International Journal of Biological Macromolecules 72 (2015) 472–479 Contents lists available at ScienceDirect International Journal of Biological Macromolecules j ourna l ho me pa g e: www.elsevier.com/locate/ijbiomac Structural data and biological properties of almond gum oligosaccharide: Application to beef meat preservation Fatma Bouaziz a , Claire Boisset Helbert b , Molka Ben Romdhane a , Mohamed Koubaa a , Fatma Bhiri a , Fatma Kallel a , Fatma Chaari a , Dorra Driss a , Laurine Buon b , Semia Ellouz Chaabouni a,c,∗ a Enzyme Bioconversion Unit (04/UR/09-04), National School of EngineeringP.O. Box 1173-3038, Sfax University, Tunisia b Service de Chromatographie Purification et analyse de polysaccharides CERMAV-CNRS, 601 rue de la Chimie 38041 Grenoble cedex 9, France c Common Service Unit of Bioreactor coupled with an ultrafilter, National School of Engineering P.O. Box 1173-3038, Sfax University, Tunisia a r t i c l e i n f o Article history: Received 22 June 2014 Received in revised form 24 August 2014 Accepted 26 August 2014 Available online 6 September 2014 Keywords: Oligosaccharides Antioxidant Antimicrobial a b s t r a c t Enzymatic hydrolysis of almond gum generates low molecular weight oligosaccharides (OAG) with a yield of 33.5%. The generated oligosaccharides were purified and identified. OAG analyses show that the most prominent residues were galactose and arabinose with traces of xylose, rhamnose, glucose and mannose. The glycosyl linkage positions were analyzed using gas chromatography–mass spectrometry showing a main chain composed of galactose units [→3)-Gal-(1→] branched mainly with arabinose residues [Ara- (1→]. The antioxidant and antimicrobial activities of OAG were investigated. As regards the in vitro antioxidant activities, the OAG showed a high total antioxidant activity (347 g ascorbic acid equiv- alent/mL), an important DPPH (1,1-diphenyl-2-picrylhydrazyl) scavenging activity (IC 50 = 0.64 mg/mL) and a high reducing capacity (RP0.5AU = 3.6 mg/mL). Furthermore, OAG had a high antimicrobial activity against Salmonella thyphimirium, Bacillus cereus, Actinomycetes sp, Klebsiella pneumoniae, Escherichia coli, Alternaria alternate and Candidat albicans. Finally, OAG efficiency was tested using 0.5%; 0.75% and 1% concentrations in beef meat preservation. Microbial growth and lipid oxidation were monitored during 9 days at 4 ◦ C. The results showed significant inhibitions (p < 0.05) of lipid oxidation and microbial growth in ground beef meat containing OAG. © 2014 Elsevier B.V. All rights reserved. 1. Introduction Food quality is defined in terms of consumer acceptability: flavor, color, texture characteristics and nutritional value. Many foodstuffs such as meat and meat products contain unsaturated fatty acids that are responsible for food deterioration and shelf- life reduction [1]. For this reason, efforts to reduce oxidation have been increased. Most often, the best strategy is the addition of antioxidants [2]. Moreover, some antioxidants may additionally exhibit antibacterial activities [3,4]. To deal with lipid oxidation issues and microbial growth in meat products; either synthetic or natural food additives are commonly used in the meat industry [5–8]. Regarding the health hazard and the toxic effects associated with numerous synthetic antioxidant molecules such as butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT), as well ∗ Corresponding author. Tel.: +216 74 67 53 31; fax: +216 74 27 55 95. E-mail address: semia.chaabouni@enis.rnu.tn (S.E. Chaabouni). as their restriction in some countries [9–11], their replacement by natural molecules has been widely investigated. Natural antioxi- dants are safe, can protect the human body from free radicals and delay the progress of many chronic diseases [12,13]. Antioxidants can prevent lipid peroxidation by scavenging initiating radicals, breaking chain reaction, decomposing peroxides, decreasing local- ized oxygen concentrations and binding chain initiating catalysts, such as metal ions [14]. Recently, the antioxidant and antimicrobial activities of some polysaccharides and oligosaccharides have been reported [15–17]. Chitosan and chitooligosaccharides were proven to have antibacte- rial and antioxidants activities [18], oligosaccharides isolated from roots, flowers and leaves of Panax ginseng showed strong antioxi- dant activities [19]. Although the investigation of antioxidant and antimicrobial activities of some oligosaccharide gum derivatives (e.g. peach gum oligosaccharides [20]), the biological activities of almond gum polysaccharides and their oligosaccharide derivatives remain undetermined. In fact, almond trees are widely available in Tunisia as well as throughout the Mediterranean countries [21] http://dx.doi.org/10.1016/j.ijbiomac.2014.08.044 0141-8130/© 2014 Elsevier B.V. All rights reserved.