Previously, a diet with a high content of MUFA hasbeen proved to decrease cardiovascular morbidity andmortality [50]. In addition, plant oils rich in PUFA (espe-cially linolenic acid and c-linolenic acid) may help to reg-ulate the blood plasma triglyceride levels in patients withdyslipidemia, lower the blood pressure, and protect againstcoronary heart disease

Carotenoids are also found in high con-tents (66.33 ± 0.90 mg kg−1 oil) in the acorn oil extractedfrom Q suber L.; this oil is also rich in chlorophylls(2.03 ± 0.01 mg kg−1 oil) [21]. Acorns (Q. faginea) are rich inlycopene compound (183 ± 141 g/g dm) and β-carotene(1312 ± 890 (μg/g dm)

e level of phenolic contents (expressed in gallicacid equivalent) ranged between 195.6 and 322.06 mg GAE/kg oil while flavonoid contents (expressed in catechinequivalent) ranged between 122.99 and 131.6 mg CE/kg ofoil. *e total phenolic compound contents in different va-rieties of acorn oil ranged between 84 and 109 mg/kg [2].*ese compounds contribute to increasing the oxidativestability of the acorn oil.

Recently, Gornaset al. [13] reported that β- and c-tocopherols are pre-dominated homologues in acorn oils from Q. rubra andQ. robur. *e total concentration of tocopherols in Q. roburacorn oil was 447.7 mg/100 g oil, whereas the concentrationin Q. rubra acorn oil was 78.4 mg/100 g oil.

Acorn oils are also anexcellent source of tocopherols, since it was found thattocopherol contents in acorn oils range from 1440 to1783 mg/kg oil, which were much higher than those reportedfor other species such as olive (240 mg/kg)

Tocopherols and Phenolic Compounds. Tocopherols arelipid-soluble phenolic compounds that naturally exist inoilseeds in four different forms (α-, β-, c-, and δ-tocoph-erols). *ese compounds are valued for their capacity toprotect humans from the oxidative damage mediated byactive oxygen and nitrogen species and prevent lipids andlipid-containing foodstuffs from oxidation during storage[41]. Furthermore, Tocopherols have been shown to play apivotal role in preventing hormone-dependent breast cancerprogression, colon carcinogenesis, lung tumorigenesis, andprostate cancer cell growth [18

induced antiproliferative effects on the growth of CHO-K1and human melanoma oncogenic cell lines [39]. Addi-tionally, docosanol displayed antiviral activity on the herpessimplex virus (HSV-1) by interfering with early intracellularevents surrounding viral entry into target cells

Furthermore, acorn oils were reported to contain ap-preciable amounts of aliphatic alcohol (2190–2240 mg/kg)[17]. Tetracosanol was the predominant compound of thisclass (43.70%–59.48%), followed by hexacosanol(18.66–26.93%), yet, docosanol and octacosanol were the lessabundant aliphatic alcohol in acorn oils, consisting of13.17–26.24% and 1.52–9.33%, respectively

Phytosterol consumption isimportant for consumers to decrease cholesterol levels in theblood [19]. In addition, it displayed anticancer properties invivo on prostate, lung, stomach, ovarian, colon, and breastcancer [

Phytosterol is present in acorn oil between4632.71 and 11576.09 mg/kg, [17] which were inclusivelyhigher than those reported for almond (1430 mg/kg), soy-bean (1600 mg/kg), olive (2210 mg/kg), pistachio (2790 mg/kg), and pine oils (4298 mg/kg), despite being in the samerange as those described for sesame and corn oils(8650–9680 mg/kg, respectively) [35–37]. *e acorn oils aregenerally characterized by a high percentage of β-sitosterol(88.3–92.5%) followed by campesterol (1.57–4.28%) andcampesterol (1.57–4.28%). However, stigmasterol, cler-osterol, 5-avenasterol, 5,24–stigmastadienol, Δ7-stigmaste-nol, and Δ7-avenasterol were present with minor amounts(lower than 2%) [17]. Moreover, [13] investigated the sterolcomposition of different varieties of acorn and foundβ-sitosterol as dominant (64.3%–68.1%) followed bycycloartenol (11.4%–15.0%), campesterol, Δ5-stigmasterol,Δ5-avenasterol, and 24 methylenecycloartanol (rang of3.0–6.7%). *e amounts of campestanol, sitostanol, and Δ7-avenasterol were below 3.0%.

Phytosterols and Aliphatic Alcohols. Plant sterols andplant stanols, known commonly as phytosterols, are animportant group of natural compounds, biologically activein the prevention of several diseases

Based on these findings, it can be concluded that acornoil is a healthy source of important fatty acids which canbe used for the dietary purpose and cosmetic uses. Inaddition, the difference in their percentages may be usefulas a biochemical fingerprint to differentiate between acornspecies.

Stearic acid is a long-chain saturated fattyacid which is known to be neutral in its effect in the cho-lesterol concentrations in human

Stearic acid (1%–4%), eicosenoicacid (0.37%), arachidic acid (0.38%), behenic acid (0.12%),and behenic acid (0.20%) are shown in minor compositionin the acorn oil.

Numerous studiesshowed that these fatty acids, especially α-linolenic acid, canhave a role in promoting blood lipid profile and treating thesymptoms of dermatitis.

Acorn oilscontain high amounts of linoleic acid (37.2%–32.6%) andc-linolenic acid (1.8% to 3.7%)

As described previously, oleic acid(OA) is the main monounsaturated fatty acid (MUFA)present in acorn oil. Several studies have revealed thebeneficial propriety, particularly in preventing diabetesmellitus T2DM and decreasing cardiovascular disease risk,besides contributing to improving hemostasis, platelet ag-gregation, and fibrinolysis

*epercentage of oleic acid in acorns is significantly higher thanin other fruits generally considered a natural source of oleicacids such as walnut (21%), peanut (38.41%), and mustardoil (36.7%) [33] with the concentration of this acid beingonly exceeded by olive oil (56%–84%)

the major saturated fatty acid ispalmitic acid ranging from 11.69% to 16.22%

Oleic and linoleic acids are the majorunsaturated fatty acids described in acorns species, rangingfrom 65.83% to 48.02% and 25.38% to 14.17% of total fattyacids

As regards the physical properties, acorn oilsshowed a refractive index ranging from 1.449 to 1.453 [21].*ese values are similar to those reported previously by [2]for acorn oils from other species and comparable to othervegetable oils such as olive oil 1.4677–1.4705.

e specific gravity ofthe oil extracted from acorn ranges from 0.912 to 0.922[2, 30], similar to the specific gravity of diesel oil (1.0) [29].*is finding revealed that acorn oils are suitable for dieselproduction.

*e free fatty acid (FFA) content is an important pa-rameter to evaluate the quality of an oil. *e oil is moresuitable for human consumption when it possesses low FFAcontent [29]. *e percentage of free fatty acids reported foracorn oils ranges from 0.92% to 5.8%. High values of FFAobserved in acorn oils may be caused by the bad conser-vation of the fruits before extraction and analysis or theincomplete ripeness of the seeds [12

*e iodinevalue represents the degree of unsaturation of the oils andthe fat, and the more unsaturation leads to a higher iodinevalue [29]. *e iodine value for acorn oil reported by [2] was75–88 g/100 g, which is comparable to the value of olive oil75–94 g/100 g. *e highest iodine value of acorn oil wasreported to be 129.6 g/100 g [21].

]. *esaponification values of acorn oils range from 160.3 to220 mg KOH/g. *e saponification value of acorn oils iscomparable to that of olive oil (184–196 mg KOH/g) [2]. *isrelatively high saponification value indicates that oils holdfatty acids with a high number of carbon atoms

Acorn oil presents good nutritional quality,and its flavor is comparable to that of olive oil

e oil content of acorn speciesranged from 5% to 20% depending on the variety and lo-calization of the collected sample. However, Ofcarcik et al.[28] reported higher oil yield (about 30%) in black and redacorn species

. In com-parison to Soxhlet extraction, SFE using carbon dioxide(CO2) is considered to be a green processing technique,avoiding the problem of contamination of the oil by a re-sidual solvent. Moreover, carbon dioxide is safe

Focused microwave-assisted Soxhlet extraction(FMASE) has already been successfully used to extract oilfrom acorns. *is method is based on the same principles asa conventional Soxhlet extractor but is modified to facilitateaccommodation of the sample cartridge compartment in theirradiation zone of a microwave oven [23]. P ́erez-Serradillaet al. [24] mentioned that FMASE provides an advantageover conventional methods because it enables total extrac-tion of the fatty acids in 30 min, which is much less than thetime required by the Folch (4.5 h), Soxhlet (16 h), ISO (8 h)reference methods, and the stirring–extraction method(56 h). Also, it was found that the degree of unsaturation ofthe oil extracted by FMASE is significantly dependent on theextraction conditions.

Soxhletextraction (SE) uses an organic solvent such as hexane andpetroleum ether which are widely applied to extract oil fromacorn [2, 12, 17, 21]. *is method is considered an efficienttechnique for over a century; the most outstanding ad-vantage of SE includes simplicity (no filtration is requiredafter the leaching step) and low energy consumption [22].Nevertheless, using a solvent is toxic and hard to be totallyeliminated, and this could result in severe contamination forthe final products

Tra-ditionally, cold pressing is one of the most methods used toproduce acorn oil. *is operation can be performed in lowpressure at about 0.5 MPa [1, 14]. Generally, cold pressing ismore preferable as it required less energy than other oilextraction techniques, is environmentally friendly, and alsoleads to the short duration of the process

Phytosterols(mainly β-sitosterol) are also present in acorn oil between4632.71 and 11576.09 mg/kg, which are inclusively higherthan those reported for almond (1430 mg/kg), soybean(1600 mg/kg), olive (2210 mg/kg), pistachio (2790 mg/kg),and pine oils (4298 mg/kg) [17]. *ese compounds withvarious biological activities are useful for promoting thedecrease of blood serum triglycerides and cholesterol levels[19].

Generally, in acorn oils, the predominant homologs oftocopherol are c-T and α-T, while β-T and δ-T are present inlow amounts or absent

*e fatty acid composition and physicochemical prop-erties of acorn oil are extremely similar to those of olive oil[2, 11, 12]. Acorn oil is rich in unsaturated fatty acids(75–90%), especially oleic acid (65%), and essential fattyacids such as linoleic (17–37%) and α-linolenic (1–4.58%)acid (Table 1), which is important in eicosanoid synthesis,promoting the decrease of blood serum triglycerides and theincrease of HDL-cholesterol levels.

Acorn oil has been receiving increasing attention due to its nutritional potentials. However, its application as a novel foodingredient has not yet been fully explored.