edit How Lemons and Limes Are Used
Lemons and limes are both very acidic but have slightly different flavors and scents. A lemon has a bitter, acidic taste, while a lime has a sour, acidic taste. Both citrus fruits are frequently used in cooking and cocktails, as well a variety of household products.
edit In Cooking
Lemon juice is added to salads and pasta dishes and squeezed over fish fillets and meats; it is even used in many jams and preserves. Similarly, lime juice is often used in pastas and rices and on fish and meats. Lemon (and occasionally lime) zest — thin shavings of the fruit's outermost peel — adds tangy citrus oil to dishes.
Desserts also make frequent use of the lemon's flavor, with lemon juice, pulp, and zest often found in ice creams and gelatos, pies and their meringues, cookies, cheesecakes, pastries, and cakes. Lime juice, pulp, and zest appear less commonly in desserts but may on occasion be found in many of the same dessert foods that lemons are. However, the key lime, which is even more acidic than lemons and limes, is often preferred, with its most well-known use being for the key lime pie.
These fruits are also sometimes used to add slight coloring to foods and are many times found in candies (e.g., Lifesavers, gummy bears, Starburst).
edit In Drinks and Cocktails
The juice from lemons and limes appears in many drinks, from lemonade and limeade to Coca-Cola and Pepsi. Lemon juice and lime juice are also popular in cocktails with alcohol. Their subtly different flavors mean that pairing them with the same alcohol can create different drinks. For example, lemon juice in vodka is known as a lemon drop, while lime juice in vodka is known as a gimlet.
edit Other Uses
Lime is somewhat less commonly used outside of food and drink, but it can be found in some perfumes and aromatherapies. Lemon-scented cleaning products are common, however, as are slices of dried lemon in potpourri and other air fresheners. Lemon is also one of the most popular flavors for throat lozenges.
edit Lemon and Lime pH
Lemons and limes are similarly acidic, with certain varieties of the fruits being more or less acidic than others. However, lemon juice generally registers between 2.00 and 2.60 on the pH scale, while lime juice registers between 2.00 and 2.35.This means lime juice may often be more acidic than lemon juice. This is on top of the fact that lemons, which have a slightly higher sugar content, are sweeter.
It is worth noting that juice becomes more acidic with time, a fact which some chefs and bartenders now consider when cooking or mixing drinks.
edit Nutritional Content
According to the USDA Nutrient Database, lemons are a richer source of vitamin C and folate than limes, with 39mg of vitamin C and 20ug of folate found in 100g of raw lemon juice, compared to 30mg of vitamin C and 10ug of folate in 100g of juice from a lime. Limes, however, offer much more vitamin A — 50IU compared to 6IU.