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ARS Home » Southeast Area » Fort Pierce, Florida » U.S. Horticultural Research Laboratory » Citrus and Other Subtropical Products Research » Research » Publications at this Location » Publication #418959
Research Project: Advancing Value-Adding Technologies for Juice Processing Co-Products

Location: Citrus and Other Subtropical Products Research

Title: Production of pectic oligosaccharides from citrus peel via steam explosion

Author
item Martorano, Toni-Ann
item Ferguson, Kyle
item Cameron, Randall - Randy
item Zhao, Wei
item Hotchkiss, Arland
item Chau, Hoa - Rose
item Dorado, Christina

Submitted to: Foods
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/15/2024
Publication Date: 11/22/2024
Citation: Martorano, T.M., Ferguson, K.L., Cameron, R.G., Zhao, W., Hotchkiss, A.T., Chau, H.K., Dorado, C. Production of pectic oligosaccharides from citrus peel via steam explosion. Foods. 13(23):3738. 2024. https://doi.org/10.3390/foods13233738.
DOI: https://doi.org/10.3390/foods13233738

Interpretive Summary: Commercial citrus juice production yields tons of peel and membrane that are converted to low value animal feed, molasses, and peel oil. While this addresses disposal, it results in little to no profit for producers. Recently, pectin fragments or pectic oligosaccharides (POS) have been reported to have biological activity or pharmaceutical properties. In this study we investigated POS from the remnants of commercial citrus juice processing after steam explosion treatment (STEX). Characterization of the POS from STEX showed that these samples are made up of mostly galacturonic acid, the major building block of citrus pectin. Therefore, the citrus juice processing waste stream has the potential to be converted to a high value product using STEX.

Technical Abstract: Steam explosion (STEX) of peel from commercially juice-extracted oranges was used to convert peel pectin into pectic oligosaccharides (POS). Surprisingly uniform populations, based on the polydispersity index (PDI; weight average molecular weight (Mw)/number average molecular weight (Mn)), of POS were obtained from Citrus sinensis var. Hamlin and var. Valencia. POS from Hamlin and Valencia peel peak 2 had a PDI of (1.23 ± 0.01, 1.24 ± 0.1), respectively. Mw for these samples were 14.9 ± 0.2 kDa for Hamlin, and 14.5 ± 0.1 kDa for Valencia, respectively. The degree of methylesterification (DM) was 69.64 ± 3.18 for Hamlin, 65.51 ± 1.61 for Valencia 1 and 65.11± 2.30 for Valencia 2. The composition of the recovered POS was dominated by galacturonic acid, ranging from 89.1% to 99.6% of the major pectic sugars. Only the Hamlin sample had a meaningful amount of rhamnose present, indicating the presence of some RG I domain. Even so, the Hamlin’s sample Degree of Branching (DBr) was very low (2.95).