Researchers at the University of California, Riverside have developed tests to measure the purity of pomegranate juice and juice blends, funded by a $50,000 one-year grant from juice company POM Wonderful.
Chemistry professor Christie Larive and graduate student Daniel Orr are using a number of spectrometry methods to identify and isolate amino acids, organic acids, sugars, pomegranate pigment compounds, and antioxidant molecules that are unique to pomegranate juice. They hope their work could also help pinpoint the specific components of other juices, wine and olive oil by building a statistical profile of their different compounds in the laboratory, in order to detect adulteration.
"We are measuring levels of unique compounds in pomegranate juice and are able to use this 'molecular fingerprint' to discriminate against adulterated juice products," said Larive.
“We have received a collection of pomegranate samples from around the world, as well as commercial juices such as beet, grape, apple and pear – to name just a few. We're looking at whether or not our molecular fingerprint method can be used to identify products claiming to contain pomegranate juice when they don't, and products claiming to be pomegranate juice when they are not."
The three spectrometry methods – nuclear magnetic resonance spectroscopy, liquid chromatography-mass spectroscopy, and gas chromatography-mass spectroscopy – can be used together to compare the metabolite profiles of pomegranate juice samples against the claims manufacturers are making on-pack, Larive said, adding that the techniques could also address adulteration concerns for other products.
"We are really curious to see how far we can push the technology," she said. "…Where our experiments are concerned, juices, wine and olive oil are simply different sets of plant compounds. So it should be relatively easy to extrapolate the work we're doing on pomegranate juices to these products."