Juice is a liquid (drink) that is naturally contained in fruit and vegetables. It can also refer to liquids that are flavored with these or other biological food sources such as meat and seafood. It is commonly consumed as a beverage or used as an ingredient or flavoring in foods or other beverages. Juice emerged as a popular beverage choice after the development of pasteurization methods allowed for its preservation without fermentation. The Food and Agriculture Organization of the United Nations (FAO) estimated the total world production of citrus fruit juices to be 12,840,318 tonnes in 2012. The biggest fruit juice consumers are German : 39.6 liters consumed annually per person. They are followed by the US, which annually consume 33 liters.
Juice is prepared by mechanically squeezing or macerating (sometimes referred to as cold pressed) fruit or vegetable flesh without the application of heat or solvents. For example, orange juice is the liquid extract of the fruit of the orange tree, and tomato juice is the liquid that results from pressing the fruit of the tomato plant. Juice may be prepared in the home from fresh fruit and vegetables using a variety of hand or electric juicers.
Although processing methods vary between juices, the general processing method of juices includes:
- Washing and sorting
- Juice extraction
- Straining, filtration and clarification
- Blending pasteurisation
- Filling, sealing and sterilization
- Cooling, labeling and packing.
After the fruits are picked and washed, the juice is extracted by one of two automated methods. In the first method, two metal cups with sharp metal tubes on the bottom cup come together, removing the peel and forcing the flesh of the fruit through the metal tube. The juice of the fruit then escapes through small holes in the tube. The peels can then be used further, and are washed to remove oils, which are reclaimed later for usage. The second method requires the fruits to be cut in half before being subjected to reamers, which extract the juice.
After the juice is filtered, it may be concentrated, which reduces the size of juice by a factor of 5, making it easier to transport and increasing its expiration date. Juices are concentrated by heating under a vacuum to remove water, and then cooling to around 13 degrees Celsius. About two thirds of the water in a juice is removed. The juice is then later reconstituted, in which the concentrate is mixed with water and other factors to return any lost flavor from the concentrating process. Juices can also be sold in a concentrated state, in which the consumer adds water to the concentrated juice as preparation.
Juices are then pasteurized and filled into containers, often while still hot. If the juice is poured into a container while hot, it is cooled as quickly as possible. Packages that cannot stand heat require sterile conditions for filling. Chemicals such as hydrogen peroxide can be used to sterilize containers. Plants can make anywhere from 1 to 20 tonnes a day.
High intensity pulsed electric fields are being used as an alternative to heat pasteurization in fruit juices. Heat treatments sometimes fail to make a quality, microbiological stable products. However, it was found that processing with high intensity pulsed electric fields (PEF) can be applied to fruit juices to provide a shelf stable and safe product. In addition, it was found that pulsed electric fields provide a fresh-like and high nutrition value product. Pulsed electric field processing is a type of nonthermal method for food preservation. Pulsed electric fields use short pulses of electricity to inactivate microbes. In addition, the use of PEF results in minimal detrimental effects on the quality of the food. Pulse electric fields kill microorganisms and provide better maintenance of the original colour, flavour, and nutritional value of the food as compared to heat treatments. This method of preservation works by placing two electrodes between liquid juices then applying high voltage pulses for microseconds to milliseconds. The high voltage pulses are of intensity in the range of 10 to 80 kV/cm. Processing time of the juice is calculated by multiplying the number of pulses with the effective pulse duration. The high voltage of the pulses produce an electric field that results in microbial inactivation that may be present in the juice. The PEF temperatures are below that of the temperatures used in thermal processing. After the high voltage treatment, the juice is aseptically packaged and refrigerated. Juice is also able to transfer electricity due to the presence of several ions from the processing. When the electric field is applied to the juice, electric currents are then able to flow into the liquid juice and transferred around due to the charged molecules in the juice. Therefore, pulsed electric fields are able to inactivate microorganisms, extend shelf life, and reduce enzymatic activity of the juice while maintaining similar quality as the original, fresh pressed juice.
In the United Kingdom the name or names of the fruit followed by juice can only legally be used to describe a product which is 100% fruit juice, as required by the Fruit Juices and Fruit Nectars (England) Regulations and the Fruit Juices & Fruit Nectars (Scotland) Regulations 2003. However, a juice made by reconstituting concentrate can be called juice. A product described as fruit "nectar" must contain at least 25% to 50% juice, depending on the fruit. A juice or nectar including concentrate must state that it does. The term "juice drink" is not defined in the Regulations and can be used to describe any drink which includes juice, however little. Comparable rules apply in all EU member states in their respective languages.
In the US fruit juice can only legally be used to describe a product which is 100% fruit juice. A blend of fruit juice(s) with other ingredients, such as high-fructose corn syrup, is called a juice cocktail or juice drink. According to the Food and Drug Administration (FDA), the term "nectar" is generally accepted in the US and in international trade for a diluted juice to denote a beverage that contains fruit juice or puree, water, and which may contain artificial sweeteners.
"No added sugar" is commonly printed on labels of juice containers, but the products may contain large amounts of naturally occurring sugars; however, sugar content is listed with other carbohydrates on labels in many countries.
Juices are often consumed for their perceived health benefits. For example, orange juice is rich in vitamin C, folic acid, potassium, is an excellent source of bioavailable antioxidant phytochemicals and significantly improves blood lipid profiles in people affected with hypercholesterolemia. Prune juice is associated with a digestive health benefit. Cranberry juice has long been known to help prevent or even treat bladder infections, and it is now known that a substance in cranberries prevents bacteria from binding to the bladder.
Many fruit juices have a higher sugar (fructose) content than sweetened soft drinks; e.g., typical grape juice has 50% more sugar than Coca-Cola. While soft drinks (e.g. Coca-Cola) cause oxidative stress when ingested and may even lead to insulin resistance in the long term, the same thing cannot be attributed to fruit juices. On the contrary, fruit juices are actually known for their ability to raise serum antioxidant capacity and even offset the oxidative stress and inflammation normally caused by high-fat and high-sugar meals. However, frequent consumption of fruits and fruit juice causes dental decay, and may be a more significant factor in the development of dental caries (cavities) than eating candy. Fruit juice causes dental decay because it naturally contains acids, which chemically dissolve the enamel of the surface of the tooth, and sugars that the bacteria in the mouth ferment to create even more tooth-destroying acids.
Fruit juice consumption overall in Europe, Australia, New Zealand and the US has increased in recent years, probably due to public perception of juices as a healthy natural source of nutrients and increased public interest in health issues. Indeed, fruit juice intake has been consistently associated with reduced risk of many cancer types, might be protective against stroke and delay the onset of Alzheimer's disease.
Some fruit juices have filtered out the dietary fiber present in the fruit. In other cases, other ingredients are added. High-fructose corn syrup, an ingredient in many juice cocktails, has been linked to the increased incidence of type II diabetes. High consumption of juice is also linked to weight gain in some studies, but not in others. In a controlled clinical study, regular consumption of grape juice for 12 weeks did not cause any weight gain in volunteers, but consumption of a soft drink did. Fruit juice in moderate amounts can help children and adults meet daily recommendations for fruit consumption, nutrient intake and calories.
The American Academy of Pediatrics says that fruit juice should not be given to infants before 6 months of age. For children ages 1 to 6, intake of fruit juice should be limited to 4 to 6 ounces per day (about a half to three-quarters of a cup). Giving children excessive juice can lead to poor nutrition, diarrhea, gas, abdominal pain, bloating, and tooth decay.
Juice cleanses have become a popular diet. The key concept of juice cleanses, detoxification, bases on the assertion that by consuming only nutrient rich substances (juice) and eliminating dairy, wheat, gluten, and fermented foods, the body can better heal physical problems. A juice cleanse requires the consumption of nothing except for juice for multiple days, with proposed health benefits including: reduction in appetite, rest for the stomach and liver, elimination of harmful foods, flooding the body with super nutrition, weight loss, energy improvement, re-hydration, detoxification, and cell healing. Unlike most diets, juice cleanses do not last for extended periods, usually ending in less than a week.
Comparison to whole fruits
Longitudinal prospective cohort studies conducted at Harvard showed a significantly increased risk of Type 2 diabetes when juices were consumed compared to whole fruits, which significantly reduced the risk.
Fruit juice has also been linked to childhood obesity. The American Journal of Public Health proposed that the Healthy Hunger-Free Kids Act of 2010 in the United States eliminate 100% fruit juices since it has been linked to childhood obesity, and substitute instead with whole fruits.
Since juices do not contain fiber from the fruits, many further benefits are therefore negated found in whole fruits instead. Prebiotics have a marked beneficial impact on calcium absorption, mineral absorption, bowel health, and promoting a healthier gut flora. Furthermore, most polyphenols are bound to the plant fibers and constitute the major portion of dietary phytonutrients. There is therefore a marked reduction in nutritional benefit from consuming fruit juice compared to the consumption of whole fruits.
A juice bar is an establishment that primarily serves prepared juice beverages such as freshly squeezed or extracted fruit juices, juice blends, fruit smoothies (a thick fruit drink, often iced), or other juices such as fresh wheatgrass juice. Sometimes other solid ingredients or nutritional supplements may be added as boosters, such as fresh bananas, eggs, nuts or nut butter, bodybuilding supplements, soy protein powder or others such as whey or hemp protein powders, wheat germ, or Spirulina (dietary supplement) or Chlorella. Also if less juice is used with these same ingredients drinks called health shakes may be produced.
Juice bars may be stand alone businesses in cities, or located at gyms, along commuter areas, near lunch time areas, at beaches, and at tourist attractions.
- Boost Juice Australia
- Booster Juice
- Jamba Juice
- Orange Julius, an orange juice based drink and chain of stands
- "La Michoacana" Mexican juice bars
One of the first regularly produced juices was lemonade, appearing in 16th century Italy, as an import, after its conception in the Middle East. Orange juice originated in the 17th century. In the 18th Century, James Lind linked citrus fruits to the prevention of scurvy, which, a century later, lead to the implementation of the Merchant Shipping Act of 1867, requiring all Ocean-bound British ships to carry citrus-based juice on board.
In 1869, a dentist by the name Thomas B. Welch developed a pasteurization method that allowed for the storage of juice, without the juice fermenting into alcohol. His method involved filtering squeezed grape juice into bottles, sealing them with cork and wax, and then placing them in boiling water. This method kills the yeast responsible for fermentation. He then sold his new product as “Dr Welch's Unfermented Wine”.
In late 18th century United States, circulation of foreign fruit juices were heavily regulated by tariffs. The McKinley Tariff Act of 1890 increased import takes from 38 to 49.5 percent, and set taxes on fruit juices based on the alcohol content of the drink. Juices with 18% or less alcohol were taxed 60 cents per gallon, while anything above 18% was taxed $2.50 per proof gallon.