Physico-chemical and functional properties of watermelon (Citrullus lanatus) seed-oil

Abstract

Citrullus lanatus (water melon) is popular fruit and the seeds were rich in oil and protein, this oil could be exploited as edible oil. Citrullus lanatus contains about 6 per cent sugar and 92 per cent water by weight. As with many other fruits, it is a source of vitamin C. The seed being an excellent source of energy and the dried composition of watermelon per 100 g edible portion (50-70% of the mature fruit) include: water 91.5 g, energy 134 KJ (32 kcal), protein 0.6 g, fat 0.4 g, carbohydrates 7.20 g. The favorable functional properties makes the seed and the oil suitable for human consumption and therefore the result of this research work would provide further information on the domestic and industrial usage of the seed and seed-oil.

Effect of Boiling and Fermentation on Physicochemical Properties, Fatty Acid and Micronutrients Composition of Hibiscus sabdariffa (Roselle) Seeds

“…The low levels of percentage FFA in the three samples (1.26, 2.01 and 2.05% respectively) indicate that the oils from them may be useful edible oils that may be stored for a long time without spoilage via oxidative rancidity. The peroxide value of the samples were higher than that reported for water melon seed (3.24 mleq/kg) by Gladvin et al [25] and different refined groundnut species (1.30 -1.73 mleq/kg) by Nkafamiya et al [26] but lower than those of Opuntia dilleni (15.60 mleq/kg) by Njoku et al [27], crude groundnut oils (22.06 -25.03 mleq/Kg) [26], Duranta repens leaf oil (20.00 mleq/kg) and Duranta repens seed oil (12.29 mleq/kg) by Agomuo et al [10]. The peroxide values of the samples of Hibiscus sabdariffa seeds increased possibly as a result of boiling and fermentation.…”

Extraction and Characterization of Underutilized Seed Oils Sampled in South-western Nigeria

“…Specific gravity of 0.88 was determined in watermelon seed oil; while that of Sesame seed oil was 0.90. Refractive index of 1.47 at 30 o C observed in this study for watermelon seed oil is similar to 1.4712 which was reported by [19] for watermelon seed oil analyzed in India; sesame seed oil also had a refractive index value of 1.47. Refractive index is an indication of the level of saturation [11], the similarity of the refractive index of the two seed oils suggests that they have similar levels of saturation [19].…”

“…Refractive index of 1.47 at 30 o C observed in this study for watermelon seed oil is similar to 1.4712 which was reported by [19] for watermelon seed oil analyzed in India; sesame seed oil also had a refractive index value of 1.47. Refractive index is an indication of the level of saturation [11], the similarity of the refractive index of the two seed oils suggests that they have similar levels of saturation [19]. Watermelon seed oil analyzed in this study had a golden brown colour, while sesame seed oil had a carton brown colour, Mbaebie et al, [18] reported a dark brown colour for sesame grown in Southeastern Nigeria.…”

“…Sesame seed oil had pH of 5.87 which is also more acidic than 6.12 reported by Saeed and Shola, [17]. Saponification values of the two seed oils analyzed were on the high side, watermelon seed had 258.99mg KOH/g oil, which is a bit higher than 218mg KOH/g oil reported by Gladvin et al, [19] for Indian watermelon seed oil. Sesame seed oil on the other hand had 261.34 mg KOH/g oil; this is higher than 192.70mgKOH/g reported by Saeed and Shola, [17].…”

“…Acid value, a measure of free fatty acid (FFA) content of oils indicates that both oils are in good non-degradable state [17]. Watermelon seed oil had acid value of 2.51mgKOH/g, this is lower than 4.4mg KOH/g oil reported by Gladvin et al, [19] while sesame seed oil had acid value of 2.13mg KOH/g, this is similar to the value reported by [18]. According to Saeed and Shola [17], maximum acceptable level for acid value is 4mgKOH/g oil, acid values of the oils analyzed is below this, which means they are acceptable for consumption.…”