Effect of chitosan nano-emulsion and fennel essential oil on antioxidant activity and biochemical contents of black mulberry (Morus nigra L.)

The use of edible coatings in increasing storage life and maintaining the quality of horticultural products is considered as a new idea in modern agriculture. Black currant fruits were treated with fennel essential oil at 0, 250, 500 and 750 μL/L, and then treated with nano emulsion of chitosan at 0, 2500 and 5000 mg/L, and stored at 4±1°C with 85-95% R.H. The anthocyanin concentration, antioxidant activity, phenylalanine ammonia-lyase (PAL) enzyme activity, pH, total soluble solids and titratable acidity were evaluated on the third, sixth and ninth days of storage. The highest anthocyanin content was recorded in fruit treated with 500 μl/L essential oil and 5000 mg/L chitosan nano emulsion on day 3th. The highest PAL enzyme activity was seen in fruit treated with the combination of 750 μl/L of fennel essential oil and 5000 mg/L of chitosan nanoemulsion on the 9th day. In addition, the greatest effect on antioxidant activity was seen on day 9th of storage in combination treatment of 750 μl/L essential oil and 5000 mg/L of chitosan nano emulsion, and it can be said that all treatments were effective in increasing antioxidant activity of the fruit. In general, the results of this research indicate the effectiveness of the studied treatments in significantly increasing the storage life and maintaining the quality parameters of black mulberry fruit during storage.