Study on the Adsorption Properties of Sweet Orange Pulp Powder to Flavor Components of Orange Oil

To explore the mechanism of citrus pulp in absorption of flavor compounds, the composition, nitrogen adsorption-desorption isotherm of sweet orange pulp powder was tested, its microstructure was observed by scanning electron microscope (SEM), its adsorption capacity for flavor components in orange oil was tested and analyzed by gas chromatography-mass spectrometry (GC-MS). The results of component analysis showed that the sweet orange pulp powder was mainly composed of dietary fiber (51.87%±3.12%), protein (20.47%±0.58%), lipid (11.33%±1.60%), and starch (4.06%±0.59%). SEM observations and analysis of the nitrogen adsorption-desorption isotherm indicated that there were lots of wedges, slits and other irregular structures in the sweet orange pulp powder. The specific surface area of the sweet pulp powder was 2.98 m²/g. The results of GC-MS analysis showed that the sweet orange pulp powder had an obvious effect on the adsorption of typical aroma components of orange oil such as limonene, γ-terpinene, β-myrcene, β-phellandrene, linalool, octanal, nonanal, etc., especially of linear fatty aldehydes and oxygenated terpenoid, while had a relatively weak effect for bicyclic monoterpenoids such as α-pinene, sabinene. In summary, the wedges, slits formed by the cross-linking of the components in the sweet orange pulp powder were the key foundation for its absorption of flavor compounds. The results could provide a reference for the further development and utilization of sweet orange pulp.