Antioxidant and flexible bioplastics based on microwave-assisted extracted coffee fruit cascara pectic polysaccharides

abstract

Pectic polysaccharides with film-forming ability are often recovered from renewable agrifood by-products through solid-liquid extraction (SLE). Targeting an organic solvent-free approach, in this work, it is hypothesized that pectic polysaccharides of interest for bioplastics development can be recovered by microwave-assisted extraction (MAE) and purified by ultrafiltration. Coffee fruit cascara (CFC) was used as raw material. MAE of CFC-derived pectic polysaccharides was carried out at 120 degrees C at different times (2 min, 5 min, and 10 min). A 3times (1 h each) sequential SLE with 2% acetic acid under reflux at atmospheric pressure was also performed. High molecular weight (HMW) extracts obtained by MAE for 2 min (HMW_MAE 2 ') and by SLE for 1 h (HMW_SLE1), composed of 60 mol% and 54 mol% uronic acids with 18% and 17% methyl-esterification, and 7% and 8% acetylation, respectively, were selected for bioplastics development. HMW_MAE 2' originated slightly transparent, dark brown, hydrophilic (ca. 32 degrees water contact angle), and antioxidant (90% ABTS center dot+ inhibition after 5 min) bioplastics, similar to HMW_SLE1-derived materials, but 10-fold more stretchable (20% and 2% elongation at break, respectively). Therefore, MAE followed by ultrafiltration showed to be a fast and clean strategy to recover low methyl-esterified CFC pectic polysaccharides with the ability to develop antioxidant and flexible bioplastics.

keywords

STARCH-BASED FILMS; BY-PRODUCTS; CELL-WALL; ACETYLATION; METHYLATION; PEEL

subject category

Science & Technology - Other Topics; Engineering; Environmental Sciences & Ecology

authors

Oliveira, G; Petronilho, S; Kapusniak, K; Kapusniak, J; del Castillo, MD; Coimbra, MA; Ferreira, P; Passos, CP; Gonçalves, I

Groups

G2 - Photonic, Electronic and Magnetic Materials
G4 - Renewable Materials and Circular Economy

Projects

CICECO - Aveiro Institute of Materials (UIDB/50011/2020)

CICECO - Aveiro Institute of Materials (UIDP/50011/2020)

Associated Laboratory CICECO-Aveiro Institute of Materials (LA/P/0006/2020)

Projeto de Investigação Exploratória: Paula Ferreira (IF_Paula Ferreira)

acknowledgements

This work received FCT/MCTES (PIDDAC) funding through CICECO-Aveiro Institute of Materials (UIDB/50011/2020; UIDP/50011/2020; LA/P/0006/2020) and LAQV-REQUIMTE (UIDB/50006/2020; UIDP/50006/2020; LA/P/0008/2020) . FCT is also thanked for the Investigator program (PF, IF/00300/2015) , Individual Call to Scientific Employment Stimulus (IG, https://doi.org/10.54499/CEECIND/004 30/2017/CP1459/CT0032, & CPP, https://doi.org/10.54499/CEE CIND/00813/2017/CP1459/CT0053) , and post-doctorate (SP, SFRH/BPD/117213/2016) and Ph.D. (GO, SFRH/BD/143191/2019) grants. GO and SP also thank the Polish National Agency for Academic Exchange for the attribution of a PROM Programme accomplished at Jan Dlugosz University (Czestochowa, Poland) . The Programme is co-financed from the European Social Fund within the Operational Programme Knowledge Education Development, the non-competition project entitled "International Scholarship Exchange of Doctoral Students and Academic Staff", realized within the Action specified in the application for funding no. POWR.03.03.00-00-PN13/18. The authors also thank SUPRACAF E S.A. (Mostoles, Madrid, Spain) for providing CFC.r Programme Knowledge Education Development, the non-competition project entitled "International Scholarship Exchange of Doctoral Stu-dents and Academic Staff", realized within the Action specified in the application for funding no. POWR.03.03.00-00-PN13/18. The authors also thank SUPRACAF E S.A. (M ostoles, Madrid, Spain) for providing CFC.