Optimization of ultrasound-assisted extraction of galactomannan from carob seeds “ceratonia siliqua L” and evaluation of their functional properties and in vitro anti-inflammatory activity

Abstract

ABSTRACT Ultrasound-assisted extraction (UAE) of galactomannan from the endosperm of ripe carob seeds (LBG.S3) was investigated through response surface methodology (RSM). The optimized UAE conditions were an extraction time of 40 minutes, a temperature of 45°C, and a solid-liquid ratio of 1:50 g/mL. Under these settings, the experimental yield of galactomannan was 47.53 ± 2.55%, which is closely aligning with the expected value of 49.78 ± 3.15%. The yield of galactomannan extracted from unripe carob seeds (LBG.S2) under the same optimal conditions was significantly higher 56.73 ± 2.76% (p < 0.05) than the yield of LBG.S3. The infrared spectroscopy (FT-IR) characterization revealed the existence of various functional groups in the spectrum of galactomannan extracted from unripe seeds, not found in LBG.S3. The galactomannan from ripe carob seeds exhibited superior functional properties, including solubility, emulsion and stability capacity, water and oil holding capacity, and viscosity, compared to LBG.S2. In vitro, tests demonstrated notable anti-inflammatory activity for both LBG.S2 and LBG.S3, as observed through the inhibition of bovine serum albumin (BSA) protein denaturation by heat and the membrane stabilization test. Carob galactomannan is a potential source of bioactive polysaccharides with anti-inflammatory and functional properties that can be used in the food and pharmaceutical industries.