Hot water blanching pre-treatments to enhance drying of seaweeds (Kappaphycus alvarezii S.) / Eric Zamora Del Rosario

Thesis (Master of Science in Agriculture Engineering) -- Central Luzon State University, February 2018.

Typically, seaweed farmers use sun drying in an open area exposed to direct
sunlight. This method in drying of seaweeds requires large open area and long drying
time which may result to low product quality. It is necessary if the period of drying could
be decreased without affecting quality of the seaweed. This research aimed to investigate
the application of hot water blanching pre-treatments to enhance drying of seaweeds
(kappaphycus alvarezii S.), moreover, to analyze the drying characteristics, proximate analysis and sensory characteristics of seaweed as affected by hot water blanching pre-
treatments and dried using solar glass dryer and heated air mechanical dryer. Simple cost analysis was also performed to assess the annual cost and custom rate of using solar glass
dryer and heated air mechanical dryer.
Results revealed that in heated air mechanical dryer, samples blanched for 5 and
15 seconds dry faster (8 hours). In solar glass dryer, seaweed samples blanched at 5
seconds dry earlier (32.67 hours). Results imply that hot water blanching affects drying
time in drying seaweeds and hot water blanching pre-treatments increased drying rate at
the initial hour of drying. All drying curves were subjected to regression analysis and
from the results obtained, it could be verified that the models fitted shows good predicting capacity and reveals good correlation coefficient between the fitted model and
experimental data.
Hot water blanching pre-treatments and types of dryers did not significantly affect
the total ash contents of the seaweed powder, while in crude protein levels, results
revealed that hot water blanching pre-treatment were not significant within the dryers but significantly different in terms of method of drying. Moreover, hot water blanching pre-
treatments within the dryer were significantly different in crude fiber levels but insignificant in comparison between dryers, except for samples blanched at 30 seconds
that were significant.
Results imply that color of the seaweed powder dried in solar glass dryer was
preferred by panels. It was observed that all seaweed samples dried using heated air mechanical dryer turned to dark color. Results revealed that hot water blanching pre-
treatments and types of dryer do not affect the texture and odor preference of the panels.

As rated by panels, general acceptability scores of the seaweed powder were
insignificantly different within dryers.
Data showed that when using solar glass dryer, it is profitable to blanch the
seaweeds before drying with custom rate of Php 67.23 per kg., payback period 0.54 year,
and annual net income of Php 12,951.21, while when using heated air mechanical dryer,
it is cost-effective to blanch the seaweeds before drying with custom rate of Php 162.32,
payback period 0.27 year, and annual net income of Php 551,204.81.