title: Analytical evaluation of virgin olive oil of first and second extraction.
abstract: Virgin olive oils from percolation (first extraction) have been compared with the corresponding oils from centrifugation (second extraction). The former were characterized by (i) higher contents of total phenols, o-diphenols, hydroxytyrosol, tyrosol-aglycons, tocopherols, trans-2-hexenal, total volatiles, and waxes; (ii) higher values of resistance to autoxidation and of turbidity; (iii) higher sensory scores; (iv) higher ratios of campesterol/stigmasterol, trans-2-hexenal/hexanal, and trans-2-hexenal/total volatiles; (v) lower contents of chlorophylls, pheophytins, sterols, and aliphatic and triterpene alcohols; (vi) lower alcoholic index and color indices; (vii) similar values of acidity, peroxide index, and UV (ultraviolet) spectrophotometric indices; (viii) similar percentages of saturated and unsaturated fatty acids, triglycerides, and diglycerides; and (ix) similar values of glyceridic indices. Stigmastadienes, trans-oleic, trans-linoleic, and trans-linolenic acid isomers were not detected in the two genuine oil kinds. Hence, the qualitative level of the first extraction oil was superior to the second extraction one.
authors.affiliation: Istituto Sperimentale per l'Elaiotecnica, Contrada Fonte Umano 37, 65013 Città S. Angelo, Pescara, Italy. elaiotec@unich.it
authors.forename: A
authors.initials: A
authors.lastname: Ranalli
authors.forename: M L
authors.initials: ML
authors.lastname: Ferrante
authors.forename: G
authors.initials: G
authors.lastname: De Mattia
authors.forename: N
authors.initials: N
authors.lastname: Costantini
mesh_terms: D005511:Food Handling; D000069463:Olive Oil; D010938:Plant Oils / Q000032:analysis*; D013056:Spectrophotometry, Ultraviolet
chemical_list: D000069463:Olive Oil; D010938:Plant Oils