Search results for "Cyclopropene"
showing 10 items of 12 documents
Extending the Shelf Life of White Peach Fruit with 1-Methylcyclopropene and Aloe arborescens Edible Coating
2020
The maintenance of high-quality standards for prolonging the shelf life of fruit and preserving sensory and nutritional quality is a priority for horticultural products. The aim of this work is to test the effectiveness of a single treatment of edible coating based on Aloe arborescens (EC) and a combined treatment of 1-methylcycyclopropene (1-MCP) and edible coating to prolong the shelf life of &ldquo
Effects of 1-Methylcyclopropene on postharvest quality traits, antioxidant activity and ascorbic acid content of mature-ripe mango fruits
2017
Introduction - Mango (Mangifera indica L.) is a climacteric fruit, very sensitive to prolonged storage with a relatively short postharvest life. The aim of this study was to investigate the effects of 1-MCP treatment on the pomological and sensory traits, antioxidant capacity and ascorbic acid content in late ripening mature-ripe mango fruits submitted to a simulated shelf life at 20 degrees C. Materials and methods - Mango late ripening fruits (cv. Keitt) were harvested from a commercial orchard, located at Furiano, province of Messina (Sicily, Italy; 38 degrees 3'N, 14 degrees 33'E; 5 m a.s.l.). Fruits were treated with 1-MCP (0.005 kg m(-3)) for 20 h in 1 m(3) closed containers and then …
1-METHYLCYCLOPROPENE DELAYS RIPENING AND IMPROVES POSTHARVEST QUALITY OF WHITE FLESH LOQUAT
2015
The ethylene inhibitor 1-methylcyclopropene (1-MCP) delayed ripening and improved postharvest fruit quality of loquat (Eriobotrya japonica Lindl.). 1-MCP was used on the white flesh sub-acid loquat cultivars ‘Claudia’ and ‘BRT20’ to evaluate the possible effect on fruit ripening and to prevent negative effects of cold storage, like internal browning and flesh leatheriness. 1-MCP was applied at 2°C for 20 h and concentrations of 1 and 5 μl L-1. After 1-MCP treatment fruit were held at 2°C for 7, 14, and 21 days and then moved to 18°C for 5 days. Fruit flesh firmness, titratable acidity (TA), total soluble content (TSS), weight loss, internal browning and flesh leatheriness were evaluated at …
Extension of Walsh's rules to more general systems
1972
It is demonstrated that location of hydrogen atoms within bonding distance of a simple triatomic molecule can alter the order of energy levels relative to that of the parent system without significantly changing the behavior of the orbital energies under geometrical variation. As a result the ground state electronic configurations of H n AB2 systems often differ from those of triatomics with the same number of electrons and this fact is shown to be directly responsible for the existence of such distinctive geometrical structures as those possessed by cyclopropane, cyclopropyl and allyl cations and cyclopropene. Thus the familiar prescription of Walsh's rules which states that isoelectronic …
Inhibition of fatty acid delta 6- and delta 5-desaturation by cyclopropene fatty acids in rat liver microsomes.
1993
delta 6-Desaturation of linoleic acid and delta 5-desaturation of dihomo-gamma-linolenic acid were measured in liver microsomes from rats fed fresh Baobab seed oil containing cyclopropene fatty acids (malvalic acid and sterculic acid) or heated Baobab seed oil practically devoid of these fatty acids or control oil. The presence of cyclopropene fatty acids in the fresh Baobab oil diet highly depressed both desaturations, but delta 6- more than delta 5-desaturation. The decreased capacity of microsomes to desaturate was reflected in the lower arachidonic acid content in microsomal phospholipids from rats fed this oil. However it was also lower in rats fed heated oil although in vitro delta 6-…
Effect of 1-methylcyclopropene on ripening of melting flesh peaches and nectarines
2004
Abstract 1-Methylcyclopropene (1-MCP), an ethylene action inhibitor, was applied to early season, melting flesh stone fruit to try to extend their shelf life. ‘Almog’ and ‘Oded’, two white flesh peaches, and ‘April Glow’, a yellow flesh nectarine, were tested. Application of 1-MCP was at both 20 and 0 °C for 5, 10 and 20 h and at concentrations from 0.5 to 20 μl l −1 . When treated at 0 °C the fruits were stored for 5 days before removal to 20 °C for ripening. 1-MCP slowed fruit softening in a concentration and time dependent manner, extending the period before the fruits became over-soft. The inhibition of softening was greater when fruits were treated and held at 20 °C than if they were t…
A DFT study of the ionic [2+2] cycloaddition reactions of keteniminium cations with terminal acetylenes
2015
Abstract The molecular mechanism of the ionic [2+2] cycloaddition (I-22CA) reactions of a keteniminium cation (KC) with acetylene and propyne has been investigated using DFT methods at the MPWB1K/6-311G(d,p) level. These I-22CA reactions take place via a two-step mechanism. The first step is the nucleophilic attack of these alkynes on the central carbon of KC, yielding cyclopropene intermediates, while the second step corresponds to the conversion of these intermediates into more stable cyclobuteniminium cations (CCs). The first step is the rate-determining step, while the second step is responsible for the formation of the two regioisomeric CCs experimentally observed in the reaction with …
Effect of 1-methylcyclopropene on cactus pear fruit at different maturity stages during storage
2019
1-Methylcyclopropene (1‑MCP) is an ethylene antagonist widely used to retain quality and prolong the postharvest storage period of various climacteric fruits. To date, there is little information about the effects of 1‑MCP on postharvest storage performance of cactus pear fruits. Recently, data revealed that exposure of 1‑MCP at 1000 ppb had several beneficial effects in preserving postharvest quality of cactus pear fruits, as indicated by inhibition of peel color change. In this paper, we investigated the effect of 1‑MCP on quality of cactus pear fruit harvested from the scozzolatura crop at early and late ripeness stages. Fruit was tested at two different ripening stages: “commercial ripe…
Multiconfigurational perturbation theory (CASPT2) applied to the study of the low-lying singlet and triplet excited states of cyclopropene
1996
The electronic spectrum of cyclopropene has been studied using multiconfigurational second-order perturbation theory (CASPT2) with extended ANO-type basis sets. The calculation comprises two valence states and the 3s, 3p, 3d members of the Rydberg series converging to the π and σ ionization limits. A total of twenty singlet and twenty triplet excited states have been analyzed. The results confirm the valence nature of the lowest energy singlet-singlet band and yield a conclusive assignment: the first dipole-allowed transition in cyclcopropene is due to absorption to a (σ → π*) state. The (π → π*) (V) state is interleaved among a number of Rydberg states in the most intense band of the syste…
Effects of 1-MCP on post harvest quality and internal browning of white-flesh loquat fruit during cold storage
2017
Introduction – Treatments with 1-methylcyclopropene (1-MCP), an inhibitor of ethylene perception, were investigated on white-flesh loquat fruit to extend its shelf life and to prevent chilling injury. Ma- terials and methods – The loquat (Eriobotrya japonica Lindl.) white-flesh fruits (cv. Claudia) were submitted to applications of 1-MCP at 1 °C for 20 h and at concentrations from 1 to 5 μL L . The treated fruits were stored at 1 °C for 21 days before removal to 20 °C for ripening (shelf life). Fruit quality was analyzed at harvest, at the end of each storage period (7, 14, 21 days at 1 °C). Results and discussion - The 1-MCP treatment slowed fruit softening depending on concentration, and …