Abstract:In order to improve the preservation of blueberries, antibacterial composite films containing different concentrations of Houttuynia cordata extracts were prepared in this study. The tensile strength, elongation at break, light transmittance, water vapor transmittance and antibacterial rate of the films were examined. The blueberry fruits were coated with a film and stored under refrigeration conditions (at 4 ℃), and the indices such as firmness, weight loss, total soluble solids (TSS), titratable acid (TA), content of anthocyanins, ascorbic acid (Vc) content, malondialdehyde (MDA) content and polyphenol oxidase (PPO) activity were determined.. The study showed that when the concentration of Houttuynia cordata extract was 0.06 g/mL, the antibacterial rate increased to 77.40%, the tensile strength of the film increased to 21.92 MPa, the elongation at break was 17.13%, the light transmittance was 80.20%, and the vapor transmission rate was 2.55×10-10 g/(m•s•Pa), indicating the best overall performance; after 20 days of storage, the firmness of the blueberry fruit was 1.17 kg/cm2, the weight loss rate was 5.80%, and TSS content was 0.13%, TA was reduced to 4.57×10-2 mmol/g, the anthocyanin content increased to 2.40 mg/g, Vc content was 19.50 mg/100 g, MDA content was 13.30 μmol/g, PPO activity was 3600 U/min•mg. The research has shown that the addition of Houttuynia cordata extract at 0.06 g/mL could effectively improve the comprehensive performance of the antibacterial composite film, provide a greater preservative effect on blueberries, thus effectively maintain the quality of blueberries and extend their shelf life by almost 10 days.
