Characterization of Acanthosicyos horridus and Citrullus lanatus seed oils: two melon seed oils from Namibia used in food and cosmetics applications

Abstract

The physicochemical characteristics, fatty acid, tocopherol, stigmasterol, β-sitosterol, and 1H NMR profiles of Citrullus lanatus and Acanthosicyos horridus melon seed oils were determined and compared among different extraction methods (cold pressing, traditional, and Soxhlet). The oil content was 40.2 ± 3.45 and 37.8 ± 7.26% for C. lanatus and A. horridus, respectively. Significant differences (p < 0.05) were observed among the different extraction methods in the characteristics studied. Physicochemical characteristics of the melon seed oils were saponification value, 180.48-189.86 mg KOH/g oil; iodine value, 108.27-118.62 g I2/100 g oil; acid value, 0.643-1.63 mg KOH/g oil; peroxide value; 1.69-2.98 mequiv/kg oil; specific gravity, 0.901-0.922; and refractive indices, 1.4676-1.4726. The dominant tocopherol was γ-tocopherol with total tocopherol in the range 27.61-74.39 mg/100 g. The dominant fatty acid was linoleic acid in the range 52.57-56.96%. The favorable oil yield, physicochemical characteristics, tocopherol, and fatty acid composition have the potential to replace or improve major commercial vegetable oils and to be used for various applications in the food industry and nutritive medicines.

Keywords: Acanthosicyos horridus; Citrullus lanatus; Melon seed oils; Namibia; Physicochemical characterization.

Conflict of interest statement

Authors report no conflict of interest.

Figures

Fig. 1

Seeds of C. lanatus (a), cold pressed (b), traditionally extracted (c) and Soxhlet extracted (d) C. lanatus melon seed oil, seeds of A. horridus (e) cold pressed (f) and Soxhlet extracted (g) A. horridus melon seed oil

Fig. 2

1H NMR spectra for cold pressed (a), Soxhlet extracted (b) A. horridus (!Nara) melon seed oil, cold pressed (c), Soxhlet extracted (d) and traditionally extracted (e) C. lanatus (Kalahari) melon seed oil