Edible Nanocoating Berbasis Biopolimer Kitosan dengan Zat Aktif Nanopartikel Perak (AgNPs) untuk Perlindungan Buah Pisang

Yoan Nikita Christina Tefa, Adhi Dwi Hatmanto, S.Si., M.Sc., Ph.D; Dr. Sutarno, M.Si.

2023 | Skripsi | KIMIA

Sintesis nanopartikel perak (AgNPs) telah dilakukan dengan metode bottom-top reduksi kimia. Sintesis AgNPs dalam larutan membutuhkan prekursor logam perak nitrat (AgNO3) dengan penambahan asam askorbat (C6H8O6) dan natrium sitrat (Na3C6H5O7), pada dengan variasi rasio volume (dalam mL) prekursor Ag:asam askorbat:natrium sitrat 1,5:10:10; 1,5:20:20; 1,5:30:30; dan 1,5:40:40. Hasil sintesis AgNPs dikarakterisasi dengan spektroskopi UV-Vis dan TEM (Transmission Electron Microscopy). AgNPs yang telah disintesis dilakukan variasi volume yaitu 2%, 4%, 6%, dan 8% untuk ditambahkan pada kitosan sebagai bahan edible nanocoating yang diaplikasikan pada buah pisang. Nanokomposit kitosan-AgNPs dikarakterisasi dengan spektroskopi FT-IR, XRD (X-ray diffraction), dan SEM (Scanning Electron Microscope) serta dilakukan pengujian aktivitas antibakteri pada bakteri Escherichia coli sebagai bakteri Gram negatif dan Staphylococcus aureus sebagai bakteri Gram positif. Nanokomposit kitosan-AgNPs selanjutnya diaplikasikan pada buah pisang.

Hasil penelitian menunjukkan bahwa AgNPs telah berhasil disintesis dengan variasi terbaik yaitu 1,5:30:30 yang memiliki morfologi berbentuk bulat (spherical) yang seragam dan memiliki ukuran diameter partikel sebesar 10,46 ± 2,35 nm. Nanokomposit kitosan-AgNPs yang telah diperoleh memiliki aktivitas antibakteri pada bakteri Escherichia coli dengan diameter daya hambat sebesar 0,34-2,90 mm dan Staphylococcus aureus dengan diameter daya hambat 1,60- 4,41 mm. Aplikasi pada buah pisang menunjukkan bahwa edible nanocoating kitosan- AgNPs dengan variasi terbaik 6?rhasil mempertahankan kesegaran pisang dan berat bobot pisang hingga hari ke-10.

Synthesis of silver nanoparticles (AgNPs) has been carried out by bottom-top chemical reduction method. The chemical synthesis of AgNPs in solution requires silver nitrate metal precursor (AgNO3) with the addition of ascorbic acid (C6H8O6) and sodium citrate (Na3C6H5O7), with a volume ratio (in mL) of 1.5:10:10; 1.5:20:20; 1.5:30:30; and 1.5:40:40. Synthesis of AgNPs was characterized by UV-Vis spectroscopy and TEM (Transmission Electron Microscopy). The synthesized AgNPs were varied in volume, namely 2%, 4%, 6%, and 8% to be added to chitosan as an edible nanocoating material that was applied to bananas. Chitosan nanocomposites-AgNPs were characterized by FTIR spectroscopy, XRD (X-ray diffraction), and SEM (Scanning Electron Microscope) and were tested on the antibacterial activity of Escherichia coli as a Gram negative and Staphylococcus aureus as Gram positive bacteria. Chitosan nanocomposites-AgNPs were then applied to bananas.

The results showed that AgNPs had been successfully synthesized with the best variation of 1.5:30:30 which had a uniform spherical morphology and had a particle diameter of 10.46 ± 2.35 nm. The chitosan-AgNPs nanocomposite that has been obtained has antibacterial activity on Escherichia coli bacteria with an inhibitory diameter of 0.34-2.89 mm and Staphylococcus aureus with an inhibitory diameter of 1.6-4.41 mm. Application to bananas showed that edible nanocoating chitosan-AgNPs with the best variation of 6% succeeded in maintaining banana freshness and banana weight until the 10th day.

Kata Kunci : Escherichia coli, kitosan, nanopartikel perak (AgNPs), Staphylococcus aureus