An Agricultural Research Service scientist has found that turmeric, a spice used from antiquity as a coloring agent, could also be used as a natural antioxidant to keep dill pickles fresh after packaging in plastic jars or pouches.
The shelf life of food products stored in plastic containers has been known to be shorter than that of products stored in glass containers, partly because the gas-permeable plastic allows oxygen to seep through over time.
Food technologist Roger McFeeters, with the ARS Food Science Research Unit in Raleigh, N.C., worked with Katherine Cleary, a graduate student at North Carolina State University-Raleigh. They found that turmeric prevented formation of aldehydescompounds that cause oxidative off-flavors in pickled cucumberswhen the pickles were packaged under conditions that simulated plastic containment over time.
The study was published recently in the Journal of Agricultural and Food Chemistry.
Consumers are accustomed to purchasing pickles packed in glass jars. However, plastic containers are lighter in weight, dont break, and are easier to open. As a result, there is interest among processors in putting more pickled vegetable products into plastic packages.
The researchers found that some aldehydes were present in pickles that were packed in the laboratory under airtight conditions, as well as in fresh-pack commercial pickle samples provided. However, excessive production of aldehydes occurred when they injected oxygen into the same packaged pickles.
Using other similar samples, the researchers then added an amount of turmeric typically used commercially as a coloring agent and an amount of oxygen comparable to that which would enter a sealed plastic container over a one-year storage period.
The amounts of aldehydes produced in the pickles with added turmeric were maintained at concentrations similar to those amounts present in high-quality commercial pickle products. The findings indicate that turmeric is an effective antioxidant for fresh-pack dill pickles, according to the authors.
ARS is the U.S. Department of Agriculture's chief scientific research agency.