-
Food Chemistry Jan 2023Intelligent packaging that provides real-time information on food quality is useful for consumers. We developed a kimchi ripening indicator that can determine the...
Intelligent packaging that provides real-time information on food quality is useful for consumers. We developed a kimchi ripening indicator that can determine the ripeness of kimchi inside packaging and evaluated its applicability and limitations. The indicator was made using calcium hydroxide, which captures CO, and four pH-sensitive dyes (cresol red, bromothymol blue, bromocresol purple, and methyl red). Fourier-transform infrared spectra of the prepared powders showed shapes similar to that of calcium hydroxide, and the dyes were evenly distributed on the calcium hydroxide surfaces. When the developed indicators were evaluated for kimchi packaging application, the indicator made from synthesized calcium hydroxide and bromothymol blue was the most reliable and clearly reflected useful kimchi ripening information. The indicator developed in this study is judged to be practically usable at temperatures of 4-15 °C. However, its usefulness is limited in that the seller cannot change the packaging capacity or kimchi capacity.
Topics: Bromcresol Purple; Bromthymol Blue; Calcium Hydroxide; Carbon Dioxide; Coloring Agents; Fermentation; Fermented Foods; Food Packaging; Hydrogen-Ion Concentration
PubMed: 36055147
DOI: 10.1016/j.foodchem.2022.134039 -
International Journal of Biological... May 2023Continuous wound monitoring is one strategy to minimise infection severity and inform prompt variations in therapeutic care following infection diagnosis. However,...
Continuous wound monitoring is one strategy to minimise infection severity and inform prompt variations in therapeutic care following infection diagnosis. However, integration of this functionality in therapeutic wound dressings is still challenging. We hypothesised that a theranostic dressing could be realised by integrating a collagen-based wound contact layer with previously demonstrated wound healing capability, and a halochromic dye, i.e. bromothymol blue (BTB), undergoing colour change following infection-associated pH changes (pH: 5-6 ➔ >7). Two different BTB integration strategies, i.e. electrospinning and drop-casting, were pursued to introduce long-lasting visual infection detection capability through retention of BTB within the dressing. Both systems had an average BTB loading efficiency of 99 wt% and displayed a colour change within 1 min of contact with simulated wound fluid. Drop-cast samples retained up to 85 wt% of BTB after 96 h in a near-infected wound environment, in contrast to the fibre-bearing prototypes, which released over 80 wt% of BTB over the same time period. An increase in collagen denaturation temperature (DSC) and red shifts (ATR-FTIR) suggest the formation of secondary interactions between the collagen-based hydrogel and the BTB, which are attributed to count for the long-lasting dye confinement and durable dressing colour change. Given the high L929 fibroblast viability in drop-cast sample extracts (92 %, 7 days), the presented multiscale design is simple, cell- and regulatory-friendly, and compliant with industrial scale-up. This design, therefore, offers a new platform for the development of theranostic dressings enabling accelerated wound healing and prompt infection diagnosis.
Topics: Humans; Precision Medicine; Bandages; Collagen; Wound Healing; Surgical Wound Infection; Bromthymol Blue; Hydrogels
PubMed: 36870632
DOI: 10.1016/j.ijbiomac.2023.123866 -
Journal of Agricultural and Food... Nov 2020This work presents a colorimetric dye-based array for naked-eye detection of chicken meat spoilage. The array is obtained by fixing five acid-base indicators, -cresol...
This work presents a colorimetric dye-based array for naked-eye detection of chicken meat spoilage. The array is obtained by fixing five acid-base indicators, -cresol purple (), -cresol red (), bromothymol blue (), thymol blue (), and chlorophenol red (), and a sensing molecule specific for thiols, 5,5'-dithiobis(2-nitrodibenzoic acid), called Ellman's reagent (), on a cellulose-based support. The dyes, being permanently charged, are fixed on the support via ion-exchange. The entire degradation process of beast poultry meat, at ambient temperature and in a domestic fridge, is followed by the change of the color of the array, placed in the headspace over the meat samples. The device is set after selection of the most suitable starting form, which could be the acidic or the basic color of indicators, being the proper dye concentration and the dimension of the spots already established. Basing on sensors colors, we identified three levels of the degradation process of chicken meat, named SAFE, WARNING, and HAZARD. By instrumental analysis, we demonstrated that sensors response was correlated to volatile organic compounds (VOCs) composition in the headspace and, thus, to meat spoilage progress. We demonstrated that biogenic amines (BAs), commonly considered a critical spoilage marker, are indeed produced into the samples but never present in the headspace, even in traces, during the investigated time-lapse. The VOC evolution nevertheless allows one to assign the sample as WARNING and further HAZARD. Some indicators turned out to be more informative than others, and the best candidates for a future industrial application resulted in a bromothymol blue ()-, chlorophenol red ()-, and Ellman's reagent ()-based array.
Topics: Animals; Bromthymol Blue; Chickens; Color; Colorimetry; Coloring Agents; Food Analysis; Food Safety; Meat; Phenolsulfonphthalein; Thymolphthalein; Volatile Organic Compounds
PubMed: 33118801
DOI: 10.1021/acs.jafc.0c03771 -
Journal of Agricultural and Food... Nov 2020The rationale behind the material and dye selection and the investigation of the properties of a solid-phase sensor array designed for following chicken meat spoilage is...
The rationale behind the material and dye selection and the investigation of the properties of a solid-phase sensor array designed for following chicken meat spoilage is presented, having in mind that the final target must be the naked eye identification of the degradation steps. The device is obtained by fixing five acid-base indicators, -cresol purple (1), -cresol red (2), bromothymol blue (3), thymol blue (4), and chlorophenol red (5), and a sensing molecule specific for thiols, 5,5'-dithiobis(2-nitrodibenzoic acid), called Ellman's reagent, (6) on a commercial cellulose-based support. The dimensions of the sensor and the amount of dye sorbed on the solid are carefully studied. The preparation protocol to get reproducible sensing materials is established, based on the kinetic study and the color change investigation. The material stability and the capacity of changing color, according to the acid-base properties of the dyes, are tested. The sources of uncertainty, coming from the technique employed for signal data acquisition and treatment and from the intrinsic variability of the spots based on the commercial support, are established. The highest variability does not come from photo acquisition by a mobile phone, the effect of the illumination equipment, the partial least-squares (PLS) model employed to assess the amount of dye sorbed into the solid but from the variability of different spots and was found equal to 10%. The uncertainty is adequate for final employment since it is referred to as replicates under different conditions that are definitively judged almost always identical by naked eye evaluation, which is our last target for assessing a change of the colors associated with spoilage.
Topics: Animals; Bromthymol Blue; Chickens; Color; Coloring Agents; Food Analysis; Meat; Phenolsulfonphthalein; Thymolphthalein
PubMed: 33125233
DOI: 10.1021/acs.jafc.0c03768