title: Investigation of functional properties and color changes of corn extrudates enriched with broccoli or olive paste.
abstract: Following the tendency of replacing common food snacks with healthier food products, extruded snacks with corn flour and broccoli (4-10%) or olive paste (4-8%) were investigated in this study. The effect of material characteristics, including feed moisture content (14-19%), and broccoli or olive paste concentration, and extrusion conditions, including screw speed (150-250 r/min), and extrusion temperature (140-180 ℃), on the functional properties (water absorption index, water solubility index, and oil absorption index), as well as color change (ΔE) of the extruded snacks was studied. Regression analysis showed that screw speed did not significantly influence (p > 0.05) the properties. After mathematical modelling it was found that broccoli and olive paste concentration, as well as temperature increment, caused a decrease in water absorption index (minimum of 5.6 and 6.4 g/g sample, respectively) and an increase in water solubility index (maximum of 18.7 and 10.9 g/100 g sample, respectively), while feed moisture presented opposite tendency. Higher extrusion temperature led to an increment of oil absorption index (approximately to 1.2 and 1 mL/g sample) and decrement of color changes. Finally, feed moisture and broccoli concentration lowered oil absorption index and color of corn/broccoli extrudates, while olive paste concentration caused their increment.
authors.affiliation: Department of Chemical Engineering, Al-Hussein Bin Talal University, Jordan.
authors.forename: Ghassan I
authors.initials: GI
authors.lastname: Bisharat
authors.affiliation: School of Chemical Engineering, National Technical University of Athens, Greece katsavou@central.ntua.gr.
authors.forename: Ioanna D
authors.initials: ID
authors.lastname: Katsavou
authors.affiliation: School of Chemical Engineering, National Technical University of Athens, Greece.
authors.forename: Nikolaos M
authors.initials: NM
authors.lastname: Panagiotou
authors.affiliation: School of Chemical Engineering, National Technical University of Athens, Greece.
authors.forename: Magdalini K
authors.initials: MK
authors.lastname: Krokida
authors.affiliation: School of Chemical Engineering, National Technical University of Athens, Greece.
authors.forename: Zacharias B
authors.initials: ZB
authors.lastname: Maroulis
mesh_terms: D001937:Brassica; D003116:Color; D003314:Corn Oil / Q000737:chemistry; D005511:Food Handling / Q000379:methods*; D005638:Fruit; D055951:Functional Food; D008962:Models, Theoretical; D031658:Olea; D012995:Solubility; D013696:Temperature; D014867:Water / Q000737:chemistry; D003313:Zea mays / Q000737:chemistry*
chemical_list: D014867:Water; D003314:Corn Oil
keywords: Extrusion; freeze drying; mathematical modelling; oil and water absorption; optical microscopy; water solubility