Evaluation and modeling of acrylonitrile migration from polypropylene for food packaging.

This study validated an analytical technique using headspace gas chromatography with flame ionization detection to quantify acrylonitrile monomer with a quantification limit of 0.10 ± 0.04 µg kg-1 . Subsequently, the acrylonitrile migration from polypropylene granules was evaluated in food simulants water and ethanol (50% v/v) and at two temperatures (20 ± 1°C and 44 ± 2°C) for up to 6 weeks, representing the service time of a bottle. From the experimental data obtained, pseudo-second-order kinetics were adjusted to represent the acrylonitrile migration into the simulants. For water, equilibrium concentrations of 13.58 and 16.58 µg kg-1 at 20 and 44°C, respectively, were obtained, while for 50% ethanol, 15.07 and 16.40 µg kg-1 were obtained for the same temperatures. The experimental results and the values estimated from the migration kinetics indicate that the maximum acrylonitrile concentration will not exceed the tolerable specific limit established in regulations. PRACTICAL APPLICATION: The migration of compounds such as acrylonitrile can be a drawback resulting in an undesirable reduction in the shelf life of liquid foods packaged in bottles made of materials such as polypropylene. In this paper, acrylonitrile migration kinetics and a methodology are proposed to determine whether the tolerable migration limits are ever reached, which can serve as a tool for producers of this type of packaging of food to predict shelf life.

Physicochemical characterization of cape gooseberry (Physalis peruviana L.) fruits ecotype Colombia during preharvest development and growth.

Cape gooseberry fruits are increasingly recognized due to their excellent organoleptic and functional characteristics as a food. As the cultivation of this fruit expands, it is necessary to determine the quality characteristics and evolution of the new growing zones. This study sought to characterize the growth and development of cape gooseberry fruits, Ecotype Colombia, in the Ventaquemada region (Department of Boyacá in Colombia). For the experiments, 50 plants were taken completely at random from which 20 flowers of the middle third were selected and marked considering that 50% of the flowers were open. The selected cape gooseberry plants were 9 months old from the establishment. Samples were carried out every 5-7 days to evaluate changes in different physiological and physicochemical properties of the fruits such as equatorial diameter, weight, dry matter, respiration intensity (RI), total soluble solids (SST), titratable acidity (TA), and maturity ratio (SST/TA). Logistic and modified enzyme kinetics models were fitted to represent the change in these characteristics as a function of growth time and to establish a suitable maturity index. A rapid increase in the growth and a substantive change in the properties of the fruits were observed between 36 and 45 days after anthesis (DAA) and stabilization between 60 and 65 DAA, which constitutes the stage of physiological maturity. At this stage, fruits with a polar/equatorial diameter of 2.2-2.5 cm, 14.9% TSS, 2.2% TA, and 191.7 cm3 CO2 /g/d RI were obtained. Likewise, from the adjusted models, it was possible to identify these changes, especially for the relative growth rate (RGR), color index, and maturity ratio. PRACTICAL APPLICATION: In this work, we present the characterization of some physicochemical properties of cape gooseberry throughout its development and preharvest growth. This fruit is of wide interest due to its broad nutritional properties and is known as a "superfruit." The monitoring of the changes in the quality characteristics is important because it allows producers to define an optimum maturity stage for its commercialization. We also fit suitable regression models to relate the evolution in the product as a function of time and provide prediction tools to monitor fruit development. The above can help growers better schedule their production cycles.

Determination of changes in physicochemical and sensory characteristics of purple passion fruit with the application of different packaging systems, including an ethylene scavenger additive.

To achieve a suitable packaging configuration, it is important first to determine the physicochemical characteristics related to the packaged product. In this study, the physicochemical characterization of fresh purple passion fruits of three different ripening stages was carried out to determine key variables for the packaging, such as O2 consumption and CO2 -ethylene production rates. Subsequently, intermediate-ripe fruits were packaged for 21 days at 6 °C under three packaging conditions: Xtend® perforated bags, low-density polyethylene (LDPE) bags, and LDPE bags with a novel ethylene scavenger active additive (ESAA). It was observed that an equilibrium modified atmosphere was formed in the packages. For the Xtend® bags, the highest values of O2 (yo2  = 0.184 to 0.192) and lowest of CO2 (yco2  = 0.033 to 0.041) were reached, whereas for the LDPE bags with ESAA these values were moderate. In the case of ethylene, the LDPE bags showed the highest levels in the headspace (26 to 31 ppm), whereas the lowest levels were obtained in the LDPE bags with additive (2 to 4 ppm). These levels resulted in a delay in the ripening of the fruits during storage, which was verified through a sensory acceptability test that was carried out on the juice extracted from the fruits. In this sensory test, panelists identified similar characteristics between the fruits packaged with ESAA and the Xtend® bags, regarding the control fruits. The LDPE bags with the ethylene scavenger performed satisfactorily and can considerably delay the ripening, which may result in longer shelf life and conservation of fresh purple passion fruits. PRACTICAL APPLICATION: This work presents a novel packaging proposal that reduces oxygen and ethylene levels in contact with purple passion fruits. Our proposed active packaging can be used to increase the fruit shelf life by improving its conservation conditions throughout the chain of storage, transport, and distribution in the market. With this, it will be possible to reduce the fruit's losses due to senescence and to reduce the substrate consumption by using a more effective packaging system.

Combined modified atmosphere packaging and guar gum edible coatings to preserve blackberry (Rubus glaucus Benth).

Blackberry fruits are fresh products with wide market possibilities but of very limited shelf life (3-6 days). To develop preservation alternatives, the effect and interaction of a modified atmosphere packaging and an edible coating based on guar gum were determined on the shelf life and quality properties of blackberry cv. Castilla stored at 5 ℃. Three types of packaging were evaluated: (1) perforated polyethylene terephthalate clamshells, (2) sealed polyethylene terephthalate clamshells, and (3) sealed polyethylene terephthalate clamshells with a polylactic acid film on top. In turn, two types of coating were evaluated: coatings of guar gum solutions at (1) 0.3% and (2) 0.4% in water. During storage, an index of deterioration and different quality properties were evaluated. In the polyethylene terephthalate packages with polylactic acid, an equilibrium modified atmosphere packaging was formed. Weight loss was much lower for the sealed polyethylene terephthalate and polyethylene terephthalate + polylactic acid (<2%) compared to fruits in perforated clamshells, with no significant differences between these two types of packaging. It was possible to observe the treatment with an edible coating of 0.3% gum guar and perforated clamshells (guar gum 0.3/N) presented the lowest deterioration rate and preserve the fruit longer time (13 days) although with a high weight loss (23.23%) while the treatment with polyethylene terephthalate and polylactic acid film + edible coating of gum guar (guar gum 03/polylactic acid) kept the samples during 12 days with a lower weight loss (1.75%). This latter combination of equilibrium modified atmosphere packaging with a biodegradable film and the guar gum edible coating can be an interesting treatment from a commercial point of view.

Evaluation and modeling of changes in color, firmness, and physicochemical shelf life of cut pineapple (Ananas comosus) slices in equilibrium-modified atmosphere packaging.

In this study cut, pineapple slices of 1 cm thick were packaged and stored at different temperatures and equilibrium modified atmosphere packages (EMAPs) to determine changes of color and firmness over time to represent physicochemical shelf life. From the experimental data, a variance analysis was performed to determine the effect of temperature and O2 level on the evolution of color (CIELAB coordinates) and firmness. It was observed that the evolution in L* , a* , and b* coordinates is independent on O2 concentration in the EMAP system. After that, suitable models were adjusted to represent the change of the quality properties as a function of temperature by using first-order models to represent color and a power model for firmness. Likewise, a modified normal distribution function was adjusted to represent the coefficient of firmness loss depending on the O2 level besides the temperature effect. The firmness model was used to obtain a suitable equation to predict shelf life of the pineapple slices for different EMAP systems. Finally, a validation experiment was performed at 8 °C obtaining a high capacity of prediction (R2 adj > 0.90) compared with the experimental data. The adjusted model can be used to configure a satisfactory EMAP system for the best preservation of minimally processed pineapple from the predicted evolution of color, firmness, and shelf life depending on temperature and O2 concentration. PRACTICAL APPLICATION: In this work, we built a mathematical model to simulate the shelf life of pineapple cut into slices based on changes in color and firmness and as a function of temperature and oxygen level. These properties are truly relevant because they are very clear evidence of the fruit deterioration, and for that reason, we chose them for the model. The model we developed can be applied in retail and supermarket systems to determine precisely how long the product on the shelf can last before being disposed of, reducing material losses.

Evaluation of Antimicrobial Coatings on Preservation and Shelf Life of Fresh Chicken Breast Fillets Under Cold Storage.

Fresh poultry products such as chicken breast are very convenient for consumption due to their availability and nutritional and sensory characteristics but they have a short shelf life (3-5 days) due to their high water activity and propensity to microbial contamination and spoilage. In this work, the characteristics of edible coatings (EC) prepared from various formulations of guar gum (GG) and isolated soy protein were evaluated. From this evaluation, and due to the guar gum EC being the most suitable, antimicrobial coatings were prepared with different proportions of GG, nisin, and oregano oil to determine its effect on shelf life and change in physicochemical and microbiological properties of chicken breast fillets under refrigerated conditions. Fresh samples were coated with a coating-forming solution based on GG and stored at 4 °C for 16 days. During this time, the change in color, firmness, acidity, pH, growth of microorganisms was determined, and sensory tests of appearance, taste, and odor were performed. GG-coated samples retained color and firmness during storage. Likewise, a decrease in weight loss was achieved in the treated samples, and the sensory attributes were preserved compared to the uncoated samples. The application of the coating considerably delayed the growth of microorganisms, increasing the product shelf life (9 days) compared to the control samples (6 days).

Evaluation and modeling of changes in shelf life, firmness and color of 'Hass' avocado depending on storage temperature.

In this study, 'Hass' avocado samples were stored at different temperatures to determine changes in firmness, color and other physicochemical support properties throughout the storage time and to represent shelf life depending on temperature from the evolution of these quality properties. From the experimental data, a set of models were adjusted to represent the change of each property as a function of time and temperature by using a first-order kinetics to represent the evolution of lightness (L*) and the chromatic coordinate b*, and a logistic equation to represent firmness and a*. The effect of temperature was represented by using Arrhenius equations. From the models of firmness and color, suitable equations were obtained to predict shelf life considering the relationship with the senescence stage (between 20 and 33 days). All the models were adjusted satisfactorily, obtaining regression coefficients higher than 0.95. In order to determine the predictive capacity of the proposed models, a validation experiment was carried out by storing fruits at 12 ℃ until reaching the senescence stage. With the models, it was possible to satisfactorily predict the changes in color and firmness and it was possible to estimate the shelf life time at 12 ℃ (28 ± 3.1 days).