Effect of Grape Seed Extract on Oxidative Stability of Meat Systems and a Model System
"This research focuses on the addition of natural plant extract high in polyphenol content to meat systems and to a model system to determine weather grape seed extract (GS) at low concentrations could significantly reduce lipid oxidation, and to clarify to what extent pro- and anti-oxidant substances normally present in meats could influence the results. Three experiments were conducted evaluating the effect of (GS) on refrigerated cooked beef and pork patties, frozen raw beef and pork patties, and a model system. The effect of GS (0.01 and 0.02%) on the beef and pork patties was compared to oleoresin rosemary (OR; 0.02%) and water-soluble oregano extract (WS; 0.02%), and the effect of GS (0.02, 0.05 and 0.10%) on the model system was compared with a mixture butylated hydroxyaniline (BHA, 0.01%) and butylated hydroxytoluene (BHT, 0.01%; BHA:BHT). GS 0.02% exhibited the highest degree of control of oxidative rancidity in refrigerated cooked beef and pork patties and in frozen raw beef and pork patties, but not in the model system. WS 0.02% showed an intermediate lipid oxidation delay while OR 0.02% showed almost none, only exhibited a little control in frozen raw pork patties. Additionally, GS reduced off-odors (rancidity and wet cardboard in cooked beef patties, and grassy in cooked beef and pork patties) associated with lipid oxidation as compared to OR and WS. GS did not change instrumental or visual red color of either the refrigerated cooked or frozen raw patties. It reduced visual green discoloration in refrigerated cooked beef patties. Therefore, GS 0.02% has the potential to reduce oxidative rancidity and improve shelf life of refrigerated cooked beef and pork patties, and of frozen raw beef and pork patties. However, a higher concentration (0.05%) was required for the model system to achieve a reduction in lipid oxidation similar to that found in a meat system (beef patties) with GS 0.02%. Moreover, GS showed the same oxidation inhibition as the BHA:BHT mixture only when was added at 0.01%. Interaction between the polyphenolic constituents of the grape seed extract and the free iron and possibly collagen present in the model system, could generate insoluble complexes that reduced the antioxidant activity of GS. Another difference found between the systems (meat system and model system) was the induction period for TBARS formation. The maximum TBARS values in the model system, except for GS 0.1%, were detected after 12 hr of storage time while in the refrigerated cooked beef patties TBARS values were unchanged until the 4th day of storage (under the same conditions). They increased from then on reaching a maximum value at day 8. The difference could be due to the structure and composition of the matrices of the systems. In the model system, all chemical reagents (oxygen, free iron, ascorbic acid and polyunsaturated fatty acids) were ""available"" to react. While in the beef model, the components involved in lipid oxidation were separated by the cellular structures of the muscle tissues, which would be expected to delay lipid oxidation and consequently the TBARS. In summary, grape seed extract high in polyphenol content has higher potential to delay the oxidative stability and extend shelf life of meat products than WS (as evaluated at the same concentrations), while OR exhibits almost no reducing effect. However, the control of lipid oxidation by grape seed extract in a system depends on the matrix structure of the system, and the type and amount of pro- and anti-oxidant constituents and their reactions."
Agriculture, Food Science and Technology
University of Illinois - Urbana-Champaign
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University of Illinois at Urbana-Champaign