Preliminary Study on the Use of Inexpensive, Unsaturated Vegetable Oils as Surface Sealants in the Long- and Short-Term Storage of Syrup Feedstocks from Sweet Sorghum

Abstract

For large-scale manufacture of biofuels and bioproducts from sweet sorghum (Sorghum bicolor L. Moench) biomass feedstocks, the long-term storage of 65 Brix (% dissolved solids) syrups is urgently needed for year-round supply and operation, efficient transport, and acceptable end-product yields. Shorter-term storage of lower Brix syrups is also required for direct fermentation. Three unsaturated, inexpensive, and readily available vegetable oils were preliminary evaluated as surface sealants (0–1.7 cm-deep layers) on stored 65 Brix sweet sorghum syrups at 25 °C. Compared to no sealant, soy bean, canola, and sunflower oil sealants preserved the 65 Brix syrups for up to 1 year. There was generally a strong surface oil layer effect, with 1.7 cm-deep layers providing the most significant (P < 0.05) protection. Soy bean oil (up to 0.5 cm) did not preserve 28 Brix syrups against severe microbial deterioration over 7 days of storage. More replicated studies are now needed to validate the results.