“All these benefits for the finished product, as well as for the manufacturer, become possible due to superior high-water-holding and -retention capacity, emulsification properties, enhanced cell structure, and neutral taste,” explains Kovalenko. He recommends using the product in bakery; meat processing; whole meat or poultry injections; dairy, sauces and dressings, and prepared salads for moisture management, yield increase, purge control, and fat replacement; and for emulsification and particle suspension in beverages. The suggested starting use rate is 0.25% to 0.75% of the total ingredient weight.
Plum products such as dried plum powder, purées, and juice concentrates can increase shelf life in a variety of products. Moisture retention is one area in which they excel. “Several characteristics of this particular variety assists in shelf life preservation,” says Degen. “One of them is sorbitol. We don’t know of any other food that has as much naturally occurring sorbitol as dried plums. It’s about 15% sorbitol, which is used very often as a humectant in bakery products. It’s also used to retain moisture in meat products. Sorbitol simply binds moisture in the natural cells of food products.” The 7.5% fiber content of dried plums also helps bind moisture.
Degen recommends dried plum powder for bakery applications. “You would incorporate that into the dried components of the formula,” he says. He recommends a starting use rate of 5% flour basis. “We’ve done energy bars, breakfast bars and products that traditionally are very low in moisture and really have no flavor whatsoever in many cases, but when you add dried plum powder or fresh plum juice concentrate or even dried plum juice concentrate, you get a much more moist product over a very long period of time,” he says.
Malic acid content (1.5% to 2.0%) is also a unique characteristic of the Petite d’Agen plum variety used. Malic acid is a flavor poteniator. According to Degen, it is particularly beneficial in low-moisture or low-fat products, such as extra-lean meats and low-fat baked goods.
For meats, Degen suggests a dried plum purée or a fresh plum juice concentrate. “We use fresh plum juice concentrate at about 3% of the raw meat block,” he says, while a marinade using herbs, spices, water and salt might use fresh plum juice concentrate at 1.5% to 2% of the raw meat block. Tumbling the marinade and whole muscle in a vacuum tumbler for 20 to 30 minutes “opens the pores of the meat, and the tumbling ensures that the liquid is absorbed into the pores,” he says. That provides around 10% to 12% more moisture in the whole muscle and nets 5% to 7% more moisture after cooking.
Using the ORAC method, dried plums contain 8,870 antioxidants per 100 grams. “The two primary antioxidants in dried plums are chlorogenic acid, and neochlorogenic acid. Those help to preserve not only the shelf life of foods but it also suppresses the growth of both natural flora as well as a number of nasty bacteria such as E. coli, Listeria and Salmonella,” says Degan. Recent research at Texas A&M University, College Station, concluded dried plums naturally reduce the amount of lipid oxidation or warmed-over flavor as compared to artificial or synthetic preservatives (Meat Science, 2008; 80(4):997-1,004). “We performed at equal to or better than both in terms of the bacteria growth and the oxidation, but also in terms of eating quality,” he says.
Films at 10
The University of Arkansas, Fayetteville, has developed an edible film system designed to improve shelf life. “We have prepared edible film solutions using proteins, starch, hydrocolloids or combinations of these and incorporated natural plant extracts during preparation,” says Navam S. Hettiarachchy, Ph.D., professor, Department of Food Science and Institute of Food Science and Engineering, University of Arkansas. “The edible film solutions were sprayed onto the products, or the products were dipped in the antimicrobial film solutions, dried, kept in storage, and the effectiveness of plant extracts in the film evaluated against the major pathogens, including Listeria monocytogenes, E. coli O157:H7 and Salmonella.” She suggests the edible films could be used on poultry, meat, hot dogs, fresh fruits and vegetables, and minimally processed fruits and vegetables.