[3][4][5] As a result, some government nutritional advice has been adjusted to encourage substitution of orange juice with raw fruit, which is digested more slowly, and limit daily consumption.

[6][7] During World War II, American soldiers rejected vitamin C-packed lemon crystals because of their unappetizing taste.

Thus the US government searched for a food that would fulfill the nutritional needs of the soldiers, have a desirable taste, and prevent diseases such as scurvy.

The US federal government and the Florida Department of Citrus worked with a group of scientists to develop a product superior to the canned orange juice available in the 1940s.

Essences, Vitamin C, and oils extracted during the vacuum concentration process may be added back to restore flavor and nutrition (see below).

The largest producers of "not from concentrate" use a production process where the juice is placed in aseptic storage, with the oxygen stripped from it, for up to a year.

Removing the oxygen also strips out flavor-providing compounds, and so manufacturers add a flavor pack in the final step,[16] which Cook's Illustrated magazine describes as containing "highly engineered additives."

[17] According to the citrus industry, the Food and Drug Administration does not require the contents of flavor packs to be detailed on a product's packaging.

[18] One common component of flavor packs is ethyl butyrate, a natural aroma that people associate with freshness, and which is removed from juice during pasteurization and storage.

In 1931, Dr. Philip Phillips developed a flash pasteurization process that eliminated this problem and significantly increased the market for canned orange juice.

Depending on storage temperature, freshly squeezed, unpasteurized orange juice can have a shelf life of 5 to 23 days.

[22] In the U.S., the major orange juice brand is Tropicana Products (owned by PAI Partners and PepsiCo Inc.), which possesses nearly 65%[citation needed] of the market share.

Competing products include Minute Maid (of The Coca-Cola Company) and Florida's Natural Growers (a Floridian agricultural cooperative that differentiates itself from the competition by being locally owned and using only Florida grown oranges; Tropicana and Simply Orange use a mixture of domestic and foreign stock).

[29] The concentrated juice is held in a cold wall tank and is stored at or below 35 °F to prevent browning and development of undesired flavors.

The bins are organized based on ratio of soluble solids to acids in order to blend oranges appropriate to produce juice with uniform flavor.

After the fruit leaves the bins, they are scrubbed with detergent on a rotary brush washer and subsequently rinsed with potable water.

The roller conveyors are efficiently built as they are well lighted, installed at a convenient height, and width to ensure all inspectors can reach the fruit to determine inadequacies.

[30] Finishers have a screw-type design that comprises a conical helical screw enclosed in a cylindrical screen with perforations the size of 0.020 to 0.045 inches.

[35] Across the UK, the final orange juice from concentrate product must contain a minimum Brix level of 11.2, excluding the additional sweetening ingredients.

The cloud is responsible for several sensory attributes in orange juice including color, aroma, texture, and taste.

[32] The continuous medium of the cloud consists of a solution of sugars, pectin, and organic acids while the dispersed matter is formed through cellular tissue comminuted in fruit processing.

[40] Specifically, the cloudiness of the juice is caused by pectin, protein, lipid, hemicellulose, cellulose, hesperidin, chromoplastids, amorphous particles, and oil globules.

A low zeta value signifies that the repulsive forces will not be able to overcome Van der Waals attractions between cloud particles and thus begin to agglomerate.

A high zeta potential will inhibit particle-particle agglomeration and maintain the free flowing nature as well as uniform dispersion in orange juice.

[41] In orange juice, pulp is responsible for desirable flow properties, taste, flavor, and mouth feel.

Pectin methyl-esterase is the enzyme responsible for hydrolyzing carboxymethyl esters and liberating free carboxyl groups and methyl alcohols.

The free carboxyl groups interact with cations to form insoluble pectic acid divalent metal ion complexes.

Ionic character relies on free carboxyl content, the presence of cations, and is favored at a high water activity.

Charge-charge repulsions along with the presence of neutral side chains are essential in inhibiting intermolecular association among pectin molecules.

The methyl ester content in orange juice determines hydrophobic character, which is favored at low water activity.