Assessment of the Usefulness of the Twin-Screw Press in Terms of the Pressing Efficiency and Antioxidant Properties of Apple Juice

Abstract

The paper presents the possibility of applying a twin-screw press for juice extraction from apples with different textural properties. The research was carried out with six different varieties; namely, Granny Smith, Modi, Ligol, Lobo, Boscop and Szampion. During the experiment, the following properties were measured: texture properties, pressing yield and polyphenolic content; and ascorbic acid content and antioxidant activity both in raw apples and apple juice. Based on the analysis, three hardness levels of apples can be distinguished, impacting the course of juice pressing in a twin-screw press (low hardness below 30 N, medium hardness 30–50 N and high hardness 50 N). The study showed that only high hardness apples are suitable for pressing on a twin-screw press. The mechanism by which texture properties influence the juice pressing process in the studied press was explained. It was further demonstrated that the hardness of apples has a positive impact on the degree of extraction of polyphenols and ascorbic acid into apple juice. This is caused by the different fracture patterns of tissues with different mechanical properties. High hardness apples (Granny Smith and Modi) were characterized by a considerably greater degree of bioactive substance extraction into juice than medium hardness apples.

The Influence of Freezing and Thawing on the Yield and Energy Consumption of the Celeriac Juice Pressing Process

“…During the pressing process, the three-phase system (pulp) is separated into liquid (cell juice), gas (air), and solid (pectin, cellulose) states. The efficiency of juice pressing is influenced by operational and construction factors, as well as the properties of the pressed raw material [10][11][12]. In industrial conditions, basket presses with a drainage hose system or roll and belt presses are most commonly used for pressing.…”

“…In industrial conditions, basket presses with a drainage hose system or roll and belt presses are most commonly used for pressing. The method of pulp preparation and its pretreatment has a strong impact on the juice quality, as well as the pressing efficiency and energy consumption [10][11][12][13]. The aim of the pretreatment is to destroy cellular structures and then reduce the flow resistance of the liquid through the filling.…”

Analysis of Selected Physicochemical Properties of Commercial Apple Juices

“…The nutritional and bioactive quality of juice depends strongly on the apple cultivar used for processing [19,20], method of extraction and further process of juice treatment [21].…”

Physicochemical Properties of Apple Purees and Peel Extract for Potential Use in Pastry Products

“…Moisture content determination was performed according to AOAC Official Method 934.06. This procedure involves drying 5 g of sample at 103 ± 2 • C until a constant mass is obtained [28,[42][43][44][45]. Three determinations were performed for each sample.…”