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|Title:||Influence of post-harvest treatment on shelf life and agar quality in seaweeds Gracilaria edulis(Rhodophyta/Gigartinales and Gelidiella acerosa(Rhodophyta/Gelidiales)|
Rao, P.V. Subba
|Keywords:||Agar yield;Gel strength;Gelling temperature;Melting temperature;Acid;Alkali;Treatment;Storage|
|IPC Code:||Int. Cl. ⁷ C08B 37/12|
|Abstract:||The effect of acetic acid and alkali (KOH) pretreatments on the shelf life of Gracilaria edulis and Gelidiella acerosa were studied with respect to the agar yield and physical properties. Algae collected from the Gulf of Mannar, southeast coast of India were treated with 1) 0.5% acetic acid for 1 hr, 2) 1% KOH for 1 hr and 3) 0.5% acetic acid 1 hr followed by neutralization in 1% KOH for 1 hour. Gracilria edulis pretreated with acid + alkali gave the maximum agar yield (69.2 ± 12.3%), gelling temperature (50.5±1ºC ) and melting temperature (82.5±1.5ºC ). However no improvement in gel strength was recorded over control. Acid treated G.elidiella acerosa yielded the maximum agar (59.2 ± 3.9%) while exhibiting a gel strength of 295.1 ± 18.6 g.cm ⁻², a gelling temperature of 53 ± 2.5ºC and a melting temperature of 88.7± 0.7ºC . When the pretreated algae were stored for 4 months, for G.edulis agar yield remained same but its physical properties decreased gradually. In G.acerosa agar yield and melting temperature were constant, but gel strength and gelling temperature decreased drastically. It is suggested that agar industry can treat Gelidiella acerosa with acetic acid and Gracilaria edulis with acetic acid and KOH prior to storage. This will help to increase the agar yield and its physical properties on immediate use and maintain agar yield on long term use.|
|Appears in Collections:|| IJMS Vol.33(3) [September 2004]|
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