Estimasi Produk Degradasi Ekstrak Kasar Pigmen Alga Merah Kappaphycus alvarezii (Doty) Doty Varian Merah, Coklat, dan Hijau: Telaah Perbedaan Spektrum Serapan - Helly de Fretes; A.B. Susanto; Budi Prasetyo; Heriyanto Heriyanto; Tatas H.P. Brotosudarmo; Leenawaty Limantara (ILMU KELAUTAN: Indonesian Journal of Marine Sciences, 2012)
Penelitian ini bertujuan untuk mengestimasi produk degradasi pigmen ekstrak kasar alga merah Kappaphycus alvarezii (Doty) Doty varian merah, coklat dan hijau yang terbentuk selama perlakuan iradiasi dan pemanasan, melalui perbedaan spektrum serapannya. Ketiga varian diekstraksi menggunakan 100% metanol. Uji fotostabilitas ekstrak pigmen dilakukan dengan iradiasi menggunakan lampu Volpi intralux 4100 pada intensitas cahaya 39300 lux, 56700 lux dan 76400 lux.  Lama waktu penyinaran 0, 5, 10, 15, dan 20 menit. Sedangkan uji termostabilitas  dilakukan pada suhu 25 dan 90 ° C selama 0, 3, 6 24, dan 48 jam. Pola spektra diukur pada panjang gelombang 300-800 nm sebelum dan sesudah perlakuan dengan spektrofotometer UV-Tampak Shimadzu 1700. Data dianalisis dengan SPINA Versi 3, untuk memperoleh intensitas maksimum dan perbedaan spektra serapan. Hasil penelitian menunjukkan bahwa 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. Kata kunci: Kappaphycus alvarezii, perbedaan spektrum serapan, produk degradasi The aims of this study were to estimate the degradation products of crude pigment extracts from red, brown, and green varieties of red alga Kappaphycus alverezii (Doty) Doty that formed during irradiation and heating treatment from their difference absorption spectra. All three variants were extracted using 100% methanol. 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 0, 5, 10, 15, and 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 were monitored successively at 300-800 nm using MultiSpec 1501 UV-VIS spectrophotometer. Data were analyzed with spina Version 3, to obtain maximum intensity and the difference absorption spectra. The results showed that 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 feofitin-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.Key words: Kappaphycus alvarezii, difference absorption spectra, degradation products