Fruit Juice Processing

Fruit Juice Processing
Most juices are derived from fleshy fruits and these may be conveniently subdivided for processing into three categories.

*Fruits which are pulped and their juices removed by pressing, e.g., apple, berry fruits
*Fruits requiring the use of specialized extraction equipment, e.g., citrus fruits, pineapples
*Fruits requiring heat treatment before processing, e.g., tomatoes, stone fruits

In most large fruit processing operations the plant is usually dedicated to one type of fruit.

Citrus fruits are unusual because the outer skin or flavedo is rich in essential oils and other tissues such as the albedo or carpellary membranes contain substances that give rise to bitter flavors.

The processing of citrus typical involves separation of these various components as an important principle and for certain products such as comminuted bases, the various components are recombined in different proportions.

The flesh of stone fruits is separated from the stones or pits, not only to facilitate ease of handling, but also because the stones are further processed to obtain both fixed oils and glycosides.

Fixed oils, such as those from peach, have application in the cosmetics industry and glycosides may be used as a source of other natural flavoring ingredients such as benzaldehyde.

Another important aspect of the processing of fruit is the presence of pectins. These substances contribute it the viscosity of fruit juices and assist in the suspension of colloidal material and tissue fragments that make up its cloud.

When most fruits are pressed, pectolytic enzymes are released and these will of not destroyed, clarify and or cause gelling of the juice.

Rapid initial processing of freshly pressed juice is therefore an important factor in determining whether cloudy juice is obtained (in which case the enzymes must be destroyed by pasteurization to at least 95 degree C) or clear juice, in which case enzymes are allowed to act and may be enhanced by the addition of synthetic enzymes on further quantity.
Fruit Juice Processing

Juice from fruit

Juice from fruit
The extraction of juice from fruit is an ancient art dating from the earliest of records where wine is often mentioned.

Fermentation of fruit juice so the alcohol content preserved the fermented juice was one of the earliest forms of food preservation by the human species.

With rapid changes taking place in most technologies during the past century, the manufacture of fruit juice had progressed from the farm or cottage industry into the efficient technology of modern food processing.

Throughout the temperature areas of the the world, fruits used for the major quantities of juices are citrus, pome, and grape or vine fruits.

Some of production of stone fruit and berry is carried out but only in small quantities.

Pineapples dominate tropical fruit juice production, with highly flavored fruits such as mango, passionfruit and guava becoming more popular as blending juices.

Methods of extracting fruit juices are dependent upon the structure and edible portion of the fruit. Preservation methods include thermal treatments, freezing, chilling, concentration (drying) and for some clear juices, fine filtration.

Juices may be taken apart by removing volatile flavor complements, water, bitterness and acidity and then recombined to produce a consistent product,

Fruit derived drink bases may be manufactured from the remaining fruit material after the juice has been extracted.
Juice from fruit

Grapefruit Juice

Grapefruit Juice
Grapefruit juice differs slightly from orange juice in its nutrient profile. An 8 oz serving of grapefruit juice contains fewer than 100 cal and has the same amount of vitamin C as orange juice (72 mg, 120% of Daily Value).

One serving also provides approx 300 mg of potassium.

Grapefruit juice contains lower concentration of the B vitamin folate, thiamin and niacin than does orange juice.

Many compounds have been proposed as active components in grapefruit juice, including both flavonoids (naringenin and naringin) and nonflavonoids (6’, 7’-dihydroxybergamottin).

The principal flavonoid in grapefruit juice is the flavanone glycoside naringin.

Red grapefruit juice also contains trace elements of the carotenoid lycopene. Lycopene has the greatest single oxygen quenching capacity (in vitro) of the dietary carotenoids.
Grapefruit Juice

Cranberry Juice Consumption Prevents Urinary Tract Infections

Cranberry Juice Consumption Prevents Urinary Tract Infections
Urinary Tract Infections (UTIs) occur when bacteria (primarily Escherichia coli) adhere o the uroepithelial cells that line the bladder, kidney or urethra and then multiply.

Bacterial adhesion to uroepithelial cells requires the production of a set of structures called p-fimbriae on the cell walls of the colonizing bacteria. Adhesion leads to colonization of the urinary tract epithelium and destruction of the lining of the bladder, as well as inflammation and rupturing of the underlying blood vessels, causing blood in the urine on some cases.

The resultant inflammation promotes a painful burning sensation; persistent, untreated UTI can lead to cystitis and pyelonephritis, which can ultimately lead to the loss of one or both kidneys.

UTIs are common, with approximately 60% of American women being affected in their lifetime.

Persistent infections often require ongoing treatment with expensive antibiotics that necessitate visits to a physician and immense costs to the health care system.

Persons at high risk for developing a UTI include the elderly, those who are parapalegic and quadrapalegic.

Folk medicine has long supported the use of cranberry juice for treatment of UTIs, although the mechanism for this effect has been difficult to determine.

Consumption of cranberry juice provides a way for affected persons to cost-effectively treat their disease independently of the health care system.
Cranberry Juice Consumption Prevents Urinary Tract Infections