Physical and chemical analysis of Passiflora seeds and seed oil from China

The physical and chemical properties of seeds and seed oil from 'Tainung No. 1' passion fruit in China have been analyzed in order to evaluate their nutritional value. Proximate analysis shows that the seeds have a high amount of protein (10.8 +/- 0.60%) and are rich in oil (23.40 +/- 2.50%). The seeds are found to be a good source of minerals. They contain considerable amounts of sodium (2.980 +/- 0.002 mg/g), magnesium (1.540 +/- 0.001 mg/g), potassium (0.850 +/- 0.001 mg/g), and calcium (0.540 +/- 0.002 mg/g). The passion fruit seeds contain the 17 amino acids that are found naturally in plant protein (tryptophan is not analyzed). The essential amino acids account for 34% of the 17 amino acids. The amino acid score of passion fruit seeds protein is 74 and the first limiting amino acid is methionine and cystine. The oil extracted by solvent and supercritical dioxide carbon is liquid at room temperature and the color is golden-orange. The specific gravity of the oil is about 0.917. Comparing the chemical properties of the oil extracted by solvent with that by supercritical dioxide carbon, the latter may be suitable as edible oil directly, while the former will be edible after it must be refined to improve on clarity. Fatty acid composition of the seed oil indicates that the oil contains two essential fatty acids (linoleic acid and linolenic acid), but the content of linoleic acid (72.69 +/- 0.32%) is by far greater than that of linolenic acid (0.26 +/- 0.00%). The present analytical results show the passion fruit seed to be a potentially valuable non-conventional source for high-quality oil.