Temperature and high pressure stability of lycopene and vitamin C of watermelon Juice

The retention of nutrient components of fruit juices during processing is an important criterion to produce better quality fruit products. Stability of nutrient components during processing vary from product to product and processing methods. Information about kinetic study of particular nutrient component under different processing conditions would enable to optimize processing parameters for better quality retention. Therefore the objective of this research was to evaluate the effect of thermal and high pressure food processing methods on stability of vitamin C and lycopene of watermelon juice. Watermelon juice was subjected to different thermal (70 to 90°C) and high pressure (400 to 600 MPa) treatments for different interval of times and the residual vitamin C and lycopene concentrations were measured. The destruction of nutrients in both thermal and high pressure processing conditions obey first order reaction rate kinetic model. In both processing conditions lycopene remains more stable as compared to vitamin C. The degradation rates of both components were faster in thermal treatment as compared to high pressure. The D value of vitamin C ranged from 40 to 176 min (z = 30.8°C) and 4 to 24 h (zp = 257 MPa) in thermal and high pressure treatments respectively whereas the D value of lycopene ranged from 15 to 83 h (z= 24.5oC) and 61 to 258 h (zP= 318 MPa) for thermal and high pressure treatments respectively. Therefore high pressure ensures better retention of the nutrients as compared to thermal treatment and hence can be used to pasteurize better quality watermelon juice.