Spectroscopic Characterization and Gel Properties of Agar from Two Gelidium Species from the Atlantic Coast of Morocco

The commercial value of agar in the phycocolloid market depends mostly on the agar yield and quality. The present study investigates the agar content and characterization of two Gelidiales Gelidium corneum and Gelidium microdon from the Moroccan Atlantic coast. Spectroscopic and rheological characterization of extracted agar without and with alkali pretreatments were evaluated. The highest agar yield was detected for mild alkaline pretreatment (N2CO3). The native agar content in G. corneum was 16.21%, while those pretreated with NaOH and N2CO3 ranged from 6.2 to 20.50 %. The agar yields of G. microdon showed values of 12.23%, 14.87%, and 17.73%, corresponding respectively to native agar, NaOH, and Na2CO3 pretreatments. Agar with alkali pretreatments depicted the better gelling property with higher gel strength and elevated gelling and melting temperatures. 13C NMR spectroscopy showed that G. Corneum has a typical unsubstituted and weakly methylated agar pattern. However, G. microdon revealed the presence of methyl and sulfate groups at the C4 of 4-O-L-galactose residues, responsible for the low gelling ability of the native agar. The decline of sulfate groups after alkali pretreatments were proved by FTIR spectroscopy. This study demonstrates that G. microdon produces a quality of agar similar to that of G. corneum. Thus G. microdon could be regarded as a potential additional source of agar industry in Morocco.

PEREMAJAAN BIBIT RUMPUT LAUT Gracilaria verrucosa HASIL KULTUR JARINGAN MELALUI SELEKSI MASSA

Penelitian ini bertujuan untuk menguji performa bibit rumput laut Gracilaria verrucosa hasil kultur jaringan yang diremajakan dengan metode seleksi massa. Penelitian dilaksanakan di tambak percobaan Marana, Maros, Sulawesi Selatan; menggunakan dua petakan tambak berukuran sekitar 2.500 m2. Seleksi dilakukan berdasarkan perhitungan laju pertumbuhan harian (LPH), menggunakan sistem long line selama dua siklus dengan durasi 30 hari/siklus. Bibit rumput laut hasil seleksi kemudian dipelihara dengan sistem tebar dasar dan dibandingkan dengan kontrol internal dan kontrol eksternal dengan memasang sembilan unit hapa berukuran 1 m x 1 m x 1 m, dengan tiga ulangan untuk masing-masing perlakuan. Perhitungan LPH, kandungan agar, dan kekuatan gel dilakukan setiap 30 hari dan setiap 15 hari dilakukan monitoring terhadap kualitas air yakni salinitas, suhu, nitrat, dan fosfat. Hasil yang diperoleh memperlihatkan adanya peningkatan LPH yang signifikan (P<0,05) dari siklus-I (2,67 ± 0,38%/hari) menjadi (3,56 ± 0,25%/hari) pada siklus-II, dengan respons seleksi sebesar 21,48%-22,34% dan diferensial seleksi sebesar 9,70%-10,16%. Pertumbuhan rumput laut hasil seleksi lebih tinggi (3,23 ± 0,50%/hari) dibandingkan dengan kontrol internal (2,12 ± 0,02%/hari), dan kontrol eksternal (1,69 ± 0,09%/hari) (P<0,05). Kontrol internal memiliki kandungan agar yang lebih tinggi (20,07 ± 12,97%) dari rumput laut hasil seleksi (16,07 ± 1,58%) dan kontrol eksternal (8,29 ± 1,69%) (P<0,05); namun hasil seleksi memiliki kekuatan gel yang lebih tinggi (761,15 ± 208,90 g/cm2) dari kontrol internal (322,44 ± 244,29 g/cm2), dan kontrol eksternal (297,42 ± 44,16 g/cm²) (P<0,05). Peremajaan bibit rumput laut hasil kultur jaringan dengan metode seleksi massa mampu meningkatkan performa bibit rumput laut G. verrucosa.This study was aimed to determine the performance of tissue-cultured seaweed seed Gracilaria verrucosa, which was propagated using mass selection method. The study was conducted in the experimental ponds in Marana, Maros, South Sulawesi. The mass selection was conducted in two ponds of 2,500 m2. The selection was made by culturing the seaweed seed using the long line system for two cycles in 30 days/cycle duration during which the daily growth rates (DGR) of seaweed seeds were measured. The selected seaweed seeds were then cultivated in the ponds using broadcast system and the growth was compared with the internal and external controls consisted of nine units of 1 m x 1 m x 1 m hapa, with three replications for each treatment (selected seed, internal control, and external control). The measurements of DGR, agar yield, and gel strength were conducted every 30 days, while water quality monitoring i.e. salinity, temperature, nitrate, and phosphate were conducted every 15 days. The results showed that the DGR of seaweed seed increased significantly (P<0.05) from 2.67 ± 0.38%/day in cycle-I to 3.56 ± 0.25%/day in cycle-II, the selection response was 21.48%-22.34% and the differential selection was 9.70%-10.16%. The daily growth rate of selected seaweed seed was significantly higher (3.23 ± 0.50%/day) (P<0.05) compared to internal (2.12 ± 0.02%/day) and external controls (1.69 ± 0.09%/day). Internal control has higher agar yield (20.07 ± 12.97%) compared to the selected seed (16.07 ± 1.58%) and external control (8.29 ± 1.69%) (P<0,05). The selected seed has higher gel strength (761.15 ± 208.90 g/cm2) compared to internal control (322.44 ± 244.29 g/cm2), and external control (297.42 ± 44.16 g/cm2) (P<0,05). Propagated tissue-cultured seaweed seed using the mass selection method could improve the overall performance of seaweed seed.

Hasil Kandungan Agar Ekstraksi Non-Alkali Gracilaria sp. yang Tumbuh di Lingkungan Berbeda

ABSTRAK: Gracilaria sp. merupakan rumput laut merah penghasil agar yang banyak digunakan untuk industri pangan maupun non pangan lainnya. Ekstraksi ini umumnya menggunakan alkali yang berdampak pada lingkungan dan keamanan bahan pangan. Informasi tentang ekstraksi perlakuan non alkali di Indonesia untuk industri pangan diduga belum ada sehingga penelitian ini perlu dilakukan. Tujuan penelitian ini untuk mengkaji apakah ekstraksi non alkali dari Gracilaria sp. dapat menghasilkan agar, rendemen, kandungan proksimat serta dianalisis FTIR dari kedua lokasi yang berbeda (laut dan tambak). Metode ekstraksi dilakukan dengan merebus sampel kering hingga didapatkan agar, yang selanjutnya dikeringkan dan dijadikan tepung. Hasil penelitian menunjukkan ekstraksi perlakuan non alkali dari kedua lokasi dapat menghasilkan rendemen dengan nilai rendah (14-15,31%). Kadar air tertinggi (15,40±0,59%) terdapat pada agar sampel dari laut, kadar abu tertinggi (41,45±0,59%) pada sampel kering dari laut, kadar protein tertinggi (8,59±0,26%) pada sampel kering dari tambak, kadar lemak tertinggi (0,63±0,13%) pada agar sampel dari laut, dan karbohidrat tertinggi (67,19±0,86%) pada sampel kering dari tambak. Hasil FTIR menunjukkan agar mengandung komposisi gugus galaktosa 3,6-anhydro-L-galaktosa. ABSTRACT: Gracilaria sp. is a red seaweed which is known as an agarophyte and widely used for food and other non-food industries. Generally agar extraction uses alkali which has an environmentally impact and food safety. Non-alkaline extraction treatment for food grade is still under observed in Indonesia. The purpose of this research is to access whether agar extraction of Gracilaria sp. can be carried out, as well as the amount of agar yield, proximate contents and FTIR analysis from two different locations. The extraction method is done by boiling a dry sample to obtain agar, which is then dried and turned into flour. The results showed that the extraction of non-alkaline treatment could be carried out on Gracilaria sp. with low yield (14-15.31%). The highest water content (15.40±0.59%) found in agar from dried seaweed form the sea, highest ash (41.45±0.91%) in dried seaweed from the sea, highest protein (8.59±0.26%) in dried cultured seaweed, highest fat (0.63±0.13%) in agar from the sea, and highest carbohydrate (67.19±0.86%) in dried cultured seaweed. FTIR analysis showed that the agars contained a composition of galactose groups of 3,6-anhydro-L-galaktose.

EVALUASI PERFORMA BIBIT RUMPUT LAUT Gracilaria verrucosa HASIL KULTUR JARINGAN DI KABUPATEN LUWU, SULAWESI SELATAN

Penelitian ini bertujuan untuk mengevaluasi performa bibit rumput laut Gracilaria verrucosa. hasil kultur jaringan yang dibudidayakan di salah satu daerah sentra produksi rumput laut di Sulawesi Selatan. Penelitian dilaksanakan di Desa Murante Kecamatan Suli Kabupten Luwu, Sulawesi Selatan pada 2014 selama tiga siklus pemeliharaan dengan lama pemeliharaan 40 hari/siklus. Luasan tambak yang digunakan pada siklus pertama adalah 1,2 ha; siklus kedua 2 ha; dan siklus ketiga 4 ha. Sebagai perlakuan adalah bibit rumput laut hasil kultur jaringan dibandingkan dengan rumput laut lokal sebagai kontrol. Padat penebaran bibit rumput laut adalah 1.000 kg/ha yang dipelihara dengan metode tebar dasar. Penimbangan rumput laut dilakukan pada awal dan akhir penelitian untuk mengetahui laju pertumbuhan harian (LPH) dan produksi, sedangkan kandungan agar dianalisis setelah panen. Analisis data dilakukan secara deskriptif dan disajikan dalam bentuk grafik dan tabel. Dari tiga siklus budidaya menunjukkan bahwa bibit rumput laut hasil kultur jaringan memiliki performa pertumbuhan, produksi, dan kandungan agar yang lebih tinggi dibandingkan bibit rumput laut lokal dengan perbedaan masing-masing 12,1%; 17,8%; dan 6,7%. Pertumbuhan tertinggi terjadi pada siklus kedua, sedangkan kandungan agar tertinggi terjadi pada siklus ketiga baik pada bibit hasil kultur jaringan maupun bibit lokal. Bibit rumput laut Gracilaria sp. hasil kultur jaringan dapat dijadikan alternatif sumber bibit yang berkualitas.This study was aimed to evaluate the performance of G. verrucosa seaweed seed produced from tissue culture and cultivated at the seaweed production center in Murante Village Suli District Luwu Regency South Sulawesi in 2014. The seeds were cultivated for three production cycles, with each cycle lasted for 40 days. The first culture period was conducted in 1.2 ha, the second in 2 ha, and the third in 4 ha of pond areas. The treatments consisted of two different seaweed seed sources, i.e: tissue cultured seaweed seed and local seaweed as a control. The seaweed stocking density used was 1.000 kg/ha cultivated using broadcast method. The daily growth rate (DGR) and biomass as production indicators were measured at the initial and the end of the culture period. The agar yield was measured after harvest. The data were analyzed descriptively and presented in graphical visualization and data tabulation. The present study showed that tissue cultured seaweed had a higher performance in terms of growth, biomass production, and agar yield with the values of 12.1%, 17.8%, and 6.7%, respectively, than that of the local seedling. The highest DGR was produced at the second cycle, and the highest agar yield was measured at the third cycle for both of seaweed seedlings. Given this result, tissue cultured seaweed can be an alternative source of quality seeds.

Growth, Agar Yield and Water Quality Variables Affecting Mass Propagation of Tissue Cultured Seaweed Gracilaria verrucosa in Pond

Mass propagation of tissue culture produced seaweed seedling was conducted in the pond. The present study aims to evaluate the growth of tissue culture produced seaweed seedling of Gracilaria verrucosa, its agar yield and related water quality variables during propagation in pond. The seedling propagation was conducted in pond using long line method for 9 cycles (30 days per cycle). The daily growth rate was calculated by weighing 30% of the total amount of seaweed at ropes line every 15 days. Agar yield was analyzed every 30 days in hot water extraction method. Water quality monitoring was conducted every 15 days. The data of daily growth rate and agar yield were analyzed descriptively. A simple linear regression analysis was conducted in order to analyze the relationship between growth and agar yield as well relationship between water quality variables, growth and agar yield. The result showed that the average daily growth rate of nine cycles was 3.38±1.49%. The highest agar yield was yielded from cycle II (27.84±1.60%) and the lowest was in cycle I (10.30%±2.15). There is no relationship between daily growth rate and agar yield (R2=0.055). Daily growth rate was mostly influenced by phosphate (P<0.05), nitrate (P<0.05), salinity (P<0.05) and light penetration (P<0.05). Meanwhile, agar yield was mostly influenced by temperature (P<0.05) and light penetration (P<0.05). Present study promising for seaweed G. verrucosa mass cultivation of tissue culture product which is a feasible alternative method to supply seaweed seedlings in seaweed farming development. Keywords: growth, agar yield, G. verrucosa, tissue culture, water quality