Edible Thai rice film incorporated with ginger extract by microwave extraction: optimization of bioactive compounds and functional properties for antimicrobials

This study aimed to integrate microwave-assisted extraction (MAE) on the dry ginger extract and to develop rice-based edible film incorporated with ginger extract. An efficient MAE was developed to extract the dried ginger using a 32 full factorial design. The optimal condition was a microwave power of 400W and an extraction time of 1 min. The extraction time was a significantly effective factor than microwave power, whist power was not a significant factor for yield, 6-gingerol, 6-shogaol, and paradol. A crude extract of dried-ginger has antimicrobial activity against S. mutans DMST 18777 with minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of 0.49 mg/mL and 31.25 mg/mL, respectively. The rice-based edible film incorporated with 32 mg/mL of ginger extract against S. mutans DMST 18777 with a mean zone of inhibition of 12.69 ± 0.07 mm. The functional property of rice film was remarkably better than the original. Significant increases in TPC, antioxidant and bioactive compounds were associated with increase ginger extract contents in rice film. The main phenolic compounds including 6- gingerol 6-shogaol, paradol, and zingerone, and essential oils including α-curcumene, α-zingiberene, γ-muurolene, α-farnesene, β-bisabolene, and β-sesquiphellandrene were found in rice film strip fortify with crude ginger extract.