title: Effect of macerate enzymes on the yield, quality, volatile compounds and rheological property of prickly pear juice.
abstract: Pectinase and cellulase enzymes were used to investigate efficacy for improving juice yield, stability and quality from prickly pear fruit. Pectinase improved the yield, stable color, color-assayed as release of anthocyanins or carotinoids and clarity of the juice. A significant increase in the effectiveness of pectinase was observed as the concentration was increased from 0.05 to 0.50% v/w. However, at concentration > 0.25% v/w they tended to impart a bitter flavor in the juice. Among three concentrations of pectinase and cellulase, pectinase at 0.50% v/w produced higher yield, a sediment-free clear juice and high-quality juice. The results indicated that depectinated clarified prickly pear juice behaves as a Newtonian fluid. It was found that the activation energy (Ea) for viscous flow was in the range of 5.02 x 10(3)-20.06 x 10(3) kJ/mol depending on the concentrations of pectinase and cellulase enzyme treatment of prickly pear juice, in contrast to 22.15 x 10(3) kJ/mol in untreated juice. Volatile compound concentrations of twelve compounds were not affected by pectinase and cellulase treatment. Overall the quality of prickly pear juice was better in pectinase-treated juice compared with untreated and cellulase-treated juice.
authors.affiliation: National Research Centre, Food Science and Technology Department, Dokki, Cairo, Egypt. haminessa@yahoo.com
authors.forename: Hesham A
authors.initials: HA
authors.lastname: Essa
authors.forename: Manal F
authors.initials: MF
authors.lastname: Salama
mesh_terms: D001628:Beverages / Q000032:analysis / Q000592:standards*; D002480:Cellulase / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D005511:Food Handling / Q000379:methods; D005638:Fruit / Q000737:chemistry* / Q000378:metabolism; D008401:Gas Chromatography-Mass Spectrometry; D029747:Opuntia / Q000737:chemistry* / Q000378:metabolism; D011096:Polygalacturonase / Q000378:metabolism*; D012212:Rheology; D013649:Taste; D014783:Viscosity
chemical_list: D011096:Polygalacturonase; D002480:Cellulase