19-08-2014, 11:32 AM
Fruits are very important part of humandiet. Due to changing lifestyle & diet consciousness demand for processed foods is enormously increasing. Juices are most important form of processed foods.
Fruits are very important part of humandiet. Due to changing lifestyle & diet consciousness demand for processed foods is enormously increasing. Juices are most important form of processed foods.
Pomegranate is very popular due to its taste and medicinal value. In addition it imparts various health benefits because of unique antioxidant properties. However fresh pomegranate juice is turbid and has a highly astringent taste making it unacceptable.
Present work includes clarification of the juice by various fining agents like gelatin, bentonite, PVP as well as enzymes like pectinase, cellulase and tannase. Effect of these agents on clarity, anthocyanins, tannins and various other physicochemical properties was studied. Mixture of pectinase and cellulase was found to be more effective. Optimization of enzyme concentration, incubation temperature, and incubation time was done for clarification of the juice production with maximum retention of its anthocyanin pigment and minimum presence of tannins. Using RSM technique clarity and anthocyanin content were increased by 4% &1.28% respectively whereas tannins was reduced by 2.6% compared to unoptimized treatment.
The enzymes pectinase and cellulase were further immobilized by entrapment in calcium alginate beads. Effect of various parameters like sodium alginate concentration, bead size, enzyme loading, and calcium chloride concentration on activity of enzyme were studied. Effect of immobilization on pH and temperature of enzymes were also studied. Reusability of beads was also checked. These immobilized systems were then tried for continuous production of juice using packed bed reactor.
Palatability of fruit juices can be increased by removal of unwanted ions. Acidity of some juices can be reduced by ion exchange treatment. Deacidification of pineapple juice was carried out with the ion exchange resin effectively. Various ion exchange resins would be screened for the same purpose with better retention of its organoleptic properties.