Nutritional value of raw and grilled Persian sturgeon fillets

Fish is an excellent protein source due to its valuable essential amino acid composition. Physical, chemical and thermal treatments applied during processing of food will influence both the nutritional value and functional properties of proteins. The purpose of this study was to determine the effects of grilling on the nutritional value of Persian sturgeon fish fillet. Fresh Persian sturgeon fillets were grilled using an automatic griller (Bq100, Delongi,Germany) for 20 min at 50-60 Hz frequency. The nutritional value of fresh fillets was determined on the basis of moisture, protein, fat, ash, and amino acid contents, while the nutritive value of cooked fillets was estimated using in vitro protein digestibility (IVPD) and various computed indices, including chemical score (CS), essential amino acid index (EAAI), biological value (BV), and protein digestibility-corrected amino acid score (PDCAAS). There were significant increases in protein, lipid, and ash contents (p<0/05) after grilling. In vitro digestibility of raw fillets was 81.50%, which increased to 93.46% after cooking. Glutamic and aspartic acids were amino acids with the highest contents, while cysteine and methionine were the limiting ones in both cooked and uncooked fillets. Grilling brought about improvements in the protein efficiency ratio, essential amino acid index, nutritional index, biological value, and chemical score. Finally, the protein digestibility- corrected amino acid score of both the cooked and uncooked samples and for both the 10-12 year-old and adult age groups was 100. The results indicate that grilling improves the nutritional value of Persian sturgeon fish fillets.