Unrefined vs Refined Seed Oils for Food and Cosmetic Applications

Selecting the right seed oil for food, nutraceutical, or cosmetic applications requires a clear understanding of processing methods, stability requirements, and shelf life. Midlands Nutrition supplies both unrefined cold pressed oils and refined oils, offering flexible specifications to support product development, private label, and bulk ingredient supply.

Unrefined vs Refined Oils: Understanding the Difference

Choosing between unrefined and refined oils depends on the intended application, stability requirements, and desired nutritional profile. At Midlands Nutrition, we specialise in producing cold pressed, unrefined seed oils in their most natural form, while also offering custom refining solutions to meet specific customer or formulation needs.

This article explains the differences between unrefined and refined oils, how they are processed, and best practices for storage, handling, and shelf life.

What Are Unrefined Oils?

Unrefined oils are oils that remain as close to their natural state as possible. At Midlands Nutrition, these oils are produced using cold pressing, without the use of heat, solvents, or chemicals.

Cold pressed, unrefined oils typically retain:

• Natural colour
• Distinct flavour
• Characteristic aroma
• Naturally occurring antioxidants and bioactive compounds

Many large-scale oil producers refine oils to remove these characteristics, creating a standardised, bland, odourless product. In contrast, Midlands Nutrition offers unrefined oils specifically for their natural nutritional value and functional health properties.

Nutritional Benefits of Unrefined Oils

Certain seed oils, such as Hemp Seed Oil, are naturally rich in antioxidants that can be significantly reduced during refining. Retaining these compounds can:

• Improve oxidative stability
• Support longer shelf life
• Deliver additional health benefits

The natural flavour and aroma of unrefined oils can also be desirable for health food, nutraceutical, and culinary applications, where authenticity and sensory qualities are valued.

What Are Refined Oils?

Refined oils are produced when a clear, stable, and odourless oil is required. Refining is commonly used to:

• Increase stability
• Improve visual clarity
• Remove flavour and aroma
• Meet cosmetic or encapsulation specifications

All refining methods used by Midlands Nutrition are food-grade and suitable for human consumption. Depending on customer requirements, refining can be achieved through physical or chemical processes.

Physical Refining Methods

Physical refining focuses on removing unwanted components without chemical alteration of the oil.

Filtering

Crude oil taken directly from pressing often appears cloudy due to seed particles or sediment. Filtration to a specific micron rating removes these solids, producing a clear, bright, sediment-free oil.

Deodorising

Strong flavours and aromas can be removed by gently heating the oil under high vacuum. This process removes volatile compounds, including oxidation products, resulting in a virtually odourless oil.

Winterisation

Some seed oils naturally contain waxes and gums that may cause haze or cloudiness during storage. Winterisation involves holding the oil at low temperatures to crystallise these compounds, which are then removed via filtration. This process is particularly important for clear-encapsulated products where visual clarity is critical.

Chemical Refining Methods

Chemical refining uses carefully controlled food-grade processes to further improve stability and appearance.

Degumming

Phosphatides (gums), chlorophyll, and destabilising metal ions are removed using high-purity water and food-grade phosphoric acid.

Neutralisation

An alkali solution neutralises free fatty acids, which are then removed along with lecithin and phospholipids.

Bleaching

The oil is mixed with a measured quantity of diatomaceous earth, which absorbs colour compounds. This is a gentle process and does not involve chemical bleach. It also removes metal ions, residual chlorophyll, and other components that may affect oil stability.

Storage and Handling of Seed Oils

Proper storage and handling are essential to maintain oil quality. Whether refined or unrefined, all oils are sensitive to heat, light, and oxygen.

Midlands Nutrition produces two main categories of oils:

• Monounsaturated oils
• Polyunsaturated oils

Monounsaturated Oils

Examples include:

• Olive Oil
• Avocado Oil
• Sunflower Oil

These oils generally have a longer shelf life and can be stored in a cool, dry place away from direct sunlight. Refrigeration is optional but beneficial.

Polyunsaturated Oils

Examples include:

• Flaxseed Oil
• Hemp Seed Oil
• Rosehip Oil

These oils are highly sensitive to heat and should not be used for cooking. Exposure to heat, light, and oxygen will reduce both shelf life and nutritional quality. These oils should be refrigerated or frozen.

Freezing oils extends freshness without damaging flavour or nutritional properties. Some oils remain liquid when frozen, while others will solidify naturally.

Packaging Best Practices

For distribution or retail, oils should be packaged in:

• Dark glass containers to protect against light
• Bottles flushed with nitrogen to remove oxygen from the headspace

Exposure to heat, light, and oxygen can cause oils to become rancid. Rancid oil develops an unpleasant taste and aroma and is unsuitable for consumption.

Shelf Life Guidelines

Bulk Oils

• Stored unopened
• Below 20°C
• Expected shelf life: 12 months

Private Label or Retail-Ready Oils

• Keep refrigerated
• Once opened, consume within 3 months

These guidelines are indicative only. Buyers are responsible for validating shelf life based on their specific packaging format and storage conditions.