Development of edible Thai rice film fortified with ginger extract using microwave-assisted extraction for oral antimicrobial properties

This study aimed to investigate microwave-assisted extraction (MAE) of dried ginger and to develop a rice-based edible film incorporating ginger extract. The optimal MAE conditions of 400 W microwave power and an extraction time of 1 min were determined using a 3(2) full factorial design. The optimized extract showed total phenolic compounds (TPC, 198.2 +/- 0.7 mg gallic acid equivalent/g), antioxidant activity measured by DPPH (91.4 +/- 0.6% inhibition), ABTS (106.4 +/- 3.1 mg Trolox/g), and FRAP (304.6 +/- 5.5 mg Trolox/g), and bioactive compounds including 6-gingerol (71.5 +/- 3.6 mg/g), 6-shogaol (12.5 +/- 1.0 mg/g), paradol (23.1 +/- 1.1 mg/g), and zingerone (5.0 +/- 0.3 mg/g). Crude extract of dried ginger showed antimicrobial activity against Streptococcus mutans DMST 18777, with a minimum inhibitory concentration and minimum bactericidal concentration of 0.5 and 31.2 mg/mL, respectively. The rice-based edible film incorporating 3.2% (w/v) ginger extract tested against S. mutans DMST 18777 had a mean zone of inhibition of 12.7 +/- 0.1 mm. Four main phenolic compounds, 6-gingerol, 6-shogaol, paradol, and zingerone, and six volatile compounds, alpha-curcumene, alpha-zingiberene, gamma-muurolene, alpha-farnesene, beta-bisabolene, and beta-sesquiphellandrene, were found in rice film fortified with crude ginger extract.

Automated summary

This study successfully developed a microwave-assisted extraction technique for dried ginger and formulated an edible film incorporating ginger extract, which exhibited excellent bioactivity and antimicrobial activity.