Bionanocomposite active films made from tapioca starch and bovine gelatin, with the addition of roselle calyx extract (RCE) and zinc oxide nanorod (ZnO-N), were created as packaging material to protect walnuts against mold, yeast contamination, and lipid oxidation. Three types of packaging were produced: tapioca starch and bovine gelatin (control sample), tapioca starch, bovine gelatin, and RCE, and tapioca starch, bovine gelatin, ZnO-N, and RCE. Approximately 30 grams of walnuts were packed using each type of packaging and evaluated for acidity value, mold and yeast count, peroxide value, and sensory tests. After 90 days, the mold and yeast count of walnuts packed with RCE/ZnO-N and RCE was 4.49 and 4.65 log cfu/g respectively, compared to 4.95 log cfu/g in the control sample. At the end of the conservation period, the aroma score was 3.59 for walnuts packed with RCE/ZnO-N, compared to 2.5 for those packed with tapioca starch and bovine gelatin. The acidity value indicated that walnuts packed with RCE and RCE/ZnO-N had a positive effect on acidity, with the lowest value found in walnuts packed with RCE/ZnO-N. The study showed that bionanocomposite packaging films containing RCE and ZnO-N are effective in protecting walnuts against fungal contamination and oxidation. 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

This work aimed to make a smart biofilm based on tapioca starch/bovine gelatin and roselle calyx extract (RCE)/nanofiller-ZnO. Then the utilization of the biofilm was studied to monitor the rainbow trout fillets. The biofilms were fabricated by casting the starch/gelatin solution with sorbitol /glycerol (3.2g) on casting plates and were dried at 25C. RCE was added into biofilms (0.5 g for TP/RCE/ZnO-N and 2g for TP/RCE), and the biofilm characteristics, such as thickness, color, and antioxidant properties were investigated. The films containing nanofiller-ZnO/RCE and RCE showed significantly (p0.05) more antioxidant activity than the neat film which respective values of 18.31 11.42 and 3.1. The thickness of the smart films significantly increased (p0.05) from 0.08 to 0.13 by the addition of RCE/nanofiller ZnO into the solution. According to the results, a value was significantly higher (p0.05) in smart film with nanofiller-ZnO/RCE and RCE. The lowest L* value was obtained in film with nanofiller-ZnO/RCE. At the end of the conservation, the TVB-N value reached 35.7 mg N/100 and with the TVB-N significantly increase (p0.05), the color properties of the smart films also changed. The color of the biofilm was purple, but the a value significantly decreased. Therefore, the film based tapioca starch/bovine gelatin/nanofiller ZnO/RCE can be applied as a natural indicator of rainbow trout fillets. Manuscript profile