Structures and compositions of the oil/wall interfaces and wall layers affected the properties of spray-dried fish oil powders

Abstract

Herein, 12 types of fish oil emulsions were used to prepare 12 types of spray-dried fish oil powders with three gelatins (positive fish gelatin, positive porcine skin gelatin, and negative bovine skin gelatin), two negative pectins (high and low methoxy pectin), and negative sodium starch octenyl succinate (SSOS). The powders consisted of microscale capsules with bi- or monolayer oil/wall interfaces, and monolayer wall layers. SSOS significantly decreased the bulk and tapped densities of the powders. All powders had low water activities (0.14–0.26). Gelatin/pectin and gelatin/pectin/SSOS powders had encapsulation efficiencies of 45.1 %–75.9 % and 70.1 %–93.0 %, respectively. The oxidative stability depended on the compositions of the powder wall layers. FG⁺/LMP/SSOS wall layer induced the lowest PV peak value (325 ± 15 mmol/kg oil). BSG⁻/HMP/SSOS wall layer induced the highest PV peak value (1273 ± 49 mmol/kg oil). The free fatty acid release percentages in the in vitro digestion system depended on the structures and compositions of oil/wall interfaces. FG⁺@LMP/SSOS interface induced the lowest FFA release percentage (33.9 % ± 1.7 %) and BSG⁻/HMP interface induced the highest FFA release (79.3 % ± 8.1 %). The results suggested useful information on the effect of oil/wall interfaces and wall layers on the preparation and properties of fish oil powders.