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This work aimed at investigating the potential of almond gum as low cost adsorbent for the removal of the cationic dye; malachite green from aqueous solutions. Almond gum was first analyzed by scanning electron microscopy (SEM) and Fourier transforms infrared spectroscopy (FTIR), and then the adsorption behavior was studied in batch system. The effects of the adsorption parameters (adsorbent dose, pH, contact time, particle size, initial dye concentration, temperature and agitation) on the dye removal have been studied. Adsorption equilibrium and isotherms were evaluated depending on temperature using the isotherms of Freundlich, Langmuir, and Tempkin. The obtained result showed that both Langmuir and Freundlich models were adapted to study the dye sorption. The maximum adsorption capacities were equal to 172.41mg/g, 181.81mg/g, and 196.07mg/g at 303.16K, 313.16K, and 323.16K, respectively. The kinetics of sorption were following the pseudo-second order model. The thermodynamic changes in enthalpy (ΔH), entropy (ΔS), and free energy (ΔG) indicated that the adsorption of malachite green at the surface of almond gum is endothermic and occurs spontaneously. Desorption experiments were conducted to regenerate almond gum, showing great desorption capacity when using HCl at pH 2., (Copyright © 2017 Elsevier B.V. All rights reserved.)

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 (IC 50 AGP=4mg/mL, IC 50 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 (RP AGP =20mg/mL, RP AGH =1.1mg/mL), and β-carotene bleaching inhibition (IC 50AGP =18.5mg/mL, IC 50AGH 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., (Copyright © 2016 Elsevier B.V. All rights reserved.)

In recent years, great interest has been devoted to the development of new applications for natural gums. These molecules were used for a variety of purposes since they are chemically inert, non-toxic, less expensive, biodegradable and widely available. They represent one of the most abundant raw materials used not only in commercial food products, but also in cosmetic and pharmaceutical products. Plant gums take their advantages compared to other gums (e.g., from animal and microbial sources) mainly because of their acceptance by consumers. Despite of the well description given in literature for the features of plant gum exudates, there is a lack distinguishing the different families that are producing gums, and their potential applications. Among these gums, the ones produced by Rosaceae family (e.g., almond, apricot, cherry, peach, and plum plants) have been taking special attention. Thus, the aim of this review is to report the recent advances in Rosaceae gum exudates. An emphasis is given for the formation mechanisms of these gums, their chemical composition, functional properties and structures, beneficial properties, as well as their food/non-food applications., (Copyright © 2016 Elsevier B.V. All rights reserved.)