Promoting the utilization of Kappaphycus alvarezii (Doty Doty) red algae through chemical and physical treatments: Disinfection, deodorisation, and microbial & sensory quality evaluation

Marine algae called Kappaphycus alvarezii (Doty Doty) are rich in nutrients and bioactive compounds. The strong and unpleasant fishy odour limits its applications and prevents it from being consumed in fresh form. This study investigated four disinfection methods and two deodorisation treatments to reduce off-odours and improve microbial quality of seaweeds, aiming to promote their fresh consumption in Sri Lanka. Sensory quality was assessed using triangle tests, nine-point hedonic scale tests, preference ranking, and free choice profiling, while microbiological quality was evaluated through the total plate count and halophilic bacteria count methods. Disinfection treatments included blanching, chlorination, liming, and salt–vinegar soaking, followed by deodorisation with green tea or 20% ethanol. All eight treatment combinations showed a significant (p<0.05) odour reduction of K. alvarezii compared to the untreated algae in the triangle sensory tests and can be recommended equally for deodorisation purposes. In the Hedonic test, the odour difference among the treatment combinations was not significantly different (p>0.05). Colour of the treated algae showed a significant (p<0.05) difference between the treatments. The blanching and green tea soak treatment combination and lime juice and ethanol treatment combinations were most preferred by the sensory panellists in terms of colour. All disinfection methods effectively reduced microbial loads below the safety threshold (<10⁵ CFU/g), supporting their suitability for edible use of fresh K. alvarezii. The findings of this study provide effective strategies for improving the quality and safety of marine algae intended for use in dietary preparations.