The humble, yet nutritious, raisin could well be the next rival to sodium nitrite in the food preservative stakes, claim researchers from the US this week who have just completed research on the celebrated beef jerky.
Mark Daeschel, a food scientist at Oregon State University (OSH), together with colleagues Karl Schilke and Cindy Bower, found that adding raisins to jerky inhibited bacterial growth, in particular those prevalent in foodborne illness - E. coli, Staphylococcus aureus and Listeria monocytogenes.
In addition to its food safety properties, the scientists claim that the nutritional element of raisins could pave the way for their introduction into naturally-positioned food products.
"Raisins are high in antioxidants and have lots of fibre. Consumers are looking for all these characteristics - low fat, high fibre and antioxidants," said Daeschel.
So how do they work? Raisins are high in sugar, which inhibits microbial growth associated with spoiled food and foodborne illness, explained Daeschel. "The sugar makes the water in food less available to microbes." Added to this, raisins are acidic, which also discourages microbes.
The scientists at OSU's Department of Food Science and Technology evaluated the taste, texture, antioxidant potential and antimicrobial properties of jerky made with ground beef. They compared these properties of the raisin jerky to typical commercial-type jerky made with sodium nitrite and jerky made without any preservatives.
In blind taste tests, a scientific panel evaluated the three types of jerky for flavour, texture, chewiness, overall liking and appearance.
"Panellists ranked the 10 per cent raisin jerky as superior to the nitrite control in terms of overall liking, flavour, texture and appearance," said Daeschel. "They said the sweet and tangy flavour imparted by the raisins was pleasing and that it made the jerky seem less salty."
As a next step, the researchers will investigate the antioxidant activity linked to raisins "that may decrease off-flavours associated with oxidation or rancidity", concluded Daeschel.