UC Food Blog
If you're like most of us, you “go bananas” for a banana for breakfast.
It's healthy, nutritious and packed with potassium.
But wait! You should probably go bananas for another fruit--that pear-shaped avocado. Did you know the avocado provides more potassium than a banana?
It does. A medium-sized banana yields 422 milligrams of potassium, while a medium-sized avocado, a whopping 708 milligrams.
“Eating more unsaturated fats -- as opposed to saturated fats and processed carbohydrate -- is a delicious step we all can take to maximize cardiovascular health,” Adams says. “Avocados are such a delicious way to do that!"
We love our avocados, our veritable green goddess that never disappoints, never deceives, never dissatisfies, whether we “butter” them on toast in the morning for breakfast, or slice or chunk or cube them for our salads at lunch and dinner. Health-conscious folks call them a superfood, and even mash and freeze them to ensure a steady supply in the winter. There's even a website on “50 Things to Love About Fresh Avocados.”
This year, California's 2000 avocado growers anticipate a yield of 374.6 million pounds. That crop forecast, according to Tom Bellamore, president of the California Avocado Commission, is nearly double the yield of the 2017 crop and “despite the ravages of Mother Nature in California's avocado growing regions.”
UC Cooperative Extension adviser and avocado researcher Ben Faber of Ventura and Santa Barbara counties, points out that the avocado is really a fruit, not a vegetable. “The Supreme Court classified the tomato in 1920 or so as a vegetable because that's the way people think of it and it was taxed differently for tariffs. Politics or botany separates a lot of things in our lives.”
“The avocado is an amazing fruit,” Faber says. “It grows on a tree and comes to maturity, reaches certain oil content and a stage at which it will ripen, but it does not ripen on the tree. It needs to be removed from the tree before it will soften. If the fruit is removed before it has reached maturity it will not soften, and will remain rubbery and inedible.”
“One of the problems is that the fruit will hang on the tree for an extended period of time and it is hard to know when they are mature,” Faber points out. “Avocados are not like apricots where you have about two weeks to get the fruit off before it falls off. As the fruit stays on the tree, it gradually develops more and more oil content and has a richer flavor.”
What if the fruit stays on the tree too long? “It can develop an almost rancid flavor,” Faber says. “So it is good to know when the best, acceptable flavor is. Avocado varieties fall into general seasonal periods when they are mature, such as ‘Fuerte' and ‘Bacon' in winter, ‘Hass' in spring/summer, ‘Lamb-Hass' in summer/fall.”
The fruit will typically be ripe in seven to ten days, Faber advises. “If you want to speed things along a bit you can take three or four avocados and place them in a loosely closed paper bag with two or three Red or Golden Delicious apples or ripe kiwifruit. The purpose of the apples or kiwifruit is that these fruit produce a natural plant hormone, ethylene, that will help stimulate the avocado to produce its own ethylene. Apples and kiwifruit are known to produce lots of ethylene. The Delicious apples are varieties that produce more ethylene than other apple varieties. You can keep them even after they are shriveled and they will be producing ethylene.”
Never place your avocados in a plastic bag “unless you keep it open since the fruit needs to breathe during this process,” he says. “Just keep the fruit on your kitchen counter or in a warm place; 68F is the ideal temperature. Lower and higher temperatures both actually slow the process.”
Plant scientists trace the origin of the avocado (Persea americana) to south central Mexico. The avocado belongs to the flowering plant family, Lauraceae. Growers and gardeners glean tips on pest management from the industry and from the UC Statewide Integrated Pest Management Program.
Of the many known varieties, avocados fall into three broad categories based on whether they are of the Mexican, Guatemalan or West Indian races of Persea americana, the avocado species and the crosses that occur between these races. Generally speaking, California varieties have been the result of crossing between the Mexican and Guatemalan races. West Indian race varieties are not common here because of their generally lower cold tolerance.”
Ben Faber, like Linda W. Adams, enjoys avocados. He usually buys them “whenever they are reasonably priced.”
“One of the reasons I do research is that all the downed fruit is not salable because it is against food safety restrictions to introduce it into the food chain and all that fruit either gets eaten by coyotes or me,” he quips, adding “The tree is too big to fit into my backyard.”
Looking for a great recipe? The California Avocado Commission offers many recipes, including what it calls “The Best Guacamole Ever."
Dietitian Adams shares one of her favorites at https://www.delish.com/cooking/recipe-ideas/a19872947/avocado-tomato-salad-recipe/.
Avocado Tomato Salad
1/4 cup extra-virgin olive oil
Juice of 1 lime
1/4 tsp. cumin
Freshly ground black pepper
3 avocados, cubed
1 pint cherry tomatoes, halved
1 small cucumber, sliced into half moons
1/3 cup corn
1 jalepeño, minced (optional)
2 tbsp. chopped cilantro
In a small bowl, whisk together olive oil, lime juice, and cumin. Season with salt and pepper.
In a large serving bowl, combine avocados, tomatoes, cucumber, corn, jalapeño, and cilantro. Gently toss with dressing and serve immediately.
Enjoy! The avocado keeps good company!
Farmer Vang Thao has been managing a successful farm south of Fresno for nearly 30 years, producing a spectacular array of vegetables – heirloom tomatoes, purple bell peppers, water spinach, bitter melon, Thai eggplant and dozens of others.
Every weekend the family traverses the Grape Vine to set up a visual feast at farmers markets in Santa Monica, Hollywood, Palos Verdes, Torrance and Hollywood. Acclaimed Los Angeles chefs rave about his produce, according to a Los Angeles Times feature story on the Thao family.
Produce like sweet potato leaves, amaranth and black nightshade are essential for families hailing from Vietnam, Laos, Thailand, the Philippines and India who seek ingredients for their traditional cuisine, but the market is limited. Now, small-scale farmers like the Thaos are on the cusp of something with much wider appeal.
One of their crops is moringa, a tropical tree that produces an abundance of fresh shoots to sell at the farmers market booth for $1 a bundle. Moringa is a delicate green that can be added to salads, soups and nearly any other dish. It has a pleasant nutty, earthy and slightly pungent green flavor. While it tastes good, it's the plant's nutrient profile that is commanding attention.
On the internet, moringas are called miracle trees. All parts of the plant are edible – the tender leaves can be cooked or eaten fresh, moringa flowers are considered a delicacy, the tree's young pods can be used like green beans, roasted seeds are said to have antibiotic and antifungal properties. The roots and bark have medicinal potential, but need more study to determine the right dose. A 100 gram serving of moringa greens has more protein than a cup of milk, more iron than a cup of spinach, and is high in calcium, potassium, vitamin C and vitamin A.
Moringa is the Superfood of 2018, according to the trend watchers at SPINS.com. UC Davis nutrition researcher Carrie Waterman is studying moringa's use, production and processing worldwide. She is pursuing moringa for therapeutic applications in treating cancer, HIV and inflammatory bowel disease.
Ruth Dahlquist-Willard, the UC Cooperative Extension advisor to small-scale farmers in Fresno and Tulare counties, recognized moringa's potential to supplement income for Southeast Asian farming families who are marketing specialty Asian vegetables and herbs to immigrant communities.
“Moringa is a drought tolerant tree known for its excellent nutritional content,” Dahlquist-Willard said. “We believe it could improve the economic viability of small-scale farms in our community. We are helping small-scale farmers with moringa product development and marketing.”
Supporting farmers growing moringa in marketing the product to new buyers is an objective of the UCCE moringa project, a partnership with the UC Sustainable Agriculture Research and Education Program, which was funded by a California Department of Food and Agriculture specialty crop block grant. Lorena Ramos, the project lead, is working on developing marketing materials, outreach opportunities, and value-added options.
While using moringa is second nature for many immigrant groups, expanding the market includes demonstrating how easily the green can be used in the kitchen. Dahlquist-Willard and Ramos called on another sector of UC Cooperative Extension – the UC CalFresh Nutrition Education Program – for assistance. UCCE offers nutrition education in schools and community settings to children and families eligible for the USDA's nutrition assistance programs. Each year, Fresno State dietetic students serve two-week internships at UCCE. In 2018, one of their tasks was developing creative, healthful recipes incorporating moringa. Among the recipes were overnight oatmeal, pesto, smoothies, guacamole and energy bites – all with moringa.
“We are publishing the best recipes to share with the public to help them add this nutritional green into their diets,” Ramos said.
Recipe cards and moringa samples will be available July 26 at the Fresno Food Expo, where UCCE is hosting a booth to raise awareness about moringa by introducing farmers to Fresno area chefs, buyers and consumers and sharing information about the vegetable's health benefits, culinary versatility and its ability support small-scale farmers in Fresno and Tulare counties.
Following is a USDA recipe ideal for incorporating moringa:
Grilled quesadilla with vegetables
Nonstick cooking spray
1 medium zucchini, diced
½ broccoli head, diced
1 green pepper, diced
1 medium onion, minced
1 carrot, peeled and grated
16 (6 inch) flour tortillas
12 ounces cheese, shredded
½ cup moringa leaves
- Wash all vegetables.
- Collect, dice, shred and measure all ingredients before starting to prepare the recipe.
- Spray a large skillet with cooking spray. Add zucchini, broccoli, green pepper, onion and carrot. Cook vegetables on medium heat for 4 to 5 minutes, stirring frequently. Remove vegetables from skillet, and put on a clean plate.
- Spray skillet with cooking spray again and place 1 tortilla in the skillet. Top with ½ cup vegetables and 1/3 cup cheese. Sprinkle on fresh moringa leaves.
- Place a second tortilla on top. Cook on medium low heat for 2 to 3 minutes or until the cheese starts to melt and the bottom tortilla starts to brown.
- Flip over the quesadilla. Cook for another 2 to 3 minutes until tortilla brons.
- Repeat steps 4 through 6 to make additional quesadillas
- Cut each quesadilla in half or quarters, serve hot with your favorite salsa or other toppings.
- Refrigerate leftovers within 2 hours. Eat within 3 to 5 days.
School food service is a multibillion dollar industry that impacts the lives of over 30 million (mostly) low-income students. Every school day and, with increasing frequency, during summer weekdays as well, this industry provides two-thirds of students' meals (breakfast and lunch), as well as snacks, contributing a large portion of the nutrients youth consume throughout their childhoods. To qualify for a free school lunch, a family of three must make less than $26,208 in 2016-17.
School food service directors have a huge charge on their hands: feed kids, every day, with a lot of requirements, for very little money. The current reimbursement rate for free meals provided to students in California is $3.31, which is required to include at least ½ cup of fruit or vegetables, and the choice to select a whole grain food, a protein food, and low-fat or non-fat milk. Elementary school kids from higher-income homes pay around $3 for the same meals.
So, when a canned mandarin from China is more economical than a local pixie tangerine, how does this impact food service directors' decisions to make sustainable and healthy food selections?
According to the San Luis Coastal Unified food service director, Erin Primer, food service directors have a lot of power to make healthy (or not so healthy) selections. Primer is a school food champion, who some have said is “murdering the lunch lady game.” Primer's first venture into institutional food service was in the private industry and catering. She learned how to get things done, how to be competitive and, ultimately, how to serve a lot of food that people want to eat.
Primer credits this background with enabling her to see things more creatively.
“Because of my background with catering, I was never limited by what school food says we can't do," Primer said. "I never let that burden me. When I came to school food, I loved the freedom to problem solve and connect all the dots with all the requirements, and then just feeding the kids.”
How do you feed kids healthy food while considering the broader impact of food purchasing decisions? Primer says it comes down to participation, it is a game of numbers. How many students and families will choose to eat a school meal on any given day? For Primer, that's about 3,000 lunches and 2,000 breakfasts every day - a number she would like to see grow.
What are some strategies to increase participation so more kids are eating school lunch? To Primer, and many food service directors that are rising to the challenge of feeding our next generation, it's about serving good food. It is easy to get stuck in the weeds of the regulatory environment of school food; and, while following the guidelines is incredibly important, it is also important to think about the food you are serving. Primer says she likes to think about the whole plate and what actually makes sense to serve to kids. You have to keep going back to asking yourself: “Will kids eat it?” and “Does it make sense?”
“We started with asking ourselves, does it taste good? Is it good quality? Is it sending the message we want to send? And if it's not, let's not do it, Primer said.
One of the biggest changes Primer has made to her menus is first, getting rid of the junk. In the world of school food, you can find chocolate doughnuts and cinnamon-sugar cereals that meet USDA regulations for the school meal program. In many cases, food processing companies have reformulated popular food items specifically to meet requirements. By adding in whole grains, or reducing the sugar, fat or sodium content in a product, they can be sold at school even if you could never find that same version of the product in the store. When students see these products at school it can send them mixed messages about what should be included as a regular part of a healthy diet.
The next change she made and continues to make includes increasing the purchase of local foods and removing items that can't be obtained locally. She is able to serve local, grass fed beef on the menu in a “blended burger” which includes mushrooms to make it larger, tastier and economically feasible. She also became one of the first school food service directors to use local grains by featuring emmer farro from a farmer that is less than 15 miles from her office. In addition, she has made some waves by replacing bananas on her menu with other local fruits, like kiwi.
Living on the central coast of California, there is an abundance of local foods available most months of the year. However, “local” does not need to be barrier for food service directors. Defining what is “local” or “regional” is up to each district or institution, who should take into consideration the surrounding agricultural landscape, seasons, and what foods are reliably available.
The last, but really important, step that Primer is working on is telling her story. Working with partners in creative ways, Primer is working hard to sell school food to all families in her district, regardless of their incomes. Her goal is to make meals that all kids want to eat and parents want to buy. She has her delivery trucks wrapped in pictures promoting the local foods they serve each day and she talks to local stakeholders, teachers, parents and school board members at every opportunity.
What are we feeding our kids? Where did it come from? How do our purchasing decisions impact our world?
These are the questions being tackled by school and institutional food service directors every day, whether they are aware of it or not. How they choose to answer those questions will have broad reaching impacts on our communities and future generations.
Will machines replace the romance of the hand-cultivated wine grape vineyard? A “touchless” vineyard was among the latest research on labor shortages, weeds and pest management by UC Cooperative Extension scientists discussed at Grape Day at the UC Davis Oakville Station, located in the epicenter of California wine country, on June 6.
About 200 wine grape growers, vineyard consultants and other industry people attended to learn about the latest UC Cooperative Extension research. Vineyard managers from boutique wineries such as Fork in the Road to Pine Ridge Vineyards to the Fortune 500 wine company Constellation Brands gathered at the research station's experimental vineyard. Several vineyard equipment representatives brought their machines to the field to demonstrate their weeding, pruning and canopy management capabilities.
Addressing labor shortages
To help growers attract and retain farm workers, Monica Cooper, UC Cooperative Extension advisor for Napa County and her research assistant, Malcolm Hobbs, are conducting a survey of agricultural workers to determine the factors that affect job satisfaction. They found the number of female workers in Napa County has increased rapidly since 2013. “Women may be moving into the labor pool to fill vacancies caused by the decline in the number of male workers migrating to the U.S. for agricultural work,” Cooper said.
They plan to provide participating companies with custom recommendations for recruiting and retaining workers.
“We will also be generating a generic summary that will be widely shared with participants and non-participants at the close of the study. For now, we cannot make any general conclusions or recommendations because data collection is ongoing,” Cooper said. “We are aiming to distribute our final report this winter, so stay tuned.”
To help growers reduce their need for hand labor, UC Cooperative Extension viticulture specialist Kaan Kurtural designed a “touchless” demonstration vineyard that is mechanically managed. The mechanized vineyard is one of six trellis systems he is studying for water use, nitrogen use efficiency, yield and fruit quality of the wine grapes.
“We're always looking for ways to improve yield, quality and to reduce cost,” said Francisco Araujo, director of viticulture for Atlas Vineyard Management. “In light of the labor shortage we're facing right now, Kaan is exploring new production systems that include new trellises, mechanization, different types of mechanization from pruning to shoot thinning and trunk suckering. He's obtaining information about how these new trellis systems that he is investigating are going to play with yield and quality.”
The touchless vineyard experiment started out as a demonstration at first, but with grower interest, it turned into a full-blown research project.
“It started as way of saving labor costs, but when we started looking at the physiological aspects of how these plants grow, we saw the benefits from the quality point of view in addition to the labor savings,” said Kurtural, who is based in the Department of Viticulture and Enology at UC Davis.
A traditional vineyard in the Napa area is about a meter or 36 inches above the vineyard floor with vertical shoots held up with wires, which are moved by hand.
“We said, ‘Why don't we turn the system upside down?' Grow a tall trunk then put the bilateral cordon about 62 inches above the vineyard floor, that way we can push the rows a lot closer,” said Kurtural, who oversees the 40-acre Oakville experimental vineyard. The leaves grow down to generate the same leaf area as a traditional vineyard, but the leaves in the mechanized vineyard use water more efficiently so the no-touch vineyard requires less water compared to traditional vineyard systems.
“This is a dense system, this is 1.5 meters by 2 meters, roughly 1,340 plants per acre – we're getting by here on a third to quarter acre foot of water,” Kurtural said.
“It costs us roughly about a dollar in labor operation costs to manage each plant in a traditionally farmed vineyard of roughly about 1,300 plants per acre on the North Coast now,” Kurtural said. “The no-touch plants are costing us about 7 cents in labor operations costs.”
“The biggest expense is pruning, after that we go through what they call trunk suckering, which is also done mechanically here, and after that they will do shoot removal to open up the canopy. That's also done mechanically. After that, if there's need, they will do leaf removal, that's also done mechanically. And one last resort, if there's too much crop here, they will shake off excess berries with a harvester.”
The conventional system yields up to 5 to 6 tons per acre whereas the mechanized vineyard yields 7 to 8 tons per acre.
“These clusters set far fewer berries than a traditionally managed vineyard, but the berry size is also very small, which is what the winemakers like,” he said.
During harvest, grapes picked by machine are sorted on board the harvester so they go into the winery in uniform sizes, whereas hand-harvested grapes have to be sorted on a tray before they are put into the press tank.
“We made wines from these last year and compared to our traditionally farmed vineyards. Until we tell people what it is, they cannot distinguish the quality of the fruit or the wine.”
Weed and pest management
John Roncoroni, UCCE weed science farm advisor in Napa County, discussed options for weed control among young grape vines.
In the past, many vineyards were fumigated before planting for disease control, but it also provided weed control for young vines.
“With the loss of most fumigants for use in vineyards, hand-weeding was often used to accomplish this task,” Roncoroni said. “Increased costs and decreased labor force have made hand weeding impractical. Mechanical cultivation, at this point, is too imprecise – either leaving weeds close to young vines or causing damage by being too close.”
Covers on young vines allow the use of many post-emergence herbicides to control weeds, but Roncoroni cautioned that application of post-emergence herbicides on vines that aren't protected by mature bark may damage or even kill the vine.
“Herbicide use on vines less than 3 years old is a risky endeavor,” Roncoroni said. “Follow all label requirements, paying special attention to soil and irrigation recommendations.”
Lynn Wunderlich, UC Cooperative Extension advisor for the Central Sierra, and Franz Niederholzer, UC Cooperative Extension advisor for Colusa, Sutter and Yuba counties, demonstrated how to calibrate sprayers and to get uniform coverage when spraying fungicides.
In 2016, UC Davis researchers identified the three-cornered alfalfa hopper, Spissistilus festinus, as a vector of grapevine red blotch virus. Cindy Preto, a Ph.D candidate in the UC Davis Department of Entomology who is assisting UC scientists studying the three-cornered alfalfa hopper's biology and host plants, provided an update on their research.
Araujo, the viticulture consultant, said he and his colleagues value the university's research. “Napa Valley is a place where quality is paramount yet more and more we have labor shortage, we have inflation, production costs are going up,” he said. “Finding a way to get maximum quality along with yield levels that will pay for the increasing costs of production is the only way we'll be sustainable now and in the future.”
Throughout Humboldt and Del Norte counties, the UC Master Food Preserver Program is actively engaging with tribal members. In fact, the UC Master Food Preserver volunteers have been “jamming it up” since 2017 with over 15 workshops for tribal community members.
Kella Roberts, of United Indian Health Services, has helped more than 280 community members improve their health and wellness - one jar, one dehydrator, one freezer bag at a time. Their workshops support existing efforts in the tribal communities to empower individuals, families, tribes, and the community to make healthy choices.
Roberts, along with her fellow UC Master Food Preserver volunteers, deserve recognition for coordinating and delivering food preservation classes to new audiences. They've adopted methods to help those with diabetes by limiting the sugar in recipes, and taught four workshops on ginger zucchini orange marmalade and strawberry jam using pectin.
Over 130 youth and adults across four workshops went through the hands-on process of mashing and drying berries to make strawberry and beet fruit leather.
Roberts kept the crunch going by teaching workshops on kosher dills, pickled green beans and pickled beets. Kale chips were another crunchy treat with healthful benefits that were highlighted at a Hands on Health Conference workshop. Other healthy food preservation workshops included smooth applesauce and fruit dehydration.
To increase participation, these workshops were held at sites where tribal members already meet and live, including the Bear River Band of Rohnerville Rancheria, Big Lagoon Rancheria, Blue Lake Rancheria, Cher-Ae Heights Indian Community of the Trinidad Rancheria, Elk Valley Rancheria, Resighini Rancheria, Wiyot Tribe, Tolowa Dee-Ni' Nation, and the Yurok Reservation.
Find a UC Master Food Preserver Program near you to get involved in sharing home food preservation techniques with your community. The program uses research-based methods to deliver home food preservation methods to Californians.