PAPER TITLE :EFFECT OF PRETREATMENT METHODS AND STORAGE TEMPERATURE ON THE QUALITY DETERIORATION OF CARROT JUICE

JOURNAL Of SUSTAINABLE TECHNOLOGY | VOLUME 7 NUMBER 1 2016

Paper Details

  • Author(s) : OYERINDE, A. S.
  • Abstract:

Quality deterioration of fresh carrot juice was investigated at three different
temperatures (15 oC, 25 oC and 37oC) using three different pretreatment methods. The extracted
carrot juice samples were divided into four. Sample A was not treated (it also serves as the control),
sample B was pasteurized, at 60oC for 30 minutes, sodium benzoate(NaC7H5O2) and sodium
metabisulphite (Na2S2O5) preservatives were added to sample C and sample D was pasteurized with
sodium benzoate and sodium metabisulphite added to it as preservatives. The total viable bacteria
count and the total mould and yeast increased significantly during storage at 37±3oC, there was
more microbial growth during storage at 37±3oC compared to other temperatures (15±3oC, 25±
3oC) and low microbial growth during storage at 15±3oC. The brix level, total carotenoids, ascorbic
acid, titratable acidity, specific gravity decreased significantly during storage, the viscosity and pH
also increased during storage. The brix level decreased when temperature was increased. The
samples with preservatives (NaC7H5O2 +Na2S2O5) were able to retain their brix levels compared to
other samples without preservatives. The concentration of total carotenoids and ascorbic acid
decreased significantly when the temperature was increased. The specific gravity decreased with
increased temperature. It was observed that there was a significant increase in viscosity when the
carrot juice is stored at 15±3oC and the viscosity reduces when the rotor speed (rpm) is increased.
It was observed that carrot juices are pseudoplastic in nature during storage because the flow
curve has a slope decreasing with increasing rate of shear.
Keywords: Carrot juice, pretreatment, beta-carotene, preservatives, rheological properties,
temperature, quality