A preliminary estimation of an apple juice composition using the method of a nuclear magnetic resonance

Abstract

The researches have been made in 2012-2013 in the Institute of physical and organic chemistry of National Academy of Sciences of Belarus together with the Institute for fruit growing. The fruits of 6 late ripening apple cultivars zoned in Belarus were the objects of the research. Among them were the following cultivars: ‗Alesya‘, ‗Byelorusskoye sladkoye‘, ‗Verbnaye‘, ‗Zaslavskoye‘, ‗Imant‘ and ‗Nadzejny‘. The method of nuclear magnetic resonance (NMR) at the nuclei 1Н and 13С was used for the analysis of juice soluble organic components. The spectra were written down on spectrometer AVANCE-500 (Bruker, Germany). A high informational content of NMR method use in the analysis of apple juice was shown. As a result of the researches it has been established that more than half of soluble dry matters is accounted for by a fructose which is introduced by 5 isomers such as b-fructopyranose, b-fructofuranose, a-fructofuranose, a-fructopiranose and ketofructose. Glucose is introduced by two isomers such as b-glucopyranose and a-glukopyranose. Some changes of the composition of soluble dry matters during apple storage time are presented. They include the reduction of sucrose content and malic acid and increase of glucose and fructose content.