Effect of press construction on yield of pressing and selected quality characteristics of apple juice

The process of fruit juices production should be characterised by a high efficiency, while the final product should have a high content of soluble solids, low acidity and a high content of health-promoting components. Currently, screw presses are becoming increasingly popular especially on small farms and households. Their construction has a great impact on yield pressing and quality characteristics of juice. The primary objective of this study was to determine the effect of the press type on juice extraction efficiency and on the total amount of released polyphenols. The scope of the study included also the determination of the juice quality parameters such as the content of soluble solids, pH, viscosity and density. Apple fruits were pressed using two types of machines: a single-screw press and a twin gear juice extractor. Study results demonstrate that the pressing efficiency depends on the press construction. The highest yield of extraction was obtained for the twin-screw press. Under the experimental conditions, there was no influence of the press type on the quality properties of the juice, except for its viscosity. However, the quality characteristics of the juice depended on the apple variety. Higher contents of the extract and polyphenols were obtained in juice from the apple var. Jonagold juice and viscosity in juice from the apple var. Ligol juice. The use of the press offers the possibility of producing juices with desirable quality traits.