Selective adsorption of volatile compounds of oyster peptides by V-type starch for effective deodorization

Abstract

Oyster peptides extracted from oysters have strong off-odors, which hinders consumer acceptance. The “empty” V-type starches (V6a, V6h, V7a, V7h, V8a, and V8h) prepared from high amylose maize starch were used as adsorbents to improve the flavor of oyster peptides. The total adsorption rates measured through headspace gas chromatography mass spectrometry (HS-GC-MS) follow the order of V6a > V7a > V6h > V7h > V8a > V8h. Moreover, the V-type starches with different structures exhibit adsorption selectivity. The V6- and V7-type starches with a smaller cavity size show selective adsorption capacity for alcohols, acids, ketones and other similar classes of volatile compounds, while the V8-type starches with a larger cavity selectively adsorb amines. In addition, successful preparation of “empty” V-type starches were confirmed through X-ray diffraction (XRD), and the inclusion complexes (ICs) between V-type starches and volatile compounds of oyster peptides were characterized by Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), and differential scanning calorimetry (DSC). It was found that the O/C ratio of V6a-ICs, V6h-ICs, and V7a-ICs increased, while that of V7h-ICs, V8a-ICs, and V8h-ICs decreased after the deodorization. Pearson's correlations indicated that the adsorption rates of aldehydes, alcohols, ketones, and alkanes have a significant negative correlation with temperature range (ΔT) and enthalpy change (ΔH). While a significant positive correlation was observed between the ratio of peak intensity at 1047/1022 cm−1 and the amine adsorption rate. These results suggested that V-type starch can improve the flavor of aquatic products effectively.