title: The Effect of Two Methods of Pomegranate (Punica granatum L) Juice Extraction on Quality During Storage at $4^\circ$ C.
abstract: The effect of two extraction methods of pomegranate juice on its quality and stability was evaluated. The first method consisted of separation of the seeds from fruits and centrifugation. The second method consisted of squeezing fruit halves with an electric lemon squeezer. During a period of 72 hours of cold storage at $4^\circ$ C, the juices were evaluated for the presence of sugars, organic acids, and anthocyanins. Delphinidin 3-glucoside was identified to be the major anthocyanin present at the level of 45-69 mg/L. Among the organic acids, oxalic and tartaric acids dominated. The major sugars detected in pomegranate juice were glucose and sucrose. No significant differences in the content of sugars, organic acids, or anthocyanins in juices obtained through application of the two different extraction methods were detected, with the exception of the drastic decrease of cyanidin $3,5$ -diglucoside level in juice obtained by seed centrifugation. The pH did not show differences between treatments. Titrable acidity and the level of sugars expressed as ${}^{\circ}$ Brix decreased after 32 and 15 hours after extraction, respectively, when juice was obtained by centrifuging the seeds.
authors.forename: Graça
authors.initials: G
authors.lastname: Miguel
authors.forename: Susana
authors.initials: S
authors.lastname: Dandlen
authors.forename: Dulce
authors.initials: D
authors.lastname: Antunes
authors.forename: Alcinda
authors.initials: A
authors.lastname: Neves
authors.forename: Denise
authors.initials: D
authors.lastname: Martins