Characterization of two Moroccan watermelon seeds oil varieties by three different extraction methods

Abstract

The purpose of this study is to assess and evaluate the physicochemical properties of the seed oils of two Moroccan varieties of watermelon “Citrullus lanatus” extracted by three different techniques, a mechanical process using cold press, and two chemical processes using a Soxhlet apparatus and a sonotrode ultrasound assisted extraction (UAE) using n-hexane. The total phenolic compounds (TPC) and antioxidant properties against the DPPH radicals (2,2-diphenyl-1-picrylhydrazyl) were also studied. The seed oils of both varieties of watermelon exhibited high concentrations of unsaturated fatty acids with the predominance of linoleic and oleic fatty acids. The primary sterol was β-sitosterol, and high levels of total tocopherols were observed. Ɣ-tocopherol was the predominant tocopherol in all tested oils. The Citrullus lanatus var. lanatus variety seeds oil exhibited the highest TPC value (89.5 ± 0.06 mg EGA/100 g; EGA: gallic acid equivalent), with 82.4 ± 0.03% DPPH free radical inhibition efficiency. Nevertheless, all tested seeds oils showed a significant amount of total phenolic compounds and a good inhibition against DPPH radicals ranging from 51.1 ± 0.1% to 84.8 ± 0.04%. In addition, the influence of the ultrasonic extraction parameters was studied using two different solvents (n-hexane and the methanol-chloroform mixture), with different particle sizes (500–300 µm), duration (10 and 20 minutes), cycle (1–0.5), amplitude (80–100%) and solvent/seed ratios (1:5 and 1:10), and the seed roasting parameter was also studied. The oil yield was mainly affected by the extraction solvent, then the solvent/seed ratio and the duration, respectively.

Valorization of apricot, melon, and watermelon by-products by extracting vegetable oils from their seeds and formulating margarine

“…Similarly, in WSO oil, the predominant fatty acids were palmitic, stearic, oleic and linoleic acids (Dumitru and Tutunea, 2017;Ok and Yilmaz, 2019;Petchsomrit et al, 2020). The same trend was observed by Ouassor et al (2020) when studying two varieties of watermelon. According to Zarifikhosroshahi and Ergun (Zarifikhosroshahi and Ergun, 2021), the order of importance of fatty acid contents in WSO is as follows: palmitic, oleic, stearic, and linoleic acids.…”

“…Besides, the AVof WSO found in this current study is in the range of the contents of the oils obtained from the two varieties of Moroccan watermelon seeds using various extraction methods (1.40 ± 0.03 and 2.80 ± 0.06 mg KOH/g oil). Nevertheless, these authors observed greater PV (6.00 ± 0.08, 4.0 ± 0.67 and 3.80 ± 0.20 meq O 2 /kg oil) (Ouassor et al, 2020).…”

“…The best content of linoleic acid was attributed to the oil resulted from Soxhlet (67.43%) for the variety "lanatus". Otherwise, the best oleic acid level (19.08%) was attributed to the oil of variety "citroides" extracted by cold pressing (Ouassor et al, 2020). The method of preservation of watermelon fruit (room temperature, at þ 4 °C for 12 months and newly harvested seeds) has shown an effect on the fatty acid contents of the oils of its seeds.…”

Watermelon seeds and peels: fatty acid composition and cosmeceutical potential

“…The oil content of watermelon seeds is in the range of 10-35%, varying depending on the genotype (Ziyada and Elhussien, 2008;Mahla et al, 2018). Watermelon seed oil is reported to be a good source of essential fatty acids, carotenoids, tocopherols, thiamine, flavonoid, riboflavin, and other phenolic substances, quantities of which vary depending on watermelon variety and extraction method (Ouassor et al, 2020). Linoleic acid is the most abundant fatty acid found in watermelon seed oil irrespective of variety.…”

Pathway among fatty acid profile, seed germination, and vigor of watermelon cultivars

“…Although the oil content of watermelon seeds vary according to the genotype, it is in the range of 10-35% (Ziyada and Elhussien, 2008;Mahla et al, 2018). Watermelon seed oil is a rich source of essential fatty acids, the amount of which varies depending on the extraction method and cultivar (Ouassor et al, 2020). Linoleic acid is the most abundant fatty acid in watermelon seed oil, regardless of the cultivar.…”