COMPARISON OF VOLATILE COMPOUNDS AND CHEMICAL AND PHYSICAL PROPERTIES IN ORANGE JUICE FROM DIFFERENT PARTS OF JINCHEN FRUIT

ABSTRACT Jinchen is a native sweet cultivar of Citrus sinensis and one of the most important varieties used in orange juice processing in China. The study of flavor components of Jinchen orange juice has not been carried out before. In this paper, the color characteristics, pH value, total soluble solids, total acids, as well as organic acids and sugars were determined in Jinchen orange juice from different parts of fruit (peeled juice, pulp juice, whole fruit juice). The color characteristics were significantly different among three types of Jinchen orange juice. The level of vitamin C and total soluble solids/total acids ratio (TSS/TA) is higher in whole fruit juice. The organic acids and sugars also changed. Pulp juice is rich in the highest amounts of organic acids and sugars. Volatiles from three juices were studied using the solid phase microextraction (SPME) combined with gas chromatography/mass spectrometry. The whole fruit juice has the highest amount of volatile compounds (53.07 mg/L) followed by peeled juice (51.044 mg/L) and pulp juice (27.107 mg/L). Some differences in the constituents of the volatile compounds of three type juices were observed. These results indicated that volatile compounds and quality properties differed in Jinchen orange juice from different parts of fruit.PRACTICAL APPLICATIONSThe peeled orange fruits are usually used for juice processing. Great amounts of aroma components with intensive odor are located in the peel of orange. The aroma of pulp possessing weak fresh citrus odor is different from peel. The different parts of the orange utilized in processing have direct impact on juice quality. It is very essential to obtain the data of chemical and physical properties in juice from different parts of orange fruit. The quality information could be used to modify the orange aroma.