Histology and physico chemical characteristic of seaweed Kappaphycus alvarezii from difference seeds original and harvesting time

Abstract

Indonesia is a rich country of natural resources, specially aquatic resources. One of them is seaweed that is a potential commodity that has a good prospect and high economic value. Kappaphycus alvarezii is also known by the trade name of Eucheuma cottonii is one of the class Rhodophyceae (red seaweeds) producing carrageenan. Carrageenan is located in the middle of lamella in the cell wall of plant forming a condensed material. Histology on seaweed aimed to observe changes in the structure of organs in some harvesting time. Histology on seeds origin from Kota Baru showed round shapes and seeds origin from Karimun tended to oval shapes after using thoulidin blue. Increasing in age of plant, the organs tended to irregular shapes. Carrageenan is a hydrocolloid secondary metabolite that is chain length polysaccharide resulted from the extraction of dried seaweed Kappaphycus alvarezii. Carrageenan is useful as gelling mixtures agent, stabilizer, emulsifier, suspending agent, and dispersing agent. The quality of carrageenan is influenced by several factors such as cultivation method, raw materials used, and methods of extraction. Dried seaweeds were taken from the Bogam Bay Kotawaringin Barat, County District Kumai, Central Kalimantan. The seeds origin of the seaweed were from two different places those are Kota Baru and Karimun Island. Both of the seeds were from aid of Marine And Fisheries Affairs of Kotawaringin Barat Regency. The observation was done on 30, 45 and 60 days of harvesting time. Water content, ash and acid insoluble ash content were analyzed. Addition of 0.05%, 0.10%, 0.15% chitosan in the extraction process aimed to refining, improving the quality of carrageenan, and reducing of chemicals materials during the process. This research resulted that only the 30 days of harvesting seaweed showed the difference structure of organs either seed from Kota Baru or Karimun Island. The yields, water content, ash content, gel strength, and viscosity were analyzed on carrageenan powder. it was obtained that seeds origin from Kota Baru which were harvested within 45 days, and addition of 0.10% chitosan in extraction process was the best quality of carrageenan. While the origin seed from Karimun Island has the best quality for 45 days harvesting with the addition of 0.15% chitosan. Heavy metal, whiteness, sulphate content, swelling point, and melting point were analyzed on the best carrageenan from both seeds origin.

Rumput laut merupakan komoditas potensial dengan nilai ekonomis tinggi serta memiliki prospek cerah. Kappaphycus alvarezii salah satu rumput laut yang berasal dari kelas Rhodophyceae (rumput laut merah) sebagai bahan baku pada pembuatan karagenan disamping juga diekspor dalam bentuk kering. Spesies ini merupakan rumput laut yang paling banyak dibudidayakan di Indonesia karena memiliki peluang pasar yang tinggi sehingga lebih diminati. Karagenan adalah suatu jenis senyawa galactan dan umum digunakan pada industri pangan dan non pangan sebagai pembentuk gel (gelling agent), penstabil (stabilizer), pengemulsi (emulsifier), pensuspensi (suspending agent) dan pendispersi. Penelitian ini mengamati secara deskriptif bentuk jaringan sel dari rumput laut berdasarkan asal bibit dan umur tanaman yang berbeda, mengamati karakteristik fisiko-kimia karagenan yang dihasilkan dari asal bibit dan umur panen yang berbeda, dan mempelajari pengaruh penambahan kitosan terhadap karagenan yang berasal dari asal bibit dan umur panen yang berbeda. Penelitian diawali dengan mengambil rumput laut hasil budidaya petani desa Teluk Bogam pada umur tanaman 30, 45 dan 60 hari sesuai dengan umur panen yang biasa dilakukan oleh petani. Rumput laut diamati secara mikroskopis dengan membuat preparat berdasarkan metode parafin sebagai acuan untuk uji histologi. Penelitian dilanjutkan dengan mengukur kadar air, kadar abu, dan kadar abu tidak larut asam pada rumput laut kering dan ektraksi karagenan dengan penambahan beberapa konsentrasi kitosan 0,05%;0,10%;0,15% kemudian dilakukan karakteristik rendemen, kadar air, kadar abu, kekuatan gel dan viskositas. Karakteristik karagenan terbaik dari asal bibit, umur panen dan penambahan kitosan diukur titik jendal, titik leleh, derajat putih, kadar sulfat dan logam berat. Data hasil pengamatan dianalisis ragam dan dilanjutkan dengan uji beda jarak berganda Duncan, dengan program SPSS 16 pada tingkat kepercayaan 95%.