Biological properties of water-soluble polysaccharides and hemicelluloses from almond gum.

The aim of this work was to investigate the biological activities of almond gum polysaccharides (AGP) and almond gum hemicelluloses (AGH). Almond gum was first fractionated into AGP and AGH using hot water and alkaline solution, respectively. The antioxidant activities of both extracted polymers revealed interesting free radical scavenging activities through DPPH test (IC50 AGP=4mg/mL, IC50 AGH=6mg/mL), 2,2'-azinobis[3-ethylbenzthiazoline]-6-sulfonic acid (ABTS) radical scavenging activity test (% inhibition ABTS=40.53±1.99% and 87.14±1% for AGP and AGH, respectively), reducing power capacity (RPAGP=20mg/mL, RPAGH=1.1mg/mL), and ß-carotene bleaching inhibition (IC50AGP=18.5mg/mL, IC50AGH 0.8mg/mL). Antibacterial activities of both polymers were tested against pathogenic strains showing interesting growth inhibition. Moreover, AGP and AGH were also efficient to inhibit ACE; the angiotensin converting enzyme (at 1mg/mL, the ACE inhibitory activity was 75.81±1.53% and 90.86±2.47%, respectively). The results obtained in this study demonstrate the attractive biological properties of fractions obtained from almond gum and their potential to be used in numerous food and non-food applications.

Water-soluble polysaccharides and hemicelluloses from almond gum: Functional and prebiotic properties.

This paper describes the extraction of polysaccharides (AGP) and hemicelluloses (AGH) from almond gum by hot water and alkaline solution, respectively. Structural and functional properties of the extracted polymers were then determined. For this purpose, infrared spectroscopy was first used to characterize functional groups of both polymers. The molecular weights of AGP and AGH were then determined using high performance size exclusion chromatography, resulting in 5.72×106g/mol and 5.39×106g/mol, respectively. Monosaccharide composition of both polymers was assessed using gas chromatography. The analysis of the functional properties showed that AGP and AGH had high water-holding (11.36g/g and 6.3g/g, respectively) and fat-binding (5.35g/g and 2.7g/g, respectively) capacities, with good emulsion properties. The prebiotic properties of AGP and AGH were then evaluated using in vitro fermentation by Bifidobacterium adolescentis and Lactobacillus acidophilus. Both polymers showed suitability for in vitro fermentation, suggesting thus their prebiotic nature. The obtained results demonstrated the promising potential of AGP and AGH for different applications in food industry.