Pengaruh Edible Coating Gelatin-Sodium Alginat dengan Penambahan Minyak Esensial Kulit Lemon terhadap Kualitas Jambu Kristal (Psidium guajava) selama Penyimpanan

Erika Purnamasari, Dr. Andriati Ningrum, S.T.P., M.Agr.; Prof. Dr. Ir. Supriyadi, M.Sc.

2024 | Tesis | S2 Ilmu dan Teknologi Pangan

        Dalam penelitian ini, efek penambahan minyak esensial kulit lemon pada edible coating berbasis gelatin ikan-sodium alginat dievaluasi pada kualitas jambu biji tanpa biji kultivar 'Kristal' (daging buah berwarna putih). Edible coating berbahan dasar gelatin memiliki sifat penghalang yang buruk terhadap transfer uap air. Kelemahan ini dapat diperbaiki dengan mengkompositkannya bersama natrium alginat. Selain itu, perlu ditambahkan antimikroba atau bahan antioksidan seperti minyak esensial kulit lemon untuk meningkatkan sifat fungsionalnya. Tujuan dari penelitian ini adalah untuk menentukan pengaruh penambahan minyak esensial kulit lemon pada warna, pH, viskositas, dan FTIR larutan edible coating gelatin–sodium alginat; serta untuk menentukan pengaruh edible coating gelatin-sodium alginat-minyak esensial kulit lemon terhadap sifat fisik (susut bobot, kekerasan, warna, struktur mikroskopis), kimia (pH, total padatan terlarut, asam tertitrasi, vitamin C, aktivitas antioksidan, laju respirasi), dan mikrobiologis (decay incidence) jambu kristal selama 13 hari penyimpanan pada suhu ruang. Rancangan percobaan yang digunakan adalah Rancangan Acak Kelompok. Variabel yang diteliti adalah konsentrasi minyak esensial kulit lemon (0%, 0,5%, 1%, dan 1,5%) dan lama waktu penyimpanan (1, 6, dan 13 hari).

        Hasil penelitian menunjukkan bahwa penambahan minyak esensial kulit lemon pada larutan edible coating gelatin-sodium alginat tidak memberikan perbedaan yang signifikan pada warna, pH, dan viskositas larutan edible coating (p > 0,05). Perlakuan edible coating, khususnya perlakuan gelatin-sodium alginat-minyak esensial kulit lemon 1,5?pat menghambat terjadinya susut bobot, penurunan kekerasan, perubahan warna, kenaikan nilai pH, kenaikan total padatan terlarut, penurunan nilai asam tertitrasi, penurunan kandungan vitamin C, penurunan aktivitas antioksidan, kenaikan laju respirasi; mampu mempertahankan keberadaan lapisan kutikula, keutuhan sel epidermis dan parenkim; serta dapat meminimalkan prosentase terjadinya decay incidence pada jambu kristal selama 13 hari penyimpanan pada suhu ruang (p < 0>

        In the present investigation, the effects of lemon peel essential oil addition to fish gelatin-sodium alginate-based coating were evaluated on seedless guava cultivar ‘Crystal’ (white fleshed) quality. Gelatin based coatings have poor barrier properties against water vapor transfer. This weakness can be improved by composing with sodium alginate. It is necessary to add antimicrobial or antioxidant ingredients such as lemon peel essential oil to improve the functional properties of edible coatings. The objectives of this study were to determine the effect of lemon peel essential oil addition on colour, pH, viscosity, and FTIR of gelatin-sodium alginate edible coating solution; and to determine the effect of gelatin-sodium alginate-lemon peel essential oil edible coating on physical (weight loss, hardness, colour, microscopic structure), chemical (pH, total soluble solids, titratable acid, vitamin C, antioxidant activity, respiration rate), and microbiological (decay incidence) properties of crystal guava during 13 days of storage at room temperature. The experimental design used was a Randomised Group Design. The variables studied were lemon peel essential oil concentration (0%, 0.5%, 1%, and 1.5%) and length of storage time (1, 6, and 13 days). 

        The results showed that the addition of lemon peel essential oil to the gelatin-sodium alginate edible coating solution did not give significant differences in colour, pH, and viscosity of the edible coating solution (p > 0.05). The edible coating treatment, especially the 1.5% gelatin-sodium alginate-lemon peel essential oil treatment can inhibit weight loss, decrease in hardness, discolouration, increase in pH value, increase in total soluble solids, decrease in titratable acid value, decrease in vitamin C content, decrease in antioxidant activity, increase in respiration rate; able to maintain the presence of the cuticle layer, the integrity of epidermal and parenchymal cells; and can minimise the percentage of decay incidence in crystal guava during 13 days of storage at room temperature. (p < 0>

Kata Kunci : Kata kunci: edible coating, gelatin, sodium alginat, minyak esensial kulit lemon, jambu kristal/Keywords: edible coating, gelatin, sodium alginate, lemon peel essential oil, crystal guava