Characterization of the seed and seed extracts of the pumpkins Cucurbita maxima D. and Cucurbita pepo l. from Macedonia

Abstract

Chemical composition of seeds of C. maxima D. and C. pepo L. cultivated in the Republic of Macedonia and physico-chemical characteristics, fatty acid profiles, and sterol and tocopherol contents in pumpkin seed extracts were determined. Higher kernel yield and content of moisture, ash, total nitrogen, proteins and carbohydrates were measured in the C. pepo than in C. maxima seed. The highest extract yield of 487.4 g/kg dry matter was obtained from C. pepo kernel, while 388.2 g/kg dry matter was extracted from C. maxima kernel, when n-hexane was used as solvent. In all extracts, the palmitic, stearic, oleic and linoleic acids were predominant. The linoleic/oleic acid ratio was higher in C. maxima extracts. D7-Sterols were predominant in all extracts, while D5-sterols content was higher in the whole seed than in the kernel extracts. Higher tocopherol content was determined in the extracts of C. pepo whole seed and kernel (153.79 mg/kg and 117.81 mg/kg, respectively), than in those of C. maxima (121.24 mg/kg and 117.55 mg/kg, respectively). In all extracts γ-tocopherol content was higher than α-tocopherol.

The influence of solvents polarity on physicochemical properties and oil yield extracted from pumpkin (Cucurbita maxima) seed

“…The saponification values of the oils were increasing with respect to the increasing polarities of the solvents signifying the influence of the solvent polarity on oil quality. The saponification values obtained in this study are in agreement with what other authors previously reported on pumpkin spp seed oil extracted using nhexane by shaking and in soxhlet apparatus (Ardabili et al, 2011;Srbinoska et al, 2012). However, Chatepa and Masamba 45 saponification values for acetone and ethanol extracted oils were more than 91.16±3.63 mg KOH/kg for pumpkin (Telfairia occidentalis) seeds oil extracted using petroleum ether in a soxhlet apparatus (Eddy et al, 2011) and 44.88 mg KOH/kg (Eze, 2012) using n-hexane in a soxhlet apparatus reported in Nigeria.…”

“…The findings in this study have shown that the choice of solvents, with respect to solvent polarity, influences the oil quality in terms of acid value. The acid value of oil extracted using cyclohexane was similar to 2.05 for Cucurbita mixta oil (Borhade, 2012) but lower compared to values of 4.07 and 4.71 mg KOH/g reported by other authors (Srbinoska et al, 2012) for C. maxima and Cucurbita pepo seed oil extracted using n-hexane in soxhlet apparatus. The Codex Alimentarius Commission (1982) recommended the maximum acid value of 10 and 4 mg KOH/g oil for virgin palm and coconut oil respectively.…”

“…The extraction efficiency increases with the increase in temperature and water content reduction (Johnson and Lusas, 1983). Oil yield of 6.46% from ethanol extraction was comparable to 5.71 and 5.92% of oil extracted using ethanol in soxhlet apparatus method (Srbinoska et al, 2012) for C. maxima and C. pepo seeds reported in Macedonia. C. maxima seeds oil extracted using petroleum ether was comparably similar to 29.0% extracted using petroleum ether in soxhlet apparatus method (Montesano et al, 2018) reported in Italy.…”

“…Furthermore, the obtained values for refractive index of the crude oil were in line with those previously reported by other authors for pumpkin maxima seed oil (1.4656±0.004) (Alfawaz, 2004) and oil from other Cucurbita spp. seed oil extracted using petroleum ether and n-hexane in soxhlet apparatus (Tsaknis et al, 1997;Srbinoska et al, 2012).…”

“…However, the quality of the crude oil from solvent extraction is dependent on the type of solvent, temperature and pretreatment of the oil seed prior to extraction process (Tasan et al, 2011). From the available literature, it is evident that studies on physical, physicochemical and phytochemical characteristics of oil extracted from C. maxima, using solvents of varying polarity, have not been extensively conducted and have been reported by limited number of authors (Montesano et al, 2018;Srbinoska et al, 2012;Tsaknis et al, 1997). In addition, there is existence of limited literature on the quality characteristics of oil extracted by solvents of varying polarities.…”