Impregnating collagen fibre with rosemary extracts could boost the antioxidant activity of the extract, and has significant potential for processed meats, say Polish scientists.
The new research, by Katarzyna Waszkowiak and Wlodzimierz Dolata from the Agricultural University of Poznan, reports the potential of rosemary-impregnated collagen fibres as ingredients in sausages.
"Collagen in fibre form was a better carrier of rosemary extract than collagen hydrolyzate in this study," wrote Waszkowiak in the journal Meat Science.
Although the rosemary extract market is growing, one problem is that the ingredient is still considered to be a flavour and not an antioxidant, even though it is often used as such. Many producers believe that this should be changed to reflect current market practices. Some authorities such as the French have recognised this fact, though European legislation has been slow to catch up.
"This protein is used only to a limited extent as a carrier for food additives," explained Waszkowiak.
"Collagen preparations are produced from readily available and cheap raw material. Low production cost and functional properties of collagen result in a continuing interest in these preparations on the part of the food industry Thus, collagen preparations applied to improve attributes of the processed meat could at the same time be carriers of substances to be introduced in these products," she said.
Waszkowiak and Dolata looked at the effect of introducing the rosemary extract (powder form, ethanol extraction from rosemary leaves) using two collagen carrier forms -collagen hydrolyzate (Nativ-WB1/S, Prowico GmgH) or collagen fibre preparation (produced by the researchers in-house) or directly (no carriers). Two sausage types were then produced a wiener-type scalded sausage and a liver sausage.
The antioxidant activity of the additive was measured using thiobarbituric acid reactive substances (TBARS) numbers and peroxide value during cold storage of the sausages lower the value, the higher the antioxidant activity.
The researchers report that, for both types of sausage, the rosemary- impregnated collagen fibre significantly enhanced the antioxidant activity of the rosemary extract with peroxide values and TBARS less than both an additive-free sausage and the extract-only sausages.
On the other hand, when collagen hydrolyzate was used as a carrier of the rosemary extract a masking effect was found to occur, with TBARS and peroxide values of the sausages higher than the extract-only sausages.
"The better antioxidant action with the use of collagen fibres may result from a more uniform distribution of rosemary extract during the production of the sausages," suggested the researchers. "In the course of the 2 per cent addition of the preparation impregnated with rosemary extract than it was for the slight amount (0.02 per cent) of the extract introduced directly."
The researchers concluded that further application of the collagen preparations as carriers is dependent on better understanding how the physical and chemical properties directly influence the antioxidant activity.
The market for rosemary extracts is already healthy. Suspicion over chemical-derived synthetic preservatives has pushed food makers to source natural preservatives such as rosemary extract instead, and market analysts Global Information pitch the global food preservative market at €422.7bn, reaching €522bn by 2008.
Source: Meat Science
January 2007, Volume 75, Issue 1, Pages 178-183
The application of collagen preparations as carriers of rosemary extract in the production of processed meat
Authors: K. Waszkowiak and W. Dolata