EFFECTS OF 1-METHYLCYCLOPROPENE AND MODIFIED ATMOSPHERE PACKING ON POSTHARVEST LIFE AND QUALITY IN TOMATOES

Characterization and application of the nanocompiste packaging films containing clay and TiO2 on preservation of tomato fruit under cold storage

BACKGROUND

Tomato (Lycopersicon esculentum), a valuable economic crop worldwide, often goes to waste due to improper packaging and handling. In the present study, three types of low-density polyethylene nanocomposite films containing 3% clay (Closite 20A), 3% TiO2 nanoparticles, and their combination were synthesized using melt blending method, and evaluated on the quality parameters of tomato fruit during 42 days of storage at 4 °C.

RESULTS

Transmission electron microscopy confirmed the degree of dispersion and exfoliation of the nanoparticles. The TiO2/clay-nanocomposite films exhibited notable enhancements in Young's modulus and tensile strength compared to conventional films. The addition of clay and TiO2 nanoparticles resulted in reduced permeability to CO2, O2, and water vapor. Fruits packed with clay/TiO2 nanocomposite films showed decreased ethylene production, mitigated weight loss, and maintained pH, titratable acidity, total soluble solids, and firmness. Furthermore, clay/TiO2 nanocomposite films enhanced membrane stability, decreased membrane lipid peroxidation, and enhanced catalase and ascorbate peroxidase enzyme activity in fruits.

CONCLUSIONS

The relatively good exfoliation of clay nanoparticles and the proper dispersion of TiO2 nanoparticles, which were confirmed by TEM, led to an increase in mechanical and physical properties in the Clay/TiO2 nanocomposite. This film displayed more potential in maintaining the quality properties of tomato fruit during cold storage. Therefore, this film can be considered a practical solution for minimizing pathogen risks and contamination, and enhancing the overall quality of tomato fruit.

Prestorage High CO2 and 1-MCP Treatment Reduce Chilling Injury, Prolong Storability, and Maintain Sensory Qualities and Antioxidant Activities of “Madoka” Peach Fruit

Cold storage is widely used to prolong the storability of peach fruit. However, prolonged storage at low temperatures results in chilling injury (CI) in some susceptible peach cultivars during or after cold storage. Prestorage high CO₂ and 1-methylcyclopropene (1-MCP) treatments are among the methods reported to alleviate CI and maintain the firmness of peach fruit. Hence, this study investigated CI, ripening-related physicochemical parameters, sensory qualities, total phenolics and flavonoids, and antioxidant activities of “Madoka” peach fruit to observe the effectiveness of prestorage treatment with high CO₂ and 1-MCP during the storage at 0 and 5°C. Based on the CI index, control fruits were acceptable for marketing up to 20 and 16 days of storage at 0 and 5°C, respectively, while the treated fruits could be marketable up to 28 days of storage. The results of firmness and firmness-related parameters [pectin content and polygalacturonase (PG) activity] also revealed that both high CO₂ and 1-MCP treatments were effective in delaying the ripening process of Madoka peach, and the storage at 0°C showed better results than at 5°C. However, based on the overall sensory evaluation results, the treated and control fruits were acceptable for marketing up to 20 and 12 days of storage, respectively, in both storage conditions. After deciding on fruit marketability based on the combined objective postharvest quality parameters and subjective sensory qualities, we analyzed the changes in total phenolics, flavonoids, and antioxidant activities at harvest, on the 12 and 20th days of cold storage. Storage of Madoka peach at 0°C maintained total phenolics, flavonoids, and antioxidant activities regardless of prestorage treatment with high CO₂ and 1-MCP. In summary, storing Madoka peach fruit at 0°C after treating it with 30% CO₂ for 6 h or 0.5 μl L^–1 1-MCP for 24 h reduces CI, prolongs storability, and maintains sensory quality and antioxidant properties.

Physiological changes in green and red cherry tomatoes after photocatalytic ethylene degradation using continuous air flux

In this work photocatalytic ethylene degradation (TiO₂-UV) was applied in green cherry tomatoes with the aim to control biochemical and physiological changes during ripening. Photocatalytic process was performed at 18 °C  ±  2 °C and 85% HR for 10 days using continuous air flux. Ethylene, O₂ and CO₂ concentration from cherry tomatoes under TiO₂-UV and control (c) fruits, were measured by GC-MS for 10 days. After that, the tomatoes were stored for 20 days. During the photocatalysis process, ethylene was completely degraded and control fruits, the ethylene was 28.73 nL g^-1. Respiration rate was lower for fruits under TiO₂-UV than control. During storage period, cherry tomatoes treated by TiO₂-UV, showed lower ethylene concentration, respiration rate, total soluble solid, lycopene, sugar and organic acid content than control showing that the fruits treated with photocatalysis did not reach the full maturity. In addition, all the cherry tomatoes showed different maturity stages. Fungal incidence was higher in control fruits than fruits treated with photocatalysis. This research showed for the first time that photocatalytic technology preserved the physiological quality of cherry tomatoes for 30 days of storage, being a promised technology to preserve cherries tomatoes.

Evaluation of a modified atmosphere packaging system in pallets to extend the shelf-life of the stored tomato at cooling temperature

A modified atmosphere packaging (MAP) system in pallets was developed and its effect on physico-chemical and sensory characteristics and shelf-life of tomato was evaluated. Tomatoes were stored at 6 °C in cardboard boxes arranged on pallets wrapped in micro-perforated low-density polyethylene (LDPE) bags. Effects of the storage time and packaging were evaluated after 0, 7, 14, and 21 days of storage. The MAP system with pallets assessed, using a packaging atmosphere composition of 10% O₂ - 10% CO₂ and silica gel as an adsorbent, extended the shelf-life of the tomato stored at refrigeration temperature. MAP delayed color evolution and reduced the firmness loss, biosynthesis of lycopene, and decay rate of tomato. At the end of storage, 100% of the unpackaged samples showed spots while only 42.9% of MAP samples had them. In addition, the percentage of tomatoes with cracks and stretch marks was reduced from 42.9% (unpackaged tomatoes) to 14.3% (MAP tomatoes).