Application of active edible coatings made from basil seed gum and thymol for quality maintenance of shrimp during cold storage

BACKGROUNDTo improve the quality of Pacific white shrimp (Litopenaeus vannamei), active coating solutions were prepared by dissolving 10gL(-1) of basil seed gum (BSG) and adding various levels of thymol (6%, 8% and 10% w/w based on gum weight) and glycerol (3.5gL(-1)) as plasticizer. The effects of coating solutions (CS1-4) on the quality changes of shrimps during refrigerated storage over 20 days were investigated. RESULTSThe total volatile basic nitrogen (TVB-N) value in shrimps coated with CS4 (containing 10% w/w thymol) was slightly higher than the upper threshold of 300mgkg(-1) on day 18, whereas that of uncoated shrimps increased to, or over, the threshold value on day 7. Active coatings significantly reduced (P < 0.05) microbial growth in shrimps during the cold storage without a negative impact on the organoleptic properties. Using CS4 on the shrimp samples immediately reduced total viable count and psychrotrophic bacteria count by 2 and 1 log colony forming units g(-1), respectively, compared to controls. CONCLUSIONThe results of the present study revealed that the active edible coatings based on BSG activated with thymol had good potential to be used in the production of active packaging for various food applications. (c) 2016 Society of Chemical Industry