The effect of storage time on the quality of ultraviolet-irradiated and thermally pasteurised pineapple juice was evaluated. The juices were irradiated with ultraviolet light (UV-C) at wavelength 254 nm (53.42 mJ/cm2, 4.918 s), thermally pasteurised at 800C for 10 minutes and stored at 40C for 13 weeks. There were significant changes in the total soluble solids, pH, titratable acidity and turbidity of UV-irradiated juice during storage, whereas for the same quality attributes of thermally pasteurised juice remained stable throughout the storage time. There were no significant changes in total phenolics for both treatments throughout the storage period. Other quality parameters (ascorbic acid, colour L, hue angle and chroma) were significantly affected by the storage time. Regarding the microbiological analysis, the total plate counts and yeast and mould counts of the UV-irradiated juice increased gradually throughout the 13 weeks of storage while these parameters remained unchanged in the thermally pasteurised juice with almost no microorganism growth. UV-irradiated pineapple juice preserved better quality attributes (TSS, pH, titratable acidity, ascorbic acid, turbidity, total phenolic, L (lightness), hue angle and chroma) than the thermal pasteurised juice during the storage time. Hence, UV irradiation has great potential as an alternative technology to thermal pasteurisation in producing products of high nutritive values.
The use of essential oils as natural antioxidant, antimicrobial and insect repellent agent was limited by the loss of bioactive components especially volatile compounds. This study aimed to improve biological properties of curry leaf essential oil (CLEO) by producing nanometer sized particles through two different synthesis techniques; nanoencapsulation and nanoprecipitation. The methods produced different nanostructures; nanocapsules and nanospheres distinguished by the morphological structure (TEM analysis). Successful loading of CLEO into chitosan nanocarrier was proven by FTIR spectra. Zeta potential values for both nanostructures were more than +30 mV implying their stability against aggregation. CLEO loaded nanocapsules exhibited highest antibacterial properties against Gram-positive bacteria compared to nanospheres. Meanwhile, CLEO loaded nanospheres recorded up until 90.44 % DPPH radical scavenging properties, higher compared to nanocapsules. Both nanostructures demonstrated further improvement in antioxidant and antibacterial activities with the incorporation of higher chitosan concentration. In vitro release analysis indicated that CLEO undergo two-stage discharge mechanism where fast discharge occurred up until 12 h followed by sustained released afterwards. The two synthesis methods applied synergistically with greater chitosan concentration successfully produced nanostructures with >60 % encapsulation efficiency (EE). This concluded that both techniques were reliable to protect the bioactive constituents of CLEO for further used.
This review article provides a comprehensive overview of recent progress in polylactic acid (PLA) extrusion, emphasizing its applications in food packaging. PLA has witnessed a significant rise in demand, particularly within the food packaging sector. A notable increase in research publications has been observed in recent years, exploring the extrusion of PLA and PLA-based composite films. In comparison to conventional techniques such as solvent casting, extrusion offers advantages in scalability and environmental sustainability, especially for industrial-scale production. The benefits of this method include faster drying times, enhanced flexibility, consistent film thickness, and less structural defects. Extensive research has focused on the effect of various PLA blends on film properties, including flexibility, elongation, and barrier properties against water vapour and gases. Furthermore, the incorporation of compounds such as antioxidants, antimicrobials, and natural pigments has enabled the development of active and intelligent PLA-based packaging. This article summarizes the types of additives employed to enhance the physicochemical properties of extruded PLA and film performance. Additionally, this article explores the diverse applications of extruded PLA in active and intelligent packaging for various food products.