Antioxidants

Antioxidants are added to oils and fats to delay the onset of oxidative rancidity, which is the major cause of spoilage. Natural constituents of foods such as tocopherols, ascorbates, phenolic compounds, also have antioxidant properties.Chelating agents such as citric acid may also contribute to antioxidant properties since they inhibit the catalytic effects of traces of copper and iron, which may be present in foods. The use of artificial antioxidants like BHA, BHT, TBHQ and gallates are permitted in certain dairy products.

Specification for Tert-Butylhydroquinone Food grade as per IS:11913-1986

1.Description: Tert-butylhydroquinone shall be a white crystalline solid having a characteristic odour. It shall be soluble in alcohol and ether but practically insoluble in water.

2. Identification: Dissolve a few mg of the product in 1 ml of methanol and add a few drops of 25 % solution of dimethyl amine in water. A pink to red colour shall be produced.

3. Melting range, °C                                                                  126.5-128.5

4. Purity (as C10H14O3), % by mass                                           99.0 Min.

5. t-Butyl-p-benzoquinone, % by mass                                    0.2 Max.

6. 2,5-Di-t-butylhydroquinone, % by mass                              0.2 Max.

7. Hydroquinone, % by mass                                                   0.1 Max.

8. Arsenic (as As), mg/kg                                                        3 Max.

9. Heavy metals (as Pb), mg/kg                                             10 Max.

10. Toluene, mg/kg                                                                25 Max.

11. UV absorbance (polynuclear hydrocarbons)                  To pass the test

Specification for Butylated hydroxyanisole (Food grade) as per IS:5343-1996

1.Description: BHA is a mixture of 3- and 2- isomer. It is white or slightly yellow waxy crystalline solid with an aromatic odour. The material is insoluble in water, freely soluble in ethanol and propylene glycol.

2. Identification

(a) When 2 ml of 2 % aqueous borax solution and a few small crystals of 2,6-dichloro quinone chlorimide are added to an ethanolic solution(1% m/v) of butylated hydroxyanisole, a blue colour shall appear.

(b) When 2 ml of ferric chloride (0.2 % FeCl3.6H20 in absolute ethanol and 2 ml of 0.2 % 2,2’ bipyridine in absolute ethanol are added to 5 ml of 0.5 % butylated hydroxyanisole in 50 % ethanol, a red colour shall appear.

 3. Melting point, °C                                                                         48-63

4. (a) Purity (as C11H16O2), % by mass                                            98.5 Min.

(b) 3-t-butyl 4-hydroxyanisole, % by mass                                      85 Min.

5. Sulphated ash, % by mass                                                           0.06 Max.

6. Phenolic impurities, % by mass                                                 0.5 Max.

7. Arsenic (as As), mg/kg                                                              3 Max.

8. Heavy metals (as Pb), mg/kg                                                     10 Max.

9. Specific absorbance E 1% (1 cm cell) in ethanol at

(a) 290 nm                                                                                    190-210

(b) 228 nm                                                                                   326-345