Modelling the evolution of O2 and CO2 concentrations in MAP of a fresh product: Application to tomato

Recent Advances in Reducing Food Losses in the Supply Chain of Fresh Agricultural Produce

Fruits and vegetables are highly nutritious agricultural produce with tremendous human health benefits. They are also highly perishable and as such are easily susceptible to spoilage, leading to a reduction in quality attributes and induced food loss. Cold chain technologies have over the years been employed to reduce the quality loss of fruits and vegetables from farm to fork. However, a high amount of losses (≈50%) still occur during the packaging, pre-cooling, transportation, and storage of these fresh agricultural produce. This study highlights the current state-of-the-art of various advanced tools employed to reducing the quality loss of fruits and vegetables during the packaging, storage, and transportation cold chain operations, including the application of imaging technology, spectroscopy, multi-sensors, electronic nose, radio frequency identification, printed sensors, acoustic impulse response, and mathematical models. It is shown that computer vision, hyperspectral imaging, multispectral imaging, spectroscopy, X-ray imaging, and mathematical models are well established in monitoring and optimizing process parameters that affect food quality attributes during cold chain operations. We also identified the Internet of Things (IoT) and virtual representation models of a particular fresh produce (digital twins) as emerging technologies that can help monitor and control the uncharted quality evolution during its postharvest life. These advances can help diagnose and take measures against potential problems affecting the quality of fresh produce in the supply chains. Plausible future pathways to further develop these emerging technologies and help in the significant reduction of food losses in the supply chain of fresh produce are discussed. Future research should be directed towards integrating IoT and digital twins for multiple shipments in order to intensify real-time monitoring of the cold chain environmental conditions, and the eventual optimization of the postharvest supply chains. This study gives promising insight towards the use of advanced technologies in reducing losses in the postharvest supply chain of fruits and vegetables.

Respiratory properties of fresh black carrot (Dacus Carota L.) based upon non-linear enzyme kinetics approach

The present work was undertaken with an objective to evaluate the impact of temperature on respiration rate of fresh black carrot using a non-linear enzyme kinetics approach. Two different models viz. Arrhenius equation (temperature effect) and enzyme kinetics (effect of temperature and headspace concentration) have been compared for predicting the respiration rate of black carrot. The respiratory behavior of black carrot was assessed using closed system technique at 5, 10 and 15 °C (± 1 °C) temperature and constant relative humidity (RH) of 85%. The O₂ consumption and CO₂ evolution rate values were 39.17, 58.88 and 68.08 ml kg^-1 h^-1; 22.15, 34.63 and 41.86 ml kg^-1 h^-1 after the attainment of steady-state condition at 5, 10 and 15 °C, respectively. The inhibition by evolved CO₂ was found to be predominantly competitive at all temperatures. The average absolute deviation in O₂ consumption and CO₂ evolution rate for Arrhenius model was 3.5% and 5.3% while for enzyme kinetics model was 8.8% and 6.3%, respectively. Dependency of respiration rate of black carrot on temperature was well defined by Arrhenius model. The outcomes of the study can be further utilized to design the MAP (modified atmosphere packages) for fresh black carrot storage at 5 °C with 85% RH.

Chromatic Sensor to Determine Oxygen Presence for Applications in Intelligent Packaging

A chromatic sensor has been designed for the detection of oxygen in package headspace. The sensor is based on the redox change of methylene blue (MB) to its leuco form. Its formulation includes the pigment, glycerol, as a sacrificial electron donor, TiO₂, as a photocatalyst and ethylene-vinyl alcohol copolymer (EVOH), as a structural polymer matrix. The final sensor design that allows its manufacture by conventional printing and laminating technologies consists of the sensing polymer matrix (MB-EVOH) sandwiched in a suitable transparent multilayer structure. The outer layers protect the sensor from the external atmosphere and allow visualization of the colour. The inner layer is sufficiently opaque to facilitate sensor reading from the outside, is thick enough to avoid direct contact with food (functional barrier), and is oxygen-permeable to expose the sensing material to the internal package atmosphere. In the absence of oxygen, the sensor becomes white by irradiation with halogen lamps in less than 60 s. All components are substances permitted for food contact except the pigment, but specific migration analysis showed no trace of migration thanks to the functional barrier included in the design.

Dried-Fruit Storage: An Analysis of Package Headspace Atmosphere Changes

The quality of packaged dried foods depends on storage conditions and is determined largely by the initial gas composition inside and the transference through the container. The aim of this work was to analyze the O₂ and CO₂ concentrations within the internal atmosphere of the packaging. In this study, dried apricots and raisins were packaged in glass jars and polypropylene trays thermosealed with different polymers, and stored at 5, 15, 25, and 35 °C. Some trays were flushed with nitrogen just before sealing. In addition, the work relates to other previous papers to investigate the effect of these gases and packages on the stored products, and compares the influence of permeable and impermeable containers on food quality parameters. When packages were flushed with nitrogen before sealing, the O₂ level in the headspace increased until the outside O₂ concentration was reached. The CO₂ concentration increased over time, regardless of the initial atmosphere. Nitrogen had a great influence on the concentration of O₂, but not on that of CO₂. Finally, this paper shows that the films and initial gas used in this study had no significant effect on the quality of the stored dried fruit.