Properties of steam exploded orange peel fiber as compared to commercial citrus fiber and peel powders†

Abstract

Citrus is a major fruit crop in the state of Florida. Most of which, is processed into juice. The remaining peel and membrane are converted to byproducts with little value. However, the properties of citrus peel and membrane make it an excellent candidate as a high value, gluten free fiber. Steam explosion (STEX) has been used as a treatment method on citrus peel and membrane in the past, but the properties of the resulting fiber have not been studied. In this research, we compared STEX citrus fiber to a commercial citrus fiber and powders. A novel STEX process was used to produce twelve steam dietary fibers from orange juice processing side streams using a combination of temperature (130, 150, 170 degrees Celsius) and hold time (1, 2, 4, 8 minutes). The STEX orange fibers were characterized and compared to commercial citrus fiber and peel powder products. Desirable properties obtained by steam treatment did not lie with a single temperature and hold time combination. STEX produced fibers with far greater water retention and water swelling capacities as compared to the commercial fiber and peel powder products. STEX fibers with median sample diameters and insoluble, soluble, and total dietary fiber values similar to those of the commercial fiber product were possible. This work shows that STEX can serve as a scalable method for converting orange juice processing side streams into fiber products with properties similar to commercial citrus fiber products.