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Wonderful umami

Mmmmm. Pepperoni and mushroom pizza. Potato chips. Umami (pronounced "oo-MA-mee") is, as a result of a series of scientific studies in the 1980s, officially recognized as a legitimate fifth primary taste, adding to the well-known sweet, sour, salty and bitter tastes.

Umami is difficult to describe in just one word; it is a pleasant, hearty, savory, tongue-coating sensation.  And because it is so complex - a taste imparted by glutamate, a type of amino acid, and ribonucleotides, including inosinate and guanylate, which occur naturally in many foods including meat, fish, vegetables and dairy products - the taste blends well with other tastes to round out the flavors. This is why it’s hard to describe the delicious flavor of chicken soup.

Umami is a relatively new concept to most Americans, but this taste has been known for more than 100 years in some parts of Europe and Japan, where chemist Kikunae Ikeda is credited with identifying the taste. Ikeda analyzed the active ingredients in kelp stock, a staple of Japanese cuisine, and discovered that the delectable taste was associated with glutamate.  Glutamate is also present in other savory foods, including those used in Western cuisine, like tomatoes, mushrooms, asparagus, cheese and meat.

Ikeda later developed and patented a method of making monosodium glutamate, or MSG, a processed additive that adds umami taste to food, much like sugar makes things taste sweet. In this country, MSG is not looked upon favorably. There are as many discussions against the use of MSG as there are for the use of MSG to flavor foods.

Hanne Siversten, a UC Davis specialist with the Department of Food Science and Technology explains, “MSG does not taste like much alone, but added to foods, it shows synergistic effects. This means that new flavors appear, as a reaction between MSG and the food itself.”

The taste of umami works much the same way. And since it is an experience naturally occurring from compounds found in many foods, you don’t have to add MSG to understand the taste. You probably eat umami-rich foods every day. Who doesn’t like their spaghetti sauce with a little parmesan cheese? Or cheese and bacon on their hamburger?  These combinations ramp up the flavor of the whole meal. Check out the Umami Information Center (http://www.umamiinfo.com/), a great online resource for Umami information, facts and recipes.

Posted on Monday, August 23, 2010 at 6:37 AM

That liquid gold called honey

If those pollen-packing honey bees were to board an aircraft, they’d be charged for their carry-on luggage.

Fortunately they don’t and they’re not.

And if we were a bee, we’d have to visit two million flowers to make a pound of honey.

Fortunately we’re not, and we don’t.

The honey bee, brought to America by the European colonists in the 1600s, will be celebrated on National Honey Bee Awareness Day, Saturday, Aug. 21, but this insect should be celebrated every day of the year.

Revered for her indispensable pollination services, she also provides us with that liquid gold we call honey. Wonderful, delectable, soothing honey.

“Honey is nature’s miraculous food,” write Ron Fessenden and Mike McInnes, co-authors of the 215-page book, Honey Revolution: Restoring the Health of Future Generations.

“The nutritional composition of honey, calorie for calorie, is closer to fruit than it is to table sugar, high fructose corn syrup or any other sweetener."

They call it “sunshine energy” and “nature’s soul food.”

Over at the Harry H. Laidlaw Jr. Honey Bee Research Facility, University of California, Davis, pop.  6 million (honey bees, that is), the faculty and staff call this insect simply “amazing.”

This week the UC Davis beekeepers are extracting honey — uncapping the combs with an electric knife, spinning the frames through the centrifugal-force honey extractor, and then gathering the flow of honey.

“It’s a sticky situation,” agreed staff research associate Elizabeth Frost, as Bryce Sullivan, a UC Davis senior majoring in biochemical engineering, and Brandon Seminatore, a UC Davis junior majoring in biochemistry and molecular biology, extracted honey — amid a few bee escapees.

The finished product is perfect for pouring on pancakes and waffles. The National Honor Board provided these recipes that kids of all ages love:

Honey Raspberry Citrus Slush
1-1/2 cups fresh orange juice
1/2 cup honey
2 tablespoons lemon juice
2 tablespoons lime juice
1-1/2 cups raspberries, fresh or frozen
1 cup crushed ice
Lemon or lime for garnish

In a blender, combine orange juice, honey, lemon and lime juices; mix until honey is dissolved. Add raspberries and ice; puree. Serve in beverage glasses garnished with a lemon or lime wheel. Makes six six-ounce servings.

Fruity Honey Yogurt Pops
1 cup fresh nectarines, pineapple or strawberries, chopped
1-1/2 cups plain yogurt
1/3 cup of honey
1 teaspoon vanilla
Eight 3-ounce paper cups and popsicle sticks or plastic spoons

In a blender, combine all ingredients; mix well. Pour evenly into eight paper cups; insert popsicle stick or plastic spoon in center of each. Freeze 4 hours or until frozen solid. Makes 8 pops.

Frame of Uncapped Honey
Frame of Uncapped Honey

HONEY EXTRACTOR and UC Davis student Bryce Sullivan (foreground), holds a frame of uncapped honey. In back is UC Davis student Brandon Seminatore. Both work at the Harry H. Laidlaw Jr. Honey Bee Research Facility at UC Davis.

Sampling
Sampling

SAMPLING the honey are Bryce Sullivan (left) and Brandon Seminatore, UC Davis students who work at the Harry H. Laidlaw Jr. Honey Bee Research Facility. (Photos by Kathy Keatley Garvey)

Posted on Friday, August 20, 2010 at 6:48 AM

It looks great, but does it taste great?

Taking a look at melons, berries, tomatoes, pears, stone fruit, and more, researchers from UC Davis, along with collaborators from the University of Florida, are focusing on increasing consumption of specialty crops by enhancing quality and safety.  Funded by the USDA, work on this Specialty Crops Research Initiative (SCRI) grant began about a year ago. 

Americans, after years of hearing that fresh produce is valuable for numerous health benefits, have still not significantly increased their consumption. So, why don’t we eat more fruits and vegetables? Researchers believe that the key reason is that the quality of produce is inconsistent – often with poor texture, flavor or aroma. It might look beautiful on the outside, but when you take a bite – Ugh! It just doesn’t match up to its attractive exterior.

Most produce found at the local market is harvested from the field or orchard before it is fully ripe, shipped a long distance, and then the ripening is completed at a regional produce distribution center or at the local market.

“Harvesting produce early reduces losses due to bruises, decay and other defects,” explained Beth Mitcham, SCRI Grant UCD project leader, “but oftentimes the product never reaches its potential, a full ripe flavor or aroma. Fresh produce, especially when harvested near full ripe stage, can be challenging to handle properly.”

The SCRI grant is an ambitious effort to understand what characteristics are critical for consumers to enjoy produce and develop better methods to measure flavor quality, then work with better tasting varietals and improved shipping and handling practices to allow economically viable delivery of truly delicious fruits and vegetables.

Consumer focus groups are being interviewed for their input, trained taste panels are enjoying a variety fresh produce, and experiments with pallet shrouds and other modified atmosphere transportation experiments are underway. Significant information has already been elicited from consumer groups. Through focus groups, the investigators have discovered that aroma and texture are nearly as important as sweetness, and shoppers get really irritated when produce looks good but tastes bad, and this keeps repeat purchases to a minimum.

Produce managers also have a tough time: set up displays of produce, keep it at the right temperature, watch people wandering around squeezing everything to see if their firmness requirements are met, meanwhile damaging the fruit. It’s a tough market for fresh fruit these days, with fewer consumers’ dollars allocated for produce purchases, but with the advances researchers are making through the SCRI project and others, sweet success is on the way.

Note:  This topic was featured on a CBS13 (KOVR) News clip dated 7/17/10, see: http://www.cbs13.com/video/?id=76639@kovr.dayport.com

Posted on Wednesday, August 18, 2010 at 1:42 PM

The skinny on beer

Drink beer to lose weight? That’s what some recent newspaper headlines trumpeted. Perhaps a bit of an exaggeration. Actually, what our favorite authority on beer — UC Davis professor Charles Bamforth (right) — said was that swapping a glass of wine for a beer every day for a week would cut out more calories than are burned off during a 30-minute jog.

Why? Because most of the calories in alcoholic beverages are in the alcohol and wine typically has a higher alcohol content than beer. “The higher the alcohol content in any drink, the more calories it contains,” says Bamforth, the Anheuser-Busch Endowed Professor of Malting and Brewing Sciences.

He contends beer has gotten a bad rap about belly bloating for too long. “For years beer has been blighted by a reputation for being more fattening than other alcoholic drinks when in reality the exact opposite is true," he says. "It really irritates me when I hear the words ‘empty calories’ attached to beer. That's utter nonsense.”

In fact, beer is loaded with stuff that’s good for you. According to Bamforth, there are significant levels of some of the B vitamins in beer — folic acid, for instance — as well as minerals and fiber. “Let me tell you that beer is pretty much the richest source of silica in the diet,” he says. “Detailed studies in the United Kingdom have linked that to bone health. Beer also contains antioxidants such as ferulate.”

And then there's the alcohol itself. The majority of folks worldwide who study the link between moderate alcohol consumption and reduced risk of coronary heart disease are now convinced that the active ingredient is alcohol and not some other component of alcoholic beverages, he adds. So beer is just as effective as wine in this context.

"Now don't get me wrong. I enjoy wine,” Bamforth confides. “But I know that if I want to be genuinely intrigued by an alcoholic drink, then there is much more going on in the world of beer. There’s such a vast array of styles. Something for the depths of winter — perhaps an Imperial stout — to the balmy days of summer — a sparkling lighter lager. All enjoyed in moderation, of course.”

You would expect a professor of brewing sciences to promote ales and lagers as the drink of choice, especially on a hot summer day:  “Ya'll better believe me, because beer truly is best.”

Got a question, comment, or request for more information from the beer professor? E-mail him at cwbamforth@ucdavis.edu.

Posted on Monday, August 16, 2010 at 10:45 AM

Winegrapes ripen, unless berry shrivel strikes

August visitors to California wine country can see winegrapes ripening – green changing to gold, red and purple. This is the critical final stage of development, and its success drives one of the state's economic engines, with wine sales generating $18 billion in revenue in 2009. Wine country is also a tourist magnet and a job generator; the industry has a $61.5 billion economic impact statewide each year.

If this is a typical year, California will produce 90 percent of the nation’s wine. In normal vines, the ripening period means sugars and pH increase, while acids (primarily malic) decrease. Other compounds such as tannins develop, and all these factors contribute to the flavors and aromas in the wine that eventually results. (See healthy Cabernet Sauvignon, at right.)

However, in recent years growers have become increasingly concerned about a malady that appears during this phase. Known as “berry shrivel,” this disorder leads to shriveling of berries on a cluster.

There are several kinds of berry shrivel. Of greatest concern to growers and winemakers are sugar accumulation disorder (SAD), in which grapes turn flabby and lack sugar, and bunchstem necrosis, (BSN) in which grapes turn raisin-like on the vine, losing juice and often developing undesirably high sugar content. (See California Agriculture) Either of these  disorders makes the fruit less desirable for winemaking, with yield and production losses.

Berry shrivel afflicts both red and white varieties. Cabernet Sauvignon and Merlot are the major red varieties to be affected so far. Among the white varieties, Sauvignon Blanc, Chardonnay, Semillon and Riesling have shown symptoms.

The malady usually becomes apparent when winemakers or sugar samplers are in the vineyard tasting fruit. Once detected, vintners will often make a pass through the vineyard just ahead of the harvest crew to drop this fruit due to its low sugar content and off-flavored juice.

"Berry shrivel usually affects a small proportion of a vineyard's fruit – perhaps 5 percent -- but in particular vineyards and years, shriveling can affect more than half of the crop," says Mark Krasnow, who was a postdoctoral student at UC Davis and is now at the Eastern Institute of Technology in Hawke’s Bay, New Zealand. "In some years and some sites, wineries will decide not to harvest a vineyard due to the amount of shrivel. Fortunately this is rare."

The origins of SAD and BSN are a mystery, in spite of research investigations. Krasnow and his colleagues at UC ran a battery of high-tech tests to determine the factors involved, but found little consistency in results and to date, all tests for pathogenic organisms have been negative.

Whether due to SAD or BSN — berry shrivel occurs in vineyards all over the world, managed under different climates, making it a globally significant problem in winemaking.

"The irregularity of when and where (or if) SAD and BSN occur makes them very difficult to study," Krasner notes. Tests conducted by UC Davis Foundation Plant Services were negative for phytoplasmas, closteroviruses (leafroll), fanleaf viruses, nepoviruses and fleck complex viruses.

“It is possible that SAD has multiple causes, and that one of those causes might be a pathogen,”  Krasnow says. “In some cases, all the fruit on a vine is affected, even clusters that appear outwardly normal. In other cases, it is only the symptomatic fruit that develops abnormally.”

Preliminary studies suggest that SAD can be propagated by chip budding, but vine-to-vine spread has not been seen, according to Krasnow.  Future studies will focus on tests for a causal organism and a more careful examination of the metabolism of fruit affected by this disorder.

Bunchstem necrosis also varies in symptoms and whether effects occur on clusters or whole vines, and can occur at bloom or at ripening (veraison). Future studies will examine varietal differences in susceptibility having to do with xylem structure, the importance of concentrations of mineral nutrients, and other cultural factors.

Posted on Friday, August 13, 2010 at 8:28 AM
  • Author: Janet L. White

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