Widya Dwi Rukmi Putri, Rizka Aulia Rahma, Ata Aditya Wardana, Zahratul Hasanah Wijayanti, Mokhamad Nur, Ahmad Zaki Mubarok
Red pitaya, one of Indonesia’s most abundantly produced horticultural products, offers a sustainable solution for reducing waste by utilizing its peel in the production of an edible film. The edible film was prepared from red pitaya peel (RPP) flour and Kappa Carrageenan (K-Carr). Konjac glucomannan (K) was added to improve the brittleness and compactness of the film specimens. The central composite design (CCD) of the response surface methodology (RSM) evaluated the effects of two variables: the proportion of RPP and K-Carr. The physical, mechanical, and thermal properties of RPP/K-Carr film were profoundly influenced by the proportion of K-Carr (0.29–1.71% w/v), and RPP powder (0.4–1.1% w/v). The optimized proportions of 0.50% (w/v) RPP powder and 1.28% (w/v) K-Carr resulted in the production of edible film with a tensile strength (TS) value of 7.75 MPa, elongation at break (EAB) of 103%, thickness (T) of 99.8 μm, color: brightness (L: 72.5), redness (a*: 13.9), yellowness (b*: 0.5), opacity (O) of 4.56 mm−1, water solubility (WS) of 81%, water absorption capacity (WAC) of 863%, and water vapor transmission rate (WVTR) of 7.56 g/m2/h. The addition of K-Carr to RPP film can improve its thermal properties. All the obtained data is corroborated by Fourier transform infrared (FTIR), scanning electron microscopy (SEM), and thermogravimetric analysis (TGA) results. Graphical Abstract: (Figure presented.) © The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature 2023.
Department of Agricultural Product Technology, Faculty of Agricultural Technology, University of Brawijaya, Malang, 65145, Indonesia; Food Science Study Program, Faculty of Agricultural Technology, University of Brawijaya, Malang, 65145, Indonesia; Food Technology Departments, Faculty of Engineering, Bina Nusantara University, Jakarta, 11480, Indonesia