The aim of this study was to evaluate the effects of different carotenoids sources in tilapia fish diets on the animals' performance and fillets characteristics. Nine hundred and sixty tilapias, Oreochromis niloticus, averaging 15 g were distributed into 24 tanks to receive one of the six treatments (four repetitions) for 80 days: basal diet with no pigment (control group), basal diet with 350 mg/kg astaxanthin 10 % and basal diets added of four different concentrations of Rubrivivax gelatinosus biomass (175, 350, 700 and 1400 mg/kg). Variables analyzed included feed consumption, weight gain, feed conversion and specific growth rate for the animals and pH, proximate composition, carotenoids, polyunsaturated fatty acids and color for the fillets. Productive parameters did not differ statistically. Moisture content was lower on the fillets of treatments with pigments. The protein contents on the fillets of diets supplemented with the bacterial biomass were higher than in control group, while pH, minerals and lipids did not vary among treatments. Lightness and yellowness did not differ among the treatments, but redness and carotenoids contents were higher for all the groups that received the pigments than for the control group. The ratio of polyunsaturated fatty acids n-6/n-3 was improved with the dietary biomass. So, it was concluded that the use of the pigmenting ingredients did not alter productive parameters but increased redness and carotenoids contents in the fillets. Moreover, the use of R. gelatinosus biomass also increased the protein contents and improved the fatty acids profile in the fillets.

This research aimed at studying the effects of different washing conditions (distilled water x distilled water + NaHCD 3 + NaCl) and cryoprotectants (NaCl + saccharose x sorbitol + sodium tripolyphosphate) for the production of tilapia surimi. The experiment used a factorial design 2 x 2 and the variables analyzed were proximate composition, non-nitrogen protein (NNP) removal, texture, color and yield. The protein and moisture contents of the surimi were influenced neither by washings nor by cryoprotectants, while the ash content was higher when NaCl + saccharose were used as the cryoprotectants and the yield was higher when only distilled water was used for the washings. Combining distilled water for the washings and NaCl + saccharose as the cryoprotectants provided the highest lipid and NNP removals. The different treatments produced surimi gels with similar colors and texture.

ABSTRACT

Resumo O objetivo deste estudo foi avaliar o efeito de temperaturas de desidratação por atomização sobre o rendimento e as características microbiológicas, físicas e químicas de claras de ovos em pó. Os tratamentos utilizados no experimento foram 90 °C, 120 °C e 150 °C, contando com cinco repetições. O rendimento foi determinado pela relação entre os pesos da clara desidratada e in natura. As claras em pó foram analisadas quanto a umidade, proteínas, lipídeos, cinzas, estafilococos coagulase-positiva, Salmonella spp e coliformes a 45 °C. A análise da cor foi feita no sistema Lab e o ΔE foi calculado a partir desses valores. Os resultados foram submetidos à análise de variância e as médias foram comparadas pelo teste de Tukey, utilizando-se nível de significância de 5%. A temperatura de secagem influenciou a umidade das claras desidratadas mas não interferiu nos teores de proteínas, lipídeos e cinzas e nas características microbiológicas. A secagem a 150 ºC proporcionou maior rendimento mas provocou escurecimento e aumento na intensidade do tom amarelo das claras desidratadas.