Physicochemical, microstructural and functional characterization of dietary fibers extracted from lemon, orange and grapefruit seeds press meals

• Published in: Bioactive carbohydrates and dietary fibre 2017-07, Vol.11, p.9-17
• Main Authors: Karaman, Elif, Yılmaz, Emin, Tuncel, N. Barış
• Format: Article
• Language: English
• Subjects: Dietary fiber; Functional properties; Grapefruit seed; Lemon seed; Orange seed
• ISSN: 2212-6198; 2212-6198
• DOI: 10.1016/j.bcdf.2017.06.001

The aim of this study was to characterize dietary fibers extracted from defatted press meals of lemon, orange and grapefruit seeds. After an ultrasound-assisted aqueous extraction, the fibers were investigated for proximate composition, soluble/insoluble fiber contents, color, viscosity, degradation temperature and enthalpy, near infrared (NIR) spectra, X-ray diffraction patterns, scanning electron microscopy (SEM) images, and functional (water and oil holding capacity, swelling capacity) properties. The fibers contain 2.0–3.45mg/g phytate, 1.36–2.26% ash, 4.95–7.95% soluble fiber, 75.95–82.24% insoluble fiber. NIR spectra showed the presence of cellulose and lignin as main components with corresponding bands. Major peak at 22–23Å X-ray diffraction also indicated presence of cellulose crystals. Crystallinity values of 33–80% were measured. SEM images showed the microfibrillar structures present in the samples. Water and oil holding capacities (4.79–7.76g/g and 3.44–4.19g/g), and swelling capacities (22.44–24.55mL/g) proved that the fibers are functional, and especially good for oil containing foods. The utilization of these new fiber sources would be important in terms of by-product valorisation. The data presented in this study may provoke further studies and/or applications of these new dietary fibers. [Display omitted]