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This study aimed to evaluate the effects of variety and harvesting age on the physicochemical characteristics and nutritional composition of the fruits from three hybrid pumpkin varieties grown in Tra Vinh province of Vietnam. An increment in nutrient accumulation between 60 and 80 days old was observed in all three studied varieties. Adequate accumulation of dry matter, fat, fiber and ash in the fruit was achieved at 70 days old for the F1 pumpkin variety - long fruit (A1) while its maximum accumulation of protein and total phenolic content (TPC) was at 65 days old. A1 variety reached the highest total soluble solid (TSS) content at 75 days old. The F1 pea pumpkin variety (A2) had the highest accumulation of ash and fiber content at 60 days while the contents of fat, protein, carbohydrate and dry matter were maximal values at 65, 75, 70 and 70 days. The highest accumulation of fat, fiber, and carbohydrate was reached at 70 days old for the F1 hybrid pumpkin variety - round fruit (A3). The research results can be used to determine the appropriate harvesting age of the fruits to increase the value of the pumpkin varieties. [ABSTRACT FROM AUTHOR]

Chitosan - the second most abundant polysaccharide on Earth has been known as a kind of non-toxic, environmentally friendly, biodegradable, antibacterial, and antifungal material. Compared with bulk chitosanbased materials, nanochitosan has superior properties in terms of permeability, solubility, and bioactivity. Nanochitosan is used as a carrier encapsulating various components via complexes with NH2 and OH groups of chitosan molecules to protect, stabilize, and deliver targeted bioactive compounds. For the first time, chitosanzinc ion nanoparticles (CSZ NPs) have been successfully synthesized by ultrasound-assisted ionic gelation to produce much smaller particles with enhanced antibacterial and antifungal activities. The fabricated CSZ NPs have a diameter from 119.3 to 212.6 nm, polydispersity index ranging from 0.2 to 0.3, and zeta potential from 16.4 to 22.4 mV. The average size of the as-fabricated CSZ NPs is two times smaller than zinc ions loaded nanochitosan without ultrasonic treatment. The spherical shape of the nanochitosan particles is confirmed, along with a wide range of elemental distributions, including C (29.74 %), O (42.14 %), Na (15.80 %), and Zn (1.11 %). The antimicrobial activities of CSZ NPs are evaluated by using the agar well diffusion method with gramnegative bacteria (E. coli, P. aeruginosa), gram-positive (E. feacalis, S. aureus, S. aureus methicillin-resistant (MRSA)), and fungi (C. albicans, A. niger). The minimum inhibitory concentration of CSZ NPs is 14 µg/mL for bacteria and more than 58 µg/mL for fungi. CSZ NPs have potential antimicrobial applications in the food industry and agriculture. [ABSTRACT FROM AUTHOR]