Effect of CaO Treatment on Quality Characteristics and Storage of Mulberry (Morus alba L.) Fruits in Yecheon

The effects of aqueous calcium oxide (CaO) treatment on the quality characteristics and shelf life of mulberry (Morus alba L.) were investigated. Mulberry fruits were immersed in 0, 0.5, 1, and $2g{\cdot}L^{-1}$ CaO solutions for 0, 1, 3, 6, and 12 min. Mulberries were then rinsed with potable tap water for 1 min and stored at $-1^{\circ}C$ for 14 days. CaO treatment was effective at promoting the retention of titratable acid, pH, and ascorbic acid as well as total flavonoid contents. CaO concentration and treatment time were significant factors affecting the sensory qualities of the fruits, including off-odor, flavor, and texture. For shelf life determinations, the total bacterial count was reduced by CaO treatment so that the samples treated with $1g{\cdot}L^{-1}$ CaO for 12 min had bacterial levels at 14 days comparable to those of the control at 4 day, and no coliform group was detected after CaO treatment. These results indicate that calcium oxide treatment is a promising approach for the preservation of mulberry fruit.