There are three to four species of cranberry, classified in two sections:
- Subgenus Oxycoccus, sect. Oxycoccus
- Vaccinium oxycoccus or Oxycoccus palustris (Common Cranberry or Northern Cranberry) is widespread throughout the cool temperate Northern Hemisphere, including northern Europe, northern Asia and northern North America. It has small 5-10 mm leaves. The flowers are dark pink, with a purple central spike, produced on finely hairy stems. The fruit is a small pale pink berry, with a refreshing sharp acidic flavour.
- Vaccinium microcarpum or Oxycoccus microcarpus (Small Cranberry) occurs in northern Europe and northern Asia, and differs from V. oxycoccus in the leaves being more triangular, and the flower stems hairless. Some botanists include it within V. oxycoccus.
- Vaccinium macrocarpon or Oxycoccus macrocarpus (American Cranberry) native to northeastern North America (eastern Canada, and eastern United States, south to North Carolina at high altitudes). It differs from V. oxycoccus in the leaves being larger, 10-20 mm long, and in its slightly apple-like taste.
- Subgenus Oxycoccus, sect. Oxycoccoides
Cranberries are related to the bilberries, blueberries, and huckleberries, all in Vaccinium subgenus Vaccinium. These differ in having stouter, woodier stems forming taller shrubs, and in the bell-shaped flowers, the petals not being reflexed.
Some plants of the completely unrelated genus Viburnum are sometimes inaccurately called "highbush cranberries".
Cranberries are susceptible to false blossom, a harmful but controllable phytoplasma disease that is most common in the eastern production areas of Massachusetts and New Jersey.
Health benefits
Cranberries are a source of polyphenol antioxidants, chemicals which are known to provide certain health benefits to the cardiovascular system and immune system.
There is some use of cranberry juice by people with spinal paralysis; regular consumption of the juice is supposed to reduce the rate of urinary tract infections. While much of the evidence is equivocal, a number of double-blind
clinical trials have been carried out that suggest there actually is an effect: a component of the juice appears to competitively inhibit bacterial attachment to the bladder and urethra[4] allowing the bacteria to be flushed out more easily. Cranberries also act as a prebiotic, promoting the growth of beneficial lactobacillus bacteria while inhibiting the growth of harmful E. coli and listeria.
An autumn 2004 caution from the Committee on Safety of Medicines, the UK agency dealing with drug safety, advised patients taking warfarin not to drink cranberry juice after adverse effects were reported.
Cranberries also contain significant concentrations of benzoic acid, which in combination with Vitamin C forms small amounts of the group 1 carcinogen
benzene.[1]
Cranberry juice contains a chemical component, a high molecular weight non-dializable material (NDM), that is able to inhibit and even reverse the formation of plaque by Streptococcus mutan pathogens that cause tooth decay.[2][3]
Cranberry juice also, supposedly prevents the formation of kidney stones.
[此贴子已经被作者于2007-3-11 12:48:16编辑过]