Run code:

    @Override
    public void start(Stage stage) throws Exception {
        final TitledPane pane1 = new TitledPane();
        pane1.setGraphic(new Label("title 1\nLong text long text"));
        pane1.setContent(new Rectangle(100, 40, Color.SKYBLUE));
        Accordion acc = new Accordion();
        acc.getPanes().addAll(pane1);

        final IntegerProperty counter = new SimpleIntegerProperty(0);

        Button button = new Button("Change alignment");
        button.setOnAction(new EventHandler<ActionEvent>() {

            @Override
            public void handle(ActionEvent t) {
                switch (counter.getValue() % 4) {
                    case 0:
                        System.out.println("left");
                        pane1.setTextAlignment(TextAlignment.LEFT);
                        break;
                    case 1:
                        System.out.println("center");
                        pane1.setTextAlignment(TextAlignment.CENTER);
                        break;
                    case 2:
                        System.out.println("right");
                        pane1.setTextAlignment(TextAlignment.RIGHT);
                        break;
                    case 3:
                        System.out.println("justify");
                        pane1.setTextAlignment(TextAlignment.JUSTIFY);
                        break;
                }

                counter.setValue(counter.getValue() + 1);
            }
        });

        VBox pane = new VBox();
        pane.getChildren().addAll(acc, button);
        Scene scene = new Scene(pane, 300, 700);
        stage.setScene(scene);
        stage.show();
    }

option changing has no effect on visual appearance of control.