Stevia plants are a good source of carbohydrates (61.93 % d.w.), protein (11.41 % d.w.), crude fiber (15.52 % d.w.), minerals (K, 21.15; Ca, 17.7; Na, 14.93 & Mg, 3.26 mg/100g d.w. and Cu, 0.73; Mn, 2.89; Fe, 5.89 & Zn, 1.26 mg/100g d.w.) also essential amino acids were found in amounts higher than those recommended by FAO and WHO for adults as well as non-essential amino acids. Stevioside was extracted and purified from the dried Stevia leaves by three methods. The first one, extraction by hot water (65 °C) at different ratios of leaves to water (1:15 to 1:75). The optimum ratio was 1:35 in which the maximum stevioside content was obtained (7.53 %), recovery of stevioside was 80.21 % and purity related to depigmentation was 97.56 %. The second method, extraction by methanol at ratio 4:1 methanol/leaves and purification, recovery of stevioside was 94.90 % and purity was 81.53 %. The third method, extraction by mixture of methanol/water (4:1) and purification, recovery of stevioside and purity were 92.34 and 79.81 %, respectively. Physical and chemical characteristics of the extracted stevioside were studied. Stevioside extractions were analyzed by HPLC in which the highest amount of stevioside (23.20 %) was obtained in methanol extract. Physical, chemical and organolyptic characteristics of extractions indicate that this sweetener has been applied as substitutes for sucrose in different drinks and baking products.

Stevia rebaudiana is considered natural antioxidants, which contained phenolic compounds and flavonoides at levels 24.01 & 18.93 mg/g dry weight basis of leaves and 33.99 & 30.03 mg/g dry weight basis of callus, these substances have been suggested to play a preventive role for human health. Antioxidant activity of water and methanolic extracts of stevia leaves and callus equivalent to gallic acid (GA) and butylated hydroxyl anisole (BHA) were determined. GA was the stronger antioxidant in both water and methanol extracts than BHA. Antibacterial and antifungal of stevia leaves and callus extracted by six types of solvent (acetone, chloroform, hexane, methanol, ethyl acetate and water) were studied. Methanol and acetone extracts had greater antibacterial potential for the strains of Listeria monocytogenes, Staphylococcus aureus, Pseudomonas aeruginosa and Escherichia coli. However, acetone, chloroform, methanol and ethyl acetate had antifungal potential for Asperigillus ochraceus, Asperigillus parasiticus, Asperigillus flavus and Fusarium. The results indicate that stevia leaves and callus extracts may be an ideal candidate for further research into their uses for food preservation and pharmaceutical due to their antioxidants and antimicrobial activities.

Liver paste or foie gras, which is a French term meaning “fatty liver”, was produced traditionally from goose and duck. Chickens are also used in the making of foie gras. The present study deals with the properties and quality of raw chicken and duck liver in comparison with manufactured liver paste (foie gras). Raw chicken liver contained 24.60% protein, 6.00% fat, 1.40 % ash, and 66.80% moisture. The average mineral values were 83.65, 50.75, 5.29, 1.15, 0.154, 0.683, 0.317 and 0.066 μg/g of Fe, Zn, Cu, Mn, Cd, Pb, Ni, and Cr, respectively. The processing of liver paste (Foie gras) changed the composition of raw liver due to a loss in moisture, a release of fat and the addition of butter as a fat source. Chicken liver paste contained 27.8% moisture, 10.1% protein, 58.2% fat, and 0.8% ash. Mineral contents were 68.90, 40.50, 1.60, 1.1, 0.08, 0.22, 0.04 and 0.04 μg/g of Fe, Zn, Cu, Mn, Cd, Pb, Ni, and Cr, respectively. The chemical, microbiological and sensory evaluation of liver paste (foie gras) manufactured from raw liver and preserved by the addition of 1000 ppm of both benzoic acid (BA) or sorbic acid (SA) and a mixture of 500 ppm of both BA plus SA with or without pasteurization at 85 °C were studied during the storage period for 9 days at 4 °C. Presumably, the mixing of liver paste (Foie gras) from chicken liver with 500 ppm of both BA plus SA and pasteurizing the product at 85 °C could be recommended for lowering thiobarbituric acid (TBA), total volatile nitrogen (TVN), peroxide value (PV), free fatty acid (FFA), ammonia, saponification value and hence for inhibiting lipid oxidation and preventing rancidity to an extent up to nine days of refrigerated storage (4 °C). This level is also recommended as a preservative agent to inhibit the bacterial deterioration of chicken liver paste (Foie gras). A sensory evaluation showed that liver paste from chicken was very acceptable from the standpoint of taste, odor, appearance, color and texture. In comparison to liver paste from duck, the results proved that no significant differences were observed between the liver paste from chicken and duck liver paste.<br><br>La pasta de hígado o foie gras es un término francés, que significa “hígado graso” y es tradicionalmente producido de oca y pato. El pollo también es usado en la manufactura de foie gras. El presente trabajo estudia las propiedades y calidad de hígado crudo de pollo y pato en comparación con la manufactura de pasta de hígado (foie gras). El higado de pollo crudo contienen 24.60% de proteina, 6% de grasa, 1.40% de ceniza y 66.80% de humedad. Los valores promedios de minerales fueron 83.65, 50.75, 5.29, 1.15, 0.154, 0.683, 0.317 y 0.066 μg/g para Fe, Zn, Cu, Mn, Cd, Pb, Ni y Cr, respectivamente. El procesado de la pasta de hígado (foie gras) cambio la composición del hígado crudo, debido a una pérdida de humedad, a una libreación de grasa, y a la adicción de mantequilla como fuente de grasa. La pasta de hígado de pollo contiene 27.8% de humedad, 10.1% de proteina, 58.2% de grasa y 0.8% de ceniza....

Meat from the ostrich is becoming increasingly popular throughout the world. The aim of the current study was to evaluate the effects of different antioxidants such as ascorbic acid (AA), α-tocopherol (Toc) and rosemary herb (Ros) on the stability of ostrich meat during storage. The chemical composition of ostrich meat showed low fat content (1.5 %) combined with high protein content (22.4 %). The combination of AA + Ros, Toc + Ros and AA + Toc was more effective in reducing the thiobarbituric acid (TBA) and peroxide values. The antioxidant showed insignificant effects on acidity as oleic acid. The addition of the efficient role of AA, Toc and Ros showed an improvement in the color stability of ostrich steaks and the combined treatment was more effective in color stability. In conclusion, the addition of AA, Toc and Ros had a positive effect on aroma quality, rancidity and discoloration of refrigerated ostrich meat.

La carne de ostra es cada vez más popular en todo el mundo. El objetivo de este estudio fue evaluar el efecto de diferentes antioxidantes tales como el ácido ascóbico (AA), el α-tocoferol (Toc) y hierbas de romero (ROS) en la estabilidad de la carne de ostra durante el almacenamiento. La composición química de la carne de ostra mostro un contenido bajo en grasa (1.5%) en combinación con un alto contenido de proteínas (22.4%). Las combinaciones de AA + Ros, Toc + Ros y AA + Toc fueron las más efectiva en la reducción de los valores de ácido tiobarbitúrico (TBA) y de peróxidos. Los antioxidantes muestran un insignificante efecto en la acidez como ácido oleico. La adicción de AA, Toc y Ros mostro una mejora de la estabilidad del color de los filetes de ostra, es más, el tratamiento combinado fue más efectivo en la estabilidad del color. En conclusión, la adicción de AA, Toc y Ros tuvo un efecto positivo en el aroma, rancidez y decoloración de la carne refrigerada de ostra

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