Highly species-specific primers for pork D-loop mtDNA have been designed. Use of these and restrictive PCR amplification conditions has improved a reliable and rapid method for detecting a PCR-amplified 531 bp band from pork. It has been proved useful for detecting both pork meat and fat in meat mixtures, including those dry-cured and heated by cooking. Absence of response in PCR-amplified samples or mixtures from bovine, ovine, chicken, and human was also demonstrated. Furthermore, wild boar and pork samples can be also easily distinguished by a simple AvaII restriction analysis.

Background: The animal blood that is produced in a slaughterhouse is a potential source of inexpensive proteins used in the food industry around the world. However, 60% of it is surplus, and it ends with a negative environmental impact. Introduction: The enzymatic hydrolysis of proteins represents a good way to produce peptides with different biological activities. Methods: Enzymatic hydrolysis of bovine plasma with subtilisin at an alkaline pH and 61.5°C was performed using the pH-stat method. Experiments were conducted considering the effects of a high initial substrate concentration (So) and the enzyme/substrate ratio (E/S) minimizing the processing time necessary to obtain a specific degree of hydrolysis (DH). Results: The best conditions obtained were 42 g/L of So and 0.89 AU/g substrate of E/S until a DH of 20% in 11,1 ± 1,1 min was achieved to the tested conditions, which result in a fitted empirical polynomial equation of degree 3. Conclusion: A kinetic equation is established to relate the DH and the reaction time to a relative error of less than 5% in the fit, to obtain a good antioxidant product in an industrially interesting time. Additionally, the results suggest a good adjustment of the data with a determination coefficient (R2) of 0.9745 in validation.

The aim of this work was to determine (1) the total phenolic compound (TPC), total flavonoid compound (TFC) and bixin and norbixin content of polar extracts of leaves (ALE) and seed (ASE) from annatto (Bixa orellana L.); (2) the antioxidant activity, the ALE and ASE by means of different antioxidant tests, and (3) the effectiveness of ALE and ASE on the growth inhibition of several bacterial strains. Five different test systems were used to determine the antioxidant activity, while the microdilution method was used to test for antimicrobial activity. ALE presented higher (P < 0.05) TPC and TFC than ASE. As regards antioxidant activity, at all the concentrations tested and with all the methods, except the Rancimat test, the ALE samples showed higher (P < 0.05) antioxidant activity than ASE samples. As regards antibacterial activity, ASE was a stronger inhibitor (P < 0.05) of bacterial growth than ALE. Both ALE and ASE could be used as alternative natural preservatives in food matrices due to mainly their broad antioxidant activity and lesser extent of their antibacterial activity. Practical Applications The B. orellana seed and leaf extracts could be suitable for application in on the food industry because It is an important source phenolic, flavonoids and carotenoids compounds, the antioxidant properties of which could be very appreciated in a big number of food processing to avoid its oxidation not only during processing but also during storage period. However, their antimicrobial action is limited. Other important reason for their suitability is their natural origin, which consumers find comforting.

No abstract

Autor a quien debe ser enviada la correspondencia ResumenEl objetivo del presente trabajo fue optimizar el contenido de ácidos y las proporciones de ensilado en dietas para peces elaboradas con ensilados de vísceras de tilapia roja (Oreochromis spp.). Además, se evalúa el impacto ambiental de la obtención dichos dietas, por medio del Análisis del Ciclo de Vida. Se evaluó el efecto de la concentración de ácido sulfúrico y ácido fórmico y sobre los recuentos de mesófilos aerobios (ufc/g), hongos, levaduras (ufc/g), coliformes totales y fecales (NMP/g). Por otro lado, se evalúo el contenido de pienso vegetal y ensilado químico desengrasado sobre propiedades como flotabilidad, índice de adsorción de agua y densidad específica. Los resultados mostraron que es posible reducir la concentración de ácidos en el ensilado, sin comprometer su calidad microbiológica. En cuanto al impacto ambiental, la preparación de las dietas es la etapa que menos aportó a la emisión de gases de efecto invernadero (5,6%) y consumo de energía (1,8%), mientras que el secado de las dietas aportó el mayor impacto, con un 84% de la energía y un 50% de las emisiones de gases de efecto invernadero.Palabras clave: análisis de ciclo de vida; ensilaje químico; impactos ambientales; vísceras de tilapia roja. AbstractThe aim of the present work was to optimize the acid content and the proportions of silage in fish diets elaborated with silage of viscera of red tilapia (Oreochromis spp.). In addition, the environmental impact of obtaining such diets was evaluated through Life Cycle Assessment. The effect of the concentration of sulfuric acid and formic acid (FA) and on the counts of aerobic mesophiles (cfu / g), fungi, yeast (cfu / g), total and fecal coliforms (NMP/g) was evaluated. On the other hand, the content of vegetable feed and degreased chemical silage on properties such as buoyancy, water adsorption index and specific density were evaluated. The results showed that it is possible to reduce the acid concentration in silage, without compromising its microbiological quality. Regarding the environmental impact, the preparation of diets is the stage that least contributes to the emission of greenhouse gases (5.6%) and energy consumption (1.8%), while the drying of diets provided the greatest impact, with 84% of energy and 50% of greenhouse gas emissions.

ResumenSe ha evaluado la actividad antioxidante de hidrolizados de plasma de bovino (HPB) obtenidos con Alcalasa 2.4 L a diferentes grados de hidrólisis. Los HPB se fraccionaron a través de membranas de ultrafiltración y se purificaron por cromatografía de intercambio iónico, con una posterior cromatografía líquida de alta eficiencia en fase reversa. Los resultados mostraron que los HPB obtenidos bajo las condiciones de hidrólisis planteadas, poseen una fuerte capacidad de captación de radicales ácido 2,2´-azino-bis(3-etilbenzotiazolin)-6-sulfónico y un alto poder de reducción comparado con las proteínas de plasma no hidrolizadas. Se encontró además, que la actividad antioxidante se incrementa en función del grado de hidrólisis, y que dicha actividad se mantiene después de someter los hidrolizados a condiciones de digestión in-vitro. Los procesos descritos permiten obtener un péptido con una actividad antioxidante similar a la presentada por algunos antioxidantes comerciales. Palabras clave: plasma bovino, hidrólisis enzimática, péptidos antioxidantes, alcalasa Antioxidant Activity of Bovine Plasma Enzymatic Hydrolysates Obtained by Effect of Alcalase ® 2.4 L AbstractThe antioxidant activity of bovine plasma hydrolysates (BPH) obtained with Alcalase 2.4 L at different hydrolysis degrees was evaluated. The hydrolysates were fractioned through ultrafiltration membranes and were purified by ion-exchange chromatography, with subsequent reverse-phase high performance liquid chromatography. The results showed that the hydrolysates of bovine plasma obtained under the established hydrolysis conditions, had strong scavenging ability on 2,2-azino bis-(3-ethylbenzothiazoline)-6-sulfonic acid free radicals and a great reduction power compared with proteins of non-hydrolyzed plasma. Additionally, it was found that the antioxidant activity increases as function of the hydrolysis degree, and that this activity remains after in-vitro digestion. The processes described allow obtaining a peptid with antioxidant activities similar to that of conventional commercial antioxidants.

Iron deficiencies continue to cause significant health problems in vulnerable populations. A good strategy to combat mineral deficiency includes fortification with iron-binding peptides. This research aims to determine the optimal conditions to hydrolyze red tilapia viscera (RTV) using Alcalase 2.4 L and recovery of iron-binding protein hydrolysate. The result showed that under the optimal hydrolysis condition including pH 10, 60 °C, E/S ratio of 0.306 U/g protein, and substrate concentration of 8 g protein/L, the obtained hydrolysate with 42.5% degree of hydrolysis (RTVH-B), displayed the maximal iron-binding capacity of 67.1 ± 1.9%. Peptide fractionation was performed using ultrafiltration and the <1 kDa fraction (FRTVH-V) expressed the highest iron-binding capacity of 95.8 ± 1.5%. Iron content of RTVH-B and its fraction was assessed, whereas iron uptake was measured indirectly as ferritin synthesis in a Caco-2 cell model and the result showed that bioavailability of bound minerals from protein complexes was significantly higher (p < 0.05) than iron salt in its free form, increased 4.7 times for the Fe2+–RTVH-B complex. This research suggests a potential application of RTVH-B as dietary supplements to improve iron absorption.

ResumenEn el presente trabajo se utilizó la metodología de superficies de respuesta para evaluar el efecto de la temperatura (60-80°C) y el tiempo de calentamiento (20-40 min) sobre el índice de peróxido (P), índice de yodo (Y), tiempo de inducción (OSI) y concentración de grasa remanente (G), en el proceso de recuperación de aceite de vísceras de tilapia roja (Oreochromis sp.), por medio de un método novedoso de calentamiento-congelación. Se ajustaron modelos polinomiales de segundo orden, que se optimizaron para definir los valores de los factores que entregaran la mejor combinación de las respuestas. Los resultados indicaron que las condiciones óptimas corresponden a 69°C y 29 min, las cuales entregaron lípidos con G del 2,653%, peróxido P de 0,014 meq/kg, Y de 161,671 g yodo absorbidos/100 g de muestra, OSI de 0,29 h y tiempo de vida útil de 808,9 h a 25°C. Palabras clave: tilapia roja (Oreochromis sp.); vida útil; tiempo de inducción; rancimat; subproductos de la piscicultura Effect of Temperature-Time on the Extracted Lipids from Viscera of Red Tilapia (Oreochromis Sp.) using a HeatingFreezing Process AbstractThe response surface methodology was used in this study to evaluate the effect of temperature (60-80 ° C) and heating time (20-40 min) on the peroxide index (P), iodine index (Y), induction time (OSI) and concentration of remaining fat (G), in the oil recovery process from viscera of red tilapia (Oreochromis sp.), through a novel method of heating-freezing. Second order polynomial models were fitted, and by optimization the values of the factors that delivered the best combination of the responses were determined. The results indicated that the optimum conditions correspond to 69 °C and 29 min, which gave lipids G 2,653%, peroxide P 0,014 meq/kg, Y of 161,671 g of iodine absorbed/100 g sample, OSI 0,29 h and a lifetime of 808,9 h at 25 ºC.