Antioxidant pectins from eggplant (Solanum melongena) fruit exocarp, calyx and flesh isolated through high-power ultrasound and sodium carbonate. (30th June 2023)

• Record Type: Journal Article
• Authors: Higuera-Coelho, Ricardo A.; Basanta, Maria F.; Rossetti, Luciana; Pérez, Carolina D.; Rojas, Ana M.; Fissore, Eliana N.
• Is Part Of: Food chemistry. Volume 412(2023)
• Publication Date: 2023-06-30
• Subjects: Agro-industrial eggplant discards -- High-power ultrasound -- Antioxidant pectins -- Polyphenols -- Carotenoids -- Skim milk protein photo-oxidation; Food -- Analysis -- Periodicals; Food -- Composition -- Periodicals; 664
• DOI: 10.1016/j.foodchem.2023.135547
• Languages: English
• ISSNs: 0308-8146

Abstract

Highlights: Eggplant fruit peel + calyces (PC) and flesh (Mes) are investigated as pectin sources. High-power ultrasound (10 min-10:200 g/mL powder:water) + 0.1 M Na2 CO3 gave best yield. High recoveries of uronic acid (UA, 80.25–93.8 %) were achieved from PC and Mes. Pectins were homogalacturonans (65 % UA) of low degree of methylation and acetylation. Pectins carrying phenolics + carotenoids preserved milk protein groups from oxidation. Abstract: Dried and milled eggplant fruit peel and calyces (PC) and mesocarp, placenta and core (Mes) were utilized as natural sources of valuable chemicals. Pectins were extracted with 0.1 M Na2 CO3 (1 h; 23 °C). A high-power ultrasound (US) pretreatment (10 min net time; 12.76 W/cm 2 power intensity) in 10:200 (g/mL) powder:water ratio led to the lowest solvent and energy consumptions after the subsequent 0.1 M Na2 CO3 stirring, permitting the highest recoveries of uronic acid (UA) from PC and Mes (80.25 and 93.8 %, respectively). Homogalacturonans (>65 % w/w UA) of low degree of methylesterification, of acetylation, and 90, 214–138, 184 Da molecular weights with low polydispersity (≈1.32–1.40) were obtained. They included released ferulate (≈3.5 mg/100 g) esterified pectins. Antioxidants (caffeoylquinic acid, putrescine and spermidine derivatives, β-carotene, lutein) gave additional technological value to their thickening effect as pectins protected tryptophan, tyrosine, alkyl side chains and sulfhydryl of skim milk proteins from UV-C photo-oxidation.