Abstract:

The essential oils from clove, garlic, ginger and pepper were separately microencapsulated using a mixture of gum arabic and maltodextrin as wall material and a mixture of Span 80 and Tween 20 as emulsifier to prepare solid preservatives. The optimal ratio of Span 80 to Tween 20 was determined to be 1:2. The key process conditions including maltodextrin-to-gum Arabic ratio, emulsifier amount, core material-to-wall material ratio and CaCl2 amount for the microencapsulation of clove, garlic, ginger and pepper essential oils were optimized using orthogonal array design. Cucumbers were treated with each of four microcapsules obtained under optimized conditions, fumigated in the presence of 0.06% 1-MCP for 2 days and stored at room temperature for 30 days, and the percentage of rotten fruits, weight loss, respiratory intensity, total sugar content and chlorophyll content of cucumbers were determined at 6-day intervals during storage. It was found that microencapsulated clove, garlic, ginger and pepper essential oils all presented remarkable fresh-keeping effect on cucumbers and that the fresh-keeping effect of microencapsulated clove essential oil was the best, followed by microencapsulated pepper and garlic essential oils.

Key words: natural volatility, vegetable storage, solid preservative