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UC Food Safety

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What makes food nutritious?

Workers sort tomatoes at Russell Ranch

Part of our mission at the Agricultural Sustainability Institute at UC Davis is to ensure access to healthy food. So we’ve focused much of our work on the intersection between agriculture and human nutrition.

An interesting new field of study in this area looks at flavonoids, which are compounds in fruits and vegetables thought to have beneficial antioxidant effects and other medicinal value – they may even help reduce cancer risk.
Measuring the amount of flavonoids is one way we can figure out just how nutritious the food we’re eating really is.

At our Russell Ranch Sustainable Agriculture Facility, UC Davis Food Science professor Alyson Mitchell has looked at the relative nutrition of organic and conventional tomatoes by measuring flavonoid levels in samples from dried tomatoes over a 10-year period.

Aerial view of Russell Ranch Sustainable Agriculture Facility

She found that flavonoid content is greater in organic than conventional tomatoes, and the differences have increased with time. Over time, it also appears that an increase in flavonoid content is correlated with lower amounts of organic nitrogen application.

These results suggest that over-fertilization can result in lower flavonoid content – and a reduction in the health benefits of tomatoes. You can find out more about this research here.

Posted on Monday, May 10, 2010 at 4:51 PM
  • Author: Colin Bishop

You've counted calories and carbs - now count catechins

Catechins are phytochemical compounds found in plant-based foods and beverages. Consumption of catechins has been associated with a variety of beneficial effects including: ability of plasma to scavenge free radicals, blood vessel expansion, fat oxidation and more.

High concentrations of these helpful compounds can be found in many foods and beverages including: red wine, broad beans, black grapes, apricots, strawberries, apples, cherries, pears, raspberries, chocolate and both black and green tea.

To learn more about the benefits and research related to catechin rich foods, please see UC ANR’s free publication, Nutrition and Health Info Sheet Catechins.

 

apricots

apples

Posted on Monday, May 10, 2010 at 7:28 AM
  • Author: Chris M. Webb

Summer strawberry smoothies

I’m lucky enough to live about a mile from a small, family-run strawberry patch in Yolo County. From some time in April until October, the Laotian family members pick berries in the mornings and sell them from their small wooden stand until they run out of fruit for the day.

Flats of 4 or 6 baskets are the most economical to buy. I carefully place the flat on the floor of the passenger seat; by the time I have walked around to the driver’s seat, the fragrance of the fresh berries has filled the car with instant summer.

Once home, I don’t wash the berries unless I plan to eat them right away. Instead I keep the berries in their baskets and cardboard flat and just cover them loosely with a paper towel. They keep their flavor and texture up to 5 days this way.

According to UC ANR Food Safety Specialist Linda Harris, washing berries in a sink filled with water can spread contaminants from one berry to another; it’s best to hold them under running water, drain them in a clean strainer and pat them dry with a paper towel. I use a clean grapefruit knife with a serrated, slightly curved tip to cut out just the green stem and white part of each berry.

On summer days I get up early and prep the berries like this before my dog and I head out for a run in the cool morning air. Then all I must do when we return—hot and thirsty—is toss the smoothie ingredients in a blender and turn it on.

You can keep your smoothie simple or pack it full of healthy ingredients, as I do below, so it essentially serves as a full breakfast. Either way, its fresh strawberry flavor is one of the culinary pleasures of an early California summer.

Strawberry Smoothie
Serves two; exact amounts are not critical

3 – 4 ice cubes
1½ – 2 cups washed strawberries, stem and core removed
1 banana, peeled
½3/4 cup protein drink, such as Odwalla Super Protein
½ cup pomegranate, orange or any real fruit juice
½–2/3 cup nonfat vanilla yogurt
Optional: a handful of other fruit such as a peeled, cored pear or a slice of cantaloupe

Place ice in the blender first, then add fruit, yogurt and juice. Cover and blend 1–2 minutes or until ice and fruit are pureed.

If you don’t use a full flat of strawberries, you can freeze, dry and can the extra berries. See Harris’ Strawberries: Safe Methods to Store Preserve and Enjoy http://anrcatalog.ucdavis.edu/pdf/8256.pdf for information on those methods.

Cleaned strawberries ready to be prepped
Cleaned strawberries ready to be prepped

Posted on Friday, May 7, 2010 at 9:30 AM

Learn about food and nutrition on YouTube UC Davis

There are a number of short (two-minute) NewsWatch segments on the UC Davis YouTube channel on various aspects of food. These timely and straightforward videos are easy to view and educational. Some food-related topics of interest include:

  • Shaking up salt perceptions [link]

  • Do we obsess about being fat? [link]

  • Why diets don’t work [link]

  • UC Davis creates “bettermilk” (dairy goat milk that protects against diarrheal diseases) [link]

  • UC Davis nutritionist advises: save your money on diet books [link]

  • Recession-proof foods (weighing cost against nutritional value) [link]

  • Beer v. wine: which is the real energy drink? (a 14-minute UC Davis Frontiers program) [link]

You can view all UC Davis YouTube videos at http://www.youtube.com/user/UCDavis.

Posted on Wednesday, May 5, 2010 at 10:57 AM

Pasta salad - more nutritious than ever

The ever popular pasta salad is sturdy and economical, but is it nutritious?

It sure can be, and research from UC Davis Department of Plant Sciences professor Jorge Dubcovsky is helping to make that so. Dubcovsky’s team discovered a gene in domesticated wheat that had been damaged, a gene that controls the distribution of nutrients to the grains in healthy grain plants. What’s more, they discovered a copy of that damaged gene in wild wheat, enabling them (and others) to breed new varieties with substantially increased levels of protein, iron and zinc.

Wheat provides about 20 percent of all the calories people consume worldwide. In other words, we eat a lot of it – it’s second only to rice as a human source of calories. Sometime during its domestication (some 10,000 years ago) wheat underwent a change that lowered the protein, zinc and iron content in its grain.

In 2006, after years of mapping, Dubcovsky and his team discovered the culprit - a mutation in a gene called NAM-B1. In healthy grain plants, NAM-B1 controls the remobilizing and distribution of nutrients to the grains when the leaves die off. Without a working copy of the gene, cultivated wheat is not a good processor of its nutrients, so large amounts of protein, iron and zinc are left in its straw.

Dubcovsky’s team then examined the ancestors of commercial wheat and found, amazingly enough, a fully functional NAM-B1 gene within the genome of wild emmer wheat. Emmer wheat can be freely crossed with domestic wheat using conventional means, so no controversial genetic engineering methods were needed to restore the lost gene.

The University of California has already released one variety – Lassik - with the increased nutritional punch. Lassik also is genetically improved for stronger gluten and resistance to both stripe-rust and leaf-rust disease. And because the new strains were bred from widely used commercial varieties, the new variety retains its farmer-friendly characteristics such as high yield and consumer-friendly trait like excellent taste.

The new plants are in the public domain, distributed to breeders across the globe. Some 2 billion people around the world lack adequate micronutrients, so more nutritious wheat could make a big difference in fighting world hunger.

So when friends ask, “What’s the secret to your fantastic pasta salad?” you know what to say:

“Protein, iron and zinc.”

For more on what the UC Davis Department of Plant Sciences is doing to make our salads more tasty, nutritious, safe and affordable, see The Spring 2010 Leaflet

Wild wheat, Triticum turgidum ssp. dicoccoides
Wild wheat, Triticum turgidum ssp. dicoccoides

Posted on Wednesday, May 5, 2010 at 9:04 AM

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