Yam: More than just great foodSunday, March 08, 2020
DR WENDY-GAYE THOMAS
WHEN Jamaica's sprint King Usain Bolt broke the world record, crossing the finish line in 9.58 seconds at the Beijing Olympic Games, he set the sporting world ablaze. Sports journalists set about investigating the reason for his speed.
Whether Bolt's father was serious or not, it was reported by one Reuters journalist that when asked why he thought his son ran so fast, his response was: “Hey, reporter person! Guess what, I definitely think it was the yams!” referring to the popular yams grown, sold and exported in volumes from Bolt's birthplace — the parish of Trelawny.
Whether or not the root tuber can be given any credit for Bolt's spectacular performance is a moot point. However, yams are considered by many as one of the most delicious tubers.
It is definitely a favourite in Jamaica and its versatility spans a wide cross section of cooking methods, such as being roasted over coals with salted fish, boiled in soups, grilled or cooked and cubed to make salads.
A root vegetable, yam has a long history of use as an alternative medicine. Modern researchers are examining possible health benefits of wild yams, which include relief from muscle cramps, rheumatoid arthritis and symptoms of menopause as well as diabetes prevention.
Yams belong to the dioscoreae or morning glory family, and the name originates from the African word “nyami”, meaning “to eat”.
Yams are native to Africa and Asia, with most of the crop coming from Africa. They are related to lilies, and can be as small as a regular potato or jumbo in size with some growing five feet long. There are up to 18 different varieties of yam cultivated in Jamaica, and they all have a unique taste, flavour and texture. Some are dry, some waxy, some soft, and some sweet, starchier and drier.
Health benefits of yam
Although they're considered to be a starchy vegetable, yams are made up of complex carbohydrates and dietary fibre allowing for slow uptake to keep blood sugar levels even, giving it the nod as a low glycemic index food. The vitamin A in yams helps to maintain healthy mucous membranes and skin, heightens night vision, supports healthy bone development, and provides protection from lung and mouth cancers.
Yams are a good source of vitamin C — 27 per cent of the daily value for fighting infections such as colds and flu — with quick wound healing, anti-ageing, strong bones, and healthy immune function. They also provide good amounts of fibre, potassium, manganese, and metabolic B vitamins such as vitamin B6 (pyridoxine — 16 per cent of the daily value), thiamin (vitamin B1), riboflavin, folic acid, pantothenic acid, and niacin. Copper, calcium, potassium, iron, manganese and phosphorus are body-beneficial minerals found in yams.
Chinese, Korean and Japanese medicine has made use of yams for eons because they contain allantoin. This compound speeds up the healing process when applied as a poultice to boils and abscesses, but is also used to stimulate appetite and relieve bronchial trouble.
Unless they're peeled and cooked, yams may contain toxins such as dioscorin, diosgenin, and tri-terpenes, so handle them with care.
The outer bark of wild yam is high in saponins and related compounds, which may help lessen inflammation, balance gut flora and prevent carcinogenesis by acting as an antioxidant and anti-inflammatory agent.
Saponins include dioscin, diosgenin and dioscorin, the latter of which one study, says, among other things: “They exhibit antioxidant, antihypertensive, immunomodulatory, lectin activities and can protect airway epithelial cells against dust mite allergen destruction.”
Saponins have properties that combat inflammation and apparently help relax and otherwise treat several conditions involving the abdominal and pelvic muscles, as well as arthritic and rheumatic conditions.
Diosgenin paved the way in the creation of the first contraceptive pill.
Over 200 million prescription drugs a year are sold that contain derivatives of this herb. Disogenin is used to produce contraceptives, treat menopause, premenstrual syndrome, sexual problems, high blood pressure, prostate hypertrophy, testicular deficiency, impotency, just to name a few.
From this herb, the pharmaceutical industry also indirectly produces cortisones and hydrocortisones.
Yams are grown throughout Africa, but Nigeria is the world's most prolific producer, exporting up to 70 per cent of the world demand. Information from the Rural Agricultural Development Authority reveals that the variety of yams being exported in large quantities are yellow, negro and sweet yam. The major export markets, in order of size, are USA, UK, and Canada.
Due to the worldwide demand for yams, growers and exporters of the product need to pay keen attention to requirements of agencies such as the US Food and Drug Administration (FDA), the Canadian Food Inspection Agency (CFIA) and the European Union, which require that all producers or handlers of food for export to their countries be fully compliant with stringent regulations.
Jamaican firm, Technological Solutions Limited (TSL), has helped several Caribbean countries address export challenges, including the FDA requirement of comprehensive prevention-based controls across their food supply chain to prevent or significantly minimise the likelihood of food-borne illnesses occurring.
TSL has focused on improving competitiveness within firms, sectors and along value chains by addressing quality, food safety, production efficiencies, industry practices and improving market access and expansion by assuring compliance of Caribbean products with international regulations.
Dr Wendy-Gaye Thomas is group technical manager, Technological Solutions Limited, a Jamaican food technology company. E-mail her at: email@example.com
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