Pectin molecule polymer of galacturonic acids which may be partially esterified
Pectin molecule polymer of galacturonic acids which may be partially esterified
Calcium interaction ◼ Interaction with cell walls and middle lamella: “Egg-box” model Calcium ions polygalacturonic acid chains (pectins)
Calcium interaction ◼ Interaction with cell walls and middle lamella: “Egg-box” model Calcium ions polygalacturonic acid chains (pectins)
Calcium interaction ◼ Interact with cell membranes and affect turgor pressure ++ ++ Phospholipid bilayer Calcium ions
Calcium interaction ◼ Interact with cell membranes and affect turgor pressure ++ ++ Phospholipid bilayer Calcium ions
Pectinmethylesterase (PME) ◼ Hydrolyzes the methyl ester linkages in pectin molecules and releases methanol and free galacturonic acid moieties ◼ Free carboxyl groups then form Ca-bridges between pectin molecules ◼ Activity ◼ Inactive at temperatures 50C ◼ Activated 50C and reacts with cell wall pectins ◼ rapidly deactivated at 70C
Pectinmethylesterase (PME) ◼ Hydrolyzes the methyl ester linkages in pectin molecules and releases methanol and free galacturonic acid moieties ◼ Free carboxyl groups then form Ca-bridges between pectin molecules ◼ Activity ◼ Inactive at temperatures 50C ◼ Activated 50C and reacts with cell wall pectins ◼ rapidly deactivated at 70C
Objective ◼ Improve texture integrity and crispiness of frozen vegetables ◼ Activation of PME ◼ LTLT pretreatment ◼ Calcium binds free carboxyl groups ◼ Addition of Ca2+ ◼ Improve color of pretreated frozen vegetables ◼ 3-step-blanching ◼ Addition of Zn2+ ◼ Increased pH - calcium lactate
Objective ◼ Improve texture integrity and crispiness of frozen vegetables ◼ Activation of PME ◼ LTLT pretreatment ◼ Calcium binds free carboxyl groups ◼ Addition of Ca2+ ◼ Improve color of pretreated frozen vegetables ◼ 3-step-blanching ◼ Addition of Zn2+ ◼ Increased pH - calcium lactate