About Orange Essential Oil
Sweet orange essential oil (Citrus sinensis) is usually cold pressed from the peel of the fruit. The most prominent element of sweet orange oil is limonene, which comprises over 90% of the composition. Orange oil also contains myrcene and alpha pinene. This bright yellow to deep orange oil is used extensively in the food industry as a flavoring agent and comes from a plant that has been used for millennia in botanical medicine. It shouldn’t be confused with bitter orange, which can be phototoxic and has a different chemical composition.
Actions & Indications
Orange essential oil is used in food production for antimicrobial benefits and is both antifungal and antibacterial. Studies evaluating these benefits for internal use for human infections, however, do not exist. Therefore, the actions cannot be extrapolated to confer antimicrobial benefits for human infections when taken internally. Orange oil is also used as an anti-inflammatory agent and for chemopreventive benefits.
Orange oil can be used for food preparation and as a preventative agent as outlined below.
Laboratory Research Studies
Food Safety: Like many other essential oils, orange has been studied in depth for use in food safety as a protective agent against resistant pathogenic microorganisms, particularly Salmonella and Escherichia coli. Studies have evaluated the use of orange essential oil both as a feed additive to reduce the presence of resistant microorganisms in the intestines of food animals and to reduce the presence of resistance microorganisms in food products directly.
For example, a 2011 laboratory study conducted at Colorado State University through a grant from the National Cattleman’s Beef Association and published in the Journal of Food Science evaluated the benefit of orange essential oil on refrigerated beef storage. The study consisted of 41 isolated bacterial strains, many of which are multi-drug resistant. The MIC was identified and the oils were used to spray 120 beef brisket samples that had been inoculated with resistant strains. The study concluded that, in a petri dish, orange oil had the ability to eliminate all but one of the strains at concentrations below 0.4%. Most fascinating, however, is that when the orange oil was sprayed on the briskets at a 3% concentration, the total bacterial counts were significantly reduced. Similarly, a 2008 in vitro study in the journal Foodborne Pathogens and Disease also found that orange essential oil can successfully eliminate similar resistant microbes.
While this doesn’t provide much information in terms of actually treating food poisoning once it occurs, it could potentially be extrapolated to infer that combining orange essential oil with beef for culinary purposes has the potential to reduce the risk of foodborne illness from commercially processed meats. Therefore, traditional orange and beef recipes or orange and chicken recipes could be enhanced with the addition of a drop or two of orange essential oil in the recipe.
Digestive Health: The abundance of studies that evaluate the use of sweet orange oil against both fungal and bacterial isolates in vitro may indicate that the substance could be used to help promote healthy gut flora in human populations. While there are not any human studies that can confirm that extrapolation, there are studies that conclude that the addition of sweet orange oil to the diet of ruminants can reduce the population of resistant microbes, further improving food safety. The inclusion of orange oil in dietary preparations for individuals with impaired gut health due to microflora does not carry any risks, and the potential for benefit is significant. Sweet orange oil is recommended in numerous aromatherapy texts as a remedy for stomach complaints due to anecdotal evidence.
Animal Research Studies
Prevention: Orange oil has also been evaluated for use in prevention through an obscure but fascinating in vivo study conducted in 2001 in Mumbai, India and published in the Indian Journal of Experimental Biology. The researchers in this study acknowledged that d-limonene had been shown to have anti-carcinogenic and antimutagenic activity through numerous other studies and sought to evaluate the reversal of carcinogenic changes.
The experiment used 32 rats and essentially exposed them to carcinogens to determine a potential mechanism of action for these protective effects. The sweet orange oil was diluted in sunflower oil for administration. It was found that sweet orange oil “significantly inhibits the growth of liver tumors.” While many essential oils are touted as being cancer preventative or even as being effective at treating cancer, few studies are actually conducted in vivo to evaluate how the compounds achieve what has been noted in petri dishes. This promising study may support the inclusion of sweet orange oil in culinary preparations as part of a healthy prevention focused diet.
Orange Essential Oil Safety
Topical application of orange oil in large concentrations can cause dermatitis. The greatest risks with orange oil involve the potential for oxidation of the limonene component. Limonene oxidizes rapidly, resulting in an extremely short shelf life for the oil–typically 6-12 months. If consuming the oil for culinary or other purposes, orange oil should be fresh and stored in cool temperatures, ideally a refrigerator.
Essential oil ingestion (aka aromatic medicine) is not recommended for children younger than the age of 7, those who are pregnant or may become pregnant, those who are breastfeeding, and those with underlying health conditions without advanced training or consultation with someone trained specifically in the science of essential oil ingestion.
Ingestion: Orange oil is primarily used in aromatic medicine as an additive to culinary preparations to protect against pathogenic microbes. Most studies add the oil at 300-900ppm, but it can be used in recipes at up to 2% for a very strong orange flavor. It can also be added at 1-2% to cough syrups and other herbal remedies to balance stronger botanical flavors and to make pediatric preparations more child-friendly. The low risk of toxicity when suitably diluted makes orange oil an ideal choice for use in populations that would not otherwise consume essential oils. For medicinal purposes, no more than 12-15 drops of orange oil should be consumed each day.
LD50: >5g/kg (oral)
Tips & Notes
Cooking Tips: Orange blends well with both sweet and savory flavors. It can be used in baking, for frostings and in baked goods. It can also be blended into sauces with any Mediterranean herbs or spices, including rosemary, lavender, and oregano.
Methods of Administration: Due to the potential for irritation of sensitive mucus membranes, orange should always be diluted.
Anderson, R., Arthington, J., Callaway, T., Carr, M., Carroll, J., & Crandall, P., (2008). Antimicrobial activity of commercial citrus-based natural extracts against Escherichia coli 0157:H7 isolates and mutant strains. Foodborne Pathogens and Disease, 5.5, 695.
Anderson, R., Arthington, J., Callaway, T., Carr, M., Carroll, J., & Crandall, P., (2011). Orange peel products can reduce Salmonella populations in ruminants. Foodborne Pathogens and Disease, 8.10, 1071.
Bodake et al, (2001). Chemopreventive effect of orange oil in the development of hepatic preneoplast lesions induced by N-nitrosodiethylamine in rats: an ultrastructural study. Indian Journal of Experimental Biology, 40(3), 245.
Pittman, et al., (2011).Activity of citrus essential oils against Escherichia coli 0157:H7 and Salmonella spp. and effects of beef sub primal cuts under refrigeration. Journal of Food Science, 76(6), 433-8.