Synthesis and characterization of starch nanocellulosic films incorporated with Eucalyptus globulus leaf extract

Carrot cellulose nano fibers (CNF) have been extracted from carrot pulp using acid hydrolysis process. The size of the CNF was in the range of 6.33-58.77 nm. Starch nano-composite films were manufactured using varying concentration of CNF (5%, 10%, 15%, 20%) and mechanical properties of the films were studied at relative humidity 50% and 75%. Nano-composite films were manufactured using Eucalyptus globulus leafs extract (1%, 2%, 3%, 4%). Physio-chemical properties, antioxidant, antimicrobial, morphological and crystalline properties of the films were studied. Nano-composite films with 4% Eucalyptus globulus leafs extract was best to provide better barrier, antioxidant properties to grapes when wrapped and stored at room temperature (25 ± 2)°C for 7 days and refrigerator temperature (4 ± 1)°C for 28 days. Wrapped grapes with NCC/Eucalyptus globulus leaf extract stored for 28 days either at 25 °C or 4 °C had bacterial surface loads reduced up to 5 orders of magnitude compared to non-wrapped samples and had 4 orders of magnitude less bacterial surface loads than at the beginning of the experiments. Wrapped grapes with NCC/Eucalyptus globulus leaf extract significantly reduced the growth of Escherichia coli, Listeria monocytogenes, Salmonella typhimurium and Penicillium spp. when the cells of these organisms were spiked onto grapes and the samples were stored either at (25 ± 2) °C or (4 ± 1) °C for 28 days. The results showed that nano-composite with 4% Eucalyptus globulus leafs extract films have immense potential as food packaging/wrapping material.