Use of Nile tilapia (Oreocromis niloticus) processing residues in the production of pâtés with the addition of oregano (Origanum vulgare) essential oil.

The effect of the use of Nilo tilapia filleting residues in the production of pâtés with the addition of oregano essential oil stored for 90 days at 4 °C was evaluated. For that, 5 treatments were performed as follows: TSA-control treatment; TES with the addition of sodium erythorbate; and formulation TOE1 with 600 ppm oregano essential oil; TOE2 with 1000 ppm essential oil; and TOE3 with 1400 ppm essential oil. The pâtés showed adequate technological and physicochemical characteristics and microbiological counts within the legislation standards. No significant differences were observed in the luminosity of the pâté formulations during storage, and the addition of oil contributed to the increase in a* values and stability of b* values. Regarding the lipid and protein oxidation, TOE3 showed lower values at the end of the shelf-life. The addition of essential oil did not affect the hardness and cohesiveness of the products. The fatty acids in greater amounts in the samples were linoleic, oleic, palmitic, and stearic acids. The analysis of biogenic amines indicated that only the treatments with the highest amounts of sodium erythorbate (TES and TOE1) showed losses of spermidine. It was observed that decreasing the inclusion of sodium erythorbate and increasing the inclusion of oregano essential oil resulted in a drop in cadaverine values. A total of 46 volatile compounds were detected in the samples with the highest amount of free fatty acids and all the formulations were well accepted sensorially.

Characterization and Strength Quality of the Oryctolagus cuniculus Leather Compared to Oreochromis niloticus Leather.

This study aimed to compare the resistance of the Oryctolagus cuniculus L. (rabbit) and Oreochromis niloticus L. (Nile tilapia) skins, as well as to observe the design of the flower of these skins and the morphology of the dermis. Tilapia and rabbit skins were placed inside the same equipment (tannery machine) for the chromium salt tanning process. The flower design of the fish leather distinguishes it from the rabbit leather, the latter being constituted by the opening of the hair follicles and pores, while the fish leather is constituted by the presence of protective lamellae and insertion of the scales. The dermis of rabbit skin consists of thick bundles of collagen fibers arranged in all directions, which differs from the morphology observed in the dermis of fish skin. However, in the Nile tilapia skin dermis, overlapping and parallel layers of longitudinal collagen fiber bundles are observed, these layers are interspersed with fiber bundles crossing the sking surface (transversely), tying the fibers together and providing greater strength, which can be proven by the strength test. The fish leathers, despite having less thickness (1.0 mm), demonstrated significantly greater tensile strength (13.52 ± 1.86 N mm-2) and tear strength (53.85 ± 6.66 N mm-2) than rabbit leathers, that is, (8.98 ± 2.67 N mm-2) and (24.25 ± 4.34 N mm-2). However, rabbit leather demonstrated higher elasticity (109.97 ± 13.52%) compared to Nile tilapia leather (78.97 ± 8.40%). It can be concluded that although the rabbit leather is thicker due to the histological architecture of the dermis (thick bundles of collagen fibers arranged in all directions with no pattern of organization of collagen fibers), it shows less resistance than Nile tilapia leather, which demonstrates an organization of overlapping and parallel layers and intercalating collagen fiber bundles transversally to the surface, functioning as tendons for the swimming process. It is recommended to use a piece of fabric (lining) together with the fleshy side of the rabbit leather, to increase resistance when used in clothing and footwear, as these products require greater tensile strength. Thus, it minimizes this restriction for the use of rabbit leather in the aforementioned purposes.

Microencapsulated dietary supplementation coupled with sexual inversion improves the immune and antioxidant response of Nile tilapia larvae under stressful conditions.

In tilapia aquaculture, the cultivation of single-sex animals is extremely widespread, as it allows for the standardization of lots, in addition to improving the general performance of the animals. However, it is possible that hormonal inversion interacts with other factors, such as environmental and nutritional management, and modulates the immune response and antioxidant system of animals in a distinct manner. In order to test this hypothesis, an experiment was carried out using Nile tilapia larvae six days after hatching, divided into four experimental groups: NI (non-inverted animals), I (sexual inverted animals), NI + M (non-inverted supplemented with microencapsulated products) and I + M (sexual inverted and supplemented with microencapsulated products; half of which were subjected to transportation-related stress after 28 days of the experiment. At the end, the survival rate was evaluated; the gene expression of heat shock protein (HSP70), interleukin 1 beta (IL-1ß) and cyclooxygenase-2 (COX 2) via RT-PCR; also evaluated were the activity of catalase (CAT) and superoxide dismutase (SOD) enzymes, as well as the total antioxidant capacity by 2,2-diphenyl-1-picryl-hydrazyl (DPPH). Animals from the I and I + M groups had the highest survival rate (p < 0.001) regardless of transportation stress. The highest expressions of HSP70 were found in the NI group (p < 0.001, with and without transportation). For the IL-1ß gene, there was an increase in expression for animals belonging to groups NI and NI + M (no transportation); and NI (p < 0.0001, with transportation). Increased COX 2 expression was observed for all groups after transportation (p < 0.0001). The highest SOD activities were observed in groups I and I + M (without transportation, p = 0.0004), and I (with transportation, p < 0.0001). The transportation decreased the total antioxidant capacity of DPPH in all treatments (p < 0.001). Finally, when evaluating all of the results together, we came to a conclusion that sex inversion improves the immune response and antioxidant profile of animals under stressful conditions when associated with microencapsulated dietary supplementation.

Flavored Amazonic pirarucu (Arapaima giga) waste flour (salted and sweet) for inclusion in food products.

This study aimed to develop flavored flours (salty and sweet) from Amazonic pirarucu waste (Arapaima gigas), include them in extruded snacks, and evaluate the nutritional, physicochemical, microbiological, and acceptance characteristics of these products. A standard flour was elaborated with pirarucu carcass, which presented 54.42% of protein and 7.24% of lipids, and from this, flavored flours were elaborated (salty and sweet). The standard flour had higher levels of protein, calcium, and phosphorus; and the salted one had higher levels of lipids. The fatty acids present in greater quantities were oleic (average of 32.21%), linolenic (average of 20.74%), and palmitic (average of 17.81%). The flavored flours were better accepted than the standard flour, for all sensory attributes and purchase intention. The snacks with sweet flour, despite better results in the sensory attributes of color, aroma, and flavor, were the ones that presented the lowest content of protein and ash, when compared to those with inclusion of standard flour. It is concluded that the pirarucu waste can be used for producing flavored flours and extruded snacks, with the purpose of improved food products.

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.