Study on Extraction and Storage Stability of Watermelon Pulp Powder as Food Ingredient
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Abstract
Watermelon fruit is well known source of carotenoids (lycopene (70-90%) and ß carotene). The objective of this work was to study the extraction and storage stability of lycopene and ß carotene rich watermelon fruit juice powder to use as a food ingredient. The effect of different pH levels (3.05, 3.45, 3.85 and 4.25) of the juice on extraction of the powder was studied. The juice was acidified with citric acid and stored at 2 o C (2h) for rapid sedimentation of the pulp. There was insignificant (p>0.05)difference in the yield of dried powder extracted at different pH levels. However there were significant (p<0.05)differences in color, lycopene and ß-carotene contents for powders extracted at different pH levels. Powder extracted at pH of 3.85 resulted in higher color values. Higher lycopene content was observed at pH 3.85 and 4.25. But better ß-carotene content was observed at pH 3.05 and 3.45. On further work, 5 g potato puree was mixed with 0.1 g of extracted powder and a significant enrichment of the puree in lycopene (>83%) and ß-carotene (91%) contents was obtained. Study on storage conditions indicated that presence of oxygen in storage container played a critical role on lycopene stability than storage temperature. However ß-carotene was found relatively stable at low temperature (-40C) with/without oxygen. Extraction pH 3.85-4.25, storage in 9% carbon dioxide concentration and low temperature gave better powder extraction and storage stability.