Understanding Antioxidants: Protection and Health Benefits

An antioxidant is a compound that can prevent or delay oxidation in a substrate by interacting with free radicals, which are highly reactive molecules with unpaired electrons. By inhibiting free radical formation, antioxidants help stabilize lipid-containing substances and slow down oxidation reactions [3][4]. Historically, antioxidants were used in industries to prevent rubber vulcanization, metal corrosion, and as food preservatives .

Oxidation is a chemical process where electrons are transferred from one molecule to an oxidizing agent, producing free radicals. These radicals initiate a chain reaction, but antioxidants stop it by neutralizing free radicals, thus preventing further oxidation [5]. Free radicals can be generated through processes like electrolysis, heat, and radiation. When free radical production exceeds the body’s antioxidant defences, it causes oxidative stress, leading to diseases such as cancer, cataracts, and stroke. This stress also damages DNA, proteins, and lipids, negatively affecting health [4].

For a substance to be considered an antioxidant, it must be effective at low concentrations and must interact with oxygen or nitrogen free radicals, producing fewer toxic byproducts [5]. There is no universal antioxidant, as different antioxidants target various free radicals through different mechanisms.

Antioxidants are classified into two main types: natural and synthetic, based on their source.

What are Synthetic Antioxidants

Synthetic antioxidants, developed for industrial and commercial purposes, are more stable, cheaper, and easier to produce than natural ones. In other words, Synthetic antioxidants are chemically produced compounds, primarily derived from petroleum, that inhibit lipid oxidation in food products. They act as primary antioxidants by breaking radical chain reactions in various industries, such as food and plastics, by interfering with reactive oxygen species (ROS) generation [6]. Some synthetic antioxidants mimic the structure of natural antioxidants, while others introduce new chemical groups that enhance their protective properties, especially in specific tissues [4]. These antioxidants are widely used to stabilize refined oils and fats, prolonging the shelf life of processed foods.

• Butylated Hydroxytoluene (BHT): A widely used preservative to prevent rancidity.
• Butylated Hydroxylanisole (BHA): Protects against spoilage by stopping oxidation.
• Propyl Gallate (PG): Stabilizes fats and prevents oxidative damage.
• Tert-Butylhydroquinone (TBHQ): Extends the freshness of oils and processed foods.

In addition, 2-naphthol (2NL), 4-phenylphenol (OPP) and 2,4-dichlorophenoxyacetic acid (2,4-DA) are the ones commonly used in fruits and vegetables 

Plants are a rich source of natural antioxidants, particularly plant phenolics and extracts, which are used to preserve meat and other products. These antioxidants are found in many fruits and vegetables and have gained significant interest for their health benefits. The antioxidants present in vegetable oils, like tocopherols, are effective at preventing oxidative damage [6] [4]. These compounds naturally inhibit oxidation, offering a safer and health-conscious alternative to synthetic antioxidants.

1. Food Stabilizers: Protect processed foods from oxidation and rancidity.
2. Dietary Supplements: Support overall health by combating oxidative stress.
3. Natural Health Products: Enhance the nutritional profile and shelf life of health-focused products.

The Food Safety and Standards (FSS) regulations of 2011 outline permissible antioxidant additives for edible oils and fats (excluding ghee and butter) and their respective concentration limits. The following antioxidants are approved for addition to such food products:

1. Ethyl Gallate: Up to 0.01%.
2. Propyl Gallate: Up to 0.05%.
3. Octyl Gallate or Dodecyl Gallate: Individually or combined, up to 0.02%.
4. Ascorbyl Palmitate: Up to 0.02%.
5. Butylated Hydroxyanisole (BHA): Up to 0.02%.
6. Citric Acid: Permitted within limits set by Good Manufacturing Practices (GMP).
7. Tartaric Acid: Within GMP guidelines.
8. Gallic Acid: Up to 0.01%.
9. Resin Guiac: Up to 0.01%.
10. Tertiary Butyl Hydroquinone (TBHQ): Up to 0.02%.

Additional provisions include:

• Dry mixes of sweets and fried snacks (e.g., rasgollas and vadas) may include BHA up to 0.02% by fat content.
• Flavored agents can incorporate antioxidants with a maximum concentration of 0.01%.
• Ghee and butter can include BHA at levels up to 0.02%.
• Fat spreads may use either BHA or TBHQ at a combined level not exceeding 0.02%.
• Ready-to-eat dry cereals can include BHA at a reduced limit of 0.005% (50 ppm).
• Infant milk substitutes may contain lecithin and ascorbyl palmitate up to 0.5 g/100 ml and 1 mg/100 ml, respectively.

When combining antioxidants (Nos. 1–4), the total amount should not exceed 0.02%.

Antioxidants help protect cells by neutralizing free radicals, which are unstable molecules that can damage the body. They do this by giving electrons to free radicals, making them stable and preventing further damage. Antioxidants can either directly remove free radicals or stop reactions that create them, slowing down oxidation. Some antioxidants work as primary protectors by breaking the chain of reactions in substances like food or plastics, while others act as secondary protectors by stopping new radicals from forming. This process helps protect cells, proteins, fats, and DNA from damage, reducing the risk of diseases like cancer and heart disease.[7]