Effects of 1-methylcyclopropene and hot water quarantine treatment on quality of "Keitt" mangos

Evaluating the potential of 1-methylcyclopropene treatments on physicochemical properties, bioactive compounds, and shelf life of mango fruits under different storage conditions

The effect of 1-methylcyclopropene (1-MCP) treatments and storage conditions in the regulation of the physicochemical and bioactive properties of mango fruits (Mangifera indica L. cv. BARI-4) were investigated during storage. Different concentrations of 1-MCP treated samples (T0 = Control, T1 = 0.5 μL/L, T2 = 1.0 μL/L, T3 = 1.5 μL/L, and T4 = 2.0 μL/L) were stored in developed storage structure (10±1 °C and 90 % RH), cold storage (3 ± 1 °C and 80 ± 2 % RH), and ambient storage (29 ± 3 °C and 65 ± 2 % RH). The change in fruit quality including weight loss, firmness, surface color, storage life, chemical, and bioactive properties were studied periodically at 10, 20, 30 and 40 days of storage. The results demonstrated that 1-MCP treatment effectively maintained the quality of fruits by retarding the loss of weight, firmness, total soluble solids (TSS), and titratable acidity, which were served as a quality parameter during storage. The 1-MCP treatment dramatically delayed the change in color, quality measures, and bioactive properties compared to the control group. The storage condition greatly influenced the postharvest quality value and storage life. In combination with the developed storage structure and 1-MCP treatment preserved the acceptability of fruits to a great extent for around 40 days. The T2 = 1.0 μL/L 1-MCP treatment preserved the fruit quality for the highest days of storage 14, 34, and 46 days in ambient storage, cold storage, and develop storage structure respectively. The developed storage structure (10 ± 1 °C and 90 % RH) with 1-MCP (1.0 μL/L) treatment suggested the optimum storage ability for preserving the postharvest storage life of mango fruits. By implementing these findings mango growers and suppliers can reduce post-harvest losses, expand market reach, and provide consumers with high-quality mangoes that retain their quality for an extended period.

Heat transfer analysis during hydrothermal treatment of mango

To export Mexican mango fruit, it is required to comply with phytosanitary regulations, which implies heat transfer. Foods are biological systems with a dynamic behavior and, when they are thermally processed, their thermophysical properties change with temperature. Suitable simulation of heat transfer with temperature-dependent thermophysical properties can provide proper estimations of temperature histories to perform heat penetration analyses. The objective of this study was to predict temperatures within mango and immersion times by varying the mass of the fruit and water temperature during hydrothermal treatments. Thermal conductivity, specific heat capacity, and apparent density of ''Kent'' mango peel and pulp were determined. Finite element analysis was used to simulate heat transfer within the mango. Thermal conductivity and density were different for peel and pulp, but thermal diffusivity for both materials was not different. Predicted temperature histories adjusted properly to experimental data throughout the heating process. This indicates that thermophysical properties as a function of temperature for mango peel and pulp, the convective coefficient, the finite element model, and the methodology used to perform the estimations can be useful in the design of hydrothermal treatments for mango. PRACTICAL APPLICATION: Proper simulation of heat transfer with temperature-dependent thermophysical properties during hot water treatments for mango can provide accurate temperature histories and profiles that allow the prediction of temperatures within the fruit or immersion times by varying the mass and temperature of the heating medium. This will allow a subsequent heat penetration study to predict larval mortality, facilitating the design of quarantine treatments.

Metabolomic and transcriptomic analyses reveal new insights into the role of abscisic acid in modulating mango fruit ripening

Mango (Mangifera indica L.) is a climacteric tropical fruit consumed around the world. Although ethylene and abscisic acid (ABA) have been considered to be stimulators that trigger mango fruit ripening, their regulation mechanisms in modulating mango fruit ripening remain uncertain. In this study, we performed integrative analyses of metabolome and transcriptome data combined with a series of physiological and experimental analyses in the 'Keitt' mango, and we characterized changes in accumulation of specific metabolites at different stages during fruit development and ripening, which were strongly correlated with transcriptional changes and embodied physiological changes as well as taste formation. Specifically, we found that ABA, rather than ethylene, was highly associated with mango ripening, and exogenous ABA application promoted mango fruit ripening. Transcriptomic analysis identified diverse ripening-related genes involved in sugar and carotenoid biosynthesis and softening-related metabolic processes. Furthermore, networks of ABA- and ripening-related genes (such as MiHY5, MiGBF4, MiABI5, and MibZIP9) were constructed, and the direct regulation by the key ABA-responsive transcription factor MiHY5 of ripening-related genes was experimentally confirmed by a range of evidence. Taken together, our results indicate that ABA plays a key role in directly modulating mango fruit ripening through MiHY5, suggesting the need to reconsider how we understand ABA function in modulating climacteric fruit ripening.

Meta-analysis of the effects of 1-methylcyclopropene (1-MCP) treatment on climacteric fruit ripening

1-Methylcyclopropene (1-MCP) is an inhibitor of ethylene perception that is widely used to maintain the quality of several climacteric fruits during storage. A large body of literature now exists on the effects of 1-MCP on climacteric fruit ripening for different species and environmental conditions, presenting an opportunity to use meta-analysis to systematically dissect these effects. We classified 44 ripening indicators of climacteric fruits into five categories: physiology and biochemistry, quality, enzyme activity, color, and volatiles. Meta-analysis showed that 1-MCP treatment reduced 20 of the 44 indicators by a minimum of 22% and increased 6 indicators by at least 20%. These effects were associated with positive effects on delaying ripening and maintaining quality. Of the seven moderating variables, species, 1-MCP concentration, storage temperature and time had substantial impacts on the responses of fruit to 1-MCP treatment. Fruits from different species varied in their responses to 1-MCP, with the most pronounced responses observed in rosaceous fruits, especially apple, European pear fruits, and tropical fruits. The effect of gaseous 1-MCP was optimal at 1 μl/l, with a treatment time of 12-24 h, when the storage temperature was 0 °C for temperate fruits or 20 °C for tropical fruits, and when the shelf temperature was 20 °C, reflecting the majority of experimental approaches. These findings will help improve the efficacy of 1-MCP application during the storage of climacteric fruits, reduce fruit quality losses and increase commercial value.

Generic Irradiation and Hot Water Phytosanitary Treatments for Mango Fruits cv. 'Ataulfo' niño Infested by Anastrepha ludens and Anastrepha obliqua (Diptera: Tephritidae)

The mango fruit cv. 'Ataulfo' niño is an underdeveloped fruit that has a split on the back and a pronounced peak, and among the current total supply of commercialized mangoes cv. 'Ataulfo', approximately 2% are classified as 'Ataulfo' niño, which are strongly infested by Anastrepha ludens (Loew) (Diptera: Tephritidae) and Anastrepha obliqua Mcquart. The objective of this study was to determine the tolerance to 150-Gy generic irradiation for fruit flies of the Anastrepha genus in comparison to the development of a hot water treatment (HWT) as phytosanitary treatments for mango fruits cv. 'Ataulfo' niño infested by A. ludens and A. obliqua. The results indicated that both treatments were effective; 150-Gy irradiation and HWT at 46.3-47°C for 51 min did not result in significant effects on the external and internal color, total sugar content, firmness, pH, or weight. The sensorial quality described by the appearance, flavor, color, and odor did not show any significant differences between treatments. For both A. ludens and A. obliqua, the third larval instar was the most thermotolerant. The efficacy test was conducted with an immersion time of 47 min. A. ludens did not survive, but for A. obliqua, three larvae out of a total of 6,890 did survive and pupate. Consequently, the confirmatory test consisted of submerging mangoes infested with third-instar A. ludens and A. obliqua in water at 46.3-47°C for 51 min. In total, 67,392 A. ludens and 22,086 A. obliqua larvae were treated, and no surviving larvae were observed.

Quality of fresh-cut products as affected by harvest and postharvest operations

There is a rising demand for fresh-cut convenience products with high quality and nutritional standards that needs to be met by the fresh-cut industry. It is well known that harvest and postharvest handling of fresh produce has a paramount impact on its quality and storage, although most of the existing literature has focused on these impacts related only to fresh produce that is destined for the final consumers. Indeed, current harvest methods and postharvest technologies have improved fruit and vegetable handling and distribution processes by slowing down physiological processes and senescence. Nonetheless, these technologies and methods may influence the quality of fresh produce as raw material for fresh-cut processing as a result of the dynamic responses of fresh produce to handling procedures and treatments. Here, we review the existing literature on the challenges facing the fresh-cut industry, focusing on the impact of harvest, maturity, and handling of fruit and vegetables on the quality of raw materials, as well as the implications for fresh-cut products. The review also highlights areas for further research with the aim of enhancing the sensorial, nutritional and biochemical quality of such products. © 2018 Society of Chemical Industry.