Typically, jelly thickeners are products made from animal byproducts and therefore are not appropriate for vegetarian diets. Vegetarian jelly makers, on the other hand, frequently use vegetable products as thickeners. These include kuzu root, agar agar, or guar gum. Many people believe that kosher jellies are suitable for vegetarian diets, but frequently kosher products contain meat byproducts. A vegetarian should always read the label of the jelly to know if it contains meat byproducts.
Some of the products that companies use to thicken vegetarian jelly include cellulose, biobin, and carob fruit. Food processors may make kosher gelatin from fish bones or beef skins, which render it inappropriate for the vegetarian diet. Other non-vegetarian kosher thickeners may be marked as "pareve" or "OU pareve." The same is true for rennet and Halal gelatin. A vegetarian needs to read the labels of jellies, jams, and preserves before using them.
Some gelatin is vegetarian safe. Companies often use xanthan, agar agar, or guar instead of animal-based products. Some of these products are available to the home cook. Agar agar, which is sometimes simplified to "agar," is a seaweed product. Some strict vegetarians do not use it because they contend that small sea life may be on the seaweed. Jelly with agar agar needs to be refrigerated, and its consistency will be very soft.
Xanthan gum, which is sometimes shortened to xanthan, is another vegetarian jelly thickener. Food processors make it by fermenting lactose, sucrose, or glucose. A vegetarian should read the label to ensure the product is proper. Lactose is a milk sugar and may not be appropriate for all vegetarian diets.
Fruit pectin is a natural thickener that is present in most fruits. Some fruits, such as apples and most citrus fruits, have more than others, such as raspberries, peaches, or cherries. Under-ripe or overly ripe fruits have less pectin than perfectly ripe fruits. A person can make vegetarian jelly by harnessing this natural thickener. A few food companies offer pectin for thickening vegetarian jelly, jam, or preserves.
Seaweed-based thickeners include agar agar, carrageenan, and furcellaran. Many in the food industry consider agar agar gum to be superior to other seaweed gums. It was the first one to have widespread use, and the others became popular when the Western world broke off relations with Japan during the second World War. Not all vegetarians consider seaweed-based products to be appropriate for their diet, however, and therefore a vegetarian should read jelly and thickener labels carefully.