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.
The Stokes sweet potato, right, has better color than the L-14-15-P experimental cultivar.
“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.
The white skinned, purple flesh sweet potato, left, is the Okinawan variety from Hawaii. On the right is a rainbow of sweet potatoes that are part of Scott Stoddard's experiments.
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."
Scott Stoddard, right, discussed sweet potato variety trials with A.V. Thomas Produce supervisor Frank Lucas, left, and field manager George Guitierrez, center.
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.”
Scott Stoddard weighs sweet potatoes as part of the variety evaluation process.
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."
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 to 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.
“What if, today, we were grateful for everything?” asks Charlie Brown.
You don't need to be a beloved cartoon character to understand the meaning of Thanksgiving. Giving thanks seems like an excellent goal for this year's celebration … and every day, really. Here are some important steps for a healthy, delicious and memorable holiday.
First, be safe Millions of Americans will be celebrating this Thanksgiving. Foodborne illness is a real concern. So, let's make sure everybody enjoys the meal and doesn't get ill.
From safely thawing a turkey to making sure it's properly cooked, the Food and Drug Administration (FDA) offers a range of tips to keep your holiday safe. (One hint: take care with the stuffing). The USDA's famous Meat & Poultry Hotline will remain open on Thanksgiving Day until 11 a.m. PST; their team of experts is on hand to answer any questions you may have.
No, Thanksgiving feast would be complete without pie. Whether you're a sweet potato or pumpkin pie fan, good crust is essential. Making a good pie crust isn't rocket science...but it does involve molecular science. In this video, University of California researcher Amy Rowat uses science to show you how to make the best pie crust ever.
Second, savor the meal
Did you know that there's a science to eating? Before you pile lots of food on your plate, take time to consider these seven steps from University of California scientists and researchers; they will assure that you savor every bite of your meal.
Third, don't waste
Enjoy your meal, but make it a point to reduce food waste this holiday season.
“Food waste presents a major challenge in the United States. Estimates suggest that up to 40% of the food produced nationally never gets consumed, causing substantial economic and environmental harms. Wasted food utilizes vast quantities of precious land, water and human resources, yet rather than nourishing people, it feeds landfills, producing methane gasses that poison the environment. Much of the food waste (43%) occurs at the household level.”
We sought out experts from UC ANR's Master Food Preserver Program for advice on how to use leftovers. Some takeaways: refer to this food storage chart to determine how long you can safety store leftover food. For more tips, click here. Leftover turkey can be used to make a delicious homemade stock that can serve as the base for additional meals. We provide a recipe and information about how to safely preserve stock here.
However you celebrate Thanksgiving, the staff of UC ANR wishes you a safe, happy and healthy holiday.
Editor's Note: UC Agriculture and Natural Resources (UC ANR) researchers and educators draw on local expertise to conduct agricultural, environmental, economic, youth development and nutrition research that helps California thrive. We operate the 4-H, Master Gardener and Master Food Preserver Programs. We live where you live. Learn more here. Are you a #veteran or #beginning farmer interested in learning more about poultry production? UC ANR is co-hosting a series of poultry workshops beginning in December and throughout 2017. Get the details here.
Learn more about native and indigenous foods from Valerie Segrest of the Muckleshoot Tribe in the Pacific Northwest; the post appears on the UC Food Observer blog.
When the weather cools in the fall and the holidays draw near, orange orbs ripen on persimmon trees in California to offer a fresh autumn sweetness in time for Thanksgiving recipes and holiday décor.
At the UC South Coast Research and Extension Center (SCREC) in Irvine, a collection of 53 persimmon varieties are at their peak in November when the public is invited for tasting and harvesting at the annual persimmon field day.
“We want to raise awareness about persimmons,” said Tammy Majcherek, SCREC community educator. “It's a beautiful tree and a great addition to any landscape. Persimmon trees provide shade in the summer, healthy fruit in the fall, then drop their leaves and allow the sun's warmth to come through in the winter. It's a win-win situation as far as landscape trees go.”
Visitors are briefed before entering the persimmon variety block to taste and harvest persimmons.
The persimmon collection came to the research center in the 1960s, when the late UCLA subtropical horticulture professor Art Schroeder arranged to move his collection of persimmon varieties to another venue because the pressure of urban development at the Westwood campus became too great.
Persimmons are native in two parts of the world, China and the United States. The Chinese persimmon made its way to Japan, where its popularity soared. The American persimmon comes from the Southeastern United States, however, most California persimmons trace their lineage to Asia.
California leads the nation in persimmon production, according to the California Department of Agriculture Crop Report, but with a value of about $21 million in 2012, it represents just a small fraction of the state's $19 billion 2012 tree fruit and nut value.
A display of fuyu-type and hachiya-type persimmons helped participants distinguish which fruits are ready to eat.
Nevertheless, to the visitors who came out to tour UC's collection at SCREC, persimmon is a choice fruit. Participants on the early-morning VIP tour received a large shopping bag to fill with various varieties of fuyu and hachiya persimmons. Fuyu are flat, yellow-orange fruit that can be eaten right off the tree like apples or allowed to mature to a super-sweet soft pulp. Hachiya are redder, heart-shaped and astringent when not fully ripened. “If you bite it, it will bite your mouth right back,” said one participant.
However, after ripening to a jelly soft pulp or dried, the hachiya is equally delicious.
Shirley Salado, supervisor of the UC Cooperative Extension Expanded Food and Nutrition Education Program in San Diego County, attended the persimmon field day to collect persimmons and information about the healthful fruit.
Shirley Salado, the UC Cooperative Extension Expanded Food and Nutrition Education Program supervisor in San Diego County, attended the persimmon tasting to gather fruit and information for her education program.
“The fuyu is great to eat,” Salado said. “When they ripen and become very soft, you can put the pulp in a blender and then freeze in zipper bags to add to healthy smoothies.”
Salado collected two large bags of persimmons to share with her nutrition education staff.
“Not everybody knows about these,” Salado said. “This gives them a chance to look at the fruit. This is what we promote.”
Jean Suan, right, plans to dry her persimmons using the traditional Japanese hoshigaki method, in which the whole fruit is peeled, as shown on the left, then hung on a string outdoors. For several weeks, the fruit is massaged every few days, until the sugars form a frost-like dust on the surface. The result is fruit with date-like texture and strong persimmon flavor.
Following the tour, coordinator of the UC Master Food Preserver program at SCREC Cinda Webb demonstrated safe consumption by making cinnamon persimmon jam, dried persimmon chips, and a gourmet persimmon, basil, beet and rice salad.
UC Master Food Preserver coordinator in Orange County Cinda Webb, right, and Master Food Preserver Mabel Alazard, make persimmon jam.
Cinda Webb adds persimmons to the salad. (Recipe below.)
Wild or brown rice persimmon salad
4 cups wild or brown rice, cooked 2 Fuyu persimmons, chopped 1 cup cooked, chopped beets 1 cup basic, chopped 8 oz feta cheese ½ cup orange cumin vinaigrette
Vinaigrette (makes about 1 cup)
½ cup orange juice ¼ cup olive oil 2 tsp rice vinegar 1 Tbsp maple syrup 1½ tsp cumin 1 tsp coriander ½ tsp salt
Whisk together vinaigrette dressing ingredients
Stir basil, beets, persimmons and feta into rice and toss with ½ cup vinaigrette.
Top with persimmon slices and extra chopped basil for presentation.
A member of the Rare Fruit Growers Association, Dewey Savage, showed a fuyu persimmon with browned flesh. The browning is caused by alcohol released by the seeds inside the fruit. The alcohol neutralizes tannins that make the persimmon astringent. The natural chemical reaction results in sweeter fruit.
UC Master Gardener volunteers prepared persimmons for the variety tasting.
Participants evaluated persimmon varieties based on attractiveness, astringency, sugar, flavor and overall performance.
Navy beans, soaked overnight and ready to cook. The name is derived from the fact that they were a staple food of the U.S. Navy in the early 20th century, according to the California Dry Bean Council. (Photo: Kathy Keatley Garvey)
If you say "I don't know beans" about beans, you ought to.
Beans are one of civilization's earliest cultivated crops, dating back to the early seventh millennium BCE. Today there are more than 40,000 varieties of beans worldwide.
Beans can also have a place on the Thanksgiving table. The Maple Spice blog for vegans shares a meat-free substitute for turkey that combines mashed white canelli beans, nutritional yeast, vital wheat gluten and spices to create a loaf that slices like turkey breast. UC CalFresh, one of the UC Agriculture and Natural Resources' nutrition education programs, developed a recipe for black bean and mango salad that makes a healthful and colorful accompaniment to a traditional Thanksgiving meal. (The recipe is below.)
"Not only are beans a healthy food choice, but they are also a healthy choice for our world," said UC Cooperative Extension advisor and dry bean expert Rachael Freeman Long. "Beans fix most of their own nitrogen so require fewer inputs for production compared to other sources of protein and they're cheap! Plus some, like garbanzos, are grown during the wintertime, so they're less dependent on irrigation."
The different varieties of beans include garbanzos (chickpeas) as well as black eyes, limas, and common beans like pintos and kidneys.
You probably won't find a bigger fan of beans than Rachael Long. "I eat them at least once a week or more," she said. "I love going on our Cal Beans website and getting new recipes. Summer time, I love beans on my salad, especially garbanzos. At this time of year, I love soups with beans. My favorite is the kale white bean sausage soup. If I want to go vegetarian, I'll leave out the sausage or sometimes fry up some tofu sausage for flavor. And, it just so happens that this is the soup in the current bean blog. I got the original recipe from one of our nutrition staff at our office."
Yolo County Farm advisor Rachael Long in a dry bean research field at the University of California, Davis. (Photo: Kathy Keatley Garvey)
Long says that Cal Beans is an important site for bean growers and industry folks, too. "It's supported by the California Dry Bean Advisory Board, an important funding source for my work. Right now, I have a grant to look at seed moisture and quality at harvest (possibly drying down seed too much at harvest results in internal injury to planting beans (seed stock)."
What do you know about beans? Do you know that California grows the canning quality beans?
"We have the perfect weather conditions for those large, creamy beige-colored beans," Long said. "Other states like Washington grow about 100,000 acres of garbanzos for humus (but a lower quality bean and we can't compete with their free water via rainfall."
California farmers supply virtually all of our country's dry lima beans, Long notes. In 2012, California farmers grew about 23,000 acres of baby and large limas, valued at $30 million that year, according to the National Agricultural Statistics Service.
California farmers supply virtually all of our country's dry lima beans, says Yolo County farm advisor Rachael Long. This photo was taken in 2013 at a research site during the UC Davis Dry Bean Field Day. (Photo: Kathy Keatley Garvey)
"Lima beans are a major dry bean crop for California, representing a significant portion of the total dry bean acreage in 2013," she wrote in the Lima Bean Production in California. "Lima beans are primarily grown for the dried edible white bean in California, although a limited but stable acreage is also for seed production. As with all dry beans, limas are a nutritional and healthy food choice, being an excellent source of protein, fiber, vitamins, and minerals. Lima beans are also an important rotation crop for farmers because the plants fix nitrogen, add biomass to the soil, and require relatively few pesticides."
Lima beans belong to the species Phaseolus lunatus, distinct from the common bean, P. vulgaris.
"Common dry beans include the market classes kidney, cranberry, pink, black, white, yellow, pinto, and red, all of which are different types of a single species (Phaseolus vulgaris) that was originally domesticated several thousand years ago in the areas that are now Mexico and South America," Long wrote in the Common Dry Bean Production Manual. "Natural selection and breeding programs lead eventually to the current market classes, which are mainly distinguished by seed size, color, and shape, and plant growth habit. Currently, there are no commercially available genetically modified varieties of P. vulgaris."
"Dry beans," Long points out, "are grown in California mainly for human consumption, though a limited but stable acreage is dedicated to seed production. Dry beans are nutritious: they are high in starch, protein, and dietary fiber, they have no cholesterol, and they are an excellent source of iron, potassium, selenium, molybdenum, thiamine, vitamin B6, and folic acid. The U.S. Department of Agriculture considers dry beans to be both a vegetable and a protein source."
Beans are delicious, nutritious and brilliant. This is a cranberry bean in the UC Davis research field. (Photo: Kathy Keatley Garvey)
Rosane Oliveira, director of the UC Davis Integrative Medicine Program and an adjunct assistant professor in the UC Davis School of Medicine's Department of Health Sciences, recently praised beans as one of the "Fab 4" plant foods in her "21-Day Food Challenge" blog.
Beans are brilliant, Oliveira says, because they:
Are an excellent source of fiber, protein, iron, and magnesium
May add up to 3-4 years to your life if you eat one cup a day
Keep your blood sugar level stable for up to six hours
A typical Thanksgiving meal has more calories than many people need in a whole day. (Photo: Satya Murthy, Flickr)
For many of us, Thanksgiving is truly a feast, and we are preparing our appetites for large servings of turkey, stuffing, and pumpkin pie. In fact, the majority of people consume more than 2,000 calories in their Thanksgiving meal, including appetizer, turkey and the trimmings and dessert, reports Diabetes.org. That's more than a sedentary man should eat in a whole day to maintain a healthy weight, according to the USDA's ChooseMyPlate.gov. This year, you can enjoy the holiday without overeating by serving a healthy and balanced meal.
Portion control: Thanksgiving is about choices. Think about which dishes you don't mind skipping, and plan to fill your plate only once. It's easy to get carried away going back for second and third helpings.
Fruits: Get your serving of fruit with a fruit-based dessert. Baked apples, poached pears and fresh figs are a few festive options.
Grains: Use whole grain or 100 percent whole wheat bread for a stuffing rich in fiber.
Protein: Serve yourself 3 ounces of roasted turkey or a portion the size of your palm. Skip the fat by removing the skin on your turkey before eating it. Go easy on the gravy.
Vegetables: Choose vegetable side dishes that include roasted or cooked vegetables, and skip the creamy sauces and added fat. Instead, season vegetables with fresh herbs to add flavor.
Dairy: Try non-fat Greek yogurt as a healthier topping for side dishes than sour cream or butter.
Don't forget to be active. After the holiday meal, go for a walk, bike ride or play football with the family.
Not sure what to do with your leftovers? Reinvent your Thanksgiving feast with these quick and easy one-sentence leftover recipes.
Cranberry smoothies Whirl cranberries with frozen low-fat yogurt and orange juice.
Crunchy turkey salad Toss cubed turkey with celery, apples, and light mayo with shredded spinach.
Stuffing frittata Mix stuffing with egg and cook thoroughly, pancake-style.
Turkey berry wrap Wrap sliced turkey, spread with cranberry sauce and shredded greens in a whole wheat tortilla.