جستجوی مقالات مرتبط با کلیدواژه « ترکیب اسید آمینه » در نشریات گروه « کشاورزی »

The main of this study was to trac the local migration of common carp in the southern  of Caspian Sea by comparing the  composition of essential and non-essential amino acids in muscle tissue. Therefore, 26 samples of Common carp from the nets of  beach sein cooprative companies was evaluated on the southern shores of the Caspian Sea in the fishing areas of Golestan, Mazandaran and Gilan provinces and control samples from Sijwal (Golestan) and Shahid Rajaei (Sari) zones reproduction centers was prepared. Fish sampeling held in 2017 and 2018. Protein extraction was performed by Isoelectric Solubilization/Precipitation point. Total amino acids were analysed by high-performance liquid chromatography (HPLC). The results showed that the samples of the three provinces were separated in terms of amino acid composition and there are probably three carp populations in the western, central and eastern parts of the Caspian Sea, but migration with short distances takes place in the border part of the three provinces. Comparison of amino acid levels in males and females showed that in most cases in males it was more than females but it was not significant. Also,very high levels of lysine in muscle tissue of Golestan province and its proximity to breeding centers can confirm the role of artificial reproduction in the reconstruction of carp stocks in Golestan province. The results of some tests indicated the proximity of Gilan and Golestan fish groups, which could be due to human intervention in the transfer of finger fish to the two provinces.

The aim of the present study was to extract gelatin from the skin of farmed great sturgeon at different temperatures, hydrolysis using Alcalase enzyme, and to measure molecular weight distribution of peptides, amino acid composition and antioxidant activity of hydrolysates.

After removing pigments and non‐collagenous proteins, defatting, and swelling of triple‐helix structure, gelatin was extracted at the temperatures of 50, 60, 70, and 80°C for 6h and then hydrolysed using Alcalase (E/S ratio of 1:20w/w) for 3h. Molecular weight distribution of peptides, amino acid composition and antioxidant activity of hydrolysates were determined in different models.

Degree of hydrolysis (DH) reached its maximum within the first 30min in all samples. The highest DH was in the 80°C. There were no significant differences among hydrolysates with regards to amino acid composition and peptide molecular weight distribution. Hydrolysates produced at the extraction temperature of 60°C showed that the content of small peptides (molecular weight<1kDa) and total amino acids (g/100g) were slightly higher compared to other samples. This could influence antioxidant activity. At higher extraction temperature of gelatin, the efficacy of hydrolysates in preventing the loss in total sulfhydryl groups content was decreased (p<0.05) while there was no effect on TBARS and surface hydrophobicity (p<0.05).

Extraction temperature of gelatin did not reveal a considerable effect on properties and antioxidant activities of the resulting hydrolysates and gelatin hydrolysates with antioxidant activity and rich in peptides with molecular weight less than 1kDa could be produced at 50°C.

Persian sturgeon (Acipenser persicus) is a valuable fish caught in the Caspian Sea. In this study, effect of frying, the most common cooking methods on nutritional properties of the Persian sturgeon fillet were investigated. The raw and fried samples were analyzed for Amino acid composition, protein and fat content, in vitro digestibility and nutritional parameters. The results showed that the in vitro digestibility of protein increased from 81.50% in raw sample to 100% in fried sample. The Amino acid composition in raw and fried sample was comparable which show that frying is not a destructive process on protein quality. PDCAAS for both samples for both ages group 10-12 years old and adults were 100 that indicates the high protein quality of Persian sturgeon fillet. The limiting amino acid for sturgeon fillet was metionin+cystein. Nutritional index increased after frying. In general, it can be observed that heating (frying) have a positive effect on the nutritional parameters of sturgeon fish fillet.