oil extracts using acute oral, dermal and irritation assays
Jirawat Eiamwat, Sareeya Reungpatthanaphong, Saranya Laovitthayanggoon, Tuanta Sematong, Paramee Pengprecha, Benjaporn Tiensong, Patthanant Natpinit