Qualidade microbiológica e vida útil de filés defumados de tilápia-do-nilo sob refrigeração ou congelamento

Abstract

Resumo -O objetivo deste trabalho foi avaliar a qualidade microbiológica e a vida útil de filés de tilápia-do-nilo, submetidos a diferentes métodos de defumação e condições de armazenamento. Foram utilizados dois processos de defumação (a frio ou a quente), em filés com ou sem pigmentação. Os produtos foram armazenados sob refrigeração ou congelados, e monitorados por 28 dias para avaliação da vida útil. Os filés congelados foram monitorados continuamente por 146 dias, apenas para a análise de ácido tiobarbitúrico (TBA). Defumação a quente e a frio reduziram a quantidade de coliformes, respectivamente em 99,78% e 97,80%. O armazenamento do produto sob refrigeração permitiu a redução de 99,73% dos coliformes, e o armazenamento sob congelamento os reduziu em 99,83%. Os valores encontrados de coliformes fecais estiveram dentro do limite permitido. Os valores de TBA nos filés atingiram o máximo no 14 o dia de armazenamento. Os valores de TBA nos tratamentos sob refrigeração foram superiores aos daqueles sob congelamento e, também, em filés defumados a frio, em comparação aos defumados a quente. O processo de defumação a quente, com posterior armazenamento sob congelamento, é a técnica mais apropriada para assegurar qualidade e maior período de vida útil para os filés de tilápia-do-nilo, independentemente do processo de pigmentação.Termos para indexação: Oreochromis niloticus, Staphylococcus aureus, coliformes fecais, defumação a frio, defumação a quente. Microbiological quality and shelf life of smoked fillets of Nile tilapia under refrigeration or freezingAbstract -The objective of this work was to evaluate the microbiological quality and shelf life of Nile tilapia fillets subjected to different smoking methods and storing conditions. Two smoking processes (cold or hot) were used in fillets with or without pigmentation. Products were stored under refrigeration or freezing, and monitored continually for 28 days for evaluation of their shelf life. Frozen fillets were monitored for 146 days for analysis of thiobarbituric acid (TBA) only. Hot-and cold-smoking reduced the coliform quantity, respectively, by 99.78% and 97.80%. Product storage under refrigeration allowed a 99.73% coliform reduction, and storage under freezing reduced them by 99.83%. Fecal coliform values were within the allowed limits. TBA values in fillets reached their maximum on the 14 th storage day. TBA values were higher in treatments under refrigeration storage than in those under freezing, as well as in cold-smoked fillets in comparison to the hot-smoked ones. Hot-smoked process, followed by refrigeration storage, is the most adequate technique to ensure quality and a larger shelf life for Nile tilapia fillets, regardless of pigmentation process.

Quality evaluation of onion biscuits with aromatized fishmeal from the carcasses of the Nile tilapia

“…They reported an increase in mineral and protein rates in the biscuits. Results by HAJ-ISA andCARVALHO (2011) andFRANCO et al (2013) corroborate current results.…”

“…According to FRANCO et al (2013), crude protein and ashes of fishmeal vary according to the origin of the prime matter (fish carcass) which is due to the type of rations supplied to fish and to the filleting method employed and thus the amount of meat remaining on the spine.…”

“…According to FRANCO et al (2013), cooked fishmeal from tilapia carcasses (spine without head and fins) provided 2.15% humidity, 45.32% crude protein, 6.93% ether extract and 38.03% ashes. On the other hand, PETENUCI et al (2010) reported that fishmeal from the tilapia spine provided 14.2% humidity, 40.8% crude protein, 18.3% ashes and 25.3% total lipids, considered to be a product with high mineral levels and an excellent calorie and protein source.…”

“…The methodology by PETENUCI et al (2010) followed the normal cooking pattern for the preparation of fishmeal, whereas the methodology used in current assay employed the smoking or aromatization method. Method by FRANCO et al (2013) comprised cooking and pressing, with a further decrease in humidity and fat rates.…”

“…In fact, it is the concern of many consumers to have less energetic food but high nutritional values. FRANCO et al (2013) evaluated home-made biscuits with the inclusion of tilapia fishmeal at different levels (0%, 6%, 12%, 18%, 24% and 30%). They obtained a product with 10.00%-10.99% humidity; 9.95%-17.71% crude protein; 9.27%-10.15% ether extract; 0.76%-6.56% ashes and a carbohydrate decrease from 69.68% to 55.58% due to the several inclusions of fishmeal in the biscuits.…”