Antioxidant and Sensory Properties of Raw and Cooked Pork Meat Burgers Formulated with Extract from Non-Compliant Green Coffee Beans.

The effects of polyphenol-rich extract obtained from non-compliant defatted green coffee beans (dGCBs) on physicochemical and antioxidant properties, as well as on the sensory profile of vacuum-packed pork burgers stored at 4 °C for 14 days and after cooking were assessed. The dGCB extract obtained by means of supercritical water extraction was analyzed for its polyphenol profile, total phenolic content, radical scavenging, and ferric-reducing antioxidant activities (DPPH and FRAP), Fe2+-chelating capacity, and total iron. The most abundant polyphenol component observed in the dGCB extract was chlorogenic acid, and the alkaloid caffeine was also present. This extract showed antioxidant properties. Thereafter, five formulations of pork meat burgers with added NaCl (1%) were prepared; one without the antioxidant (negative control, C) and one with the use of a synthetic antioxidant (0.05% ascorbic acid = positive control, A), while the other three were supplemented with a different amount of dGCB extract (P15 = 0.15%; P30 = 0.30%; P60 = 0.60%). The addition of dGCB extract increased the antioxidant activity of the raw and cooked burgers and reduced the lipid oxidation of the cooked burgers (0.47, 0.21, and 0.20 vs. 1.28 and 0.55 mg MDA eq./Kg, for P15, P30, and P60 vs. C and A, respectively). No negative effects were observed on the meat's color parameters and its stability during refrigerated storage and after cooking, nor on sensory attributes (color and aroma) for the lowest concentration of coffee extract. The results obtained indicate that 0.15% dGCB extract is a promising alternative to commercial synthetic antioxidants to improve the quality of refrigerated pork burgers.

Processed Meat and Polyphenols: Opportunities, Advantages, and Difficulties.

Currently, processed meats appear increasingly as a nonhealthy food because of their content of fat, salt, nitrite, and particularly in red meat, for the heme-iron concerning oxidant effect and radicals formation in human gut. Polygonum cuspidatum and rosemary extract has been tested to counteract these effects and experiments were carried out to add polyphenols into whole meat cuts with the aims to improve their healthiness. The addition of these extracts can reduce the oxidation-reduction potential of products, increasing the antioxidant power. Nevertheless, a low percentage of polyphenols were found in the products because of the process effects and an interaction with the ascorbate residue was observed. In addition, some drawbacks were a decrease in of yield and a worsening of some sensorial properties when large amount of extract was added. The balance between the improvement of the wholesomeness content and the acceptability of products is the challenge the current research have to overcome.

Feasibility of addition of polyphenol-rich vegetable extracts in whole cooked products: Benefits and drawbacks.

Pork loins were cooked with 5 different polyphenol-rich vegetable extracts: Polygonum cuspidatum, oregano extract, rosemary extract, white grape extract and green tea extract. These extracts were added to brine, taking into account their solubility, for subsequent injection and cooking. Loins with added vegetable extracts exhibited higher antioxidant effect compared to controls, as shown by the oxidized/reduced ascorbate ratio, the potential of reduction and the fat oxidation rate. However, some effects were observed in terms of taste, colour changes and, in some cases (green tea and oregano), presence of blots on meat slices. Poor diffusion of the brine through the muscle fibres and insolubility of the extracts in localized spots are weaknesses of these products. A significant amount of polyphenols was lost or destroyed during the cooking phase of the process. Sensory tests show that only Polygonum cuspidatum and rosemary extract result in an acceptable product. In this case the contribution of active molecules in the final product is rather limited.