The characteristic flavour and taste of banana chips fried in coconut oil have appealed to food lovers across the country and beyond. Rancidity however is a major problem in the storage of banana chips, affecting its shelf life and acceptability.

The Department of Processing Technology at the College of Agriculture, Vellayani, here has come up with a simple solution to overcome the problem. An investigation carried out by C. Mini and B.V. Adrika of the department revealed that curry leaf, a natural antioxidant, could be used to delay rancidity.

According to Dr. Mini, Associate Professor and Head of the Department, rancidity occurs due to oxidation of the oil used for frying. “The addition of antioxidants is effective in retarding the oxidation process. But synthetic antioxidants used in food have been reported to be having toxicological effects. This has sparked interest in research to identify safe antioxidants based on natural extracts from plants.”

The researchers at the department found that simple addition of dried curry leaf powder to the oil used for frying chips could delay rancidity. Oven-dried and ground curry leaves were added to unrefined coconut oil at smoke point of 165 degrees Celsius. Chips produced by this method had least oil uptake and highest integrity. The research established that curry leaf is better than sodium ascorbate and tocopherol acetate, the two commercially available antioxidants.

The investigation also found that rancidity could be delayed by replacing the commonly used thin plastic pouches with laminated pouches for packing. “By adding dried curry leaves to oil and packing in the treated chips in laminated pouches, the chips can remain fresh for up to three months without becoming rancid. The additional expense incurred for one kg of banana chips is just 88 paise,” says Dr. Mini.