Fruit Characteristics of Wild Vaccinium stamineum in the Southeastern U.S

The fruit of Vaccinium stamineum, a wild diploid species, exhibits an unusually large size compared to other wild relatives. Fruit diameters generally range between 5 mm and 16 mm, although some exceptional plants have produced berries up to 19 mm in diameter. This variation in size appears to be positively correlated with the number of seeds developing within each fruit. Studies have shown that the number of potentially viable seeds per berry ranges from 5 to 29. Notably, the largest average fruit sizes have been observed in populations growing in Lexington County, South Carolina, and along the coastal border of North and South Carolina, suggesting that regional environmental factors may influence fruit development.

The color of mature V. stamineum fruit is highly diverse, displaying a broad spectrum that includes greenish-white, yellowish, light and dark red, blue, purple-blue, purple-black, reddish-black, and dark purple. This wide range of coloration adds to the species' visual appeal and may indicate differing levels of ripeness or genetic variation across populations. The surface of the berries may either be glaucous—covered with a whitish waxy coating—or glabrous, lacking such coating. There is a noticeable association between glaucousness on the fruit and on the plant's vegetative parts, with the most glaucous specimens commonly found in the sandhill regions of South Carolina.

Taste-wise, the fruits typically have a slightly bitter skin, although sweetness and bitterness vary considerably between individual plants and regions. Interestingly, the most palatable fruits, characterized by a more favorable balance of sweetness and reduced bitterness, are also found in the sandhill areas of South Carolina. Upon ripening, the berries tend to detach from the plant and fall to the ground. Due to the continuity between the calyx tube and the pedicel, the pedicel remains firmly attached to the fruit post-detachment, a feature useful in identifying ripe specimens in the field.
Fruit Characteristics of Wild Vaccinium stamineum in the Southeastern U.S

Cranberries post-harvest

The fruit are harvested at full maturity with good color (anthocyanin content) but prior to the fruit becoming over-ripe. Timing of harvest is important for fresh-market fruit so that the berries are sufficiently red but retain good storage quality.

The onset of color is associated with a distinct rise in ethylene production by the fruit. Fruit should have intense red color, surface shine, uniform size, good firmness, and freedom from defects.

At the processing plant, cranberries were sorted by visual inspection into four ripeness stages: dark-red, light-red, blush, and white. Fruit showing rot, mechanical injury, disease, or flesh softness were discarded.

Cranberries are cleaned in fanning mills, then dropped some distance to eliminate soft or rotten specimens (the defective berries do not bounce, those suitable for food bounce up over a barrier), then washed, first in acid or alkaline solutions to remove spray residues, then in water.

Cranberries handled as fresh are packed in paper fined wooden boxes, and the product is slowly cooled to 36 – 40 °F. The use of refrigeration and proper temperature control is the primary postharvest technology used to extend the storage life of fresh fruits.

Many factors can affect chilling sensitivity and the expression of damage to the fruit. These factors include growing conditions, cultural practices, and fruit maturity. In addition, the expression of physiological breakdown is dependent on storage duration. Cranberries should be held at 36 - 40 °F until sold to the consumer.

At this temperature, cranberries have a storage life of several months. Cranberries may be held frozen prior to the manufacture of jelly or sauce. They are placed in large metal containers, frozen, in bulk in cold-air rooms, and held in this condition until defrosted for purposes of preparing cooked products.
Cranberries post-harvest

Harvesting cranberries

Cranberries grow on vines in beds that have layers of sand, peat, gravel, and clay. People call those beds, bogs, as the fields are flooded with water at harvest time.

For harvesting cranberries, the bogs may be flooded with water to float berries, which can then be shaken off by machine and collected from the water. The workers then use hoses, rakes and nets to gather the berries floating on the surface of the water.

In other instances, the bogs are not flooded; the berries are stripped from the vines mechanically and collected on catching frame.

Dry harvest utilizes a picking machine that combs the berries off the vines, and may also prune the runners that come in touch with its multiple knives. Dry-picked berries are typically sold for the fresh market.

Water harvest is generally used for berries intended for processing (mainly juice). New Jersey harvests more than 95% of its cranberry crop by water harvesting. A small percentage of the crop is dry harvested for fresh market sale.
Harvesting cranberries

Cranberries fruit

The cranberry is a native American fruit. Its native range extends in temperate climate zones from the East Coast to the Central U. S. and Canada and from Southern Canada in the north to the Appalachians in the south.

Cranberry fruit are true berries that are borne on short vertical uprights from the trailing stems of the cranberry plant. Fruit set occurs in late June and fruit reach maturity by mid September through early November depending on cultivar, season, and location.

Fresh cranberry fruit quality is based on color, size, and texture. Fruit should have intense red color, surface shine, uniform size, good firmness, and freedom from defects. The flesh should be creamy white.

Fruit ripening is primarily determined by anthocyanin formation that gives the fruit a dark red color. Ripening appears to be initiated by a combination of environmental factors including accumulation of growing degree days, photoperiod, and light exposure.

Cranberry fruits are grown mainly for processing purposes, but in the U.S., strong markets for fresh fruit exist for the Thanksgiving and Christmas holiday seasons. In addition to the traditional aspects of cranberry consumption, health benefits of the fruit have become increasingly important.

The majority of human studies have focused on cranberry’s effect on urinary tract health. In addition, research has explored the impact of cranberries on cardiovascular disease, cancer prevention, oral health, glycemic response, and infections such as by Helicobacter pylori (H. pylori) bacteria, a cause of gastritis and peptic ulcer disease.
Cranberries fruit

Cranberry Production in United States

Cranberries have a deep and rich history that many have not yet discovered. Native Americans used the fruit for a wide variety of purposes. Dating back to 1550’s where they applied cranberries to heal arrow wounds from battle, created dyes, and cured meats.

Commercial cranberries production is carried out mostly in Massachusetts, Wisconsin, New Jersey, Washington, and Oregon. Wisconsin controls more than 46 percent of the production and is the primary cranberry producer in the United States.

There are a number of commercial varieties of cranberries growth in swamp lands or under similar conditions. A period of about 4 years is required from planting to the first harvesting period.

United States 2017 total cranberry production is forecast at 9.05 million barrels, down 6 percent from 2016.

There are two basic methods of harvesting cranberries. The first, dry harvesting dates back to the origins of cranberry cultivation. The second system, flood or water harvesting dates to the 1920’s and was first mechanized in the mid-1950’s.

Nationally, cranberries are harvested from early September until early November. The exact harvest dates vary by region, weather conditions, and cultivar being harvested. In addition, some consideration must be given to whether the fruit will be sold in the fresh market, used in white juice products, or used for other processing.

Since blossoms develop in the spring and are susceptible to frost damage, and the plants are susceptible to freezing damage, bogs where the berries are grown may have to be flooded with water, as a protection against cold damage.

Diesel oil or chemical may be used to control weeds and moss is cranberry bogs. For harvesting cranberries, the bogs may be flooded with water to float berries, which can then be shaken off by machine and collected from the water. In other instances, the bogs are not flooded; the berries are stripped from the vines mechanically and collected on catching frame.
Cranberry Production in United States

Chemical composition of cranberries

The cranberry has a unique chemical composition that sets it apart from other North American fruits. 

Cranberries contain about 90% of water along with flavonoids, anthocyanins, triterpenoids, catechin, phenolic compounds, glucose, and fructose.

They are also good source of vitamin C. Other nutrients include folate, iron, magnesium, manganese, phosphorus, potassium, selenium, sulfur, zinc, vitamin A, B1, B2, B3, B5, and E.

The carbohydrate load of cranberries is relatively large, particularly for diabetic patients. The combination of high-acid content (~7.5% Brix) gives pure cranberry juice a Brix/acid ratio of about 3.75, which makes it extremely tart and unpalatable in a single strength form.

Another unique characteristic of the cranberry is astringency created by significant quantities of tannins. The cranberry also contains an unusual mixture so organic acids.

Cranberries contain large amounts of benzoic and phenolic acids (i.e, ~5-6 g/kg fresh weight) with the most abundant acids being benzoic acid, p-coumaric acid and sinapic acid.

In fresh form, cranberries are low in calories, sodium, and free from cholesterol and saturated fats.
Chemical composition of cranberries