Pectin is a type of fiber in most fruits and some vegetables. It's most commonly used as a thickener in jams and preserves. In a glaze, pectin binds the sugar and water molecules together to form a clear viscous liquid.
Making a neutral glaze is a simple process, and one you can do several days ahead of time.
Boil 2 parts water with 1 part sugar and 1/5 part pectin for 2 to 3 minutes, until the sugar is dissolved and the liquid is clear. Let it cool slightly before using.
Store the glaze in the refrigerator until you're ready to use it. Reheat gently in the microwave or on the stove until it returns to a liquid consistency.
If you plan to glaze a fruit dessert, such as a tart, the glaze can add a hint of flavor as well as a shiny texture. A fruit glaze made from premade jam or preserves already has pectin in it. Heat the jam or preserves in a small saucepan. Add water or fruit liqueur to thin the glaze to the desired consistency. Strain out any fruit solids, and use as you would a neutral glaze.
Glazes are used by pastry chefs to give fruit tarts their shiny appearance, but the glaze isn't all about show. It also helps keep the dessert from getting stale by locking in the juices and protecting the fruit from air.
Chefs also use glazes on cakes to preserve them and keep them moist before decorating.