High Throughput Screening for Bioactive Volatile Compounds and Polyphenols from Almond (Prunus amygdalus) Gum: Assessment of Their Antioxidant and Antibacterial Activities

Abstract

This work was devoted to recover and identify bioactive polyphenols and volatile compounds from almond gum, which can be used as food additives and/or nutraceuticals. For this purpose, solvent extract was obtained after hydrodistillation of almond gum and the extracted volatiles were identified using gas chromatography-mass spectrometry (GC-MS). The major compounds were 9-octadecenoic acid (18.47%), 3-eicosene (17.04%), hexadecanoic acid (13.82%), benzyl salycilate (9.54%), 1-octadecene (7.28%), cetene (4.38%) and turmerone (3.2%). Subsequently, the antioxidant and antibacterial activities of the obtained extracts rich in polyphenols and volatile compounds were evaluated. Antioxidant activities showed 90.2% DPPH free radical inhibition and 206.8 µg ascorbic acid equivalents/mL using 50 mg/mL solvent extract, whereas the reducing capacity at 700 nm and 30 mg/mL was 0.8 ± 0.09. In addition, the antibacterial activities against 10 pathogenic strains were studied, showing the maximum growth inhibition, when using 50 mg solvent extract, against Enterobacter spp., Salmonella typhimurium, Listeria monocytogenes, Micrococcus luteus and Bacillus subtilis with diameter of inhibition zones of 30.4 ± 0.5, 19 ± 1.3, 27.5 ± 1.2, 28.2 ± 1.0 and 25.5 ± 0.3 mm, respectively. Practical Applications Nowadays, there is a growing demand for natural food additives, to replace the synthetic ones which have been restricted in many countries regarding their potential health-related issues. Therefore, bioactive volatile compounds from almond gums may play crucial roles as antioxidants, food pathogen inhibitors, shelf-life enhancers, texture promoters, organoleptic agents and toxicity-reducing agents for being used during processing and storage of food products. Thus, the recovery of these compounds constitutes a great challenge.