Posts Tagged: sweet potato

Trying leafy greens from a sweet potato plant

This time of year, it can be hard to resist the pull of sweet potatoes — roasted, mashed with butter, and topped with a combination of delectable treats from maple syrup to pecans to marshmallows. But did you know that the green leaves of the sweet potato plant also have the potential to be a tasty, nutritious food?

In Ethiopia, where sweet potatoes can be a staple crop, UC Davis graduate student Lauren Howe recently helped farmers taste test the leaves and consider this familiar crop in a new culinary light.

Watch a video to learn how to prepare sweet potato leaves:

The leaves of this drought-tolerant plant offer farming households there an alternative — and nutritious — food in the lean season, while they are waiting for its starchy, tuberous roots to be ready to eat. Introducing sweet potato leaves as a food option is intended to help farmers better diversify their families' diets, to include a wider variety of vegetables in addition to staple foods, especially during the dry season.

Lauren shared her experiences in Ethiopia on the Agrilinks website, where she recently won the Agrilinks Young Scholars blog contest with her writing and a short video from the field.

Lauren traveled to Ethiopia this summer to work with an organization called Send A Cow Ethiopia (SACE), on a Trellis Fund project. As part of the Horticulture Innovation Lab, each Trellis Fund project connects an organization in a developing country with a grad student from a U.S. university, to work together to benefit local farmers, while building the capacity of both the local organization and the student.

In Ethiopia, SACE helped Lauren better understand local contexts by connecting her with farming households to interview about their current farming practices and the role of sweet potatoes in their diets.

Later they traveled to meet with a group of about 25 farmers in the Ukara community to harvest leaves, cook together and discuss their perceptions of the leaves as a vegetable option.

Reflecting on taste tests, new foods, and rural communities

Background and related international agricultural research

Lauren's experience with a Trellis Fund project in Ethiopia was supported by the Horticulture Innovation Lab, a research program led by Elizabeth Mitcham of the UC Davis Department of Plant Sciences, with funding from the U.S. Agency for International Development. With a focus on fruit and vegetable innovation, the Horticulture Innovation Lab seeks to empower smallholder farmers in developing countries to earn more income and better nourish their communities — as part of the U.S. government's global Feed the Future initiative.

Past research from the Horticulture Innovation Lab has focused on other leafy greens, specifically African indigenous vegetables, and also on sweet potatoes themselves (orange-fleshed sweet potatoes, that is). Though the program has not done in-depth research on sweet potato leaves for human consumption beyond this small Trellis Fund project, you can find more information about eating sweet potato leaves and tips in this bulletin from the University of Arkansas Cooperative Extension, and a wealth of information about sweet potato farming and gardening from the University of California Vegetable Research and Information Center. 

Related Food Blog posts:

• New reason to give thanks for sweet potatoes
  How orange-fleshed sweet potatoes are making a difference in some African countries
• More African indigenous vegetables on more plates
  A brief look at some leafy greens popular in Eastern Africa
  
• Connecting with farmers over pineapple postharvest practices
  Another Trellis student experience with a video
  
• ‘Local' farm inspiration from half a world away
  A UC Cooperative Extension specialist reflects on his time as a Trellis student
  

 

Sweet potato leaves in Ethiopia - Horticulture Innovation Lab photo by Lauren Howe/UC Davis

close-up on sweetpotato leaves, stems and plant

Los camotes de un vibrante morado son una saludable sorpresa en el Día de Acción de Gracias

 

En inglés

Los camotes endulzados –chorreando mantequilla, azúcar morena y nueces – o una cacerola de camotes machacados y cubiertos de malvaviscos tostados - son platillos tradicionales en la mesa del Día de Acción de Gracias.

Estos ricos platillos contradicen la naturaleza dulce de los camotes, los cuales son tubérculos ricos en nutrientes y con un bajo nivel glicémico que pueden ser parte de una dieta saludable todo el año.

Un estudio realizado por Scott Stoddard, asesor de Extensión Cooperativa de UC, tiene como objetivo convertir a los camotes en un alimento aún más saludable y atractivo. Stoddard trabaja junto con productores de camotes del condado de Merced para explorar si los camotes de cáscara de tono morado oscuro y pulpa de un morado brillante, conocidos en inglés como purple/purples (morado/morados), pueden ser cultivados por más granjeros en California. El inusual color y mayores beneficios a la salud comandan un mayor precio, abriendo un potencial nicho en el mercado.

“Los camotes de pulpa morada contienen beta-caroteno, como las variedades de color naranja que son más comunes, además de antocianinas”, dijo Stoddard. “Es como comerse un puñado de arándanos azules con su camote”.

California es un importante productor de camotes. Alrededor de un 80 por ciento del cultivo en este estado – 16,000 acres – se realiza en el condado de Merced, en granjas con superficies que van desde cinco acres a varios miles de acres. En el 2015, el valor del cultivo en el condado de Merced fue de 195 millones de dólares. En el condado de Kern existen alrededor de mil acres de cultivo y dos mil en el de Stanislaus. Estas ubicaciones cuentan con suelos arenosos y arenosos limosos ideales para que los camotes puedan desarrollar su distintiva forma y cáscara lisa.

Los camotes de pulpa morada no son comunes, pero han existido desde hace ya un buen tiempo. Por ejemplo, son el principal tipo de camote que se cultiva en Hawaii. Hace varios años, los cultivadores del condado de Stokes, N.C., seleccionaron un cultivar particularmente hermoso y sabroso al que nombraron camote Stokes y lo comercializaron a nivel nacional a través de Frieda's Specialty Produce. En California, A. V. Thomas Produce, de Livingston, adquirió un acuerdo exclusivo con la compañía para cultivar y comercializar el camote Stokes purple/purples.

“El número de acres de Stokes se ha realmente expandido en pocos años”, mencionó Stoddard. "Existe mucho interés en los camotes de pulpa morada por parte del consumidor".

Eso no cierra la puerta del camote purple/purples a otros granjeros de California interesados en el nicho. Stoddard conduce pruebas de campo en cooperación con granjeros locales que incluye el purple/purples. En una de las pruebas, se están cultivando 50 tipos de camotes de colores diferentes, para poder determinar si cuentan con las características claves necesarias para producirlos localmente. De allí, él elige un número limitado para cultivar en pruebas replicadas, con el propósito de determinar su potencial para obtener una producción grande, que puedan ser almacenados bien y desarrollar el tamaño, forma, color y sabor adecuados. De estos, solo uno de los camotes purple/purples pasó a la prueba replicada.

“En algunos purple/purples, el sabor puede ser apagado o amargo”, indicó Stoddard. “De esos nos deshicimos inmediatamente”.

Uno de los cultivares en el estudio de Stoddard, que recibe el código experimental L-4-15-P, fue producido en el 2014 por Don La Bonte, un productor de plantas de la Universidad del Estado de Luisiana, en Baton Rouge. Este camote cuenta con algunos buenos atributos, pero carece del color uniforme e intenso de la variedad Stokes.

“Desafortunadamente, probablemente no es lo suficientemente bueno para desplazar a Stokes”, dijo Stoddard. “Es un buen inicio, pero necesitamos seguir estudiando al purple/purples para encontrar una variedad que ofrezca resistencia a las enfermedades, una buena cosecha y pulpa de color morado intenso y consistente".

Un buen alimento

Los camotes pueden comerse crudos o cocidos. Para comerlos crudos, simplemente quíteles la piel, córtelo en palitos y sírvalos con aderezo ranch bajo en grasa o puré de manzana. Raye camotes frescos sin cocer y agréguelos a burritos, tacos o ensaladas para darle un toque nutritivo y crocante.

Los camotes cocidos pueden comerse durante el desayuno, almuerzo y cena, con cáscara y todo, solos o con un poco de mantequilla.

Una manera rápida de preparar esta verdura es en el microondas. Lávelos y séquelos. Pínchelos con la punta de un cuchillo en dos o tres lugares. Cocine en alta potencia durante cinco minutos. Deles la vuelta. Cocine durante otros cinco minutos, más o menos.

El experto en camotes de Extensión Cooperativa de UC, Scott Stoddard, señaló que él prefiere los camotes horneados.

“Es mucho mejor hornearlos”, mencionó el experto. “Al hornearlos les da tiempo de convertir el almidón en maltosa”.

Los camotes están compuestos en su mayoría de almidón, pero contienen una enzima especial que cuando se les cocina, convierte el almidón en maltosa. Cocerlos lentamente en el horno convencional da tiempo a esta conversión, dándole un sutil sabor dulce acaramelado.

Para hornearlos, precaliente el horno a 400 grados. Cubra la rejilla inferior del horno con papel aluminio, luego pinche los camotes con un tenedor y colóquelos directamente en la rejilla media, arriba de la que está cubierta con papel aluminio. Hornee camotes de dos a tres pulgadas de diámetro, durante 45 minutos.

Vibrant purple sweet potatoes are a healthful Thanksgiving surprise

Candied sweet potatoes – dripping with butter, brown sugar and pecans – or a casserole of mashed sweet potatoes smothered with toasted marshmallows are common sides on the Thanksgiving table. These rich dishes belie the true nature of sweet potatoes, which are nutrient packed, low-glycemic root vegetables that can be a part of a healthy diet year round.

Research by UC Cooperative Extension advisor Scott Stoddard is aimed at making sweet potatoes an even more healthful and attractive food. Stoddard is working with sweet potato growers in Merced County to see if sweet potatoes with dusky purple skin and vibrant purple flesh, called purple/purples, can be grown by more farmers in California. The unusual color and health benefits command a higher price, opening a potentially profitable niche market.

“Purple flesh sweet potatoes have beta-carotene, like the more common orange varieties, plus anthocyanins,” Stoddard said. “It's like eating a handful of blueberries with your sweet potato.”

California is a significant producer of sweet potatoes. About 80 percent of the California crop – 16,000 acres – is grown in Merced County, on farms ranging from 5 acres up to several thousand acres. In 2015, the crop's value in Merced County was $195 million. About 1,000 acres are grown in Kern County and 2,000 acres in Stanislaus County. These locations have the sandy and sandy-loam soils ideal for sweet potatoes to develop their distinctive shape and smooth skin.

Sweet potatoes with purple flesh are not common, but they have been around for quite some time. They are the main type of sweet potato grown in Hawaii, for example. Several years ago, growers in Stokes County, N.C., selected a particularly beautiful and tasty cultivar, naming it the Stokes Sweet Potato and marketing nationwide with Frieda's Specialty Produce. In California, A. V. Thomas Produce in Livingston acquired an exclusive agreement with the company to grow and market Stokes purple/purple sweet potatoes.

“The number of acres of Stokes has really expanded in just a few years,” Stoddard said. "There is a lot of consumer interest in purple-fleshed sweet potatoes."

That doesn't close the door on purple/purples for California's other growers interested in the niche. Stoddard conducts field trials in cooperation with local farmers that include purple/purples. In one trial, 50 types of sweet potatoes of many different colors are being grown to determine whether they have key characteristics needed for local production. From there, he selects a limited number to grow in replicated trials, to determine their potential to produce a high yield, store well, and develop good size, shape, color and flavor. Of these, only one purple/purple made it into the replicated trial.

“In some purple/purples, the flavor can be off, or bitter,” Stoddard said. “We get rid of those right away.”

One of the cultivars in Stoddard's study, which goes by the experimental code number L-14-15-P, was bred in 2014 by Don La Bonte, a plant breeder at Louisiana State University, Baton Rouge. The potato has some good attributes, but lacks the uniform deep purple color of the Stokes variety.

“Unfortunately, it's probably not good enough to displace Stokes,” Stoddard said. “It's a good start, but we have to continue screening purple/purples to find a variety that offers disease resistance, good yield, and consistent deep purple flesh color."

Good eats

Sweet potatoes can be eaten raw or cooked. To eat raw, simply peel, cut into sticks and serve with low-fat ranch dressing or apple sauce for dipping. Grate fresh, uncooked sweet potatoes and add to burritos or tacos or sprinkle on salads for a sweet, nutritious crunch.

Cooked sweet potatoes can be eaten for breakfast, lunch or dinner, skin and all, plain or with a small pat of butter.

Microwaving is a great way to quickly prepare the vegetable. Wash potatoes and pat dry. Prick skin with a knife in 2 to 3 places. Cook on high for 5 minutes. Turn over. Then cook for another 5 minutes, more or less.

UC Cooperative Extension's sweet potato expert Scott Stoddard says he prefers his sweet potatoes baked.

“Baked is way better,” he said. “Baking gives time to convert the starch to maltose.”

Sweet potatoes are mostly starch, but have a special enzyme that breaks down starch into maltose when cooking. Slower cooking in the oven provides time for the conversion, imparting a subtly sweet caramelized flavor.

To bake, preheat the oven to 400 degrees. Line the lower oven rack with foil, then prick sweet potatoes with a fork and place directly on the middle oven rack, above the rack with foil. Bake 45 minutes for sweet potatoes 2 to 3 inches in diameter.

Enjoy California sweet potatoes around the clock and calendar

Sweet potatoes are perhaps most familiar in the U.S. smothered with melted marshmallows in a Thanksgiving casserole. But baked, boiled or raw, they can be a healthful part of California cuisine any time of year.

California is a significant producer of sweet potatoes. About 90 percent of the California crop – 18,000 acres – is grown in Merced County, on farms ranging from 5 acres up to several thousand acres. In 2011, the crop’s value statewide was $125 million.

However, you probably won’t find sweet potato farmers at your local farmers market.

“Even smaller growers tend to work with a packing shed and have their crops combined with others and marketed,” said Scott Stoddard, UC Cooperative Extension advisor in Merced County.

A few years ago, when sweet potato fries began showing up at high-end restaurants and fast food chains across the country, the U.S. and the California sweet potato industries overestimated the future growth in sweet potato consumption, Stoddard said. In addition, improvements in growing practices boosted yield per acre, leaving the country with something of a sweet potato glut. Currently, acreage is inching down again as growers balance supply with demand.

Most sweet potato breeding programs are conducted in the South, such as Louisiana and North Carolina, but the characteristics sought in that part of the country are different than California. Stoddard is conducting specialized variety trials in California to select varieties with red, purple or garnet skin.

“In California, we are going for a red-skinned sweet potato,” Stoddard said. “Especially, a red-skinned variety that stores well.”

Some people incorrectly believe that sweet potatoes with moist orange flesh are yams. True yams can be found elsewhere in the world, but in the U.S., a sweet potato is a sweet potato, whether the flesh is orange, yellow or white and whether the skin is tan, dusty pink or garnet red.

Sweet potatoes are a featured California crop in Dirt Fresh News, a monthly newsletter produced by UC Cooperative Extension in Stanislaus County that introduces school children to fresh, locally grown food. The newsletter says sweet potatoes are a good source of potassium, fiber, beta-carotene and vitamins B-6, E and C.

To eat them raw, simply peel, cut into sticks and serve with low-fat ranch dressing or apple sauce for dipping. Grate fresh, uncooked sweet potatoes and add to burritos or tacos or sprinkle on salads for a sweet, nutritious crunch.

Baked sweet potatoes can be eaten for breakfast, lunch or dinner, skin and all, plain or with a small pat of butter.

“Microwaving is a great way to save energy if you are just baking 1 or 2 potatoes,” the newsletter says. “Wash your potatoes and pat dry. Prick skin with a knife in 2 to 3 places. Cook on high for 5 minutes. Turn over. Then cook for another 5 minutes, more or less.”

Following are recipes from the Sweet Potato Council of California:

Warm sweet potato and green bean salad

3 medium sweet potatoes, cooked, pared and cut into ¼-inch slices (about 2 lbs.)
½ pound fresh whole green beans
1 small red onion, halved and sliced
1 clove garlic, minced
2 tablespoons vegetable oil
1 cut watercress springs (optional)
1 tablespoon red wine vinegar
½ teaspoon salt
¼ teaspoon freshly ground pepper

In large skillet over medium-high heat, brown sweet potatoes and cook green beans with onion and garlic in oil until crisp-tender. Remove from heat. Stir in remaining ingredients. Service warm. If esired, top with Parmesan cheese shavings.

Sweet potato Leek Soup

1 bunch leeks, white and light green portion
2 tablespoons butter or margarine
2 fresh sweet potatoes
4 cups water
1 teaspoon salt
1/2 teaspoon thyme
1/2 cup heavy cream
1 tablespoon lemon juice
1/4 teaspoon white pepper
1 pinch cayenne or ground red pepper

Slice leeks and saute in butter until soft. Thinly slice sweet potates; add to leeks; saute 3 minutes. Add water, salt and thyme. Bring to a boil; reduce heat and simmer, partially covered, 20 - 25 minutes, stirring occasionally, until vegetables are very soft. Puree and strain. Add cream, lemon juice, white and red pepper. Adjust seasonings to taste. For garnish, julienne additional leek and sweetpotato into 3/4" strips; saute in 2 tablespoons butter until crisp-tender. Just before serving, stir into soup. Makes 4 to 6 servings.

New reason to give thanks for the sweet potato

What if you could significantly improve the nutritional quality of your diet, just by switching one of the vegetables you eat every day?

In parts of Africa, some people are doing just that by switching from yellow or white sweet potatoes to orange-fleshed varieties.

In many African countries, sweet potatoes are a common staple—though not the orange-fleshed varieties I’m used to finding on the Thanksgiving table.

That orange color signifies the potato’s beta-carotene content, which our bodies convert to vitamin A. Vitamin A deficiency is the leading cause of preventable blindness in children and is crucial to the survival of children and pregnant women, according to the World Health Organization.

So scientists and organizations who are working to increase vitamin A in African diets have turned to the orange-fleshed sweet potatoes as a potential solution, wherever light-colored sweet potatoes loom large.

With funding from the U.S. Agency for International Development, Horticulture CRSP  is working in Ghana to strengthen the entire value chain of orange-fleshed sweet potato — from farmers and food processors, to markets and consumers.

Though Horticulture CRSP is led by UC Cooperative Extension’s Elizabeth Mitcham at UC Davis, this project includes a team of international researchers with experts from Tuskegee University, Penn State and Ghana University. Together, they are working to:

• provide farmers with germplasm and best management practices
• teach women entrepreneurs to process orange-fleshed sweet potatoes into bread flour, purees and dehydrated chips
• formulate a weaning food for babies that incorporates orange-fleshed sweet potatoes with other, traditional foods

Find out more about this Horticulture CRSP sweet potato project (including a 2-minute video).

Did you know? In 2011 California was the second largest producer of sweet potatoes in the United States, with North Carolina leading the way (source). Find out more in this related ANR News Blog post or from the UC Vegetable Research and Information Center.

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