Antibacterial activity of pullulan films containing thymol

Abstract

Thymol displays strong activity against microorganisms that are of interest in clinical field and in food industry. Pullulan can form homogeneous films, which is an important property for its use as a coating material in the food industry. The present study determining the effect of thymol incorporated into a pullulan film against selected bacteria. The final content of thymol in the dried films ranged from 2.5 mg/cm 2 to 52.9 mg/cm 2 . The structure of the surface and cross-section of the films were observed under a scanning electron microscope. The fruits were coated with a pullulan film, with thymol incorporated in the concentrations of 1.2, 1.5 and 3.0% and were evaluated for appearance and aroma. The pullulan films with thymol content ranging from 26.5 mg/cm 2 to 52.9 mg/cm 2 expressed strong inhibitory activity against the tested bacteria, compared with the pullulan films containing lesser concentration of thymol. The surface of the coated fruits was found to be shiny as compared with the non-coated fruits. Though the characteristic aroma of thymol was detectable it did evoke any undesirable sensory changes. Pullulan films containing thymol, which were effective against the tested bacteria, can be applied to extend the shelf life of packaged food products.

Edible Coatings Enriched with Essential Oils and their Compounds for Fresh and Fresh-cut Fruit

“…Pullulan films are formed from extracellular polysaccharide produced by the fungus Aureobasisium pullulans, and when combined with thymol expressed strong inhibitory activity against Bacillus subtilis ATCC6633, Staphylococcus aureus ATCC25923, Salmonella enteritidis ATCC13076, and Escherichia coli ATCC25922 [77]. In this work, the authors also reported that the aroma of thymol introduced in the pullulan film was not perceptible after the skin of the mandarins had been peeled or after the film had been removed from the surface of apple.…”

Characterization of an antimicrobial poly(lactic acid) film prepared with poly(ε‐caprolactone) and thymol for active packaging

“…Based on the images presented in Fig. c–f, it might be speculated that the addition of thymol to PLA/PCL led to changes in the structure of films . The higher the thymol content in the PLA/PCL blends, the more and larger were the micro‐voids that appeared in the film.…”

“…Thymol displays strong antimicrobial activity against natural spoilage bacteria and food borne pathogens, e.g. Salmonella typhimurium , Escherichia coli , Listeria monocytogenes , Bacillus cereus , and Staphylococcus aureus . Recently, films containing thymol have been prepared by a wide variety of raw materials, such as zein, gelidium corneum, pullulan, polypropylene, and low‐density polyethylene .…”

“…Salmonella typhimurium , Escherichia coli , Listeria monocytogenes , Bacillus cereus , and Staphylococcus aureus . Recently, films containing thymol have been prepared by a wide variety of raw materials, such as zein, gelidium corneum, pullulan, polypropylene, and low‐density polyethylene . However, to the best of our knowledge, no references were recorded dealing with PLA films containing thymol for the development of antimicrobial packaging films.…”

Silan/biopolymer microgels for functionalization of cotton fabric: dual responsive pH and temperature and antibacterial properties

“…Pullulan is an important biopolymer compound have a repeated glucose unit linked as a (1/6) (Catley et al, 1986;Zajic and LeDuy, 1973). Pullulan containing materials with biocide agents have a good antibacterial properties (Gniewosz and Synowiec, 2011). In addition, it has an excellent physical properties, such as, solubility in water, anti-inflammatory, antithrombotic, anticoagulant and adhesive properties.…”