Influence of pitanga leaf extracts on lipid and protein oxidation of pork burger during shelf-life.

The effect of pitanga leaf extracts, as source of natural antioxidants, on physicochemical properties as well as lipid and protein oxidation of pork burgers during storage at 2 ±â€¯1 °C, packed under modified atmosphere, was assessed. Formerly, the in vitro antioxidant and antimicrobial activities as well as the phenolic profile of pitanga leaf extracts were also studied. Thereafter, five samples were prepared, including control (without antioxidants), commercial synthetic antioxidant (BHT at 200 mg/kg) and three concentrations of pitanga leaf extracts: PLL (at 250 mg/kg), PLM (at 500 mg/kg) and PLH (at 1000 mg/kg). The predominant phenolic compounds identified in pitanga leaf extracts were hydroxycinnamic acids, followed by tyrosol and other phenolics (alkylmethoxyphenols, hydroxycoumarins and hydroxyphenylpropenes). Pitanga leaf extracts showed a high antioxidant and antimicrobial in vitro activity. The addition of pitanga leaf extracts improved the redness of pork burgers during the whole display. On the other hand, the addition of natural antioxidants decreased the lipid oxidation from day 7 till the end of storage period. Burgers with antioxidant showed a similar protein oxidation level, observing an inhibition between 36% and 49% compared to control treatment. From the results, it can be concluded that pitanga leaf extract is a good alternative to commercial synthetic antioxidants to improve the quality and extend the shelf-life of pork burgers.

Guarana seed extracts as a useful strategy to extend the shelf life of pork patties: UHPLC-ESI/QTOF phenolic profile and impact on microbial inactivation, lipid and protein oxidation and antioxidant capacity.

The antioxidant and antimicrobial effects of guarana seed extracts (GSE) added to pork patties were evaluated for 18 days storage at 2 ±â€¯1 °C. Five treatments were prepared: i) without natural antioxidant [control (negative control)], ii) with BHT at 200 mg/kg (positive control), and iii) with three different concentrations: 250  mg/kg (guarana seed low dose-GSL), 500  mg/kg (guarana seed medium dose-GSM) and 1000  mg/kg (guarana seed high dose-GSH) of guarana extracts, respectively. The pH, instrumental colour (CIE L*, a*, b*), total viable counts (TVC), Pseudomonas spp. counts and lactic acid bacteria (LAB) counts, 2-thiobarbituric acid reactive substances (TBARS) and carbonyl content were determined after 0, 7, 11, 15 and 18 days of storage period. The in vitro antioxidant activity together with the phenolic profile of GSE was also studied. Microbial analysis showed that GSE had no antimicrobial activity on pork patties. The untargeted UHPLC-ESI-QTOF approach confirmed the wide phenolic composition of GSE able to explain the antioxidant power (28.2 g/kg of phenolic equivalents). Low doses (GSL) of GSE were able to preserve the values of colour parameters, obtaining higher L*, a* and b* values during storage, which is reflected in the lowest colour differences during storage (ΔE*0-18 = 4.56). TBARS and carbonyls values in GSE added samples were lower than control and BHT ones. GSL and GSM provided better results than the synthetic antioxidant (0.08 and 0.07 vs 0.18 mg MDA/kg; 2.47 and 3.13 vs 3.23 nmol/mg, for GSL and GSM vs BHT, respectively). These findings show that GSE are very effective against colour deterioration, lipid and protein oxidation in pork patties and possessing the potential to be used as natural antioxidants.

Rosemary and Pitanga Aqueous Leaf Extracts On Beef Patties Stability under Cold Storage

ABSTRACT Because processing and storage conditions affect several beef quality attributes, the food industry uses a variety of synthetic antioxidants. However, some synthetic antioxidants have been questioned regarding its safety, and thus the interest in using natural antioxidants in food products is increasing. This paper aimed at assessing leaf aqueous extracts of Rosemary (Rosmarinus officinalis Linnaeus) and Pitanga (Eugenia uniflora Linnaeus) as antioxidants in beef cold storage. After 48h storage, patties added of Rosemary leaf extracts showed increased pH. Patties added of Pitanga extracts had the lowest a* color values. Oxymyoglobin levels were significantly higher for Negative control, than for Pitanga treatment. The 10% extract addition increased lipid oxidation of beef patties. Correlation coefficients between lipid and myoglobin oxidations were all above 0.85. Pitanga leaf extracts negatively influenced beef color, probably because of its higher chlorophyll content. Lipid oxidation of beef patties was increased with the addition of leaf extracts. The inclusion of 10% leaf extract into beef patties seems not suitable, because it may enhance the amount of prooxidant compounds, as well as the amount of substances capable of reacting with lipid secondary products. Correlations between lipid and myoglobin oxidations demonstrated strong relationship.

Monitoramento populacional de capivaras (Hydrochaeris hydrochaeris Linnaeus, 1766) em Pirassununga, SP, Brasil / Capybara (Hydrochaeris hydrochaeris Linnaeus, 1766) population monitoring in Pirassununga, SP, Brazil

O monitoramento semanal de um grupo de capivaras (Hydrochaeris hydrochaeris) foi realizado durante 12 meses (fevereiro/2003 a janeiro/2004) ao anoitecer. As observações consistiram na coleta de informações comportamentais, classificação etária e contagem direta de indivíduos avistados durante o pastejo. No período de estudo, foi feita uma captura, com a contenção dos animais, pesagens, sexagens, marcações, bem como a definição das classes etárias dos 15 animais apreendidos. A densidade ecológica média foi de 0,58±0,05ind ha-1 e o número médio de indivíduos foi de 21±5,6. O grupo apresentou uma mudança de comportamento, com o aumento da área de pastejo e a diminuição do número de indivíduos, principalmente jovens, causando uma diminuição da densidade ecológica da população nos meses de junho a setembro de 2003. Machos jovens foram provavelmente expulsos dos grupos não somente em virtude do período reprodutivo, mas também como uma medida de ajuste populacional em função da escassez de alimento. O aumento da área de vivência durante a seca, juntamente à provável expulsão de indivíduos em função da alimentação e/ou reprodução, mostraram a capacidade da espécie em driblar condições pouco favoráveis encontradas durante o ano.

A capybara (Hydrochaeris hydrochaeris) population was monitored weekly at nightfall for 12 months (February 2003 to January 2004). Information about behavior, age class and animal number at pasture activities were collected during the observations. Fifteen animals were captured once and thus, their contention, weighing, identifications, sex definition, as well as, the age class confirmation could be done. The average ecological density was 0,58±0,05ind ha-1 and the mean individual number was 21±5,6. The capybara group changed its behavior by increasing the pasture area and decreasing the number of animals observed (mainly juveniles) from June to September (2003). Juvenile males were probably banished from the group to provide population adjust because of reproduction season and food scarcity. Home-range increase during dry season added to animals' banishment for food and/or reproduction reasons show the capybaras' ability to react against difficult environmental conditions during the year.

Rendimento de carcaca e composicão química da carne da perdiz nativa (Rhynchotus rufescens) / Carcass income and chemical composition of the native partridge (Rhynchotus rufescens - Tinamiformes) meat

A composicão química da carne e o rendimento de carcaca de perdizes (Rhynchotus rufescens) adultas, com 12 meses, criadas em cativeiro com racões balanceadas, foram determinadas neste trabalho. Para rendimento de carcaca, após o abate e evisceracão, foram feitos dois cortes: peito e coxa+sobrecoxa+dorso. Para análise química, foram retiradas três amostras de cada corte para determinacão da composicão centesimal da umidade, proteínas totais, lipídeos totais, cinzas e colesterol. Os valores observados mostraram um rendimento médio de carcaca de 74,4 por cento com 36,6 por cento de carne de peito. Os componentes químicos apresentaram para os cortes de coxa-sobrecoxa e peito, respectivamente, umidade 62,4 e 55,9 por cento; proteínas 25,2 e 29,1 por cento; lipídeos 1,6 e 5,6 por cento; cinzas 1,4 e 1,2 por cento e colesterol 234 e 70mg/100g. O excelente rendimento de carcaca, somado à composicão química de sua carne, mostra o potencial desta espécie para a producão de carnes especiais.