Fruitful Research Leads to Nutritious Sweets
Molded and extruded fruit purees can enhance the nutritional quality of
candies, baked goods, and frozen treats.
Satisfying both your sweet tooth and your nutritional goals could soon be
easier than ever. Thats because ARS scientists have developed a way to
add more fruit to confections, baked goods, and frozen treats.
Many candies and baking ingredients already include some fruit, but
they often contain mostly sugar. By creating products with fruit as the main
ingredient, consumers can get a more nutritious end product, says ARS
research food technologist Tara H. McHugh.
Fruit growers could also benefit from an expanded market for fruits like
peaches, pears, and apricots, she says. And the fresh fruit could be pureed
during the growing season and then processed year-round.
McHugh and colleagues combine fruit puree with unique gelling agents and
then form the mixture into shapes using molds or twin-screw extruders. So far,
theyve included up to 30 percent fruit in the molded pieces, with
moisture, starch, and sugar making up the other ingredients. With the extrusion
process, the product can be made entirely of fruit puree.
Agricultural engineer Charles C. Huxsoll and technicians Julie Hsu and
Joseph Carlos also work on the project. All are in the ARS Process Chemistry
and Engineering Unit at the Western Regional Research Center in Albany,
"Restructuring fruit by using gelling agents with twin-screw extrusion
is new, and it may take the industry process to a new level of
sophistication," says Huxsoll. The gelling agents, which include new
combinations of starch and gelatin, make the texture of the fruit mixture
adaptable to a wide variety of uses.
Depending on the ingredients used with the puree, textures could range from
soft and chewy to hard and crunchy.
The puree mixture can be poured into molds to make virtually any shape. The
twin-screw extruder combines the ingredients and pushes the mixture through a
die. The long rope of fruit product is then cut into pieces such as stars,
squares, or circles, depending on the shape of the die.
"Restructured fruit pieces that would be developed by confectioners
into candy alternatives would require different functional properties than
pieces to be incorporated into baked or frozen foods. By using different
gelling agents, the properties can be developed to meet the needs of these
varied applications," says McHugh.
One potential limiting factor to molding the puree mixture is its viscosity.
"If the viscosity of the fruit mixture is too high, it won't flow
smoothly into the mold. The resulting pieces would be irregularly shaped and
less appealing to consumers, says McHugh.
The extrusion process overcomes this limitation, because the mixture is
blended and shaped within the extruder and doesn't require pouring. It's also
faster, taking only minutes to produce the final product. Molded pieces may
take about 1 day to set.
Researchers are ready to move the technology from the lab to commercial
applications. The confectionery, or candy, industry would likely be the first
and largest user. -- By Kathryn Barry Stelljes, ARS
McHugh is in USDA-ARS Process Chemistry and Engineering Research Unit,
Western Regional Research Center, 800 Buchanan St., Albany, CA 94710; phone
"Fruitful Research Leads to Nutritious Sweets" was
published in the November 1996
issue of Agricultural Research magazine.