Evaluation Of Active Edible Coating From Chitosan Incorporated With Thai Herb Extract For Fresh-Cut Guava (Psidium Guajava L.)

Abstract

Fresh-cut guava is one example of convenient novel foods that fit the many needs of modern lifestyle while it is also very perishable. Thai Herb extract might have antimicrobial activity as one of an alternative for prolonging shelf-life of fresh-cut product. Objectives of this research are study antimicrobial activity of Thai Herbs and application of active edible coating from chitosan incorporated with Thai Herb extract on fresh-cut guava (Psidium guajava L.) during storage. Screening of Thai Herbs, extracted with ethanol 50% and then dried with freeze drying method, for choosing the best one as an antimicrobial agent in edible coating was done by disk diffusion method. Total phenolic compound (TPC) and antioxidant capacity were analyzed using Folin-Ciocalteu method and DPPH scavenging activity respectively. Piper betle as selected Thai Herb extract had antimicrobial activity against Gram-positive and negative bacteria also yeast from 7.15±0.36 to 18.81±0.06 mm and TPC of 79.20±1.42 mg GAE/g sample also antioxidant activity of 674.59±1.48 μmol TE/g sample. The concentration of Piper betle extract used for formulation was determined according to minimum inhibitory concentration (MIC) with broth microdilution method and minimum bactericidal concentration (MBC). Highest MBC value was 12.5 mg/mL and concentration of extract used for coating solution was 25 mg/mL. Application of coating from chitosan incorporated with Piper betle extract for fresh-cut guava did not reduce amount of microbial growth until 6.37±0.21 log CFU/g at the end of storage and could not inhibit browning reaction as shown by L (62.28±4.45), a* (2.32±2.90), and b* (17.41±0.51) value. This coating process could not delay ripening process according to total titratable acidity (0.07±0.03 g citric acid/100 mL), total soluble solid (7.27±0.45°brix), and weight loss (0.12±0.01%). It also had the lowest hedonic score compared to control in sensory evaluation at day 8 for attributes of appearance (2.1±0.99), texture (3.9±1.73), aroma (2.9±1.37), and overall (2.8±1.23).