In the study, the bioactive, physicochemical and antimicrobial properties of koruk juice and dried koruk pomace were investigated. The total phenolic contents of koruk juice and pomace were determined as 1119.670 and 1182.170 mg GAE/L, respectively. Higher DPPH radical scavenging activity found in koruk pomace, which was consistent with total phenolic contents. Organic acid, total sugar and ascorbic acid contents of koruk juice (3.44%, 4.737 g/L and 2.559 mg/100 mL) were higher than koruk pomace (0.19%, 0.866 g/L and 0.242 mg/100 mL). The counts of Total Psychrophilic Aerobic Bacteria and mold-yeast in pomace were determined as 0.694 and 1.016 log CFU/g, respectively, while no growth was observed in koruk juice. Koruk juice and pomace indicated antimicrobial effect on all test microorganisms in the range of 31.3-500.0 µg/mL (Minimum Inhibition Concentration). The most sensitive bacteria to koruk juice were Bacillus cereus, while Pediococcus acidilactici was the most sensitive one to koruk pomace. Koruk juice also showed bactericidal effect on all test cultures at concentration ranging between 250.0 and 500.0 µg/mL (Minimum Bactericidal Concentration), koruk pomace was not showed bactericidal effect on Escherichia coli O157:H7, Salmonella Typhimurium, E. coli and B. cereus. This study demonstrated that the koruk products could be used in food applications as natural antioxidant and antimicrobial substance.

This study investigated the effects of different processing techniques and sol-gel coating on the physical properties of biocomposite material. Two dispersion series from corn starch, clay, and sorbitol were prepared by conventional and microwave-assisted processing, and casting technique. One film from each series was sol-gel coated by immersion. All the samples were subjected to moisture content (MC), water solubility (WS), water absorption (WA), FT-IR, DSC, and SEM/digital microscopy tests. The results showed that the coated films contained higher MC (11.5±0.5%) than the non-coated films (5.3±0.6%) and absorbed less water (44.7±12.4%), compared to the non-coated ones (166.3±2.5%). Non-coated films exhibited less solubility in water (26.1±0.2%) than the coated ones (51.0±0.7%). FT-IR test detected cross-linking (1723 cm-1 ester) in the microwave-assisted coated film. The sol-gel coating increased the latent heat of melting and specific heat values by 14.9% and 19.4% for conventionally fabricated samples, and 22.3% and 25.3% for microwaved films, respectively, whereas it reduced the temperature of melting by 23.1% for conventionally fabricated ones, and 6.6% for microwaved ones. Microscopic tests revealed that microwaved compact morphology indicated better gelatinization of starch. Overall, microwaving and sol-gel coating need further investigation to improve the physical properties of biocomposite materials for food packaging.