**2.5 Stone fruits**

Stone fruits are a diverse group, mostly of the genus Prunus, that includes peach, apricot, among others. This group is characterized by a lignified endocarp, a fleshy mesocarp and a thin exocarp or skin [56]. In "Madoka" peach (*Prunus persica* L.), the 1-MCP application in fields has been investigated with regard to fruit physiological and biochemical responses and quality attributes. Lee et al. [57] have observed not only delayed firmness loss but also an inhibition of ethylene production and

respiration during the storage of the peach fruit preharvest-treated with 1-MCP. The inhibition of the expression of the genes related to sugar accumulation and cell wall softening, and of the genes responsive to ethylene receptors, has also been found. These findings suggest that the preharvest 1-MCP application can extend the shelf life of peaches by the inhibition of ethylene production and respiration.

Another assay, which compared the effect of preharvest sprayable 1-MCP (Harvista®) or postharvest fumigable 1-MCP (Smartfresh®) treatments on the quality attributes and enzymatic activities of cell wall hydrolases during the cold storage of "Hetsal Haunkeybee" peaches, has reported that fruit flesh firmness was significantly enhanced by SmartFresh®, but not by Harvista® [58]. The SmartFresh® treatment significantly reduced the enzymatic activities of α-galactosidase, β-galactosidase, β-glucosidase, β-arabinosidase, β- xylosidase, and α-mannosidase during cold storage compared to the untreated and Harvista-treated fruits.

A study on apricot (*Prunus armeniaca* L.) cv. Canino has been conducted to evaluate the effect of preharvest 1-MCP and other field treatments (CaCl2 and AGV), and their combination, on fruit quality parameters during cold storage. This study showed that treatment not only improved fruit postharvest quality but also lowered the incidence of disorders throughout storage. The combination of the three compounds was the most effective treatment in maintaining fruit quality and prolonging storability up to 30 days [2].

#### **2.6 Other fruits**

With mango (*Mangifera indica* L.), the postharvest 1-MCP treatment is necessary for delaying the fast ripening that initiates before fruit harvest maturity. In this situation, preharvest treatment would be a good option for prolonging fruit storability and allow exportation [59]. In mango cv. "Carabao," the preharvest 1-MCP treatment at 10 ppm is effective in slowing external color evolution, delaying ethylene peak, and controlling both ripening and deteriorated visual quality at harvest and during storage at 13°C. However, fruit firmness does not significantly vary among treatments [60]. The fruits treated twice with 1-MCP (10 and 5 days before harvest) obtain the best results than those treated once. The authors concluded that the second application time is crucial because of the variation in the biochemical composition of fruit tissues.

Application time is also critical for the proper response of preharvest 1-MCP in Mangosteen (*Garcinia mangostana* L.). Lerslerwong et al. [61] observed that when treatment was applied in the fruit climacteric stage, it delayed the ripening process by about 1 week. This shows its potential use to retard the harvest period. However, treatment had no effect on fruit ripening when applied before the climacteric peak.

Figs (*Ficus carica* L.) are a postharvest technology challenge because of their very short shelf life and high susceptibility to diseases. The fig ripening process is classified as climacteric, with higher respiration rates and ethylene production at the beginning of the ripening phase. Yet unlike most climacteric fruits harvested before ripening onset, it does not ripen after harvest [62]. The postharvest 1-MCP treatment does not affect the ripening parameters of treated fruits (unlike other climacteric fruits), but applications to fruit on trees improve fruit storage capacity by inhibiting deterioration with minor effects on fruit growth and ripening [63, 64]. The 1-MCP application before or after harvest has also been used as a tool for studying the ethylene-related genes involved in the natural ripening process of attached fruit [22], and a possible

#### *Recent Development in the Preharvest 1-MCP Application to Improve Postharvest Fruit Quality DOI: http://dx.doi.org/10.5772/intechopen.109724*

feedback reaction has been proposed. This downstream component of ethylene signal transduction can play a role in regulating ethylene synthesis during the reaction to 1-MCP, which causes the non-climacteric behavior of fig ethylene production.

The preharvest 1-MCP influence on the development of fruit on trees and storage capacity has been studied in "Brown Turkey" figs [22]. Treatment was applied as gas in plastic bags 3 days before harvest at preclimacteric stage, which delayed fruit senescence and improved storage life up to 7 days as manifested by fruit color, firmness, internal texture, weight, size, shriveling, and decay.

Yellow pitahaya (*Selenicereus megalanthus* Haw) is a tropical fruit that undergoes physiological damage associated with cold storage, including peel browning and necrosis [65, 66]. In addition, fruit quality loss during storage has been associated with ethylene production and fruit respiration. Therefore, postharvest 1-MCP applications are done to extend fruit shelf life. Cock et al. [65] observed that the 1-MCP application 15 days before harvest in yellow pitahaya produced significant beneficial effects on chemical, physical, and sensory properties and extended fruit shelf life by 5 days with no large differences between treatment concentrations (200 or 400 μg L−1). Another study conducted with yellow pitahaya under the same preharvest 1-MCP conditions showed that treatment accelerated epicarp coloration, maintained firmness, and delayed weight loss and the maturity index [66]. However, the higher applied concentration led fruit to show undesirable signs of senescence. The authors suggested that the preharvest 1-MCP application in this fruit could trigger the metabolic processes responsible for shortening fruit preservation, which has been related to both the magnitude and sensitivity to ethylene rises because fewer receptors are evaluable, and effects depend on the compound concentration, application time, and storage time.

Melon (*Cucumis melo* L.) presents a high diversity of ripening behaviors, including climacteric and non-climacteric genotypes [67, 68]. Cantaloupe melons possess typical climacteric behavior with ethylene playing a major role in the regulation of the ripening process and by affecting the ripening rate. Nevertheless, Pech et al. [3] have reported that climacteric (ethylene-dependent) and non-climacteric (ethylene-independent) regulation coexist during climacteric fruits ripening. In two cantaloupe melon cultivars (cv. Caravelle and cv. Mission), the effect of the preharvest 1-MCP application was evaluated in relation to fruit quality, harvest synchrony, and maturity [69]. Treatment was applied at a concentration between 5 and 25 g ha−1 and from 22 to 7 days before harvest. It presented very little or no effect on fruit quality at harvest or after cold storage. Only the cv. Mission treated with the highest concentration presented greater firmness than the other treatments after 9 storage days.

Despite most studies on preharvest and postharvest 1-MCP applications showing positive beneficial effects on maintaining fruit firmness and overall postharvest quality, in blueberry (*Vaccinium corymbosum* L.) the 1-MCP treatment applied at both the pre- and postharvests had negative effects on fruit firmness at harvest and during storage. Previous studies have demonstrated that the postharvest 1-MCP application to "Rabbiteye" blueberry led to increased ethylene production, which caused fruit softening [70]. On to the preharvest treatment, Blaker and Olmstead [71] observed in cv. 'Star" and "Sweetcrisp" that the 1-MCP application 5 days prior to harvest decreased fruit firmness, while the fruit treated 9 days before harvest did not differ from the control. However, the authors are still unclear why the preharvest treatment could result in firmness loss.

### **3. Non-climacteric fruits**

As opposed to climacteric fruits, non-climacteric fruits are characterized by ripening transitions that do not strictly depend on a significant increase in ethylene production and an associated rise in the respiration rate [72, 73]. Although the ripening process of climacteric fruits is well documented, it is not very accurate for non-climacteric fruits. Recent studies using metabolomics, proteomics, and transcriptomics have significantly increased knowledge about molecular processes during non-climacteric fruits ripening [72]. These studies have demonstrated the involvement of different hormones, such as abscisic acid (ABA), auxin, gibberellins, among others. However, the complex mechanisms underlying the regulation and crosstalk between these hormones during fruit development and ripening require further research.

In non-climacteric fruits, applying 1-MCP at the postharvest for ripening control does not make sense because these fruits do not have a response to ethylene for maturation. However, 1-MCP has been applied to some non-climacteric fruits for other purposes to, for instance, provide insights into the occurrence of ethylene-dependent and ethylene-independent events during ripening, including changes in genes expression [10]. A positive effect of the postharvest 1-MCP application on the inhibition of senescence processes has been reported in some non-climacteric fruits, such as reducing rachis browning in grapes and delaying leaf senescence in "Shatangju" mandarins marketed with attached leaves [74, 75].

The postharvest 1-MCP treatment has also been reported to inhibit the development of some physiological disorders, such as scald development in pomegranate, pericarp browning in litchi, water soaking in watermelon, internal browning in loquat, and internal flesh browning of pineapple [76, 77]. Inhibition of degreening and color change are observed in several citrus fruits, strawberry, and olive when 1-MCP has been applied [76].

Very few studies report the preharvest effects of 1-MCP applications on nonclimacteric fruits. In citrus fruits (*Citrus spp*.), the preharvest 1-MCP treatment has been reported to result in reduced undesirable tree defoliation when ethephon is applied to diminish fruit removal force [22, 78]. In "Washington" navel oranges, a higher yield per tree and increased fruit elongation have been found when a combination of preharvest 1-MCP and gibberellic acid (GA3) was applied [79]. Besides, fruit drop considerably reduced when fruits were treated with 1-MCP alone or combined with either NAA or GA3. The combination of 1-MCP with either NAA or GA3 also enhanced the maturity index compared to untreated fruits.

In "Bing" sweet cherry (*Prunus avium* L.), reduced flesh firmness during postharvest life occurred when ethephon was applied to stimulate fruit abscission during mechanical harvest. The 1-MCP treatment performed 3 days after the ethephon application counteracted ethephon-induced flesh firmness loss without inhibiting fruit removal force reduction [80].
