Quality enhancement of frozen Nile tilapia fillets using rosemary and thyme oil / [Melhoria da qualidade de filetes de tilápia do Nilo congelados com óleo de alecrim e tomilho]

The food industry and the frozen fish sector in particular have benefitted greatly from advancements in food processing technologies. This study investigated the effect of adding natural antioxidants such as rosemary and thyme oil to frozen fillets of Nile tilapia (Oreochromis niloticus) in order to preserve their quality for consumers. Fillets were treated with rosemary and thyme at two concentrations (1% and 1.5%) and then were stored at 4°C. Samples were analyzed over 4 days for bacteriological (aerobic plate count, psychotropic count, and coliform count), chemical (determination of pH, thiobarbituric acid reactive substances-TBARS, and total volatile base nitrogen-TVB-N), and sensory quality examination (color, texture, and odor). Significant differences (P<0.05) were observed among different groups in terms of aerobic plate count, psychotropic count, and coliform count during the storage. Moreover, pH, TVB-N, and TBARS mean values in the treated groups were lower than those in the untreated group. The best sensory quality was obtained at the highest concentrations (1.5%) of thyme and rosemary oil.(AU)

A indústria de alimentos e o setor de peixes congelados, em particular, se beneficiaram dos avanços nas tecnologias de processamento de alimentos. Este estudo investigou o efeito da adição de antioxidantes naturais, como óleo de alecrim e tomilho, a filetes congelados de tilápia do Nilo (Oreochromis niloticus), a fim de preservar sua qualidade para os consumidores. Os filés foram tratados com alecrim e tomilho em duas concentrações (1% e 1,5%) e, em seguida, foram armazenados a 4°C. As amostras foram analisadas durante 4 dias para análises bacteriológicas (contagem de placas aeróbicas, psicotrópicas e coliformes), químicas (determinação do pH, substâncias reativas ao ácido tiobarbitúrico-TBARS e nitrogênio base volátil total-TVB-N) e exame da qualidade sensorial (cor, textura e odor). Diferenças significativas (P<0,05) foram observadas entre os diferentes grupos na contagem aeróbia de placas, contagem psicotrópica e contagem de coliformes durante o armazenamento. Além disso, os valores médios de pH, TVB-N e TBARS nos grupos tratados foram inferiores aos do grupo não tratado. A melhor qualidade sensorial foi obtida nas maiores concentrações (1,5%) de tomilho e óleo de alecrim.(AU)

Some Quality Parameters of Powdered Soups Prepared from Different Fish Species

Abstract In this study, we aim to determine the shelf life of dried and ready to use-powdered soup samples obtained from different types of fish species such as Rainbow trout (Oncorhynchus mykiss), sea bream (Sparusaurata L.) and sea bass (Dicentrarchuc labrax). For this purpose, the chemical (moisture, protein, fat, carbohydrate, ash, pH, Thiobarbituric acid (TBA), Total volatile basic nitrogen (TVB-N), microbiological (total mesophilic aerobic bacteria, total yeast and mold, total coliform, Staphylococcus spp. and Salmonella spp.) and sensory properties of fish soup samples were determined during 6-month storage period. The pH, TBA and TVB-N values of all samples increased during the storage period, but these values were within the consumption limits. Additionally, the microbiological properties of all fish soup samples were found within the consumption limits during storage. As a result, a product has been obtained with high nutritional value and rich with regard to protein, oil, and minerals by adding the fish meat to soup samples. It has been determined that the product quality and shelf life significantly increased by using the boiled product for the production of soup samples.