Production of biodegradable film from soy protein and essential oil of lemon peel and use it as cheese preservative

Abstract

Soy protein with essential oil of lemon peel was used to produce a biodegradable film, which showed inhibition activity against some species of selected bacterial strains. The films were white cheese coating and studied for its biodegradation in the soil. The percentage of soy protein extract was 15% (W: W) while the percentage of lemon peel essential oil was 3% (V: W). The GC-MS result of lemon peel essential oil consisted of 38 compounds, of which the main compound is D-Limonene in 63.43%. The films produced showed inhibition activity against both Gram-positive and Gramnegative bacteria. Inhibition activity was highest against Staphylococcus aureus (22 mm zone), while E. coli O157: H7 had the lowest inhibition (18mm) when 0.1mL of essential oil with 10mL film mixed. The coating process of white cheese reduced the total microbial population (CFU/g) during 30 days of storage time. The TCB, TC, ST and MY of cheese coating were 4.28, 1.53, 1.62 and 1.33 log. CFU/g respectively after 30 days compared to the cheese non-coating samples, with 6.53, 2.51, 3.17 and 1.81 log. CFU/g, respectively. The biodegradation in soil was 97 and 72% for soy protein film and soy protein film with lemon peel essential oil after 35 days.