Wheat.

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wax

Commercial source: vegetable, synthetic, animal (insect- or cow-derived).
Used in: chewing gum base, candy.
Used on: produce, food packages.
Definition: The name for substances which are similar to fats and repulse water. They are most often used as fruit and vegetable protective coatings.
Typically Vegetarian

wheat gluten

Also known as: wheat isolate, wheat gluten, vital wheat gluten.
Commercial source: vegetable.
Used in: seitan, bread, baked goods.
Definition: A mixture of proteins from wheat flour.
Vegan

whey

Commercial source: animal (milk).
Used in: baked goods, ice cream, dry mixes, processed foods.
Definition: The watery material which remains after most of the protein and fat have been removed from milk during the cheese-making process. Whey does contain much of the enzyme used to make the cheese. The most common source of enzyme is microbial although it may be animal in some cases.
Typically Vegetarian

wine

Commercial source: vegetable.
Definition: An alcoholic beverage made from plants or fruit, especially grapes. Wine may be made clear through treatment with a small amount of animal protein such as gelatin, albumen, or casein. (See gelatin, albumen, and casein). It may also be made clear through a mineral filter known as bentonite. (See bentonite).
May Be Non-Vegetarian

xanthan gum

Also known as: corn sugar gum.
Commercial source: vegetable.
Used in: dairy products, salad dressings, sauces, baked goods, pie fillings, beverages.
Definition: A widely used and versatile vegetable gum which is sometimes used as a thickener.
Vegan

yeast extract

See autolyzed yeast extract.

yeast food

Commercial source: Typically vegetable or mineral.
Examples: malt, sugar, calcium phosphate.
Used in: baked goods, beer, wine.
Definition: A general term for all the substances added to nourish yeast and speed up the process by which they produce alcoholic beverages or baked goods.
Typically Vegan

zein

Commercial source: vegetable.
Used in: nuts, grain products, confections.
Definition: A corn protein which functions as a coating or glaze.
Vegan