Effect of polylactic acid-based nanofiber packaging containing cinnamaldehyde on the shelf life of kaymak

Plastic packaging is one of the packaging materials widely used in the food industry. Since petroleum-based synthetic packaging materials cannot be degraded for a long time, they have disadvantages such as environmental protection and the amount of toxic substances. In order to prevent increasing environmental problems, the use of biodegradable food packaging materials is increasing as an alternative to synthetic packaging materials. Compared to plastic packaging, biodegradable packaging materials have a longer lifespan, then mix with nature, protect the environment, and do not leave behind stored substances that are harmful to nature. Because natural resources such as cellulose and protein produced by these materials are used as (biodegradable) materials. Biodegradable materials include products such as superior cellulose members, polyhydroxyalconates, polylactic acid, poly-β-hydroxy butyrate, polycaprolactone, polyvinylalcohol and chitosan. The industrial applicability of the electrospinning method in nanofiber production is difficult; With low efficiency production, the need for electrical field and the production method of less homogeneous fibers, studies have shifted to the solution-blown spinning method. The solution-blown spinning method stands out due to its high efficiency production, lack of need for electrical field and homogeneous fiber production. Recently, there has been an increase in studies on the electro-blown spinning method, which combines the advantages of these two methods with high efficiency production, low voltage usage and homogeneous fiber production. In this study, it was aimed to produce and characterize biodegradable polylactic acid (PLA) based cinnamaldehyde added nanofibers by electro-blown spinning method. In the study; PLA solution was prepared to contain 4 different amounts of cinnamaldehyde. For this purpose, only PLA solution was used as the control group. After adding cinnamaldehyde at the rate of 20%, 30% and 40% of the PLA dry weight into the PLA solution, the solutions were mixed on the magnetic stirrer for another 30 minutes to create a homogeneous mixture. Nanofibers were formed by taking 20 ml of the prepared solution into a sterile syringe, placing it in the syringe pump, and placing it in the electro-blown spinning system. Nanofibers were subjected to mechanical, barrier, morphological and thermal analyses. The produced nanofibers were applied to the cream by sticking them to the inside of the cream box lids. Chemical (pH, peroxide), microbial (total number of organisms, coliform number, mold-yeast number), color analysis and sensory taste tests were performed on the cream samples.It was observed that as the cinnamaldehyde concentration increased, the thickness of the nanofibers decreased from 0,087 µm to 0,072 µm, while the b* parameter, which expresses the yellowness of the nanofibers, increased from 1,95±0.05 to 7,32±0.17. The highest breaking force (KK) was measured as 2,87±0.17 MPa in PLACin20 and the lowest was 0,92±0.08 MPa in PLACin40. Elongation at break (KU) increased from %8,32±1.53 to %55,13±3.70 as the cinnamaldehyde concentration increased. When the explosion force (PK) was examined, the lowest value was measured as 110,77±9.73 g in PLACin0 and the highest was 217,20±11.91 g in PLACin30. As for burst elongation (PU), the lowest value was measured as 1,47±0.06 mm in PLACin0, and the highest value was 4,85%±0.24 mm in PLACin30. As the amount of cinnamaldehyde increases, the water vapor permeability (SBG) value decreases to 4,665 g.mm/m².h. kPa to 3,988 g.mm/m².h. It was determined that it decreased to kPa. When morphological features are evaluated; It was observed that as the concentration increased, the nanofiber diameters decreased from 623,23 nm to 291,58 nm. Considering the thermal properties of nanofibers, with the increase in cinnamaldehyde concentration, the glass transition temperature (Tg) increased from 61,10 °C to 23,87 °C, the cold crystallization temperature (Tcc) increased from 74,23 °C to 61,16 °C and It was determined that the melting temperature (Tm) decreased from 172,50 °C to 163,75 °C. Thermal decomposition temperature (Td) varied between 356,09 °C and 363,28 °C, and the difference was found to be statistically insignificant. The temperatures at which the first mass losses occurred were measured as 27,59 °C for Cinnamaldehyde and 47,64 °C for PLACin0, respectively. For PLACin0, the temperature at which the greatest mass loss occurred was determined as 178,59 °C. It was determined that the highest mass loss in PLA nanofibers with cinnamdehyde added was at 187,92 °C. As a result, it was revealed that the addition of cinnamaldehyde increased the thermal resistance of nanofibers. When the pH, peroxide number, total live and mold-yeast counts in the cream samples coated with nanofibers were compared with the control sample without nanofibers, a decrease in the rate of increase of these values was observed as the cinnamaldehyde concentration increased. The pH value varied between 6,50±0.07 and 6,92±0.01, and the peroxide value varied between 5.19±0.10 and 0.94±0.02 meq O2/kg oil. The total number of living things was observed between >3000 and 210±28.28. When we look at the number of molds and yeasts, the number of molds and yeasts are between 0-220±28.28 and 0-100±0.01, respectively. Additionally, in the sensory taste test, panelists did not perceive any difference between the control sample and the cream samples coated with cinnamaldehyde-added PLA nanofibers. As a result, when the analyzes are evaluated; It has been revealed that nanofibers containing PLA with cinnamaldehyde may help extend the shelf life of cream by showing antioxidant and antimicrobial activity.