Diffusion of linalool and methylchavicol from polyethylene-based antimicrobial packaging films

The diffusion of linalool and methylchavicol from thin (45–50 μm) antimicrobial low-density polyethylene-based films was evaluated after immersion in isooctane and the effect of temperature (4, 10, or 25 °C) on the diffusion rate was evaluated. The kinetics of linalool and methylchavicol release showed a non-Fickian behavior at the lowest temperature. An increase in temperature from 4 °C to 25 °C resulted in an increase in the diffusion coefficient from 4.2 × 10−13 m2 s−1 to 2.5 × 10−12 m2 s−1 for linalool and from 3.5 × 10−13 m2 s−1 to 1.1 × 10−12 m2 s−1 for methylchavicol. The effect of temperature on the diffusion coefficient followed an Arrhenius-type model (r2 = 0.972) in relation to a time-response function with a Hill coefficient. Activation energies of 57.8 kJ mol−1 (linalool) and 42.8 kJ mol−1 (methylchavicol) were observed

Study of antimicrobial polymeric packaging films containing basil extracts

The quality and safety of foods may deteriorate due to the surface growth of microorganisms. The integration of antimicrobial (AM) agents in polymeric packaging films to enhance microbial stability of foods may have a crucial effect on extending the shelf life of packaged food products or on maintaining food safety. Linalool and methylchavicol are the principal constituents of basil and exhibit an AM effect against a wide spectrum of bacteria, yeasts and mould. These compounds are generally recognized as safe (i.e. possess GRAS status) and are stable at the high temperatures that prevail during the extrusion film blowing process. Therefore, films containing these substances might have a potential use as AM packages. The present study generally aimed at investigating AM polymeric packaging films containing the principal constituents of basil

Loss of AM Additives from Antimicrobial Films During Storage

Films based on linear low-density polyethylene (LLDPE) and low-density polyethylene (LDPE) containing linalool or methylchavicol were prepared by extrusion film blowing. Film rolls of LLDPE containing linalool or methylchavicol were stored at ambient temperature for 1 year. Samples of these films were then evaluated for the amount of linalool or methylchavicol retained and for their antimicrobial (AM) activity by the agar disc diffusion assay. In addition, film rolls of LDPE-EVA (LDPE-ethylene vinyl acetate) containing linalool or methylchavicol were stored at 25 and 35 °C. Samples of these films were periodically collected to quantify the amount of linalool or methylchavicol retained as a function of time. For the AM LLDPE films, a decrease in additive retention was observed but there was no statistically significant difference in their AM activity against Escherichiacoli at the beginning and after 1 year of storage. For the AM LDPE-EVA films, the amount of additive in the film decreased with time and the additive retention in all films tended to deviate from the theoretical first-order decay. These findings suggest that an amount of linalool or methylchavicol that is sufficient to maintain AM activity remained in the polymeric matrix after the storage period. This study confirms the potential use of polymeric films containing basil constituents as AM films for enhancing quality and safety as well as the extension of the shelf life of foods

Preparation of Methylcellulose Film-Based CO2 Indicator for Monitoring the Ripeness Quality of Mango Fruit cv. Nam Dok Mai Si Thong

Day-to-day advancements in food science and technology have increased. Indicators, especially biopolymer-incorporated organic dye indicators, are useful for monitoring the ripeness quality of agricultural fruit products. In this investigation, methylcellulose films—containing pH dye-based indicators that change color depending on the carbon dioxide (CO2) levels—were prepared. The level of CO2 on the inside of the packaging container indicated the ripeness of the fruit. Changes in the CO2 level, caused by the ripeness metabolite during storage, altered the pH. The methylcellulose-based film contained pH-sensitive dyes (bromothymol blue and methyl red), which responded (through visible color change) to CO2 levels produced by ripeness metabolites formed during respiration. The indicator solution and indicator label were monitored for their response to CO2. In addition, a kinetic approach was used to correlate the response of the indicator label to the changes in mango ripeness. Color changes (the total color difference of a mixed pH dye-based indicator), correlated well with the CO2 levels in mango fruit. In the ‘Nam Dok Mai Si Thong’ mango fruit model, the indicator response correlated with respiration patterns in real-time monitoring of ripeness at various constant temperatures. Based on the storage test, the indicator labels exhibited color changes from blue, through light bright green, to yellow, when exposed to CO2 during storage time, confirming the minimal, half-ripe, and fully-ripe levels of mango fruit, respectively. The firmness and titratable acidity (TA) of the fruit decreased from 44.54 to 2.01 N, and 2.84 to 0.21%, respectively, whereas the soluble solid contents (SSC) increased from 10.70 to 18.26% when the fruit ripened. Overall, we believe that the application of prepared methylcellulose-based CO2 indicator film can be helpful in monitoring the ripeness stage, or quality of, mango and other fruits, with the naked eye, in the food packaging system

Antimicrobial properties of basil and its possible application in food packaging

Basil (Ocimum basilicum L.) is a popular culinary herb, and its essential oils have been used extensively for many years in food products, perfumery, and dental and oral products. Basil essential oils and their principal constituents were found to exhibit antimicrobial activity against a wide range of Gram-negative and Gram-positive bacteria, yeast, and mold. The present paper reviews primarily the topic of basil essential oils with regards to their chemical composition, their effect on microorganisms, the test methods for antimicrobial activity determination, and their possible future use in food preservation or as the active (antimicrobial), slow release, component of an active package

Efficacy of polyethylene-based antimicrobial films containing principal constituents of basil

The feasibility of low-density polyethylene (LDPE)-based films containing linalool or methylchavicol as antimicrobial (AM) packages to retard microbial growth on food surfaces was investigated. The AM LDPE-based films were tested for inhibition against selected microorganisms. Both compounds retained their AM activity, after an extrusion film-blowing process, against Escherichia coli in solid medium. Cheddar cheese was wrapped with the AM films and the packaged cheese samples were stored at 4 1C. The changes in the mesophilic aerobic bacteria and coliform, as well as yeast and mould counts were monitored. In addition, cheese samples inoculated with E. coli or Listeria innocua were wrapped with the AM films, stored at refrigerated (4 1C) or at abuse (12 1C) temperatures and the count of these microorganisms was monitored as a function of time. The results showed an inhibitory effect of these AM films against microbial growth in naturally contaminated cheese and in inoculated samples. The effect on suppression of E. coli and L. innocua growth was more pronounced at the abuse temperature. Methylchavicol-LDPE-based film exhibited a higher efficacy of inhibition than that of linalool- LDPE-based film. In addition, a sensory evaluation was performed with regards to possible taint in the flavour of the cheese. Taint in flavour as affected by linalool or methylchavicol was not significantly detectable by the panelists at the end of the storage period of 6 weeks. This study shows the potential use of polymeric films containing the principal constituents of basil as the AM components for enhancing quality and safety of cheese

Novel Color Change Film as a Time–Temperature Indicator Using Polydiacetylene/Silver Nanoparticles Embedded in Carboxymethyl Cellulose

Time–temperature indicators (TTIs) can be important tools in product applications to monitor food quality losses, especially for fruits and vegetables. In this context, the effects of silver nanoparticles (AgNPs) and glycerol on the color change of polydiacetylene/AgNPs (PDA/AgNPs) embedded in carboxymethyl cellulose (CMC) film as time–temperature indicators (TTIs) were investigated. A CMC film prepared with 30 mg/L AgNPs and a 1:3 (v/v) PDA:AgNP ratio exhibited a faster color change than under other conditions. At 35 °C, the films with PDA/AgNPs changed color from purplish-blue to purple and purple to reddish-purple over time due to the higher thermal conductivity of AgNPs and larger PDA surface area exposed to specific temperatures. The total color difference (TCD) of PDA/AgNP-embedded CMC film directly changed with regard to time and temperature. However, adding glycerol to the system resulted in a symmetrical chemical structure, a factor that delayed the color change. Scanning electron micrographs showed AgNPs embedded in the CMC films. Transmission electron micrographs indicated a core-shell structure of PDA/AgNP vesicles in the CMC matrix. PDA/AgNP vesicles were confirmed by second derivative Fourier transform infrared spectroscopy, with a new peak at 1390–1150 cm−1. The kinetics of TTIs from PDA/AgNP-embedded CMC films yielded an activation energy of 58.70 kJ/mol