Chemical and Sensory Characterization of Orange (Citrus sinensis) Pulp, a by-Product of Orange Juice Processing Using Gas-Chromatography-Olfactometry

Volatile composition of commercial orange pulp (from Brazil and Florida, U.S.A.) was analyzed by gas chromatography-mass spectrometry (GC-MS) and GC-Olfactometry (GC-O). In both samples 72 volatiles were detected, of which 58 were identified. Odor-active compounds with a high frequency of detection (≥5 out of 9) or intensity characterizing the aroma of sweet orange pulp were monoterpene hydrocarbons (α-pinene, β-pinene, β-myrcene, α-phellandrene, 3-carene, α-terpinene and limonene), ketones (1-octen-3-one, carvone, (E)-β-damascenone and β-ionone), esters (ethyl-2-methyl butanoate and ethyl hexanoate), aldehydes (methional and octanal), alcohols (linalool and 1-octanol) and 3 unidentified compounds. A few differences in the odor-active volatiles between orange pulp samples were perceived, which might be due to cultivar, growing and processing conditions, but overall, the chemical composition of the two samples was similar. Sensory data described both sweet orange pulp samples with descriptors for orange odor and flavor including orange peel and fruity-non-citrus flavor, sweet and sour taste. Practical Applications Orange pulp is used in the beverage industry to add texture and mouthfeel. It is also added to orange juice for consumer appeal to make it more “natural.” This study characterized the flavor of orange pulp. Orange pulp consisted of yellow–orange floating intact cells. Pulp added to a sugar-acid solution (5% pulp, 10.5% sucrose and 0.25% citric acid) imparted an orange, fruity and fresh flavor. Information from this study on sweet orange pulp flavor will be useful for orange juice processors and beverage manufacturers.