Produtos de acerola: estudo da estabilidade de vitamina C

A acerola é um fruto altamente perecível e que contém altos teores de vitamina C, sendo este o seu principal atrativo em termos nutricionais. A atual legislação brasileira prevê uma variação de, no máximo, 20% do teor dos nutrientes especificados no rótulo. Devido a essa exigência seria importante que os fabricantes considerassem tanto o teor inicial de vitamina C quanto a perda ao longo da armazenagem dos produtos de acerola. Neste trabalho, foi feito o acompanhamento da estabilidade da vitamina C em polpa pasteurizada e acerola in natura congeladas, ambas armazenadas a -12ºC e -18ºC, e em suco de acerola pasteurizado engarrafado, mantido a temperatura ambiente, ao longo de 4 meses de armazenagem. As polpas congeladas não apresentaram degradação significativa durante este período, já as in natura apresentaram cinética de degradação de 1ª ordem e o suco de ordem zero. Após 4 meses de armazenagem as acerolas armazenadas a -12ºC e -18ºC apresentaram teores de 869±12 e 1.223±148 mg vit.C/100g, representando uma perda de 43% e 19%, respectivamente, em relação ao teor inicial. Polpas a -12ºC e -18ºC apresentaram teores de 1.314±6 e 1.322±2 mg vit.C/100g, respectivamente, representando uma perda de, aproximadamente, 3% e o suco apresentou uma perda de 32%, correspondendo a um teor final de 673±17mg vit.C/100g.

Qualidade microbiológica e ocorrência de leveduras em polpas congeladas de frutas

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Utilização dos isótopos estáveis de carbono e nitrogênio na detecção de adulteração e avaliação energética de bebidas de laranja

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Serological profile of Toxoplasma gondii and Neospora caninum infection in commercial sheep from São Paulo State, Brazil

Neosporosis and toxoplasmosis are two important infections in young and adult sheep, leading to low production and abortion. This study aimed to determine the frequency of antibodies to Toxoplasma gondii and Neospora caninum in sheep from the eastern region of São Paulo State, Brazil. Serum samples (382) were collected from the sheep and assayed for T. gondii through modified agglutination test (MAT) and indirect fluorescent antibody test (IFAT), and for N. caninum antibodies, through IFAT, with cut-off titers equal to 16 (T. gondii) and 25 (N. caninum). All frozen samples were sent to the Center for Zoonoses Research (NUPEZO), Department of Veterinary Hygiene and Public Health (DHSVP), FMVZ, UNESP, for serological tests. A total of 71/382(18.6%) samples reacted to T. gondii, especially at titers 16 (28; 39.4%), 64(15; 21.1%), 256 (21; 29.6%) and 1024 (6; 8.5%) by MAT, and 16(34: 47.9%), 64 (18; 25.4%), 256 (14; 19.7%) and 1024 (5; 7%) by IFAT. As regards N. caninum, 49/382 (12.8%) samples reacted at titers 25 (17; 34.7%), 50 (11; 22.5%), 100 (11; 22.5%), and >= 200 (10; 20.4%). These animals presented infection but no clinical signs. Six and ten animals had high titers for toxoplasmosis and neosporosis. No significant association was observed between antibodies for both parasites (P = 0.535) according to Fisher's exact test, and no correlation was found between T. gondii (MAT) and N. caninum antibody titers (r = -0.0068; P=0.895), T. gondii (IFAT) and N. caninum antibody titers (r = -0.0025; P = 0.961). Thus, T. gondii and N. caninum infections were observed in farms located in São Paulo State, where sheep play an important economical role for the national and regional business. (C) 2010 Elsevier By. All rights reserved.

Effect of refrigeration systems upon frozen bull sperm viability assessed by computer-assisted sperm analysis and fluorescent probes

Sperm cryopreservation success depends upon the maintenance of spermatozoa fertility potential. Sperm cells must preserve both integrity and functionality of several cell structures. The stabilization phase must allow the exit of water from the sperm cells via osmosis. This study aimed to compare the effect of refrigeration in the commercial refrigerator (CR) and the transport/refrigeration box (TRB) upon the viability of frozen bull sperm diluted in three different extenders (A, B and C). Ten Nellore bulls, Bos taurus indicus maintained in Artificial Insemination Center were used and the spermatozoa samples was assessed for Plasma Membrane Integrity and CASA evaluation. The stabilization phase (5 degrees C/4 hours) was performed in the CR as well as in the TRB, and then samples were exposed to nitrogen vapor during 20 minutes and then plunged into nitrogen. The statistical analysis was done using the variance analysis and the significance level was set at 5%. In the CR the post-thawing parameters for PM and ALH were higher (p < 0.05) in the extender A (glicine egg-yolk) and extender B (glicine egg-free) when compared with extender C (TRIS egg-yolk). As for BCF, STR and LIN, the parameters were higher (p < 0.05) in extender B than in C. Samples that were stabilized in the TRB presented higher post-thawing parameters (p < 0.05) for PM and LIN in extender A and extender B when compared with C. BCF and STR parameters were higher (p < 0.05) in extemder B when compared with C. Extender B samples had higher (p < 0.05) PMI when stabilized in CR. The findings in this experiment enable us to say that both CR and TRB were effective in keeping the viability of post-thawing bull semen.

Freezing point and thermal conductivity of tropical fruit pulps: Mango and papaya

The freezing point depression of mango and papaya pulps was measured by using a simple apparatus, consisting of two major sections: a freezing vessel and a data acquisition system. The thermal conductivity of both pulps as a function of frozen water fraction and temperature was also investigated by using a coaxial dual-cylinder apparatus. Thermal conductivity above the initial freezing point was well fitted by polynomial equations. Below the freezing point, the thermal conductivity was strongly affected by both the frozen water fraction and temperature. Simple equations in terms of frozen water fraction and temperature could be fitted to the experimental data of freezing point depression and thermal conductivity.

Vitrification of immature feline oocytes with a commercial kit for bovine embryo vitrification

The aim of this study was to evaluate the suitability of a commercial kit for bovine embryo vitrification for cryopreserving cat oocytes and to evaluate comparatively the effects of its use with slow freezing procedure on cryotolerance in terms of morphology and oocyte resumption of meiosis. Germinal vesicle stage oocytes isolated from cat ovaries were either vitrified (n=72) using a vitrification kit for bovine embryo or slow frozen (n=69) by exposing oocyte to ethylene glycol solution before being transferred to a programmable embryo freezer. After thawing and warming, oocytes were cultured for 48h and then were examined for meiosis resumption using bisbenzimide fluorescent staining (Hoechst 33342). Fresh immature oocytes (n=92) were used as the control group. The proportion of oocytes recovered in a morphologically normal state after thawing/warming was significantly higher in frozen oocytes (94.5%) than in the vitrified ones (75%, p<0.01). Morphological integrity after culture was similar in vitrified (73.6%) and slow frozen oocytes (76.8%); however, only 37.5% of the morphologically normal oocytes resumed meiosis after vitrification compared to 60.9% of those submitted to slow freezing procedure (p<0.01). Fresh oocytes showed higher morphological integrity (91.3%) and meiosis resumption rates (82.6%, p<0.002) than cryopreserved oocytes, irrespective of the procedure used. These results suggest that immature cat oocytes vitrified with a kit for bovine embryos retain their capacity to resume meiosis after warming and culture, albeit at lower rates than slow frozen oocytes. Vitrification and slow freezing methods show similar proportions of oocytes with normal morphology after culture, which demonstrate that thawed and warmed oocytes that resist to cryodamage have the same chances to maintain their integrity after 48h of culture. © 2012 Blackwell Verlag GmbH.