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Harvesting Fruits Nutritional PowerHarvesting Fruits Nutritional Power

February 22, 2011

15 Min Read
Harvesting Fruits Nutritional Power

By Kimberly J. Decker, Contributing Editor

Its universally acknowledged among food and beverage marketers that healthy" is a tough sellexcept, that is, when youre talking about fruit. Witness the breathless gushing over superfruits to see how health benefits, or even a rumor thereof, can turn a little-known berry into a celebrity.

But solid evidence supports the nutritional value of all fruits, not just the superstars. Even so, product developers cant help keeping an eye out for the next it" fruit to feature in their products.

Superfruits to the rescue

The superfruit hardly needs introduction. But to be clear, a superfruit is a fruit having exceptional nutrient richness, antioxidant quality and novel taste," says Kasi Sundaresan, Ph.D., manager, research, development and quality, iTi tropicals, Inc., Lawrenceville, NJ. For example, a fruit like acerola or camu camu is a superfruit because of exceptionally high vitamin C values."

Other exotic superfruits include the maqui berry, a dark-purple Patagonian export that promoters claim has higher antioxidant values than any other fruit, and guarana, a native of Brazils and Venezuelas rainforests with about twice as much caffeine, seed per bean, as coffee. The Indian gooseberry, or amla, has high levels of tannins and a long history of use in ayurvedic treatments. Uchuva, or Cape gooseberry, is a sweet-tart fruit from Colombiaand cultivated in South Africarich in dietary fiber. Gac, a spiny Southeast Asian specimen rife with carotenes has long been used in Eastern medicine for eye health, but has the unfortunate drawbacks of toxic skin and flesh, and seedsthe only edible partthat resemble intestines.

Health or hype?

With more superfruits entering the market from different parts of the world," Sundaresan says, there are no clear favorites among them. Some fruits, like açaí, are very popular due to their nutrient densitytheyre rich in omega-3s, fiber and proteinand some others, like guava, camu camu and acerola, are rich in vitamin C. Pomegranate, mangosteen and goji are all known for their high antioxidant potential."

But is the ballyhoo over superfruits a healthy addition to the discussion, or a lot of hype? The current superfruit marketing can be misleading," Sundaresan allows. There are no guidelines for superfruit inclusion or labeling in foods and beverages, and this is having a negative effect on perceptions, as more consumers face claims that products containing superfruits can make them healthy or cure disease."

Thomas J. Payne, market development, U.S. Highbush Blueberry Council, Folsom, CA, agrees: The term superfruit, like the term Super Bowl, has proved an effective marketing tool. It has directed consumers attention to ingredients that they might never have noticed otherwise." But many of the most-talked-about superfruits are not well-known or well-studied in the western world," he says.

Payne also raises the issue of food safety, as consumers have been given reason for concern about the origins of their foods, especially with the exotic and unfamiliar."

Then theres that all-important matter of taste. Retailers and foodservice purveyors are buying for flavor and not necessarily for their nutritional profile," says Robert Schueller, director, public relations, Melissas World Variety Produce, Los Angeles. Some healthy fruits, he admits, arent such a treat. For example, açaí has a notoriously oily taste; dragon fruit has been described as like crunchy water"; and the durian supposedly tastes heavenlyif you can get past an aroma not unlike dirty gym socks left to fester in a sewer.

By the numbers

The marketing hype has made a growing chorus of skeptics question the nutrition stories of some fruits. Firstly, theres no guarantee that enough of the contributing fruit makes it into a product to deliver the purported benefits. But even beyond matters of formulation, the very validity, or at least the utility, of all those reported antioxidant levels deserves scrutiny.

Antioxidants get much of the credit for fruits current nutritional cachet as they are thought to help protect the body against the damaging effects of free radicals and the diseases associated with the aging process," says Payne. ORAC (oxygen radical absorbance capacity) is a well-known analytical method that measures a foods antioxidant levels; the higher the ORAC valueusually stated in micromoles of Trolox equivalents (TE) per 100 grams of samplethe better the ability to neutralize free radicals. (Other measures of antioxidant capacity include TEAC, or Trolox equivalent antioxidant capacity, and FRAP, or ferric reducing ability of plasma.)

But ORAC and its like open only one windowand a foggy one at thatinto a substances real-world radical-quenching potential. Most fruits possess a whole set of antioxidants; ORAC doesnt tell us which are most effective. Furthermore, it measures antioxidant capacity mainly against the peroxyl radical, whereas many different oxidative species assault us in nature. And, while ORAC supplies an antioxidant snapshot under experimental conditions, it doesnt predict how those antioxidants will behave in the complex soup of the human digestive system or, if they survive the journey, in individual cells.

Finally, most of what we know about ORAC values comes from a smattering of studies that, taken in isolation, hardly comprise the definitive word on the subject. Consider that many of those studies are commissioned by parties with a vested interest in the outcome and the cause for skepticism rises.

Apples to oranges

For the average consumer craving a healthful snack, fussing over oxygen-radical quenching capacities and Trolox equivalents is overkill. Experts agree that the simplest, most-effective nutrition strategy is to keep an eye on color. When you think of red, you think of the antioxidant lycopene," Scheuller says. When you think of blacks and blues and purples, you think of anthocyanins, which have been touted in superfruits known to have high levels of antioxidants."

Measuring a fruits nutritional benefits is one thing, but ranking those benefits is quite another. Does a melon high in lycopene trump a mango thats richer in a different carotene? Does a high-fiber fruit top a vitamin E powerhouse? Maybe we ought to stop comparing apples to orangesor mangos to loquatsand realize that all fruit, to some degree, is super.

Not to say that the superfruit phenomenon has been a bust. Its certainly opened up the consumer market to new and viable fruits, and its been particularly effective in helping indigenous farmers in developing countries," says Chris DiLorenzo, chief executive and president, Pocantico Resources, Tarrytown, NY. But are these superfruits better than the fruits we all know?" Maybe not; even a modestly stocked supermarket carries enough domestic superfruits to match the Amazon.

Feeling blue

Blueberries were one of the first domestic fruits touted as a superfruit. Most superfruit rankings not only list blueberries, but compare other fruits against them as a sort of gold standard for superfruitiness."

The U.S. Highbush Blueberry Council estimated the U.S. domestic per-capita fresh blueberry consumption to be 12.3 oz. per person in 2008, a 33% increase over the previous high of 9.2 oz. per person in 2007. Payne credits much of the fruits popularity with its ability to subdue free radicals, which can damage cell membranes and DNA through a process known as oxidative stress." While such stress leads to many of the diseases and disorders associated with aging, blueberries help protect the brain and may reduce the effects of age-related conditions," he says.

In one study conducted at the neuroscience laboratory at the USDA Human Nutrition Research Center on Aging, Boston, mice fed the human equivalent of one cup of blueberries per day performed a series of motor skills tests better than their control-group counterparts, and also demonstrated an increase in exploratory behavior. Autopsies of the mice brains revealed marked decreases in oxidative stress and improved retention of signal-transmitting neurons compared with the controls. Researchers credit blueberry anthocyaninsthe key color components in the fruit, as well as important antioxidantswith the benefits.

The superfruits next door

Blackberries, raspberries, currants and strawberries are also nutrient powerhouses. Strawberries, for example, are particularly high in a class of polyphenol antioxidants known as ellagitannins. These are anthocyanin compounds that not only give strawberries their color, but appear to confer anti-inflammatory properties by way of their ability to inhibit the activity of the enzyme cyclo-oxygenase, or COX.

Grapes are berries, too, although we dont often think of them as such. The French Paradox" introduced the general public to red-wine resveratrol, the flavanoid-like (chemically, its actually a stilbene) phytonutrient that gives red wineand grapesa cardioprotective effect. Along with the flavonoid quercitin, resveratrol seems to decrease the risk of heart disease by reducing platelet clumping and subsequent blood clots, andin another example of antioxidants at workshielding low-density lipoprotein (LDL) cholesterol from free-radical damage that leads to LDLs artery-damaging actions.

Watermelon is not usually the first fruit that comes to mind for its nutrition, but as a rich source of the antioxidant carotenoid lycopene, its more than just a summertime treat. Lycopene has proven in many studieswith human, as well as animal, subjectsto have a beneficial effect with respect to cancers, including prostate, breast, endometrial, lung and colorectal. According to a 2003 study published in the American Journal of Clinical Nutrition (78(6):1,219-1,224), patients with colorectal adenomas, polyp precursors to colorectal cancers, had blood lycopene levels 35% lower than those of polyp-free subjects.

Stone fruits may not be exotic, but theyre super, too. Fresh and dried plums (Prunus domestica) are high in antioxidant phenolics neochlorogenic and chlorogenic acid. These are especially effective at neutralizing the destructive superoxide anion radical, and they also preferentially protect fats from oxidation, helping defend cell membranes, neurons and cholesterol molecules from oxidative damage.

Research on cherries, specifically tart cherries (Prunus cerasus), indicate they also deserve to be called superfruits. Their red color comes from anthocyanins, and they contain a unique array of these compounds--cyaniding, cyanidin 3-glucosylrutinoside (anthocyanin 1), cyanidin 3-rutinoside (anthocyanin 2), cyanidin sophoroside, peonidin, peonidin 3-glucoside--not found in other fruits. Other phytonutrients found in cherries include: quercetin, kaempferol, chlorogenic acid, p-coumaric acid, gallic acid, perillyl alcohol and D-glucaric acid. They also contain a hefty helping of beta carotene, are rich in vitamins C and E, and provide potassium, magnesium, iron, folate and fiber.

The nutrients in tart cherries might be responsible for a host of health benefits, including easing arthritis pain, and reducing risk factors for heart disease, diabetes and some types of cancers. Anthocyanins 1 and 2 help block the enzymes in the body called COX-1 and COX-2 that may be responsible for their ability to alleviate pain. (Aspirin, for example, is a COX-1 and -2 inhibitor.) Research conducted by USDAs Human Nutrition Research Center at the University of California, Davis, found that consuming 280 grams of cherries after an overnight fast showed a 15% reduction in uric acid levels, as well as lowered nitric oxide and C-reactive protein levels (Journal of Nutrition, 2003;133:1,826-1,829.). Tart cherries also contain melatonin, a compound that can help regulate sleep, aid with jet lag and prevent memory loss.

Researchers have looked at the nutrient values for citrus and found considerable density across the spectrum, from mandarins and tangerines to the various orange varietiescolor-rich blood oranges, cara-carasgrapefruits, and the petite kumquat. Again, it appears that antioxidants get the credit. Researchers at Brigham Young University, Provo, UT, publishing in the Journal of Food Science (2010; 75(6):C570-C576), identified several combinations of antioxidants in oranges, including hesperidin and naringenin, the combined effect of which may protect against oxidation over and above what a vitamin C supplement could do on its own.

The all-American apple contains quercetin, catechin, phloridzin and chlorogenic acid, all phytonutrients that have been linked to lowering cholesterol, inhibiting cancer-cell growth and decreasing lipid oxidation (Nutrition Journal, 2004; 3:5).

"In a large-scale review from Germany, researchers looked at the specific cancer-preventative components of apples, apple juice and apple extracts. In the research, they found that apples contain a variety of polyphenols, phytochemicals and fiber," says Jeannie Curry-Swedberg, director business development, Tree Top, Inc., Selah WA. "These apple nutrients appear to affect cancer activity by fighting inflammation, disrupting tumor growth and increasing antioxidant activity. In animal research, apple products have been shown to help prevent skin, mammary and colon cancers. And in large population human studies, regular consumption of one or more apples a day may reduce the risk for lung and colon cancers."

Putting fruit to work

For manufacturing, ease and predictability in superfruit sourcing always is an issue. Mother Nature always plays a factor, and global demand is steadily increasing," DiLorenzo says. But quality is relatively stable in the natural form. Although in the processed forms, variance is significant and requires care and knowledge. R&D and quality start in the field and continue through the whole manufacturing process."

As for quality, the best is fresh, but since shelf stability and transportation are realities, freeze-drying is the next best option, as it preserves all the characteristics of the fruit without any additives," DiLorenzo says. Depending on the finished-product requirements, freeze-dried whole fruit, pieces or powders are the most-practical processing forms."

They may be the most nutritious, too. A study published in the Journal of Food Processing and Preservation (2009; 33(1):11-21) analyzed the effects of air-drying, freeze-drying and subsequent storage on the polyphenol and anthocyanin content of raspberry, strawberry and bilberry fruit. According to the study authors, Despite exposure to atmospheric oxygen, the stored freeze-dried fruit retained the properties of the raw material better than the air-dried product."

DiLorenzo recommends using freeze-dried fruit ingredients as snacks on their own, and in powdered drink mixes, granola, cereal bars, candy or dairy.

"Dried and concentrated fruits offer the versatility of storing and shipping the fruit at ambient temperatures, shipping at least 25% less weight, and the user controls the rehydration/reconstitution ratio," says Curry-Swedberg. "IQF fruit is quickly frozen as to preserve the fruit with minimal damage to the cell structure. IQF fruit is free flowing and is as close to fresh fruit as you can get.

"In todays world economy, cost has become a major factor in finished-product formulation," continues Curry-Swedberg. "As such, some fruits may be too costly to use. Low- and regular-moisture apple pieces can be transformed into virtually any color and flavor a formula requires. For instance, if you want to use blackberries but they dont meet you price parameters, naturally colored and flavored dried apples may just be the ticket. These types of products are being successfully used in many baking items. Available in a granule or nugget form, this shape mimics many berry type fruits. Another possible economic fruit solution to consider is IQF apples mixed with more-expensive fruits. IQF apples are neutral in flavor and will absorb the color and flavor of other fruit."

Payne notes that frozen natural blueberries are in plentiful year-round supply and work in a variety of formulations and processes. And, while dried blueberries appear in cookies, bagels and bars, the frozen format makes satisfying, rich smoothies and energy drinks, and complements creamy dairy products," he says. Their natural sugar levels help balance the sour taste sometimes associated with yogurt." Blueberries contain about 12% sugar and acid levels around 1.9%, giving them a sweet-tart balance that blends well with more-acidic juices. Powdered blueberries have shown up in rice cakes and bar cookies, while sweetened blueberries are excellent fillings in pies, toaster pastries, doughnuts and croissants," he says.

Whole berries can clinch that coveted visibility factor. But beyond the optics, whole fruits provide a greater nutritional kick than extracts. Integrate the skins of the blueberry into the formulation to benefit from all the anythocyanins in the pigments," Payne says. Researchers have found that whole cranberries, tooas opposed to extracts or supplementsdeliver a package" of nutrients that seems to be more effective than any single cranberry component at preventing oxidation and inflammation.

Using the whole fruit, Payne says, fits with the thrust of todays whole-food trend. According to analyses of new product trends for 2011, real ingredients are the choice of todays consumers, from boomers to millennials," he says.

Sundaresan stresses the importance of minimal processing to ensure maximum nutrition, as well as practical formulation. Minimal processing, proper packaging and good manufacturing practices can make the worlds healthiest fruits deliverable in prepared foods," she says. Beverages with minimal processing are the best delivery systems for these fruits, as they have the greatest mass appeal."

Kimberly J. Decker, a California-based technical writer, has a B.S. in consumer food science with a minor in English from the University of California, Davis. She lives in the San Francisco Bay Area, where she enjoys eating and writing about food. You can reach her at [email protected].

An Apple a Day

With everything fruit has going for it, its a surprise were not eating more. The Centers for Disease Control and Prevention (CDC), Atlanta, estimates that, in 2009, only 32.5% of Americans consumed fruit two or more times per day, a slight but significant decrease from 34.4% in 2000.

And this is despite overwhelming research showing that the vitamins, minerals, fiber and phytonutrients in fruits not only promote good health and enhance feelings of satiety, but can protect against chronic disease. According to the CDC, people who include generous amounts" of fruit as part of a healthful diet enjoy reduced risk of stroke and possibly other cardiovascular diseases and certain cancers compared to those who consume only minimal amounts of fruit.

Government and public health agencies have tried to turn the consumption numbers upward with initiatives like the National Fruit & Vegetable Program. And laudable though these efforts are, none has done as much to raise fruits profile than the sheer market power and public profile of the superfruit.

Growth Hooks

According to SPINS Inc., Schaumburg, IL, overall combined-channel sales growth for the five top-selling superfruitsaçaí, pomegranate, coconut oil, elderberry, and goji berryhit 7.2% in 2010, a figure that promises to grow as superfruit ingredients expand into new food and beverage categories. Continued success will depend upon two qualities: a compelling nutritional hook," and a seductively exotic provenance.

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