Submitted to: Journal of Food Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 18, 1999
Publication Date: N/A
Interpretive Summary: Processing of oranges and grapefruit generates a large amount of byproducts such as peel, cores and fruit membranes. These residues are rich in soluble sugars which are partially recovered by liming and pressing operations. The resulting peel juice is evaporated to citrus molasses which is marketed as a cheap cattle feed ingredient. Broader utilization of citrus molasses is hampered by its dark color and extreme bitterness, caused by the presence of limonoids and phenolic compounds. We have investigated removal of objectionable components by adsorption on non-ionic macroporous resins and other adsorbents. Complete removal of bitter components has been achieved by a sequential adsorption on non-ionic macroporous resins followed by adsorption of residual phenolic compounds by activated carbon or anion exchanger beads. The resulting sweet syrups can serve as natural sweeteners in juice or soft drink products.
Technical Abstract: Citrus peel juice and molasses are extremely bitter and unpalatable byproducts of orange and grapefruit juice production. Major components of interest are soluble sugars, glucose, fructose and sucrose, which account for 60-70% of the dry solids. Our analyses indicate that the remaining components are suspended cell wall fragments, proteins, organic acids, mineral ions, phenolic compounds and polyols. We tested a preliminary purification sequence which removed a majority of bitter limonoids and phenolic compounds by adsorption on non-ionic, macroporous resins. Residual phenolic compounds were removed by adsorption on activated carbon or anion exchange resin, which also removed anions of organic and inorganic acids. Taste panel results suggested that debittered products could be acceptable for food uses.