"The results indicate that WGDF had good functional properties, high water and oil retention capacity, and considerable swelling properties, which would make it useful as a natural ingredient in foods," reported Isabel Sánchez-Alonso in the Journal of Food Science.
Oxidation processes in food can lead to organoleptic deterioration in taste, colour and texture. And fish products are particularly susceptible to oxidation processes because of the high unsaturated lipid content.
The food industry has long been aware of this, and is increasingly seeking natural solutions rather than artificial additives, such as like butylhydroxyanisole (BHA) and butylhydroxytoluene (BHT), to extend the shelf life of milder-tasting products.
The researchers, from the Instituto del Frio (CSIC), looked at using white grape dietary fiber concentrate (WGDF) as a natural antioxidant to increase the shelf life of minced fish muscle (MFM). The WGDF is described as a "natural product containing high concentrations of dietary fiber (DF) with a high-soluble DF (sDF)/insoluble DF (iDF) ratio and associated bioactive compounds".
Three different concentrations of WGDF were used in the tests; zero (control), two and four per cent. The minced fish meat was subsequently stored at minus 20 degrees Celsius for six months.
Sánchez-Alonso and her co-workers report that addition of the grape fibre resulted in softer, less springy and cohesive meat samples. Using scanning electron microscopy, they observed that the fibre was well dispersed in the minced meat, but said the overall food matrix was less continuous than the control.
"In sensory evaluation, samples containing two per cent of WGDF scored highest in overall acceptance as compared with the control," said the researchers.
The results also suggest that the nutritional value of the meat could also be boosted by using antioxidant-rich grape pomace (peels and seeds) – a significant number of studies have reported that grape polyphenols such as gallic acid, caffeic acid, catechins, and anthocyanidins have potential benefits for heart health.
According to a 2003 report by Frost and Sullivan, the synthetic antioxidant market is in decline, while natural antioxidants, such as herb extracts, tocopherols (vitamin E) and ascorbates (vitamin C) are growing, pushed by easier consumer acceptance and legal requirements for market access.
Source: Journal of Food Science
Published on-line ahead of print, doi: 10.1111/j.1750-3841.2007.00273.x
"Physical Study of Minced Fish Muscle with a White-Grape By-Product Added as an Ingredient"
Authors: I. Sanchez-Alonso, M.T. Solas, A.J. Borderias