Functional Potential of White Grape Dietary Fiber Explored

Researchers from the Universidad Complutense de Madrid, Spain, have shown that white grape dietary fiber concentrate (WGDF), a byproduct of grape processing in the wine industry, holds potential as a natural-source antioxidant to safely lengthen the shelf life of food. The results of the study were published online last week in the Journal of Food Science (see Physical Study of Minced Fish Muscle with a White-Grape By-Product Added as an Ingredient at http://www.blackwell-synergy.com/doi/abs/10.1111/j.1750-3841.2007.00273.x).

The researchers obtained WGDF from wine-industry residues and studied the ingredients potential in seafood products. They note that WGDFs main point of interest is that it is a natural product and that it contains a high concentration of dietary fiber. Therefore, the ingredient might potentially help product designers target three areas of general concern: the increasing need for natural antioxidants, improving shelf life, and possibly fortifying the products with healthful attributes.

The Spanish researchers added WGDF to minced fish muscle of horse mackerel (Trachurus trachurus) at levels of 2% and 4% and then stored the samples at -20°C. They then studied the samplesincluding control samples (0% WGDF)in detail on a monthly basis. Some samples were vacuum packaged to determine if such packaging would affect the results.

The researchers note that results show 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. The results also showed that adding WGDF to the fish samples made them softer and less springy while improving water retention and cooking yield. Sensory evaluation showed samples containing 2% WGDF scored highest in overall acceptance compared to the control. The researchers also noted that vacuum packing did not significantly affect the properties considered during frozen storage.