Composition

Oleoresins are viscous, resinous extracts composed of :

• Volatile Compounds: Essential oils responsible for aroma and flavour. Examples are terpenes, aldehydes, and ketones.

• Non-Volatile Compounds: Resins that impart color, texture, and shelf stability. These resins can be further categorized as oleoresins, gum resins, and balsams which have specific roles in the final product's characteristics.

Key Sources of Oleoresins

Oleoresins can be extracted from many plants, including:

• Spices: Black pepper, paprika, ginger, garlic, onion, cardamom.

• Herbs: Rosemary, thyme, mint, parsley.

• Flowers/Fruits: Saffron, chamomile, star anise, vanilla.

These sources are used in a myriad of products for creating flavors and fragrances.

Extraction methods

The production of oleoresins involves different extraction techniques chosen based on the desired product quality. Two of the most commonly used methods are supercritical CO2 extraction and solvent extraction.

1. Supercritical CO2 Extraction

Supercritical CO2 extraction is considered the most advanced method for obtaining oleoresins [2]. It utilizes carbon dioxide in its supercritical state, where it behaves like both a gas and a liquid. CO2 is transformed into its supercritical state by being heated and pressurized beyond its critical points of pressure and heat (Tc, Pc) simultaneously. This unique property allows it to dissolve non-polar compounds efficiently, including essential oils and resins, without leaving harmful residues. Supercritical CO2 is especially effective for extracting oleoresins from spices such as black pepper, turmeric, and paprika, ensuring they retain their flavor and health-enhancing properties.

Advantages:

• Purity: Produces ultra-pure extracts free from solvent residues.

• Eco-Friendly: CO2 is non-toxic, GRAS (Generally Recognized As Safe), recyclable, and leaves no environmental pollutants.

• Precision: Offers high selectivity, enabling customized extraction of specific compounds.

• Gentle on Compounds: Operates at lower temperatures, preserving sensitive bioactives.

Limitations:

• May be more costly compared to other methods.

2. Solvent Extraction

In this traditional method, organic solvents like ethanol, hexane, or acetone dissolve the plant's oil and resin components. After extraction, the solvent is removed to leave behind a concentrated product, however, often times solvent residue is still found in the final product. A common solvent used is hexane, which raises concerns regarding its presence in the final products and its environmental impact [3].

Advantages:

• Less costly to produce meaning its products are generally cheaper compared to those of Supercritical CO2 Extraction.

Limitations:

• May leave traces of solvent in the final product.

• The use of higher temperatures in the process may degrade valuable sensitive compounds.

Applications

1. Food Industry: Oleoresins are used to replace raw/ground spices in food processing to contribute to consistent quality, extended shelf life, and concentrated flavors. Examples such as ginger, pepper, and turmeric oleoresins improve flavor and provide health benefits with anti-inflammatory and antioxidant effects [4]. They are used in foods such as sausages, snacks, sauces, beverages, baked products, confectionery, etc.

2. Pharmaceuticals/Health Supplements: Bioactive compounds present oleoresins, like curcumin in turmeric, are essential for therapeutic purposes, specifically antimicrobial and anticancer applications [5]. They are used in ointments, capsules, softgels, topic patches, creams, etc.

3. Cosmetics: Their natural aroma and bioactive characteristics make them sought after in skincare products for anti-aging and wound healing. They are used in aromatherapeutic products, perfumes, skincare, etc.

[1] The European market potential for oleoresins | CBI. (2022, October 19). https://www.cbi.eu/market-information/natural-food-additives/oleoresins/market-potential

[2] Devani, B., Jani, B., Balani, P., & Akbari, S. (2019). Optimization of supercritical CO2 extraction process for oleoresin from rotten onion waste. Food and Bioproducts Processing, 119, 287–295. https://doi.org/10.1016/j.fbp.2019.11.014

[3] Cravotto, C., Fabiano-Tixier, A., Claux, O., Abert-Vian, M., Tabasso, S., Cravotto, G., & Chemat, F. (2022). Towards Substitution of Hexane as Extraction Solvent of Food Products and Ingredients with No Regrets. Foods, 11(21), 3412. https://doi.org/10.3390/foods11213412

[4] Procopio, F. R., Ferraz, M. C., Paulino, B. N., Sobral, P. J. D. A., & Hubinger, M. D. (2022). Spice oleoresins as value-added ingredient for food industry: Recent advances and perspectives. Trends in Food Science & Technology, 122, 123–139. https://doi.org/10.1016/j.tifs.2022.02.010

[5] Aggarwal, B. B., Sundaram, C., Malani, N., & Ichikawa, H. (2007). CURCUMIN: THE INDIAN SOLID GOLD. Springer eBooks, 1–75. https://doi.org/10.1007/978-0-387-46401-5_1