Pantanal yacare (Caiman yacare) tail fillets subjected to traditional hot smoking and liquid smoke.

BACKGROUND: The present study aimed to evaluate the effects of hot smoking and liquid smoke on process yield, physicochemical properties, microbiological parameters, fatty acid profile, benzo(a)pyrene levels, and sensory profile of Pantanal yacare tail fillets. The fillets were subjected to two types of smoking processes: hot smoking and liquid smoke flavoring. RESULTS: The process yield of liquid-smoked fillets was higher (69.8%) compared to hot-smoked fillets (58.0%). All fillets were with good microbiological quality and low benzo(a)pyrene levels and were well accepted by consumers. The hot-smoked fillets and the liquid-smoked fillets presented 456.2 and 589.7 g kg-1 moisture, 262.3 and 263.7 g kg-1 crude protein, 218 and 85 g kg-1 total lipids, and 26.0 and 20.9 g kg-1 ash, respectively. The major fatty acids identified in the smoked tail fillets were palmitic, stearic, oleic, and linoleic acids. CONCLUSION: The liquid-smoked fillets had lower lipid content, and higher process yield because of lower losses; thus, they proved to be more advantageous and practical to obtain than the hot-smoked fillets. © 2022 Society of Chemical Industry.

Imbalance of the redox system and quality of tilapia fillets subjected to pre-slaughter stress.

The objective of this study was to evaluate the effect of oxidative stress on the instrumental and sensory quality of Nile tilapia fillets. The experiment was conducted in a 2x2 factorial arrangement, evaluating densities (60 and 300 kg m-3) and depuration times (1 and 24 hours) in a total of four treatments. The serum levels of cortisol and gene expression levels of catalase (CAT), glutathione peroxidase (GPx) and 70 kDa heat shock protein (HSP70) as well as the pH, color, tenderness, water-holding capacity and sensory analysis of the fillets were evaluated. High density (300 kg m-3) resulted in higher mean cortisol levels, lower expression of CAT and GPx enzymes as well as higher expression of HSP70. Fish under this treatment also exhibited fillets with greater tenderness, higher lightness, lower redness and lower sensory acceptance. The longer depuration time (24 hours) resulted in lower expression of the CAT and GPx enzymes and fillets with higher lightness. The water-holding capacity was not affected by the different treatments. Therefore, low density and longer depuration times are recommended for decreased stress and improved quality of fillets.

Natural and artificial spawning strategies with fresh and cryopreserved semen in Rhamdia quelen: Reproductive parameters and genetic variability of offspring.

This study evaluated the reproductive parameters and genetic variability of offspring of Rhamdia quelen from mating by natural spawning and by controlled fertilization with fresh and cryopreserved semen. After hormonal manipulation, three R quelen pairs were used for natural spawning in high-flow tanks, three pairs were used for mating with fresh semen, and another three pairs were used with cryopreserved semen. Matings were performed in triplicate. For matings with fresh and cryopreserved semen, semen from each male was used to individually fertilize oocytes from each female. Pools of semen and oocytes were made, and aliquots of these gametes were taken for fertilization. No differences (P > 0.05) were detected for absolute or relative fecundity, fertilization rate, or egg hatching rate. The use of fresh semen led to a higher (P < 0.01) percentage of normal larvae. The use of fresh semen in pooled mating resulted in a greater effective number of alleles and a higher expected heterozygosity. Offspring from natural spawning presented higher observed heterozygosity and a lower inbreeding coefficient. The highest inbreeding coefficient was found in offspring from individual matings using fresh semen. Regarding paternal contributions, a single male dominated in matings with fresh semen, whereas two males dominated in natural spawning and matings using cryopreserved semen. The use of gamete pools for mating and natural spawning resulted in higher genetic variability of offspring, and mating using cryopreserved semen found no effects on genetic variability of offspring but did reduce the percentage of normal larvae. Other reproductive parameters were not influenced by spawning strategies.