Active biodegradable films prepared from polylactic acid (PLA)/roselle calyx extract (RCE)/Zinc Oxide Nanorod (ZnO-N) were fabricated as natural packaging materials for hazelnuts protection against microbial contamination and lipid oxidation. The PLA active films with ZnO-N (1, 3, and 5% w/w), and roselle calyx extract (0.5 g) were made by the casting solution technique. The fungal, microbial, chemical, and sensory properties of hazelnuts were measured during 9 months of conservation at 4°C. On the 6 and 9th months, moisture content was evaluated as %2.6 and 2.2% in the control sample whereas the moisture content of hazelnuts was measured as 3.6% and 2.9% packaged with PLA/RCE/%5 ZnO-N. At the last of experiments, the peroxide value (PV) was measured as 0.91 meq O2 kg-1 packaged with neat biocompatible films, whereas PV value was detected as 0.65 meq O2 kg-1 in packaged hazelnuts with %5 ZnO-N. Total microbial count ranged between 4.9 cfu g-1 for hazelnuts packaged with neat PLA and 3.7 cfu g-1 for hazelnuts specimens packaged with %5 ZnO-N after 9 months of storage. At 9 months, by increasing the level of ZnO-N from 1% to 5%, the mold count was reduced from 3.64 to 3.01 CFU g-1. The fungal contamination in the neat specimens was 3.95 CFU g-1. Sensory quality indicated that hazelnuts with ZnO-N had a significant impact on flavor and aroma, and the highest quality of sensory evaluation was related to hazelnuts packaged with PLA/5% ZnO-N/RCE. Flavor and aroma indices of hazelnuts packaged with %5 ZnO-N reached 3.5 and 4.5 respectively after 9 months of storage. The obtained findings indicate that biopackaging could be utilized to enhance microbial quality and inhibit oxidation reactions of hazelnuts during cold storage. Our results could be beneficial for introducing attractive characteristics to the biodegradable film packaging for example active film containing anthocyanin/nanofiller and can be applied when selecting a smart packaging for detection of food spoilage. Manuscript profile

Edible films based on starch are applied for food protection to extend shelf-life of food products. The biodegradability of film compounds was significantly improved by the utilization of biopolymer molecules in comparison to petroleum packaging, and it could be a replacement for synthetic packaging. In the presentation work, the effects of nano titanium dioxide (TiO2-N) were studied on the moisture content, water solubility, moisture uptake, and antimicrobial properties of soluble soy polysaccharide (SSPS) starch/cold water fish gelatin films. The nano titanium dioxide was incorporated into the SSPS starch/cold water fish gelatin dispersion at various levels (1, 2, 3, and 5 w/w% based on SSPS starch). The moisture content of the biofilms decreased from 14.12% to 12.28% and water solubility decreased from 93.18% to 71.46% by the incorporation of 5% TiO2-N into the biopolymer matrix. Increasing TiO2-N from 0 to 5% decreased the moisture uptake, a value of 9.83–6.81 g/g dried film. According to an increased inhibition zone of 1-5% TiO2-N for Staphylococcus aureus and Escherichia coli from 32.44 to 62.27 mm2 and from 22.15 to 45.17 mm2 respectively, SSPS starch/cold water fish gelatin/TiO2-N films showed antimicrobial characterizations against Staphylococcus aureus and Escherichia coli. In summary, TiO2-N improves the functional properties of SSPS/cold water fish gelatin biofilms and can be applied in the food industry. Manuscript profile