ANSWER
Oxidative rancidity of oils and fats in dressing refers to the undesirable odours and flavours which develop when such products are exposed to the oxygen in the air. Food antioxidants are compounds that help in increasing the resistance of fats to oxidation that leads to deterioration or rancidity.
Range of Food Antioxidants
| Natural Antioxidant | Synthetic Antioxidants | Antimicrobial Preservatives |
Common Food Antioxidants used in Dressings
| Ingredients | Tocopherols | BHT (Butylated hydroxytoluene) | BHA(c) | Calcium disodium EDTA |
| Functions | Free radical terminator in oxidation reactions | An antioxidant that stabilizes free radicals. Helps to prevent rancidity in fats and oils in dressings | An antioxidant that stabilizes free radicals. Helps to prevent rancidity in fats and oils in dressings | A metal inactivator in inhibiting rancidity (disagreeable odour or taste of decomposing oils or fats) in dressings |
| Appearance | Brown coloured, slightly viscous liquid | White granular crystals | White or slightly yellow waxy solid | White crystalline powder |
| Solubility | Soluble in vegetable oils but insoluble in water | Soluble in lipids and insoluble in water | Soluble in lipids and insoluble in water | Moderately soluble in water and insoluble in lipids |
| Heat Sensitivity | Heat Stable | Not as stable as BHA | Heat Stable | Heat Stable |
| *ADI (according to General Standard for Food Additives: GSFA 2011) | 0.15-2 | 0-0.3 | 0-0.5 | 0-2.5 |
Common Food Antioxidants used in Dressings
| Ingredients | Tocopherols | BHT (Butylated hydroxytoluene) | BHA(Butylated Hydroxyanisole) | Calcium disodium EDTA |
| Antioxidant Ability | Tocopherol < BHT < BHA < EDTA | |||
| Recommendation | Not a single substance but in a mixture of forms(homologues) namely, Alpha (α), Beta (β), Gamma (γ) and Delta (δ) Tocopherol
and 4 tocotrienol homologues (γ, δ, β, α). antioxidant potency: delta > gamma > beta > alpha |
BHA and BHT act synergistically to provide greater antioxidant activity than either antioxidant alone (BHA/BHT mixtures at level up to 0.02% with ratio 1:1) | BHA and BHT act synergistically to provide greater antioxidant activity than either antioxidant alone (BHA/BHT mixtures at level up to 0.02% with ratio 1:1) | Efficacy of EDTA could be further improved when used in combination with ascorbyl palmitate and tocopherol |
References
Codex Alimentarius Commission. (2018). General Standard for Food Additives (Codex Stan 192-1995).
Hamid, A. A., Aiyelaagbe, O. O. , Usman, L. A., Ameen, O. M. & Lawa, A. (2010). Antioxidants: Its medicinal and pharmacological applications. African Journal of Pure and Applied Chemistry, 4(8), 142-151.
Igoe, R.S. (2011). Dictionary of Food Ingredients. (5th ed.). USA: Springer.
Madhavi, D. L., Deshpande, S. S. & Salunkhe, D.K. (1995). Food Antioxidants: Technological: Toxicological and Health Perspectives. New York: Marcel Dekker.
Maga, J. A. & Tu, A.T. (1995). Food Additive Toxicology. New York: Marcel Dekker.
