Effects of Molecular Distillation on the Chemical Components, Cleaning, and Antibacterial Abilities of Four Different Citrus Oils

Abstract

Essential oils (EOs) from citrus fruits are excellent aromatic resources that are used in food, cosmetics, perfume, and cleaning products. EOs extracted from four citrus varieties, sweet orange, grapefruit, mandarin, and lemon, were separated into two fractions by molecular distillation. The composition, physicochemical properties, cleaning ability, and antimicrobial activity of each EO were then systematically evaluated. The relationships between each of the aforementioned characteristics are also discussed. In keeping with the principle of “like dissolves like,” most citrus EOs show better cleaning ability than acetone and all tend to dissolve the fat-soluble pigment. The key components of citrus EOs are 1-Decanol, α-terpineol, geraniol, and linalool for the inhibition of Staphylococcus aureus, Escherichia coli, Candida albicans, and Vibrio parahaemolyticus, respectively. The findings of this study will be of significant importance for the effective utilization of citrus peel resources and in the development of future applications for citrus EOs.Chemical Compounds Studied in This Article: (+)-α-Pinene (PubChem CID: 6654); β-Phellandrene (PubChem CID: 11142); 3-Carene (PubChem CID: 26049); β-Myrcene (PubChem CID: 31253); D-Limonene (PubChem CID: 440917); γ-Terpinene (PubChem CID: 7461); Octanal (PubChem CID: 454); Decanal (PubChem CID: 8175); Linalool (PubChem CID: 6549); 1-Octanol (PubChem CID: 957); β-Citral (PubChem CID: 643779); α-Terpineol (PubChem CID: 17100); Hedycaryol (PubChem CID: 5365392); α-Citral (PubChem CID: 638011); 1-Decanol (PubChem CID: 8174); Geraniol (PubChem CID: 637566).

The Chemical Composition and Antibacterial and Antioxidant Activities of Five Citrus Essential Oils

“…These results are in agreement with the present study that the antibacterial effect of GEO against E. coli was better than that of Salmonella . It suggests that the antimicrobial activity of citrus EOs was strain-dependent [ 27 ]. Viuda-martos et al [ 28 ] found that orange, lemon, mandarin and grapefruit EOs had lower inhibitory activity against Lactobacillus curvatus and L. sakei , which was confirmed by the present study, with the lowest inhibitory effect against these two bacteria at the highest concentration.…”

Comparison of different extraction methods of active ingredients of Chinese medicine and natural products

“…At present, the classical extraction methods of CM and natural products mainly include decoction [25, 26], maceration [27–29], reflux [30, 31], percolation [21], steam distillation [32] and sublimation [33, 34]. With the development of modern separation science and equipment, some new technologies such as ultrasonic wave‐assisted extraction (UAE) [35–38], microwave‐assisted extraction (MAE) [39–42], supercritical fluid extraction (SFE) [43–47], enzyme‐assisted extraction (EAE) [48, 23, 49], membrane separation extraction (MSE) [50–57], ultrafine grinding technology (UGT) [58–64], microporous resin adsorption technology (MRAT) [65–70], semi‐bionic extraction (SBE) [71, 72], immune selective extraction (ISE) [73–77], molecular‐distillation technology [78–82], molecularly‐imprinted polymer extraction (MIPE) [83–88], UPE [89–93], liquid chromatographic extraction (LCE) [94–99], solid‐phase extraction (SPE) [100–107], liquid–liquid extraction (LLE) [108–112], etc. have been given birth to.…”

“…Cheng et al used it to extract palmitoleic acid from the fruit of Sea buckthorn [80], while Meng et al used it for the purification of industrial lactic acid [81]. It has the advantages of gentle extraction process, easy degradation of effective components, multi-stage series to further improve the extraction selectivity, organic solvent removal and high efficiency of decolorization and deodorization [78,79], but it is not suitable for mixed high boiling point components with similar molecular weight. Besides it requires pre-concentration and other pretreatment [82], so the operation is more complicated.…”

“…When the liquid mixture flows along the heating plate and is heated, the light and heavy molecules will escape from the liquid surface and enter the gas phase. Because the free path of the light and heavy molecules is different, if a cold condensing plate can be set in the right position, the light molecules will be condensed out of the plate, and the heavy molecules will be discharged with the mixed bottom liquid [78,79]. At the same time, the distance between the evaporator and the cold condensing plate can be adjusted for the separation of different molecular weights.…”

Antibacterial efficacy of Citrus hystrix (makrut lime) essential oil against clinical multidrug-resistant methicillin-resistant and methicillin-susceptible Staphylococcus aureus isolates

“…Citrus plants belong to the family of Rutaceae containing around 1,300 species ( Kamal et al, 2011 ). The citrus EOs are colorless to yellowish transparent liquids with a density of around 0.8 g/mL and a refractive index of approximately 1.46–1.47 ( Yang et al, 2021 ). The major component is d-limonene accounting for 25–97% of the total component ( Jing et al, 2014 ).…”