Effects of Fruit Peel on Flavor Quality and Flavonoid Contents of Juices from Citrus ‘Niihime’ and ‘Kara’

Abstract

The juices of whole, mature fruit of ‘Kara mandarin’ and immature and mature ‘Niihime’ were squeezed at various levels of pressure: 6, 8, 10, 12 and 14 Mpa, with a compressed juice machine. The squeezing ratio increased as the pressure rose regardless of the fruit’s maturity or cultivar. The flavonoid content of whole fruit juice was determined by the HPLC method. The juice of ‘Niihime’ contained significant amounts of sinensetin, tangeretin, eriocitrin, and nobiletin, and their concentrations increased as the squeezing pressure rose. The taste of whole fruit juice was evaluated with a taste sensor system. The whole fruit juice showed higher values for astringency and bitterness compared with that not including the peel Furthermore, the smell of the whole fruit juice was slightly fishy, and evaluation using a smell sensor revealed that it contained more amine components than the other juices.