STABILITY AND ISOMERISATION OF LYCOPENE IN OIL-BASED MODEL SYSTEM DURING ACCELERATED SHELF-LIFE TESTING

Shelf-life prediction of a product could be assessed by measuring quality attributes through accelerated shelf-life testing (ASLT) under extreme conditions. The ASLT could be beneficial to specify the effects of different storage temperatures on quality properties of food products in some cases where the environmental conditions exceed the limits. The objective of this study was to evaluate the effect of temperature and light on lycopene stability in oil-based food model system during 100 days of storage. Extract of lycopene in oil-based model system was prepared from 'Tolstoi H' tomatoes and virgin rapeseed oil and poured into transparent vials. Samples were tested at 1 +/- 1 degrees C temperature in absence of light, ambient temperature at 20 +/- 1 degrees C in natural light, ambient temperature at 20 +/- 1 degrees C in absence of light, at 40 +/- 1 degrees C temperature in absence of light and at 40 +/- 1 degrees C temperature in UV irradiation. Lycopene and its cis-isomers in oil-based model system and control were determined by high performance liquid chromatography (HPLC/DAD). The colour measurements of the samples were made using MiniScan XE Plus spectrophotometer. The addition of tomato extracts to vegetable oil might increase the level of lycopene in a human diet and enhance its bioavailability. The optimum storage conditions for lycopeneenriched oil were at 20 degrees C in the dark. The temperature and light irradiation has a combined influence on the lycopene stability and isomerisation (from 17 to 100 % changes from trans- to cis-lycopene isomers). ASLT is useful and practical tool for the stability monitoring of lycopene.