Nutritional Composition, Textural, Histological and Structural Properties of Giant Sea Catfish (Arius thalassinus) Roe as Affected by Size

Fish roe is consumed in different forms, e.g., caviar. The large and firm spherical roe from giant sea catfish (GSC, <i>Arius thalassinus</i>), which have a high price, are popular in some countries, like Thailand. However, the information on their nutrition and properties is scarce. Roe of different sizes from GSC, including medium (GSC-M), large (GSC-L), and extra-large (GSC-XL) sizes, were rich in protein (29.52-32.70%), fat (4.07-5.65%), and essential amino acids, particularly leucine and lysine. Vitelline was the major protein in GSC roe. Polyunsaturated fatty acids, including eicosapentaenoic acid and docosahexaenoic acid, were abundant, although GSC-M showed lower PUFA content (21.91%) than GSC-L and GSC-XL (25.56-25.94%). No significant differences in texture property were found between sizes, despite the microstructural and histological differences. Larger voids and strands were found with augmenting size, while GSC-L showed greater membrane thickness (133.55 µm). FTIR spectra confirmed the presence of peptide and ester bonds associated with proteins and triacylglycerols, respectively. GSC-L had the highest cholesterol content (651.2 mg/100 g), whereas GSC-M showed the highest α-tocopherol level (1.64 mg/kg). Phosphorus was the dominant mineral (3473-3894 mg/kg), followed by calcium and other minerals. Hence, the roe from GSC, regardless of size, possess high nutritive value and could be used as a wholesome marine food or functional ingredient.