Investigating carotenoid loss after drying and storage of

Main experiment
144
6. Effect of pre-treatment
Optimal concentrations of pre-treatment solutions have been tested in a pre-trial
experiment. In the main experiment pre-treatments concentration of sodium
metabisulphite in solution was reduced from 1% to 0.5% because of the risk of allergy.
Sodium metabisulphite is a food additive (E223) and FAO/WHO Expert Committee on
Food Additives stated that its consumption should not exceed 0-0.07mg/kg body
weight/day (Russell and Gould 2003). Results of main experiment on total carotenoid
content are presented in Table 6-4 on an insoluble basis.
Table 6-4: Total carotenoid content (!g.g -1 ) on water insoluble basis (insb) for
Ejumula variety of orange-fleshed sweet potato after combined pre-treatement and
drying
Pre-treatment TC insb**
Deionised water (control) 237.7 (24.0) a
0.5% Citric acid 232.2 (17.6) a
0.5% Sodium Metabisulphite 250.0 (12.8) b
1% Salt 251.4 (18.8) b
0.5% Citric acid; 1% Salt 254.7 (34.6) bc
0.5% Citric acid.; 0.5% Sodium Metabisulphite 259.6 (13.8) cd
1% Ascorbic acid.; 1% Salt 260.4 (12.6) cd
1% Ascorbic acid 260.8 (11.5) d
Un-soaked 269.4 (14.9) e
Each value represents the mean (standard deviation) of 2 2 analyses (two drying trials;
two extractions per trial).Two way ANOVA (factors: pre-treatement (9 levels); trial (2
levels)); Different letters a, b, c, d, e in columns represent significant differences
between treatments. Tukey test; p