Impact of packaging materials and storage durations on physico-chemical, techno-functional, antioxidant and oxidation properties of tomato seed protein isolate

The aim of this research was to investigate the effect of storage of tomato seed protein isolate (TSPI) in various packaging materials [Aluminium (Al) laminate, High Density Polyethylene (HDPE) and Low Density Polyethylene (LDPE) pouch] on the physico-chemical, functional, phytochemical, antioxidant, functional group, and color properties. The TSPI were stored under ambient temperature and relative humidity conditions for a period of 4 months and examined at interval of one month. Results depicted that the moisture, water activity, bulk density and turbidity significantly (p <= 0.05) increased during storage in all the packaging materials. Browning index was found to be lower in Al laminate than HDPE and LDPE and techno-functional properties were significantly (p <= 0.05) affected by storage period. The degree of oxidation of TSPI was increased in terms of significant decrease in sulfhydryl content and significant increase in carbonyl derivatives (p <= 0.05). Total phenolic content, total flavonoid content and % radical scavenging activity of TSPI decreased after storage in all packaging materials. The TSPI structure disordered as the alpha-helix increased and beta-sheet decreased. Among all the packaging materials, the Al laminate was found to be the most appropriate for storage of TSPI at ambient conditions.