Studi Komposisi, Kandungan Pigmen, Fotostabilitas dan Termostabilitas Serta Analisis Produk Degradasi Ekstrak Kasar Pigmen Alga Merah Kappaphycus alvarezii (Doty) Doty Varian Merah, Cokelat, dan Hijau

Lembar Pengesahan tidak disertai tanda tangan dosen pembimbingTujuan dari penelitian ini adalah untuk mengetahui komposisi dan kandungan pigmen, stabilitas pigmen terhadap perlakuan iradiasi dan termal, serta menganalisis produk degradasi dari ekstrak kasar pigmen alga merah Kappaphycus alverezii Doty (Doty) varian merah, cokelat, dan hijau. Kromatografi Cair Kinerja Tinggi (KCKT) yang dilengkapi dengan detektor diode array, digunakan untuk menganalisis komposisi pigmen. Uji fotostabilitas ekstrak kasar pigmen dilakukan dengan penyinaran ekstrak kasar pigmen menggunakan lampu Volpi Intralux 4100, pada intensitas cahaya 39300 lux, 56700 lux dan 76400 lux selama 20 menit, sedangkan uji termostabilitas dilakukan pada suhu 25 dan 90°C selama 0, 3, 6, 24, dan 48 jam. Spektrum serapan ekstrak kasar pigmen sebelum dan setelah perlakuan masing-masing berturut-turut diamati pada panjang gelombang 325-700 nm dengan menggunakan Spektrofotometer UV-Tampak MultiSpec 1501(Shimadzu, Kyoto). Produk degradasi dianalisis dengan mengukur pola spektra pada panjang gelombang 300-800 nm sebelum dan sesudah perlakuan menggunakan spektrofotometer UV-Tampak Shimadzu 1700. Data dianalisis dengan SPINA Versi 3, untuk memperoleh intensitas maksimum dan perbedaan spektra serapan. Hasil menunjukkan sebanyak 17 pigmen dapat dipisahkan dari ekstrak kasar pigmen. Komposisi pigmen hampir sama untuk ketiga varian. Zeaxantin dan klorofil a masing-masing ditemukan sebagai pigmen karotenoid dan klorofil dominan. Ekstrak kasar pigmen varian hijau tampak lebih stabil terhadap iradiasi dibandingkan dengan varian cokelat dan merah. Selama perlakuan termal pada suhu 90C, ekstrak kasar pigmen varian cokelat memiliki stabilitas tertinggi diikuti oleh varian merah dan varian hijau, sedangkan pada suhu kamar (25C) ekstrak kasar pigmen dari ketiga varian tampak stabil. Produk degradasi pigmen ekstrak kasar alga merah K. alvarezii dapat diidentifikasi melalui spektrum serapan dan hasil perbedaan spektra serapan. Isomer cis karotenoid, karotenoid tidak berwarna, dan feofitin a diestimasi sebagai produk degradasi yang terbentuk selama perlakuan iradiasi dengan intensitas cahaya 76400 lux dan perlakuan pemanasan pada suhu 90°C selama 48 jam. Penurunan intensitas warna larutan pigmen juga mengindikasikan terbentuknya produk degradasi selama perlakuan.The aims of this research were to determine the composition and content of pigment, to determine the stabilities toward irradiation and thermal treatments, and also to analyze the degradation products of crude pigment extracts from red, brown, and green varieties of red algae Kappaphycus alverezii (Doty) Doty. A High Performance Liquid Chromatography (HPLC), equipped with diode array detector,was used to analyze the pigment composition and pigment content. The pigment content was determined based on the peak area at 430 nm. The photostability assay of crude pigment extracts was conducted by irradiating the crude pigment extracts with a day light lamp (Volpi, Intralux 4100) at 39300 lux, 56700 lux and 76400 lux light intensity during 20 minutes treatment, whereas the thermostability assay was performed at 25 and 90°C for 0, 3, 6 24, and 48 hours. The absorption spectra of the crude pigment extract before and after each treatment are monitored successively at 325-700 nm using UV-Vis spectrophotometer, MultiSpec-1501 (Shimadzu, Kyoto). The degradation products were analyzed by measuring spectra pattern before and after each treatment at 300-800 nm using UV-Vis spectrophotometer 1700 Shimadzu. Data were analyzed with SPINA Version 3, to obtain maximum intensity and the difference absorption spectra. The result shows that 17 pigments could be well separated from the crude pigment extracts. The pigment composition was almost similar for all three varieties. Zeaxanthin and chlorophyll a were found to be the dominant carotenoid and chlorophyll, respectively. The crude pigment extract from the green variety shows to be more stable against irradiations as compared to the brown and the red varieties. During the thermal treatmentat 90C, the crude pigment extract from the brown variety has the highest stability followed by red and green varieties, respectively, whereas at room temperature (25C) the crude pigment extracts from three varieties were stable. The degradation products of crude pigment extracts from red alga K. alvarezii could be identified by absorption spectra and difference absorption spectra. Cis isomers carotenoids, colorless carotenoids, and pheophytin-a were estimated as degradation product formed during the irradiation treatment with 76400 lux of light intensity and heating treatment at a temperature of 90°C for 48 hours. Decrease in the intensity of the color of pigment solution also indicates the formation of degradation products during treatment