Proximate Composition and Physicochemical Properties of Matoa (Pometia pinnata) Seed and Seed Oil

Matoa (Pometia pinnata) trees can be found in many Asian countries. The flesh of matoa fruit is sweet and resembles the taste of other tropical fruits (longan, lychee and rambutan). This fruit is native to Indonesia; however, the seeds are considered waste. This study aims to determine the proximate composition of Indonesian matoa seeds and the physicochemical properties of matoa seed oil. The main composition of matoa seeds was moisture, carbohydrates, fiber and fat. The oil of dried matoa seeds was obtained through maceration extraction using n-hexane as a solvent. The oil extraction process was performed in a water bath shaker at 28 °C for 24 h. The oil yield of matoa seeds was 22.43%, with a yellowish green colour and a liquid state at ambient temperature. The physicochemical propertiesof oil, such as the refractive index (1.46), unsaponifiable matter (3.52%), slip melting point (26°C), smoke point (149.50 °C), iodine (46.09 g iodine/100 g oil) and saponification (144.41 mg KOH/g) values of the oil, were investigated. The acid (1.68 mg KOH/g), peroxide (0.97 mEq/kg), p-anisidine (0.78 mEq/kg), and totox (3.60 mEq/kg) values were also investigated to determine oil quality. Differential scanning calorimetry (DSC) thermograms of the oil displayed thermal transitions at low-temperature regions in crystallisation (below 0°C) and meting (below 26°C) profiles. Matoa could be a potential source of edible seeds and oil; however, intensive studies on the composition, antioxidant activity and toxicology are needed to explore the potential applications of these seeds and oil.