RESUMEN
The objective of this research was to evaluate the effectiveness of antioxidant-rich extracts from rose hip (Rosa canina L.; RC) and hawthorn (Crataegus monogyna Jacq.; CM) at minimizing the oxidative damage to proteins and lipids in beef patties subjected to a highoxygen (HiOx-MAP) and vacuum (Vacuum) packaging atmosphere. The extracts of RC and CM were characterized by quantifying bioactive compounds, namely, phenolic compounds, tocopherols and vitamin C. Both fruits had high concentrations of bioactive compounds, with RC having the highest total phenolic and vitamin C content. Yet, CM was the most efficient in protecting beef patties against protein carbonylation, reducing, as a result, the instrumental toughness in cooked beef patties. The use of CM and RC extracts in beef patties significantly improved consumer purchase intention in HiOx-MAP packaging systems. The use of CM and RC extracts or their combination in future research would be an effective antioxidant means to decrease the pro-oxidative effects caused by HiOx-MAP in red meat.
Asunto(s)
Antioxidantes , Crataegus , Animales , Bovinos , Especies Reactivas de Oxígeno , Oxígeno , Ácido Ascórbico , Extractos Vegetales/farmacologíaRESUMEN
The connections between the redox imbalance in post-mortem muscle, early protein oxidation and the onset of pale, soft and exudative (PSE) condition in chicken breast are studied. PSE was induced by incubation of post-mortem chicken carcasses at 37°C for 200min. PSE-induced muscle consistently had faster pH decline and lower pH at 200min (5.84 vs. 6.59) and 24h (5.69 vs. 5.96), higher L(∗) (54.4 vs. 57.3), and lower texture and water holding capacity (WHC) than normal meat. The activities of catalase, glutathione peroxidase and superoxide dismutase were significantly lower in PSE-induced samples than in the normal counterparts. PSE was more susceptible to proteolysis and protein oxidation than normal meat during succeeding chilled storage with more intense tryptophan and thiols depletion, higher protein carbonylation and more intense formation of protein cross-links. We provide plausible explanations to support the role of protein oxidation in the impaired quality PSE chicken.
Asunto(s)
Proteínas Aviares/química , Carne/análisis , Animales , Pollos , Manipulación de Alimentos , Concentración de Iones de Hidrógeno , Oxidación-Reducción , Control de Calidad , Agua/análisisRESUMEN
Los merozoítos del parásito Plasmodium falciparum contienen en su superficie los fragmentos producidos por el primer procesamiento proteolítico de la proteína MSP-1 (merozoite surface protein-1). Dichos fragmentos tienen pesos moleculares relativos aproximados de 83, 42, 38 y 28-30 kDa, respectivamente. En este estudio se describe la producción y caracterización de un anticuerpo monoclonal, denominado 8F4, que reconoce la proteína MSP-1 dadas las siguientes características del antígeno: 1) localización subcelular, 2) peso molecular relativo, 3) período de expresión durante el ciclo eritrocítico, 4) tipo de asociación con la membrana plasmática del parásito y 5) presencia de epítopes compartidos con MSP-1. Adicionalmente, se estableció que 8F4 reconoce el fragmento de 28-30 kDa, producto del primer procesamiento proteolítico de MSP-1. Los análisis realizados permiten confirmar que MSP-1 subíndice 28-30 no permanece en la superficie del merozoíto después de ocurrida la invasión, lo cual sugiere que hace parte del complejo de polipéptidos que es liberado por el merozoíto previamente al evento de la invasión. 8F4 es el primer anticuerpo monoclonal reportado hasta el momento que reconoce específicamente este fragmento