Percorrer por autor "Morcuende, David"
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- Characterization of Selected Wild Mediterranean Fruits and Comparative Efficacy as Inhibitors of Oxidative Reactions in Emulsified Raw Pork Burger PattiesPublication . Ganhão, Rui; Estévez, Mario; Kylli, Petri; Heinonen, Marina; Morcuende, DavidIn the present study, water, ethanolic, and methanolic extracts from seven selected wild fruits originally from the Mediterranean area, namely, strawberry tree (Arbutus unedo L., AU), azarole (Crataegus azarolus L., CA), common hawthorn (Crataegus monogyna L., CM), blackthorn (Prunus spinosa L., PS), dog rose (Rosa canina L., RC), elm-leaf blackberry (Rubus ulmifolius Schott, RU), and rowan (Sorbus aucuparia L., SA), were analyzed for the total amount and profile of phenolic compounds and for the in vitro antioxidant activity against the DPPH and ABTS radicals (study 1). The seven fruits showed different chemical compositions, which consequently led to different antioxidant potentials. Among the seven fruits initially analyzed, AU, CM, RC, and RU had the highest amount of phenolic compounds and displayed the greatest antioxidant activity in vitro. Extracts from these four fruits were tested as inhibitors of lipid oxidation in raw pork burger patties subjected to refrigerated storage at 2 °C for 12 days (study 2). The quantitative measurements of thiobarbituric acid reactive substances (TBA-RS), hexanal content, and color stability were used as indicators of oxidative reactions. The four selected fruits displayed intense antioxidant activity against lipid oxidation, which highlights the potential usage of these fruits as ingredients for the manufacture of healthy meat products. Among them, RC and AU were particularly efficient as their protective effect against lipid oxidation was more intense than that displayed by quercetin (230 mg/kg of burger patty).
- Protein oxidation in emulsified cooked burger patties with added fruit extracts: Influence on colour and texture deterioration during chill storagePublication . Ganhão, Rui; Morcuende, David; Estévez, MarioThe influence of protein oxidation, as measured by the dinitrophenylhydrazine (DNPH) method, on colour and texture changes during chill storage (2. °C, 12. days) of cooked burger patties was studied. Extracts from arbutus-berries (Arbutus unedo L., AU), common hawthorns (Crataegus monogyna L., CM), dog roses (Rosa canina L., RC) and elm-leaf blackberries (Rubus ulmifolius Schott., RU) were prepared, added to burger patties (3% of total weight) and evaluated as inhibitors of protein oxidation and colour and texture changes. Negative (no added extract, C) and positive control (added quercetin; 230. mg/kg, Q) groups were also considered. The significant increase of protein carbonyls during chill storage of control burger patties reflect the intense oxidative degradation of the muscle proteins. Concomitantly, an intense loss of redness and increase of hardness was found to take place in burger patties throughout refrigerated storage. Most fruit extracts as well as Q significantly reduced the formation of protein carbonyls and inhibited colour and texture deterioration during chill storage. Likely mechanisms through which protein oxidation could play a major role on colour and texture changes during chill storage of burger patties are discussed. Amongst the extracts, RC was most suitable for use as a functional ingredient in processed meats since it enhanced oxidative stability, colour and texture properties of burger patties with no apparent drawbacks.
- Role of Phenolics Extracting from Rosa canina L. on Meat Protein Oxidation During Frozen Storage and Beef Patties ProcessingPublication . Utrera, Mariana; Morcuende, David; Maneta Ganhão, Rui Manuel; Estévez, MarioRecent findings suggested that using frozen material for meat processing leads to products with increased protein oxidation rates and impaired quality traits. Therefore, the effects of frozen storage and the addition of a phenolic-rich dog rose extract (Rosa canina L.; RC), on lipid and protein oxidation, moisture losses, color stability, and hardness of beef patties were investigated. Protein oxidation was assessed by means of tryptophan loss and the formation of specific lysine oxidation products: α-aminoadipic semialdehyde (AAS), α-aminoadipic acid (AAA), and Schiff bases. Frozen storage increased proteins susceptibility towards oxidation during successive technological processes. The addition of the RC extract inhibited the formation of AAS, AAA, and had an antioxidant effect towards tryptophan oxidation, but promoted the formation of Schiff bases and incremented the hardness of beef patties. The antioxidant effect may be attributed to the phenolic compounds, mainly procyanidins, found on the RC extract. Further knowledge on the interactions between phenolics and proteins is needed to optimize the application of these antioxidants against meat protein oxidation.
- Suitability of the TBA method for assessing lipid oxidation in a meat system with added phenolic-rich materialsPublication . Maneta Ganhão, Rui Manuel; Estévez, Mario; Morcuende, DavidNumerous protocols and modifications of the thiobarbituric acid (TBA) test are available in the literature. The present paper compares the effectiveness of different TBA tests in minimizing the interferences caused by the addition of phenolic-rich materials (wild fruits) as antioxidants in cooked burger patties. The aqueous acid extraction procedure (EM) and a modified distilation TBA method (DM) were tested with different conditions of incubation - boiling (B) vs. room temperature (RT) - for monitoring lipid oxidation in cooked burger patties during refrigerated storage. DM-B and DM-RT were more suitable than EM procedures for assessing TBA-reactive substances (TBA-RS) in meat samples containing compounds such as anthocyanins, with similar spectral properties than that of the TBA-malondialdehyde (MDA) adduct. Additionally, interferences caused by browning development during incubation were avoided by DM procedures or by performing RT incubations. Correlations between TBA-RS numbers and hexanal contents in cooked pork burger patties were calculated in order to corroborate the suitability of the tested TBA procedures. The DM-RT procedure showed the highest correlation with hexanal content (R2 = 0.90; p < 0.001). © 2010 Elsevier Ltd. All rights reserved.
- Tryptophan Depletion and Formation of α-Aminoadipic and γ-Glutamic Semialdehydes in Porcine Burger Patties with Added Phenolic-Rich Fruit ExtractsPublication . Ganhão, Rui; Morcuende, David; Estévez, MarioThe effect of added fruit extracts on the oxidation of muscle proteins in porcine burger patties subjected to cooking and chill storage was studied. Extracts from arbutus berries (Arbutus unedo L., AU), common hawthorns (Crataegus monogyna L., CM), dog roses (Rosa canina L., RC), and elmleaf blackberries (Rubus ulmifolius Schott, RU) were prepared, characterized, added to burger patties (3% of total weight), and evaluated as inhibitors of protein oxidation. Negative (no added extract, C) and positive control (added quercetin, 230 mg/kg, Q) groups were also included in the design. Protein oxidation was assessed by means of tryptophan loss using fluorescence spectroscopy (FS) and formation of the specific protein carbonyls αaminoadipic (AAS) and y-glutamic semialdehyde (GGS) using liquid chromatography and mass spectroscopy (LC-MS). Both advanced methodologies (FS and LC-MS) were found to be reliable and specific protein oxidation measurements that allow us to gain chemical insight into protein oxidation. The mechanisms likely involved In the oxidative reactions affecting proteins during cooking and storage of burger patties are profusely discussed. Phenolic-rich fruit extracts protected tryptophan residues against oxidation and Inhibited the formation of both semialdehydes In burger patties during cooking and subsequent chill storage. In general, RC, RU, and AU were the most effective inhibitors of protein oxidation, with this effect being more intense than that of pure polyphenols like quercetin. These fruit extracts could be considered functional ingredients as their antioxidant actions contribute to the enhancement of the nutritional value of the meat products.