Stability of vitamin A in fortified soybean oil during prolonged storage and heating

Abstract

This study investigates the storage and thermal stability of vitamin A in fortified edible oils, focusing on the effects of PET (polyethylene terephthalate) and Pouch packaging under light and dark conditions over a 12-month period. Vitamin A levels in PET-packaged oils stored in light conditions dropped from 2.51 mg/100 g to undetectable levels with 100 % loss after 9 months, while Pouch-packaged oils decreased from 2.35 mg/100 g to 0.89 mg/100 g with 62.13 % loss after 12 months of storage. Dark storage conditions showed a more gradual decline, with PET and Pouch-packaged oils retaining 1.48 mg/100 g with 40.56 % loss and 1.14 mg/100 g of with 51.28 % loss of vitamin A, respectively after 12 months of storage. Besides, the oils were heated at 150 °C for 5 and 10 minutes, the oils retain about 85 % and 79.5 % of vitamin A respectively. Simultaneously, at 175 °C for 2, 5, 10 and 15 min of heating, the oils retain about 89.54 %, 77.20 %, 50.24 %, and 45.69 % of vitamin A respectively. And at 190 °C for 5 and 10 min of heating, the oils retain about 64.23 % and 50.93 % of vitamin A respectively. Acid and peroxide values increased with temperature and time, indicating quality deterioration, while free fatty acid content also rose, reflecting hydrolytic breakdown. The study suggests that light exposure and high temperatures significantly degrade vitamin A, and recommends improved packaging (Pouch packaging) and storage conditions (dark storage) to preserve vitamin A content in fortified oils.