Analysis of Different Brands of Fruit Juice with Emphasis on their Sugar and Trace Metal Content

Ten brands of commercial fruit juice were analysed for pH, specific gravity, total solids, reducing sugar, total sugar, and metal contents. The sugar content was determined using the Lane and Eynon method, sodium and potassium were determined by flame photometry, calcium and magnesium by complexometric titration using EDTA, while the other metals were determined by atomic absorption spectrophotometry. The juices had a pH range of 1.80-3.40, specific gravity of 1.002-1.054, total solids of 0.68-12.49%, content of reducing sugar 0.34-8.25% and content of total sugar 0.54-10.69%. Other derived values were calcium (0.01-1.25ppm), magnesium (0.06-0.43ppm), sodium (0.84-3.11ppm), potassium (0.16-7.42ppm), copper (0.28-5.06ppm), zinc (0.01-0.10ppm), chromium (0.03-0.09ppm), manganese (0.11-6.96ppm), cobalt (0.01-0.06ppm), nickel (0.03-0.15ppm), iron (0.45-50ppm), cadmium (0.16-0.38ppm) and lead (0.11-0.33ppm). The Nigerian made fruit juices had higher amount of added sugar. The pineapple juice brand had very high concentration of iron and the presence of cadmium and lead in some of the samples is a clear case of contamination. However the contamination level cannot yet present health threat to the consumer.Keywords: Fruit juice, Added sugar, Reducing sugar, Low level contamination, Trace metal

Removal of humic acid from peat water using untreated powdered eggshell as a low cost adsorbent

The main objective of this study is to investigate the possibility of powdered eggshell used as an adsorbent material for removal of humic acid from peat water. The influences of contact time, dose of eggshells, pH, and temperature were the factors considered in the removal processes of humic acid from peat water. In addition, adsorption isotherms of humic acid onto the powdered eggshell were also evaluated with the Langmuir and Freundlich approximations. Our results showed that the equilibrium of the process was eventually established after 60 min of the contact time, and also found that using 5 g of the powdered eggshell nearly 95 % of humic acid has been successfully removed from the peat water. The removal of humic acid gave better result when it was conducted at low pH, and it was almost unaffected the temperatures variation. The data was well fitted to Freundlich isotherm with the correlation coefficient of not <0.999, and could uptake the humic acid about 126.58 mg/g at pH 4.01, estimated from the Langmuir model. The kinetic experimental data proportionally correlated with the pseudo-second-order kinetic model with a rate constant in the range of 0.016-0.112 g mg -1 min -1 , while intra-particle-diffusion were the main rate determining step in the humic acid removal process. The powdered eggshell investigated in this study, thus, exhibited as a high potential adsorbent for the removal of humic acid from peat water