Functional characterization of basil (Ocimum basilicum L.) seed mucilage

Abstract

Basil seed mucilage (BSM- 20.49%) was extracted from basil seeds to investigate its functional, thermal, rheological, and morphological properties. BSM was purified into basil seed gum (BSG- 18.75%) and further fractionated into alcohol soluble fraction (F1- 6.80%), alcohol insoluble fraction (F2- 13.70%), and protein free fraction (F3- 18.50%). Total dietary fibre content observed for basil seed mucilage was 98.50%. Analysis of functional properties showed higher values for water absorption capacity (35.16–38.96 g/g), and emulsification capacity (101–115.55 g/g). However, lower values were found for protein solubility (0.06–0.59%), oil absorption capacity (5.40–17.38%), foaming capacity (41.42–50%) and syneresis (1.27%). Hydration of mucilage in salt solutions (KCl, NaCl, and CaCl2) revealed that salts sufficiently reduced the hydration capacity. Cholesterol binding (3.49–3.56%), bile-acid binding (5.85–57.35%) and α-amylase inhibitory activity (55.20–55.34%), were also investigated. Thermal measurements involved the study of glass transition temperature (Tg) by differential scanning calorimetry (DSC). Results for Tg indicated stability at high temperatures. Values for Tg and heat capacity were in the range of 122.5–148.3 °C and 9.44–29.89 J/g, respectively. Samples were analysed for visometry using rapid visco analyzer (RVA). Results showed a final viscosity of 190–714 cP. Rheological measurements showed shear thinning behaviour and an increase in storage and loss modulus on increasing angular frequency. Scanning electron micrographs showed a strong fibril-network which depicted gel-like characteristics.