Abstract:

Konjac glucomannan (KGM) as a film-forming agent and Chinese traditional herbal extract as an antibacterial agent were mixed to form a compound coating agent. To evaluate the fresh-keeping effect of the compound coating agent, the weight loss rate, decay index and harness of ‘Gala’ apples treated with the compound coating agent were determined after 108-day storage at (0 ± 1 )℃. To achieve an optimal compromise among low weight loss rate, low decay index and high firmness, the optimal formulation of the compound coating agent and the optimal treatment time were investigated using orthogonal array design. Results showed that the optimal compound coating agent formula was that 1 L of the finished compound coating agent contained 3 g of KGM, water extract from 6 g of Flos Caryophyllata, 0.3 mL of Tween-20 and the optimal treatment time was 20 min. The treatment with the compound coating agent delayed the decrease of fruit firmness and the degradation of titratable acids, total soluble solids and vitamin C, postponed the appearance of respiratory peak and ethylene release peak, lowered the values of respiratory peak and ethylene release peak, weight loss rate and decay index.

Key words: konjac glucomannan, Chinese traditional herbal extract, apple, coating agent, storage quality