Citrus juices technology

Citrus fruits are widely grown throughout the world and contain various bioactive compounds with antioxidant activities including vitamin C, carotenoids, and phenolic compounds. These components are very important for human health and provide protection against harmful free radicals. Citrus fruits are mostly consumed as fresh fruits or fruit juices. To obtain high quality and safe citrus juice, certain critical points (oil extraction from peel, juice extraction, pulp removing, pasteurization, evaporation, and aseptic filling) need to be taken into consideration during citrus juice processing. Firstly, oil extraction from the peel is a necessary step to limit the level of peel oil components in the juice. Secondly, selected juice extraction techniques and process conditions are very important for the yield and total quality of the juice. Thirdly, the pulp removal is an important step to remove most of pectinmethylesterase (PME) and its heat resistance isoenzymes. Further inactivation of remaining PME enzymes and pathogenic or spoilage microorganisms is also obtained with the pasteurization step. Finally, equipment used for the juice production and the concentration conditions have various effects on the sensory properties of the citrus juices. As a result, minimal processing would be applied to citrus juices if the processing steps detailed above are optimized. Obtaining clarified citrus juices from the citruses which have lower carotenoid content including lemon and lime juice is a new trend these days. It is needed to be focused on enzymation (depectinization), clarification assistance agents, and filtration conditions during the clarified juices production. Citrus peel (flavedo) and layer of albedo are the main byproducts of the citrus juice industry. Citrus peel oil is obtained from flavedo layer which has a significant commercial value. Recently, promising nonthermal food preservation technologies were developed including pulsed electric fields (PEF), high pressure processing (HPP), and ultrasonication process (US). These technologies are highly appreciated for their ability to extend the shelf life of food products without the application of heat, thus also preserving the quality attributes such as sensory quality and nutritional value, as well as controlling the microbiological safety of food products. © 2014, Springer Science+Business Media New York