title: Modelling the effect of essential oil of betel leaf (Piper betle L.) on germination, growth, and apparent lag time of Penicillium expansum on semi-synthetic media.
abstract: The current study aimed at characterizing the chemical components of betel leaf (Piper betle L. var. Tamluk Mitha) essential oil (BLEO) and modelling its effect on growth of Penicillium expansum on semi-synthetic medium. Gas chromatography-mass spectrophotometry (GC-MS) analysis of BLEO revealed the presence of different bioactive phenolic compounds in significant amounts. Among 46 different components identified, chavibetol (22.0%), estragole (15.8%), β-cubebene (13.6%), chavicol (11.8%), and caryophyllene (11.3%) were found to be the major compounds of BLEO. A disc diffusion and disc volatilization method were used to evaluate antifungal activity of the oil against a selected food spoilage mould. The logistic model was used to study the kinetics of spore germination. Prediction and validation of antifungal effect of BLEO was performed on semi-synthetic medium (apple juice agar) using predictive microbiological tools. The Baranyi and Roberts model was used to estimate maximum growth rate (μmax in mm/day) and apparent lag time (λ in days) of the mould. Secondary modelling was performed using a re-parameterized Monod-type equation based on cardinal values to study the effect of different BLEO concentration on estimated growth parameters. Emax (minimum concentration of oil at which mould growth was inhibited) and MIC (minimum inhibitory concentration of BLEO at which lag time is infinite) value of BLEO against P. expansum was estimated to be 0.56 and 0.74 μl/ml, respectively, which was found to be similar on potato dextrose agar (PDA) as well as apple juice agar (AJA) medium. The correlation between estimated growth parameters of the mould on both the media was obtained with satisfactory statistical indices (R(2) and RMSE). This study revealed inhibitory efficacy of BLEO on spore germination, mycelial growth and apparent lag time of P. expansum in a dose-dependent manner. Hence, BLEO has potential to be used as a natural food preservative.
authors.affiliation: Agricultural and Food Engineering Department, Indian Institute of Technology Kharagpur, Kharagpur, 721302, West Bengal, India. Electronic address: suradeepbasak@gmail.com.
authors.forename: Suradeep
authors.initials: S
authors.lastname: Basak
authors.affiliation: Agricultural and Food Engineering Department, Indian Institute of Technology Kharagpur, Kharagpur, 721302, West Bengal, India.
authors.forename: Proshanta
authors.initials: P
authors.lastname: Guha
mesh_terms: D000362:Agar; D000935:Antifungal Agents / Q000494:pharmacology*; D003470:Culture Media / Q000737:chemistry; D005519:Food Preservation; D005520:Food Preservatives / Q000494:pharmacology*; D008401:Gas Chromatography-Mass Spectrometry; D007700:Kinetics; D008826:Microbial Sensitivity Tests; D009822:Oils, Volatile / Q000737:chemistry / Q000494:pharmacology*; D010407:Penicillium / Q000187:drug effects* / Q000254:growth & development; D031721:Piper betle / Q000737:chemistry*; D013172:Spores, Fungal / Q000187:drug effects / Q000254:growth & development
chemical_list: D000935:Antifungal Agents; D003470:Culture Media; D005520:Food Preservatives; D009822:Oils, Volatile; D000362:Agar
keywords: Monod-type equation; Predictive mycology; antifungal activity; spore germination kinetics