Physical properties investigation of polylactic acid marker film with anthocyanins extracted from red cabbage and beetroot

In the present study, the properties of polylactic acid marker film combined with red cabbage and beet anthocyanins were investigated. There were four samples: 1 (polylactic acid without anthocyanins), 2 (polylactic acid containing red cabbage anthocyanins), 3 (polylactic acid containing beet anthocyanin) and 4 (polylactic acid containing beet anthocyanin and red cabbage). Thickness, solubility, mechanical properties and changes in color indices were analyzed. The results showed that there were no statistically significant differences in the thickness of the film samples (p> 0.05). The highest solubility belonged to the sample 1 and the minimum solubility was detected insample 4. The highest increase in elongation at break was seen in samples 3 and 4 and the lowest increase in elongation at break belonged to sample 1 (p≤0.05). In all the films except sample 1, by pH rise (up to pH = 14), L * factor increased significantly (p≤0.05). In all pH ranges, sample 1 had the highest L * and sample 3 had the lowest one (p≤0.05). a * indice in sample 3, at pH = 1-6, had an increasing trend and then decreased to pH = 14 (p≤0.05). In samples 2 and 4 at pH = 1-13, a decreasing trend was observed and then up to pH=14 an increasing trend was observed (p≤0.05). For b *in sample 2 there was a decline at pH = 1-12, then up to pH = 14, an increasing trend was detected (p≤0.05). The b * of sample 3 and 4 had a fall until pH=11 and 12 respectively following an increasing trend up to pH=14 (p≤0.05). The best sample was sample 4 due to suitable physical properties and clearer color changes at different pH.