New Zealand yams belong to the Oxalidaceae, or wood sorrel, family with the Latin name Oxalis tuberosa Molina. This interesting herbaceous plant is a native of the Andean region and is cultivated in subtropical or tropical climates. It was introduced to Europe as a competitor for the potato and is popular in New Zealand, which lent its name to this root vegetable.
New Zealand Yam Quick Facts
Name:
New Zealand Yam
Scientific Name:
Oxalis tuberosa Molina
Origin
Andes in South America
Colors
White, red, yellow, purple (Tuber)
Shapes
Claviform to ellipsoid or cylindrical; Length: 3-15 cm; Width: 3 cm (Tuber)
New Zealand Yam (Oxalis tuberosa Molina) is an herbaceous plant that belongs to the Oxalidaceae family. It is also called Kao, Oka, Oca, Papa Roja, New Zealand Yam, and Cuba Yam. It is cultivated as a perennial plant in subtropical or tropical climates for its tuberous root which is a great source of phosphorus, carbohydrates, and others.
NEW ZEALAND YAM FACTS
New Zealand Yam is cultivated as potato but its tubers are smaller and are from a family called Oxalis. New Zealand yam is second in agricultural importance after potato. It is a great source of phosphorus, carbohydrates, iron, amino acids which enhance the health, functions of muscles, nails, organs, skin and hair.
Name
New Zealand Yam
Scientific Name
Oxalis tuberosa Molina
Native
Andes in South America
Common/English Name
Kao, Oka, Oca, Papa Roja, New Zealand Yam, Quiba Yam
Cylindrical, succulent, yellow, green-purplish red; Height: 25 cm (10 inch)
Leaf
Trifoliate, heart-shaped, clover like, green
Flowering Season
August, September
Flower
Tristylous, yellow
Tuber shape & size
Claviform to ellipsoid or cylindrical; Length: 3-15 cm; Width: 3 cm
Tuber color
White, red, yellow, purple
Flesh color
White, yellow, cream, pink, orange, red, purple
Tuber peel
Shiny, waxy, crinkled
Major Nutritions
Vitamin B6 (Pyridoxine) 0.22 mg (16.92%)
Vitamin A, RAE 86.69 µg (12.38%)
Carbohydrate 12.49 g (9.61%)
Vitamin B2 (Riboflavin) 0.12 mg (9.23%)
Potassium, K 361.27 mg (7.69%)
Vitamin B1 (Thiamin) 0.06 mg (5.00%)
Iron, Fe 0.33 mg (4.13%)
Total dietary Fiber 1.14 g (3.00%)
Vitamin B3 (Niacin) 0.41 mg (2.56%)
Protein 1.16 g (2.32%)
Health Benefits
Brain function
Enzymes
Assist vision
Enhance immunity
Treats anemia
Bone health
Maintain blood pressure
Assist RBC production
Treat Alzheimer’s Disease
Cardiovascular health
Calories in 135 g
60 Kcal.
How to Eat
The tubers are boiled, roasted, baked and fried.
The tubers are also added to salads, stews, soups or also pickled in vinegar.
In the Andes, the genotypes are consumed raw.
In Mexico, New Zealand yam is sprinkled with lemon, salt and hot pepper.
In the Andes, New Zealand yam is sun dried and parboiled, roasted and prepared as pachamanca.
The flour is used to make desserts and porridges.
The tubers are used as a quality starch for alcohol or food industry.
Young shoots and leaves are consumed as green vegetable.
Matured stems are used as rhubarb.
New Zealand yams are baked and microwaved with lemon juice, butter and sprinkle with brown sugar.
New Zealand yams are roasted and added to the potato wedges.
The crispy sliced yams are great in the stir fries.
A yam goes well with ginger, orange, sweet or sour type sauces.
They are added to winter stews and soups.
The fresh leaves add a bit of flavor to a green salad.
The leaves are the perfect substitute for a sorrel.
Sun dried yams are consumed as dried figs or stewed as a fruit.
The leaves and flowers are added to salads.
New Zealand Yam Scientific Classification
Scientific Name: Oxalis tuberosa Molina
Rank
Scientific Name & (Common Name)
Kingdom
Plantae (Plants)
Subkingdom
Tracheobionta (Vascular plants)
Superdivision
Spermatophyta (Seed plants)
Division
Magnoliophyta (Flowering plants)
Class
Magnoliopsida (Dicotyledons)
Subclass
Rosidae
Order
Geraniales
Family
Oxalidaceae (Wood-Sorrel family)
Genus
Oxalis L. (Woodsorrel)
Species
Oxalis tuberosa Molina (Oca)
Synonyms
Acetosella crenata (Jacq.) Kuntze
Acetosella tuberosa (Molina) Kuntze
Oxalis aracatcha hort. ex Zucc.
Oxalis arracacha G. Don
Oxalis chicligastensis R. Knuth
Oxalis crassicaulis Zucc.
Oxalis crenata Jacq.
Oxalis melilotoides var. argentina Griseb.
Xanthoxalis crassicaulis (Zucc.) Small
Xanthoxalis tuberosa (Molina) Holub
The plant is compact, perennial, and tuberous, bearing trifoliate, heart-shaped, clover-like, green leaves and tristylous, yellow flowers. The edible tuberous root is claviform to ellipsoid or cylindrical with a waxy, crinkled skin whose color ranges between white, red, yellow, and purple. Its flesh ranges from white, yellow, cream, pink, orange, red, and purple. The plant of New Zealand yam is 20 to 30 cm high which has cylindrical, succulent, yellow, green-purplish red stems upto 25 cm (10 inches) in height.
History
New Zealand yam is native to the Andes in South America. It is not clearly known that from when New Zealand Yam was cultivated. It was one of the oldest crops of Andean. It is a substantial basic crop of Andean peoples.
New Zealand yam was sent to the Central Highlands of Mexico in the Mid-Late 1700s which became the earliest maintained crop outside the Andes. It is now also cultivated there as papa rational or papa Roja. Though New Zealand yam was exported to the United States and Europe it did not become popular until the 1970s.
New Zealand yam was cultivated as early as 1835 in France. Jean Louis who is a French chemist produced the first nutritional analyses of the two varieties in 1850.
Nutritional Value
135 grams of New Zealand yam provides 60 calories. It covers 16.92% of Vitamin B6, 12.38% of Vitamin A, 9.61% of Carbohydrate, 9.23% Vitamin B2, 7.69 % of Potassium, 5% of Vitamin B1 and others. It offers 1.16 grams of protein, 0.214 grams of total fat, 1.14 grams of total dietary fiber, and 4.44 grams of total sugars.
Nutritional value of New Zealand Yam unpeeled, boiled and drained
Serving Size: 135 g
Calories 60 Kcal.Calories from Fat 1.89 Kcal.
Proximity
Amount
% DV
Energy
60 Kcal
N/D
Energy
249 kJ
N/D
Protein
1.16 g
2.32%
Total Fat (lipid)
0.21 g
0.60%
Saturated
0.031 g
N/D
Carbohydrate
12.49 g
9.61%
Total dietary Fiber
1.14 g
3.00%
Total Sugars
4.44 g
N/D
Minerals
Amount
% DV
Calcium, Ca
3.51 mg
0.35%
Iron, Fe
0.33 mg
4.13%
Potassium, K
361.27 mg
7.69%
Zinc, Zn
0.22 mg
2.00%
Vitamins
Amount
% DV
Water-soluble Vitamins
Thiamin (Vitamin B1)
0.06 mg
5.00%
Riboflavin (Vitamin B2)
0.12 mg
9.23%
Niacin (Vitamin B3 )
0.41 mg
2.56%
Pyridoxine (Vitamin B6 )
0.22 mg
16.92%
Folate
43.35 µg
N/D
Vitamin C (Ascorbic acid)
0.62 mg
0.69%
Fat-soluble Vitamins
Vitamin A, RAE
86.69 µg
12.38%
*Above mentioned Percent Daily Values (%DVs) are based on 2,000 calorie diet intake. Daily values (DVs) may be different depending upon your daily calorie needs. Mentioned values are recommended by the U.S. Department of Agriculture. They are not healthbenefitstimes.com recommendations. Calculations are based on average age of 19 to 50 years and weigh 194 lbs. Source: https://ndb.nal.usda.gov/
Health Benefits of New Zealand yam
New Zealand yam is a great source of phosphorus, carbohydrate, iron, and amino acids. Some of the health benefits provided by New Zealand yam are:
Brain function
Vitamin B6 assists in brain function as well as development. The studies show that deficiency of Vitamin B6 affects memory function and leads to Alzheimer’s, cognitive impairment, and dementia. Vitamin B6 controls the homocysteine levels which are the main causes of heart ailments and neuron damage. Vitamin B6 has a vital role in making norepinephrine and serotonin hormones which control energy, mood as well as concentration. Low level of serotonin results in ADHD in children which results in behavior and learning disorders. (1)
Enzymes
Vitamin B6 works with enzymatic systems in the body to assist in the functions of enzymes effectively. There is a close relationship between enzymes and Vitamin B6 which adds a sense of the proper function of the nervous system, builds immunity, and relives arthritis. (2)
Assist vision
Vitamin A prevents macular degeneration which is a major cause of age-related blindness. The study shows that the intake of Vitamin C, A, E, copper, and zinc reduced the chances of macular degeneration by 25 percent. Vitamin A eye drops effectively treat dry eyes. Vitamin A also slows down the development of Stargardt’s disease which is an eye disease that causes vision loss in the young. (3)
Enhance immunity
Vitamin A promotes the immune power to counteract against infections by raising the lymphocyte response against the disease-causing antigens. It ensures better immunity and promotes the white blood cells activities by keeping the mucus membranes moist. It prohibits the entering of germs and counteracts the infections which exist in the body. It ensures double protection. (4)
Treats anemia
The low production of red cells is the cause of anemia due to blood loss and unable to carry oxygen in the blood. Vitamin B2 plays a vital role in these functions and also prevents anemia. Vitamin B2 is essential for the production of red blood cells and steroid hormone synthesis. It transports oxygen to the cells and also mobilizes iron. An adequate amount of Vitamin B2 helps to prevent the deficiency of riboflavin and also reduces the chances of anemia. The low presence of Vitamin B2 results in shortness of breath, fatigue, problems in exercise, and others. The research shows that Vitamin B2 effectively lowers the high level of homocysteine in the blood. (5)
Bone health
Potassium prevents weak bones and the chance so fracture and breaks. Potassium forms into citrate which is converted to bicarbonate. The deficiency of potassium is related to low bicarbonate precursors which are essential to counteract acids that are present in the foods such as animal proteins. The low bicarbonate precursors result in demineralizing, porous, and weak when one lacks potassium. This increases the chances of fractures and osteoporosis. (6)
Maintain blood pressure
Potassium is an essential component that helps to maintain normal blood pressure in the body. This reduces the chances of hypertension and heart disease. Potassium also regulates blood pressure. Potassium acts as a vasodilator that relieves the tension in blood vessels which are the major cause of high blood pressure. (7)
Assist RBC production
Vitamin B2 helps to form the red blood cells as well as antibodies in humans which increase the oxygenation and circulation to different organs of the human body. (8)
Treat Alzheimer’s Disease
Vitamin B1 slows down the development of Alzheimer’s disease. The Alzheimer’s patients were benefited from an intake of 100 mg supplements in a day. The studies are still going on to find out the mechanism due to which this occurs. (9)
Cardiovascular health
Thiamine helps in the production of acetylcholine which is a neurotransmitter that relay messages between the muscles and nerves. The heart depends on these signals. The proper signaling between nerves and muscles helps to maintain the proper cardiac functions as well as healthy heartbeats. The study shows that Vitamin B1 effectively treats heart disease and maintains the healthy function of ventricles and also treats heart failure. (10)
Health Benefits Of Yam/Oca
1. Brain Function.
It contains a unique compound called Diosgenin, which helps to promote neuron growth and enhance brain function.
A 12-week study found that those who took a yam extract supplement second higher on a brain function test. Diosgenin also improved memory and learning abilities in maize found in maze tests.
2. May Fight With Cancer Properties.
Yams have several antioxidants that help in anticancer properties. In a study of Animals, it was found that antioxidants It helps in the protection of cancer disease.
Extract from Chinese Yam, mainly the peel, obstructs the liver tumor growth and offers antioxidant properties.
The researchers and studies limit that these tests are yet to test on humans.
3. Diminish Inflammation.
This Chronic disease is connected with numerous long-term health problems, like diabetes, obesity, and heart disease.
Numerous studies have shown that yam powder helps to reduce inflammation related to several illnesses, such as color cancer, stomach unclear and IBS (irritable bowel syndrome).
The outer bark of yam is full of saponin. it is a compound that may help with fighting inflammation and can contribute to healthy gut health. Also helps in pelvic muscle relaxation and abdominal muscles relief.
4. Good Source Of Dietary Fiber.
It is composed of complex carbohydrates and soluble dietary fiber.
Dietary fiber help reduce constipation, decreases bad (LDL) cholesterol levels by Sticking to it in the intestines, and lowers colon cancer risk by preventing toxic compounds in the food from adhering to the colon mucosa.
Additionally, being a good source of complex carbohydrates, it controls a steady rise in blood sugar levels. For the same reason, yam is recommended as a low glycemic index healthy food.
5. May Help In Diabetes.
One study on rats shows that when rats were given Yam and allantoin they show an antidiabetic effect. (NLM)
Also, this substance may modulate oxidative stress, antioxidant activities, and lipid profiles; improve kidney and liver function; promote the release of GLP-1, and improve the function of β-cells, thereby maintaining insulin and glucose levels
This is all done on rats, Further research is needed. (Always Consult With Dr before taking any action)
6. Good Source Of B- Complex Vitamins.
It contains most of the B complex vitamins in it, Provides adequate daily requirements of pyridoxine (vitamin B6), thiamin (vitamin B1), riboflavin, folates, pantothenic acid, and niacin. These vitamins mediate various metabolic functions in the body.
7. Good Source Of Minerals.
It contain many minerals Like – Copper, Potassium, Zinc, Magnesium, manganese, etc.
Which all are required for different-different task in body like potassium which is help to cell and body fluid to control heart rate and blood pressure.
Copper is essential to produce Red blood cells.
Preparation Tips
Yams should never be consumed uncooked since they carry naturally-occurring plant toxins including Dioscorides, diosgenin, and triterpenes. The tuber must be peeled and cooked in order to remove these bitter proteins.
Unlike Them, Japanese Yam can be eaten raw cause they already socked in vinegar to remove toxins.
It can be used in verity it can be baked, fried, boiled or sometimes roasted You can make Puree, chips, fries, or can baked it. as per your choice.
Safety Profile
Wild yam has been shown to interact with certain medications. For example, it can interact with estradiol, which is a substance used in certain birth control pills or hormone replacement therapies.
Avoid Eating Wild Yams During pregnancy, breastfeeding, or for young children, Due to insufficient research.
People who have hormone-sensitive conditions, such as breast cancer or uterine fibroids, should not use wild yam. It is possible for wild yam to influence estrogen production and worsen the condition.
It is best to take advice from a Doctor or from a medical advisor.
Yams are packed with many health benefits. easy to add to the diet and come with amazingly good benefits.
Oca is a highly productive perennial plant with waxy, brightly colored tubers that are perfect as a season-extending crop. It is an excellent source of carbohydrates, phosphorus and iron, as well as essential amino acids that promote the health and proper function of muscles, organs, nails, hair, skin and more.
Oca is one of the highest vegetable sources of carbohydrate and energy. They are a good source of pro-vitamin A (beta carotene), and also contain potassium, vitamin B6 and small amounts of fibre.
Potassium may help to maintain healthy blood pressure. Dietary fiber from vegetables helps reduce blood cholesterol levels and may lower risk of heart disease.
Folate (folic acid) helps the body form healthy red blood cells. Women of childbearing age who may become pregnant and those in the first trimester of pregnancy need adequate folate to reduce the risk of neural tube defects and spina bifida during foetal development.
The Uses of Oca
Food Uses of Oca
Oca is a highly productive perennial plant with waxy, brightly colored tubers that are perfect as a season-extending crop. It is cultivated primarily for its edible stem tuber, but the leaves, flowers, and young shoots can be eaten as green vegetables also. Add oca’s flowers and shamrock-shaped leaves to salads.
Mature stems can be used similarly to rhubarb. Andean communities have various methods to process and prepare tubers, and in Mexico oca is eaten raw with salt, lemon, and hot pepper. The flavor is often slightly tangy, but there is a considerable degree of difference in flavors between varieties and some are not acidic at all. Texture ranges from crunchy (like a carrot) when raw or undercooked, to starchy or mealy when fully cooked.
Oca tubers contain oxalates (as a member of the oxalis family) as is evident when the plants are growing, with their distinctive oxalis leaf shape. Although gardeners need not worry as these Ocas are not invasive. Oxalates, concentrated in the skin of the tuber, are reduced if the harvested tubers are exposed to sunlight (tubers do not go green like potatoes). This process also sweetens the taste.
Oca tubes tend to have a slightly tangy lemon taste. The flesh is firm but juicy and crisp when eaten raw or lightly cooked, and becomes more starchy if fully cooked. The tubes don’t require peeling when eating Oca raw – just wash them clean, and they can be sliced to add a hint of a lemony zest to salads.
There are many ways to cook oca, including baking, boiling, steaming, roasting, and stir-frying. Alternatively, cook them in the same way as potatoes – boiled, baked, grilled or fried.
They also make an excellent addition to winter soups and stews. The T&M Oca loses its skin color on boiling and turns a more cream color and loses any lemon flavor, becoming more ‘nutty’ in taste. The tubes contain over 70% water but are nutritionally rich in carbohydrates, calcium, and iron. You can even pick some of the fresh leaves in summer for their tangy, lemon taste which adds that bit of zest to a green salad.
Growing Oca Tubers on the World
History + In South America Because the plant plays a large role in stories about the origin of many South American peoples, botanists at Cornell University and the Field Museum in Chicago analyzed the genetics of oca to determine its source. It appears to descend from two wild ancestors in Bolivia, but has undergone so much genetic alteration due to human intervention and continued selection over the past 1,000 years that the chemistry of the cultivated plants is quite distinct from the wild forms. For example, pre-Incan people bred out some of the acids found in the skin of the tubers, altered day length sensitivity, and increased the proportion of starches. As a result, there are literally thousands of South American varieties – although most of them don’t have commercial names. Grown primarily byQuechuaandAymarafarmers, oca has been a staple of rural Andean diets for centuries.Of all Andean root and tuber crops, oca is presently second only topotatoin areas planted within the Central Andean region.Oca is important to local food security because of its role incrop rotationsand its highnutritional content. In its native lands of Bolivia and Peru, oca is second only to the potato in agricultural importance. Its most common name is Oca, the Spanish spelling thought to be derived fromoqa, a word from the Quechua language indigenous to the Andean region and spoken by the Incas. However, in many parts of South America, other names such asCuba,hibias,timbo,apilla and evenpapa roja(“red potato”) are common, so reading regional cookbooks can be challenging unless you have a South American dialect dictionary on hand. + In North America and Europe Actually, oca is not new to horticulturists – it was introduced to England, the United States, and France as a novelty during the 1830s. Known as “South American wood sorrel” (it’s a cousin of the common wood sorrel), it caused such a stir that enthusiasts held oca parties where entire meals were constructed around these fascinating tubers. In North America and Europe, oca tuber is relatively unknown and not cultivated commercially. However, many people living in the UK and North America have reported great success in growing ocain their gardens. This is not surprising since oca is known to tolerate poor soil and different climatic conditions. The major challenge vegetable gardeners are facing in these regions is the difficulty to find oca seeds in the stores. However, searching for oca seeds may be well worth the effort – this nutrition-packed, health-promoting tuber boasts a wide range of micro and macronutrients includingvitamin C, iron, zinc, flavonoids, B vitamins, and fiber. It is also low in calories. + In New Zealand
In New Zealand, where oca has been cultivated as a commercial crop under the name “New Zealand Yam” since the 1860s, there are quite a few named varieties, and there is a continuing program to develop better ones. It is these New Zealand varieties that we are beginning to see in U.S. produce markets because they adapt most readily to our growing conditions. In New Zealand, oca are planted in November. About February, when the foliage is about 30cm high, the oca are mounded up. In mid-March, the yellow flowers appear and the tuber production begins.
4.2- Varieties and cultivars Oca is a perennial plant extensively cultivated in the central and southern Andes for its edible tubers. This tuberous root vegetable is the second most widely grown root crop behind the potato in Peru and Bolivia.
Andean farmers cultivate numerous varieties of oca. Oca diversity may be described with respect to morphological characters, local cultivar names, or molecular markers.
It’s hard to generalize about oca’s flavor and culinary attributes, because there are so many kinds: Some are best eaten raw; others are best boiled, baked or steamed. Sun-dried oca can be eaten like dried figs or stewed like fruit. Oca tubers also can be grilled, fried or candied like sweet potatoes. As for flavor, they vary from potatolike, to chestnut-sweet, to apple and celery. ‘Apricot,’ a new variety from New Zealand, is similar in taste to its namesake. Oca’s cloverlike leaves and yellow, trumpet-shaped flowers are edible and make great additions to salads.
Sour oca and sweet oca form distinct genetic clusters based on AFLP data. This suggests the possibility of distinct evolutionary histories for each use-category. According to Purdue University, however, oca actually has less oxalic acid than spinach, and one would have to eat nothing but oca to experience any harmful effects. Furthermore, most of the oxalates in oca are water-soluble, which means all you have to do is boil or steam it and pour off the water. And when left in the sun for a few days, several varieties will undergo a chemical change in which some of the acidic elements are converted to sugars. To play it safe, anyone who has an allergic reaction to rhubarb, sorrel, beet greens or spinach, or anyone suffering from gout or kidney stones, might want to avoid oca.
4.3- Growing Oca Tubers Oca is propagated from tubers, so it’s cloned in a manner similar to potatoes. It prefers sandy soil, partial shade and cool, damp weather. Plant whole tubers in pots in late winter, and once they form healthy vines, transfer them to tubs or into the ground after the threat of frost has passed. Planting at this early date is important because the plants must be well established before hot weather sets in. They don’t tolerate hot sun and a hard drought certainly will kill them unless they’re well watered.
The small tubers are best planted individually in a 15cm (6″) pots of multipurpose compost during April. As they are frost tender they should be grown on in the greenhouse or on the windowsill. Plant out the small plants when frost risk has past in late May and cover the plants with fleece until established. Each tuber makes quite a bushy plant so allow at least 90cm (36″) between plants for optimum tuber production. Some of the stems which rest on the soil will readily root and the plant can grow to a sizeable bush. Oca also make a decorative container plant throughout the summer and up to the first frosts when the foliage will die back. The cultural practice is similar to potatoes. Planting is done in rows or hills 80-100 cm apart, with plants spaced 40-60 cm apart in the rows. Monoculture predominates, but interplanting with several other tuber species, including mashua and olluco, in one field is common in Andean production. Often this intercopping consists of several different varieties of each species. Such mixed fields may later be sorted into tuber types during harvest or before cooking. Alternatively, tubers can be planted directly outdoors in late May. By this time they may well be showing small ‘sprouts’. Plant Oca directly into a shallow drill, about 8cm (3″) deep, and cover with soil or compost and a layer of fleece. Remove the fleece from early June or as the soil and weather warms. Plants can be ‘earthed up’ as you would potatoes to give some further growing room and anchorage, although this is not essential. Oca prefers well drained soil and an application of a general fertiliser will be appreciated as the plants grow. A mulch of well rotted compost or grass cuttings around the plant during summer will keep the soil moist and aid the plant’s growth. Water plants well during dry spells, and especially from mid September when tuber initiation commences, as this will promote larger tubers.
