Optimizing decolorization and deodorization to remove pigments and fishy odors while preserving antioxidant activity in Asian swamp eel (Monopterus albus) hydrolysate

The objective of this study was to develop an efficient method for decolorizing and deodorizing Asian swamp eel (ASE) hydrolysate. At an activated carbon (AC) dosage of 0.5 % and pH 4.0, insoluble peptides from trichloroacetic acid (TCA), which have poor antioxidant activity, were effectively removed. Meanwhile, other nitrogenous fractions with better antioxidant activity were retained, achieving a decolorization rate of 74.02 ± 0.38 %. Orthogonal partial least squares discriminant analysis (OPLS-DA) successfully distinguished the solid phase microextraction gas chromatograph-mass spectrometery (SPME-GC–MS) results of samples treated with different deodorization methods (ASE stock hydrolysate, AC treatment, AC + complex bacteria, AC + yeast, and AC + cyclodextrin). A total of 22 differential volatile compounds with variable importance projection (VIP) values greater than 1 were identified. The combination of AC treatment and cyclodextrin encapsulation effectively removed undesirable odors, enhancing the sensory quality and market competitiveness of the final product.