The preservation effect of biodegradable gelatin coating incorporated with grape seed oil on glazed shrimp.

BACKGROUND: This study was conducted to investigate the quality and shelf life of shrimps (Parapenaeus longirostris, Lucas 1846) glazed with biodegradable gelatin solutions combined with grape (Vitis vinifera L.) seed oil (GSO). Therefore, shrimps were divided into five groups and were glazed with distilled water (control), G (gelatin), G + 5% GSO (gelatin with 5% GSO), G + 10% GSO (gelatin with 10% GSO) and G + 15% GSO (gelatin with 15% GSO). Glazed shrimps were vacuum packaged and stored at -18 °C for 12 months. Proximate composition of the shrimps was determined, and the microbial (total viable counts, psychrotrophic bacteria count and Enterobacteriaceae), sensorial, chemical (residual sulfite, pH, total volatile basic nitrogen, trimethylamine nitrogen, thiobarbituric acid reactive substances) analysis, colour measurement, and melanosis formation were evaluated throughout the storage period. RESULTS: According to the analysis results, edible G + GSO coatings improved the meat quality and the brightness of the shrimps. The combined treatment reduced the quality loss of the shrimps which was caused by lipid content and prevented the total psychotropic bacteria growth throughout the storage. Moreover, glazing with G + GSO retarded the melanosis formation of the frozen shrimps. CONCLUSION: The study results revealed that GSO may be a recommended alternatively to sodium metabisulfite, which is a hazardous chemical substance commonly used against melanosis of shrimps. © 2023 Society of Chemical Industry.

Assessment of the effects of sex and harvesting season on lipid and fatty acid composition of Sparidae species.

In the present study, the lipid amount and fatty acid profile of different Sparidae species, including gilthead seabream, juvenile gilthead seabream, annular seabream, white seabream, common two-banded seabream were evaluated. Fish were seasonally collected from Köycegiz Lagoon (Mugla, South Western Turkey) from June 2018 to June 2019 and after collection, the sex of each specimen was recorded. According to the results of the study, the highest lipid amount was found in female annular seabream individuals as 8.09 ± 0.78% in November and the lowest lipid amount was found in male juvenile gilthead seabream as 0.98 ± 0.12% in March. Palmitic acid and oleic acid were determined as the most abundant SFA and MUFA for all species, respectively. The highest value of DHA, which was the predominant PUFA was assessed as 15.33 ± 0.26% in female white seabream in November whereas the lowest value (3.83 ± 0.36%) was found in gilthead seabream in December. The n-6/n-3 ratio was determined between 0.27 ± 0.00 (for male common two-banded seabream in July)-1.20 ± 0.03 (for male gilthead seabream in December) and it followed within the range of healthy values for all species. As a conclusion, it was found that values of lipid and fatty acid profiles among the examined Sparidae species vary among the season of collection. The results of the study gave the seasonal nutritional values of four economically-important Sparidae species that being rich in healthy polyunsaturated fatty acids such as DHA, have beneficial in human nutrition.

Effects of multiple freezing (-18 ± 2 °C) and microwave thawing cycles on the quality changes of sea bass (Dicentrarchus labrax).

Sensory, chemical [pH, total volatile basic nitrogen (TVB-N), trimethylamine (TMA-N), thiobarbituric acid (TBA)] and composition (crude protein and crude lipid) analyses were carried out on whole, gutted and fillets of seabass that were frozen (-18 ± 2 °C) and thawed more than once in microwave. It was detected that the sensorial acceptability values decreased certainly for all fish samples (whole, gutted and fillets of sea bass) when compared with control group. While chemical (pH, TVB-N, TMA-N, TBA) values increased, crude protein and crude lipid values decreased after the multiple freezing and thawing cycles under microwave. The obtained results offered that thawing by microwave is not appropriate sea bass because of the undesirable cooking effect of microwave to the some parts of fish such as tail, eye and fins. Also skin dryness, moisture losses in eye fluids and textural deteriorations were observed. Significant differences (P < 0.05) were found in general acceptability values and pH, TVB-N, TBA and crude protein results among the sea bass groups thawed in microwave conditions.

Detecting the specific parameters that affect the maturation of farmed sea bass (Dicentrarchus labrax) fillets stored in sunflower oil.

In this study, it was aimed to detect the specific parameters that effect the maturation of farmed sea bass fillets stored in sunflower oil. Sea bass fillets were taken into the pickling solution (2.5% acetic acid and 11% sodium chloride) at 4 °C(±1). Fish meat in each group was analysed for the following parameters; pH, moisture%, acetic acid% and NaCl% in the maturation pickling solution and in sunflower oil. At the end of the 90 days storage, there were not any negative situations about the fish in terms of the scientific approach. It was detected that the skinless samples had the less NaCl and acidity values but scaly and scaleless samples had the higher values. Main reasons are: for the scaly and scaleless samples, the skin acted as a barrier in the pickling solution or oil and for scaly samples, scales depart from the skin and defeat the passing of NaCl and acid to the meat. When evaluating this study results, the fillet group samples which contain more salt and acetic acid are thought to be more appropriate for marinating in terms of shelf-life and quality.