Carboxymethyl cellulose from renewable rice stubble incorporated with Thai rice grass extract as a bioactive packaging film for green tea

The combination of commercial carboxymethyl cellulose (CMC) and CMC from rice stubble was used to form CMC-film. Additionally, CMC-film incorporated with rice grass extract microencapsulated powder (CMC-MP-film) as bioactive packaging was investigated on the quality of green tea during storage compared with commercial high density polyethylene (HDPE) film. The CMC-MP-film effectively prevented dried green tea from lipid oxidation. Moreover, the total phenolic content (TPC) of green tea packed in CMC-MP-film was equivalent to that packed in HDPE, having the highest acceptability score from the sensory evaluation. Based on the change in the TPC of the green tea drink, the estimated shelf life of green tea leaves at 25°C in HDPE, CMC-MP-film and CMC-film was 110, 110 and 91days, respectively. Thus, bioactive CMC film provides an effective alternative to synthetic film to maintain the quality and extend the shelf life of dry and oily food products. Practical applications Rice stubble is an agricultural waste but still contains the high amount of cellulose which can be produced carboxymethyl cellulose (CMC) and used in combination of commercial CMC as biopolymer film. Moreover, rice grass microencapsulated powder was incorporated with CMC-film (CMC-MP-film) as bioactive packaging to maintain the qualities of green tea compared with commercial plastic (high density polyethylene, HDPE). The CMC-MP-film prevented effectively dried green tea from lipid oxidation. Moreover, the total phenolic content (TPC) of green tea packed in CMC-MP-film was equivalent to that packed in HDPE with similar shelf life. Therefore, bioactive CMC film provides an effective alternative to synthetic film to maintain the quality and extend the shelf life of dry and oily food products. Moreover, the CMC from rice stubble and rice grass extract, the agricultural waste from rice field, will add value as a potential renewable bioactive packaging material for the food industry.