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When is an orange not an orange?

It's an orange! It's a tangerine! It's a grapefruit! Well, actually, it's all three.

"It's one-half orange, three-eights tangerine, and one-eight grapefruit," says plant breeder C. Jack Hearn.

Ambersweet, the newest orange hybrid developed by ARS horticulturist Hearn in the 1960's and released to growers in 1989, has been classified by the Florida Citrus Commission as an orange.

"This was for the purpose of fresh fruit sales," says chemist Manuel G. Moshonas. But about 90 percent of Florida's orange crop, he says, goes for processing into fresh and frozen orange juice.

Although Ambersweet looks, tastes, and smells like an orange, the U.S. Food and Drug Administration must decide how it should be classified on labels of processed juice products. Because it's a hybrid, current regulations would limit its use to 10 percent or less if the product is to be labeled orange juice.

"Right now, sweet orange, Citrus sinensis, is the only species that can be used without limitation in orange juice under FDA standards," Moshonas explains.

Moshonas has developed data to give FDA a scientific basis for its critical review, which will determine whether or not Ambersweet is classified as a juice orange.

Since Ambersweet is not currently considered part of the C. sinensis species, FDA analysts would need concrete data before agreeing to review their regulations on orange juice.

So at the ARS Citrus and Subtropical Products Laboratory in Winter Haven, Florida, Moshonas and fellow chemist Philip E. Shaw set to work. They needed objective evidence that would prove this new orange hybrid to have more characteristics of its orange lineage than of the grapefruit or tangerine.

With the help of Robert D. Carter from the Florida Department of Citrus, Moshonas and Shaw analyzed Ambersweet flavor and aroma constituents.

"We analyzed not just the juice, but oil from the juice and peel," Moshonas says, "and compared them with similar constituents from orange, tangerine, and grapefruit."

All 21 components identified in fresh orange juice were identical to those in Ambersweet juice. The same held true for oils.

"We did analogous comparisons with tangerine, Orlando tangelo, and grapefruit. Major differences in juice and oils, both qualitative and quantitative, were apparent," says Moshonas.

When he and Shaw used mass spectrometry and gas chromatography, even these highly sensitive computerized instruments were unable to differentiate juice of freshly squeezed Valencia oranges from Ambersweet juice.

"However, the equipment registered differences between Ambersweet and tangerine, Orlando tangelo, and grapefruit," Moshonas says.

Appearance Is Also Important

"To consumers, flavor and color are the most important characteristics of orange juice," says Shaw. Processors now must often blend juices from late-maturing orange varieties, imported orange juices, or small amounts of hybrid juices with juice from early-season varieties to meet USDA grade standards for color. For example, Hamlin--the major early-season variety--produces a very pale, weak-looking juice.

This blending process can be burdensome and expensive. Frozen concentrate has to be stored from the previous season for blending with Hamlin and Valencia juice. The costs are passed on to consumers in the form of higher prices for orange juice.

Processors imported about $641 million worth of orange juice in 1990, most of which was mixed with orange juice produced in the United States that didn't meet color standards.

But Ambersweet juice can stand on its own. In fact, because it exceeds the minimum color standards, it can be mixed with other orange juices that don't meet the government color requirements.

Bobby F. McKown is the executive vice president of Florida Citrus Mutual, which represents 12,300 citrus growers.

"Our members strongly support Ambersweet as an orange not just because of its juice color, but primarily because it's cold hardy and matures early," he says. [See Agricultural Research, July 1990, pp. 13-15.] "We sometimes call it a designated hitter because it can serve both fresh and processing markets. Several varieties are well suited for one or the other, but Ambersweet is an excellent variety that suits both."

Ambersweet, which could stand alone or be blended with Hamlin, could make the processing industry less dependent on imports.

rocess Protects Consumers

FDA's Division of Regulatory Guidance, FDA is evaluating the May 1991 citizen's petition filed by the citrus industry that was based on Moshonas and Shaw's work.

"We have 180 days to either approve or deny the petition or make an interim response," he says.

If FDA agrees with the petition to modify existing standards of identity for various orange juice products, it would have to publish a proposal in the Federal Register, allowing an appropriate period for public comment.

If there are any objections to the proposed change, FDA must evaluate and consider them before publishing a final order.

"We are reviewing the Ambersweet petition but have not yet made a decision about publishing it as a proposal," Stutsman continues.

This regulatory process is designed to protect consumers by ensuring that competing products labeled with a common name meet common standards of identity.

FDA's decision is important also to citrus growers, some of whom have already planted substantial acreages to Ambersweet.

According to Roland L. Dilley, "We're talking about $200,000 worth of Ambersweet trees from our nursery alone that growers want to plant if they can use the fruit for processing." Dilley is president of one of Florida's largest nurseries, Roland L. Dilley & Son, located in Avon Park.

More than 200 Florida citrus nurseries are planting Ambersweet trees for marketing, with a few nurseries producing only Ambersweet.

ore Like Fresh-Squeezed

Providing a scientific basis to classify a new orange variety is but one way the ARS Winter Haven lab is working to enhance the marketing of domestically grown citrus, for the benefit of consumers and growers alike.

"We've come up with a way to help processed orange juice taste more like fresh squeezed," Philip Shaw says. "Because of heat during pasteurization, it's almost impossible for processors to keep the delicate flavor of fresh-squeezed orange juice."

Again using gas chromatography, he and Moshonas accurately defined the mix of flavor components in fresh orange juice and the balance of the same compounds in commercially processed juices.

Natural flavor compounds are separated out of orange juice concentrate then added back in another stage of processing. Until now, according to Shaw, there had been no mechanism to identify and maintain the proper flavor balance.

Moshonas and Shaw are continuing their flavor research with aseptically packaged juice. They've found a way to retard flavor deterioration and add shelf life at the same time.

Packaged orange juice gets some of its flavor from orange peel oil and some from orange essence, both of which are added currently by the processing industry. However, peel oil can deteriorate at room temperatures, causing an off-flavor, Moshonas says.

To get around this problem, Moshonas and Shaw tried substituting concentrated orange essence in the process.

In the early stages of processing, a water distillate is collected that contains various flavor volatiles and other compounds. This is orange essence. It contains very little limonene, which tends to impart a bitter flavor.

Moshonas says that after the concentrated orange essence is added back to the product near the end of the processing, it markedly increases aroma and fruity flavor in the final juice product.

"An experienced 12-member flavor taste panel preferred juice flavored with our concentrated essence over juice flavored with peel oils," he says.

After all, taste is important and it's a key to nutrient quality. Last year, Shaw did a study that proved that if your morning 6-ounce serving of orange juice tastes good, then it probably contains enough vitamin C to meet the U.S. Recommended Daily Allowance.

"That study showed that in orange juice, flavor loss parallels vitamin C loss," Shaw reports.

PHOTO : Cold-hardy Ambersweet oranges. (K-4391-1)

PHOTO : Gas chromatograph charts show how closely juice volatiles from Ambersweet resemble sweet orange's but differ from those of a tangerine.

PHOTO : Plant breeder Jack Hearn shows Ambersweet's easy peeling quality. (K-4391-5)

Manuel G. Moshonas and Philip E. Shaw are at the USDA-ARS Citrus and Subtropical Products Research Laboratory, P.O. Box 1909, Winter Haven, FL 33880. Phone (813) 293-4133.
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Author:Stanley, Doris
Publication:Agricultural Research
Date:Feb 1, 1992
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