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.

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.

Active and intelligent packaging: The indication of quality and safety.

The food industry has been under growing pressure to feed an exponentially increasing world population and challenged to meet rigorous food safety law and regulation. The plethora of media consumption has provoked consumer demand for safe, sustainable, organic, and wholesome products with "clean" labels. The application of active and intelligent packaging has been commercially adopted by food and pharmaceutical industries as a solution for the future for extending shelf life and simplifying production processes; facilitating complex distribution logistics; reducing, if not eliminating the need for preservatives in food formulations; enabling restricted food packaging applications; providing convenience, improving quality, variety and marketing features; as well as providing essential information to ensure consumer safety. This chapter reviews innovations of active and intelligent packaging which advance packaging technology through both scavenging and releasing systems for shelf life extension, and through diagnostic and identification systems for communicating quality, tracking and brand protection.

Fabrication of Novel Bioactive Cellulose-Based Films Derived from Caffeic Acid Phenethyl Ester-Loaded Nanoparticles via a Rapid Expansion Process: RESOLV.

Caffeic acid phenethyl ester (CAPE) nanoparticles (NPs) with an average size of ∼40 nm obtained from TEM and binomial average sizes of ∼90 and ∼400 nm obtained from DLS were successfully produced by rapid expansion of subcritical solutions into liquid solvents (RESOLV). The minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs) of CAPE and CAPE-NPs were determined by plate count method against 12 pathogenic and spoilage bacteria and 3 strains of yeast. Total phenolic content (TPC) and antioxidant activities of CAPE-NPs were quantified and subsequently investigated using two assays, including 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging and ferric reducing antioxidant power (FRAP). CAPE-NP-incorporated cellulose-based films were prepared and characterized. MICs and MBCs of CAPE-NPs against most bacteria and Candida albicans were 700 and 1400 µg/mL, respectively. CAPE-NPs yielded a TPC value of 426.74 µgGAE/mg and lower antioxidant activities than those of CAPE in ethanol (CAPE-EtOH), whereas BHT yielded lower FRAP than that of CAPE-NPs. The impregnation of CAPE into cellulose-based films was confirmed by FTIR spectra. Moreover, incorporation of only 0.5 wt % CAPE-NPs into the films resulted in an inhibitory effect against microorganisms. Fortunately, incorporation of higher concentration of CAPE-NPs-MC films led to a significantly higher antioxidant activity and vice versa. This indicated that CAPE-NPs significantly enhanced the antimicrobial and antioxidant activities of CAPE. The results show that the environmentally benign supercritical CO2 technique should be generally applicable to NP fabrication of other important bioactive ingredients, especially in liquid form. In addition, it is suggested that CAPE-NPs can be used to reduce the dosage of CAPE and improve their bioavailability and thus merit further investigation for bioactive packaging film and coating applications.

Development of a food spoilage indicator for monitoring freshness of skinless chicken breast.

A colorimetric mixed-pH dye-based indicator with potential for the development of intelligent packaging, as a "chemical barcode" for real-time monitoring of skinless chicken breast spoilage, is described. Also investigated was the relationship between the numbers of microorganisms and the amount of volatile compounds. This on-package indicator contains two groups of pH-sensitive dyes, one of which is a mixture of bromothymol blue and methyl red, while the other is a mixture of bromothymol blue, bromocresol green and phenol red. Carbon dioxide (CO2) was used as a spoilage metabolite because the degree of spoilage was related to the amount of increased CO2, and which was more than the level of total volatile basic nitrogen (TVB-N) during the storage period. Characteristics of the two groups of indicator solutions were studied, as well as their response to CO2. A kinetic approach was used to correlate the response of the indicator label to the changes in skinless chicken breast spoilage. Color changes, in terms of total color difference of a mixed-pH dye-based indicator, correlated well with CO2 levels of skinless chicken breast. Trials on skinless chicken breast samples have verified that the indicator response correlates with microbial growth patterns, thus enabling real-time monitoring of spoilage either at various constant temperatures or with temperature fluctuation.

Antioxidant activities of curcumin and ascorbyl dipalmitate nanoparticles and their activities after incorporation into cellulose-based packaging films.

Curcumin (Ccm) and ascorbyl dipalmitate (ADP) nanoparticles (NPs) with average sizes of ∼50 and ∼80 nm, respectively, were successfully produced by rapid expansion of subcritical solutions into liquid solvents (RESOLV). Pluronic F127 was employed as a stabilizer for both Ccm- and ADP-NPs in an aqueous receiving solution. Antioxidant activities of the Ccm-NPs and ADP-NPs were subsequently investigated using four assays, including 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging, ABTS radical cation decolorization, ß-carotene bleaching, and ferric reducing antioxidant power. Ccm-NPs and ADP-NPs showed higher antioxidant activities than those of Ccm and ADP. Ccm-NPs yielded higher antioxidant activities than those of Ccm in ethanol and water (Ccm-EtOH and Ccm-H(2)O), respectively. ADP-NPs yielded lower antioxidant activities than that of ADP in ethanol (ADP-EtOH) but higher activities than that of ADP in water (ADP-H(2)O). Moreover, incorporation of Ccm-NPs and ADP-NPs into cellulose-based films indicated that Ccm-NPs and ADP-NPs significantly enhanced the antioxidant activities of Ccm and ADP (p < 0.05). Our results show that the environmentally benign supercritical CO(2) technique should be generally applicable to NP fabrication of other important bioactive ingredients, especially in liquid form. In addition, we suggest that Ccm-NPs and ADP-NPs can be used to reduce the dosage of Ccm and ADP and improve their bioavailability, and thus merit further investigation for antioxidant packaging film and coating applications.

Development of a novel colorimetric indicator label for monitoring freshness of intermediate-moisture dessert spoilage.

A colorimetric mixed pH dye-based indicator with potential for the development of intelligent packaging, as a "chemical barcode" for real-time monitoring of intermediate-moisture dessert spoilage, is described. This on-package indicator contains mixed pH-sensitive dyes, bromothymol blue and methyl red, that respond through visible color change to carbon dioxide (CO(2)) as a spoilage metabolite. Both indicator solution and indicator label characteristics were studied, as well as their response to CO(2). A kinetic approach was used to correlate the response of the indicator label to the changes in intermediate-moisture dessert spoilage. Color changes, in terms of total color difference of a mixed pH dye-based indicator, correlated well with CO(2) levels of intermediate-moisture dessert. Trials on golden drop have verified that the indicator response correlates with microbial growth patterns in dessert samples, thus enabling the real-time monitoring of spoilage either at various constant temperatures or with temperature fluctuation.

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.