Development of Intelligent Gelatin Films Incorporated with Sappan (Caesalpinia sappan L.) Heartwood Extract

Orapan Romruen (1) , Pimonpan Kaewprachu (2) , Thomas Karbowiak (3) , Saroat Rawdkuen (1, 4)

1 Food Science and Technology Program, School of Public Health, Curtin Health Innovation Research Institute, Curtin University
2 CMU - Chiang Mai University
3 PCAV - Physico-Chimie de l'Aliment et du Vin
4 School of Agro-Industry [Mae Fah Luang University - Thaïlande]

This study aimed to develop intelligent gelatin films incorporated with sappan (Caesalpinia sappan L.) heartwood extracts (SE) and characterize their properties. The intelligent gelatin film was prepared through a casting method from gelatin (3%, w/v), glycerol (25% w/w, based on gelatin weight), and SE at various concentrations (0, 0.25, 0.50, 0.75, and 1.00%, w/v). The thickness of the developed films ranged from 43 to 63 μm. The lightness and transparency of the films decreased with the increasing concentration of SE (p < 0.05). All concentrations of gelatin films incorporated with SE exhibited great pH sensitivity, as indicated by changes in film color at different pH levels (pH 1–12). Significant decreases in tensile strength were observed at 1.00% SE film (p < 0.05). The addition of SE reduced gelatin films’ solubility and water vapor permeability (p < 0.05). The chemical and physical interactions between gelatin and SE affected the absorption peaks in FTIR spectra. SE was affected by increased total phenolic content (TPC) and antioxidant activity of the gelatin film, and the 1.00% SE film showed the highest TPC (15.60 mg GAE/g db.) and antioxidant activity (DPPH: 782.71 μM Trolox/g db. and FRAP: 329.84 mM/g db.). The gelatin films combined with SE could inhibit S. aureus and E. coli, while the inhibition zone was not observed for E. coli; it only affected the film surface area. The result suggested that gelatin films incorporated with SE can be used as an intelligent film for pH indicators and prolong the shelf life of food due to their antioxidant and antimicrobial activities.

Mots clés: Caesalpinia sappan; color indicator; gelatin films; intelligent packaging; pH sensitivity

Domaines: Ingénierie des aliments

Orapan Romruen, Pimonpan Kaewprachu, Thomas Karbowiak, Saroat Rawdkuen. Development of Intelligent Gelatin Films Incorporated with Sappan (Caesalpinia sappan L.) Heartwood Extract. Polymers, 2022, 14 (12), pp.2487. ⟨10.3390/polym14122487⟩. ⟨hal-03712889⟩