Basil leaves

Description
Basil leaves come from the aromatic herb Ocimum basilicum (Lamiaceae), widely used in Mediterranean and Asian cuisines. They are bright green, soft, and highly fragrant, with a fresh, sweet-herbaceous and slightly balsamic aroma. Their characteristic flavour is mainly due to the essential oils stored in the leaf tissues.

Indicative nutritional values per 100 g (fresh leaves)

• Energy: 20–25 kcal

• Water: ≈ 92%

• Carbohydrates: 2–3 g

  • of which sugars: ≈ 0.3–0.6 g

• Protein: 2.5–3.5 g

• Total fat: ≈ 0.6 g

  • SFA (saturated fatty acids; excessive intake may adversely affect cardiovascular health): traces

  • MUFA (monounsaturated fatty acids; generally considered heart-friendly): traces

  • PUFA (polyunsaturated fatty acids; involved in cellular and metabolic functions): traces

• Dietary fibre: 1.5–2 g

• Vitamins: vitamin C, vitamin K, provitamin A (β-carotene)

• Minerals: calcium, potassium, iron, manganese

Values may vary depending on variety, maturity, cultivation system and storage.

Key constituents

• Essential oils: linalool, eugenol, methyl chavicol (estragole)

• Phenolic acids: rosmarinic acid, caffeic acid

• Flavonoids: orientin, vicenin and related compounds

• Carotenoids: β-carotene, lutein

• Vitamins: C, K, provitamin A

• Minerals: potassium, calcium, iron, manganese

• Plant fibres and small amounts of natural sugars

Production process

• Cultivation in open field, greenhouse or hydroponic systems with controlled irrigation and fertilisation

• Manual harvesting of the leaves to preserve integrity and stimulate regrowth

• Sorting and washing to remove soil, foreign bodies and damaged leaves

• Gentle drying of surface moisture to reduce browning and microbial growth

• Packaging in punnets, bunches, pouches or as potted plants

• Refrigerated storage and distribution to maintain freshness and aroma

• Possible processing into pesto, frozen leaves, dried herbs, extracts and essential oils

Physical properties

• Thin, soft, light leaves with smooth or slightly crinkled surface

• Bright green colour, turning darker or brownish when damaged or aged

• High moisture content and high perishability

• Rapid oxidation and darkening after cutting or strong mechanical stress

• Heat sensitive: prolonged cooking degrades colour and aroma

Sensory and technological properties

• Aroma: fresh, sweet-herbaceous, slightly spicy and balsamic

• Taste: aromatic, delicate yet persistent

• Best performance when used raw or added at the end of cooking

• Essential oils are volatile and easily lost with high temperatures or long cooking times

• Suitable for pestos, cold sauces, infused oils and vinegars, marinades, herbal blends and infusions

• Drying modifies the aromatic profile, enhancing some notes (spicy, hay-like) and reducing fresh green notes

Food applications

• Traditional preparations such as pesto and fresh tomato sauces

• Salads, starters, carpaccio-style vegetable dishes, Mediterranean recipes

• Topping for pizza, pasta, soups and stews (added at the end)

• Flavouring for oils, vinegars, preserves and pickles

• Aromatic component in beverages, flavoured waters, syrups and some desserts

Nutrition & health

• Basil leaves contain natural antioxidants (rosmarinic acid, flavonoids, carotenoids) that support cellular protection.

• They are a rich source of vitamin K, important for blood clotting and bone metabolism.

• Essential oils provide refreshing and mildly antimicrobial effects within appropriate intake limits.

• Low energy density with a relatively dense micronutrient profile.

• Their intense flavour can improve palatability and may help reduce added salt in recipes.

Portion note
Typical culinary portion: 5–10 g of fresh leaves (around 1–2 heaped tablespoons, chopped).

Allergens and intolerances

• Does not contain the main allergens listed in EU legislation.

• Individual sensitivity to essential-oil components (e.g. eugenol, estragole) is possible.

• High vitamin K content should be considered by individuals on vitamin K–sensitive anticoagulant therapy (always follow medical advice).

Storage and shelf-life

• Fresh leaves: 2–5 days in the refrigerator in a ventilated container or loosely wrapped.

• Avoid excess moisture and very low temperatures (risk of mould and chilling injury leading to blackened leaves).

• Freezing: possible, preferably as chopped leaves mixed with oil or as pesto.

• Dried leaves: shelf-life of several months if kept in a cool, dry, dark place in sealed containers.

• Preparations (pesto, flavoured oils): refrigerate and consume within the times indicated on the label.

Safety and regulatory aspects

• Must comply with EU limits for pesticide residues (MRL) and contaminants.

• Production and handling must be carried out under GMP and HACCP systems.

• Fresh-cut/ready-to-eat basil leaves require strict microbiological control and cold-chain management.

• Extracts and essential oils used in food or cosmetics must meet specific purity and safety requirements and be correctly labelled.

Labelling

• Product name: “basil leaves” or “fresh basil”.

• Country of origin.

• Lot code and packing date.

• Storage conditions (e.g. “keep refrigerated”).

• For processed products: full list of ingredients, nutritional declaration, net quantity and any additives.

Troubleshooting

• Blackened leaves → oxidation, mechanical damage or temperature shock.

• Wilted leaves → insufficient humidity or inappropriate storage temperature.

• Loss of aroma → prolonged storage, exposure to light/heat or repeated temperature changes.

• Bitter or off taste → very old product, leaves from plants at advanced flowering stage, or improper drying.

Sustainability and supply chain

• Can be grown with precision irrigation and integrated or organic pest management to reduce environmental impact.

• Local, urban and hydroponic production shortens the supply chain and improves freshness.

• Plant residues are fully compostable and suitable for organic-waste streams.

• Increasing use of recyclable or compostable packaging (cardboard, PET, bioplastics).

• Short and transparent supply chains help reduce transport emissions and support product quality.

Main INCI functions (cosmetics)
Basil leaf extracts and essential oils used in cosmetics typically provide:

• Antioxidant activity

• Soothing effect

• Purifying and mildly deodorant action

• Refreshing sensation

• Skin-conditioning properties in creams, lotions and hair products

Conclusion
Basil leaves are a high-value aromatic ingredient with strong culinary, nutritional and phytochemical interest. Their characteristic fragrance and rich content of bioactive compounds make them ideal in numerous food applications and attractive as a raw material for cosmetic extracts. Careful management of cultivation, harvesting, handling and storage is essential to preserve their aroma, colour, quality and safety.

Mini-glossary

• SFA – Saturated fatty acids; excessive intake is linked to increased cardiovascular risk.

• MUFA – Monounsaturated fatty acids; generally beneficial for blood lipid profile and heart health.

• PUFA – Polyunsaturated fatty acids; important for cell membranes and anti-inflammatory processes.

• MRL – Maximum Residue Level; legal limit for pesticide residues in foods.

• GMP – Good Manufacturing Practices; hygiene and process rules ensuring correct production.

• HACCP – Hazard Analysis and Critical Control Points; preventive system for managing food-safety risks.

Studies

Basil studies

(1) Sestili P, Ismail T, Calcabrini C, Guescini M, Catanzaro E, Turrini E, Layla A, Akhtar S, Fimognari C. The potential effects of Ocimum basilicum on health: a review of pharmacological and toxicological studies. Expert Opin Drug Metab Toxicol. 2018 Jul;14(7):679-692. doi: 10.1080/17425255.2018.1484450. 

Abstract. Basil (Ocimum basilicum L., OB) is a plant world widely used as a spice and a typical ingredient of the healthy Mediterranean diet. In traditional medicine, OB is indicated for many maladies and conditions; OB-containing nutritional supplements are increasingly sold. Conversely, safety concerns have been raised about the promutagens and procarcinogens alkenylbenzenes contained in OB. Areas covered: A critical review of the current status of OB as a nutraceutical, the pharmacology of its bioactive components, the rationale for its indications, and its safety. Expert opinion: Due to the polyphenolic and flavonoidic content, OB can be considered as an important ingredient in healthy diets; OB preparations may be effective as chemopreventive agents or adjunctive therapy in the treatment of different clinical conditions. From a toxicological perspective, since the tumorigenic potential of alkenylbenzenes is counteracted by other OB constituents such as nevadensin, it can be concluded that OB consumption in food and preparations is safe. The only concern relates to OB essential oils: in this case, a concentration limit for alkenylbenzenes should be precautionary defined, and the use of plant chemotypes with no or low levels of these alkylbenzenes for the preparation of essential oils should be made compulsory.

Suppakul P, Miltz J, Sonneveld K, Bigger SW. Antimicrobial properties of basil and its possible application in food packaging. J Agric Food Chem. 2003 May 21;51(11):3197-207. doi: 10.1021/jf021038t.

Abstract. Basil (Ocimum basilicum L.) is a popular culinary herb, and its essential oils have been used extensively for many years in food products, perfumery, and dental and oral products. Basil essential oils and their principal constituents were found to exhibit antimicrobial activity against a wide range of Gram-negative and Gram-positive bacteria, yeast, and mold. The present paper reviews primarily the topic of basil essential oils with regards to their chemical composition, their effect on microorganisms, the test methods for antimicrobial activity determination, and their possible future use in food preservation or as the active (antimicrobial), slow release, component of an active package.

Fang JY, Leu YL, Hwang TL, Cheng HC. Essential oils from sweet basil (Ocimum basilicum) as novel enhancers to accelerate transdermal drug delivery. Biol Pharm Bull. 2004 Nov;27(11):1819-25. doi: 10.1248/bpb.27.1819. 

Abstract. The purpose of this study was to evaluate the essential oils from sweet basil (Ocimum basilicum, OB) as skin permeation enhancers to promote the percutaneous absorption of drugs. The in vitro and in vivo irritancy of the essential oils was also examined. Terpenes with various carbon numbers (mono-, sesqui-, di-, and tri-) were identified in both the lower-polarity fraction (OB-1) and higher-polarity fraction (OB-2). In vitro skin permeation and deposition of indomethacin were significantly enhanced after treatment with OB essential oils. The enhancing effect of OB-1 was greater than that of OB-2 in the in vitro permeation and in vivo cutaneous microdialysis analyses as well as in the plasma concentration of indomethacin. On the other hand, the in vivo study showed that OB-2 had a greater ability to retain the drug within the skin than did OB-1. Enhancement of the skin permeation of drugs by OB essential oils might be mainly due to improvement in the partitioning of the drugs to the stratum corneum. Both in vitro cell cultures (keratinocytes and skin fibroblasts) and in vivo transepidermal water loss showed no or only negligible irritation to skin by OB essential oils.

Sakkas H, Papadopoulou C. Antimicrobial Activity of Basil, Oregano, and Thyme Essential Oils. J Microbiol Biotechnol. 2017 Mar 28;27(3):429-438. doi: 10.4014/jmb.1608.08024.

Abstract. For centuries, plants have been used for a wide variety of purposes, from treating infectious diseases to food preservation and perfume production. Presently, the increasing resistance of microorganisms to currently used antimicrobials in combination with the appearance of emerging diseases requires the urgent development of new, more effective drugs. Plants, due to the large biological and structural diversity of their components, constitute a unique and renewable source for the discovery of new antibacterial, antifungal, and antiparasitic compounds. In the present paper, the history, composition, and antimicrobial activities of the basil, oregano, and thyme essential oils are reviewed.