Polysaccharides extracted from pistachio external hull: Characterization, antioxidant activity and potential application on meat as preservative

In the present study, polysaccharides were isolated from pistachio (Pistacia vera L.) external hull, with a yield of 4.10 % (w/w). The crude polysaccharides were composed by carbohydrates (80.64 +/- 0.98 %), while protein (1.80 +/- 0.28 %), ash (6.32 +/- 0.26 %) and fat (0.04 +/- 0.005 %) contents were low. Structural characteristics were determined using FTIR spectroscopy and C-13 NMR spectroscopy. The results by thin layer chromatography showed that the carbohydrate fraction was mainly composed of rhamnose, glucose, galactose, mannose, xylose, arabinose, and galacturonic acid. Antioxidant activities of the crude polysaccharides were investigated by various antioxidant assays: DPPH radical-scavenging capacity (IC50 = 0.08 mg/mL), reducing power, beta-carotene bleaching inhibition (IC50 = 0.068 mg/mL), and ABTS assay. The application of crude pistachio hull polysaccharides on minced meat, as preservative, reduced the lipid oxidation during chilled storage for 9 days. The obtained results also showed significant improvement of meat color stability. Overall, these findings indicated that crude polysaccharides are worthy being developed as functional and bioactive components for the food and nutraceutical industries.