1-Methylcyclopropene interactions with diphenylamine on diphenylamine degradation, alpha-farnesene and conjugated trienol concentrations, and polyphenol oxidase and peroxidase activities in apple fruit

1-Methylcyclopropene (1-MCP) is a new technology that is applied commercially to inhibit ethylene action in apple fruit, but its interactions with existing technologies such as diphenylamine (DPA) for control of superficial scald development in fruit during and after storage is unknown. To investigate possible interactions between 1-MCP and DPA, Delicious apples were untreated or treated with 2 g L(-1) DPA, and then with or without 1 microL L(-1) 1-MCP. Ethylene production and respiration rates of fruit were measured immediately following treatment, and fruit was stored at 0.5 degrees C for 12 weeks. Internal ethylene concentrations (IEC), alpha-farnesene and conjugated trienol (CTol) concentrations, activities of peroxidase and polyphenol oxidase (PPO), and DPA levels in the skin of the fruit were measured at intervals during storage. 1-MCP reduced the rate of DPA loss from peel tissue so that by 12 weeks of storage concentrations of the chemical were 25% higher than in untreated fruit. 1-MCP, with and without DPA, markedly inhibited ethylene production and respiration rates, maintained low IEC and alpha-farnesene and CTol concentrations, while DPA had little effect on these factors except inhibition of CTol accumulation. Treatment effects on peroxidase and PPO activities were inconsistent.     

Temperature-dependent autoxidation of conjugated trienols from apple peel yields 6-methyl-5-hepten-2-one, a volatile implicated in induction of scald

Conjugated triene (CT) oxidation products of alpha-farnesene have long been thought to be involved in development of superficial scald in apple fruit. Early studies found that CT hydroperoxides and the volatile 6-methyl-5-hepten-2-one (MHO) are major in vitro autoxidation products of alpha-farnesene. However, it was recently shown that > or =99% of the oxidation products of alpha-farnesene that accumulate in apple peel are conjugated trienols (CTols), isomers of 2,6,10-trimethyldodeca-2,7,9,11-tetraene-6-ol. HPLC-purified CTols from fruit of two scald-susceptible cultivars, Granny Smith (GS) and Red Delicious (RD), were used to study autoxidation of these compounds in vitro. Incubation of CTols in sealed glass vials under air resulted in accumulation of MHO. Oxygen enrichment did not increase the amount of MHO produced. Regardless of which cultivar CTols were derived from, at 0 degrees C autoxidation yielding MHO was quite slow and linear, whereas at 20 degrees C MHO production was much more rapid, and after several hours the rate increased abruptly. However, CTols isolated from GS and RD fruit differed in the duration of the initial lag phase and the overall level of MHO generated at 20 degrees C. The sharp increase in MHO production occurred after 3 h with GS CTols and at about 12 h with RD CTols. Also, the yield of MHO from GS CTols after 6 h at 20 degrees C was nearly 6-fold greater than that from RD CTols after 20 h at 20 degrees C. The antioxidants butylated hydroxytoluene and diphenyamine reduced the yield of MHO by about 97%. Recent work has shown that MHO can induce scald-like symptoms in apple peel and that tissue sensitivity increases with time in storage. This may explain the correlation between high CTol levels and scald development, and why symptoms rapidly intensify when fruits are removed from cold storage.     

Influence of 1-methylcyclopropene on ripening,storage life,and volatile production by d'Anjou cv. pear fruit

d'Anjou cv. pear fruit (Pyrus communis L.) exposed at harvest to 0, 0.42, 4.2, or 42 micromol m(-)(3) 1-methylcyclopropene (1-MCP) for 12 h at 20 degrees C were stored at 1 degrees C for up to 8 months. After storage, half of the fruit was continuously exposed to ethylene (0.45 or 4-18 mmol m(-)(3)) for 7 days at 20 degrees C. All fruit treated with 1-MCP had lower respiration and ethylene production compared to untreated controls. Fruit quality changes were delayed following 1-MCP treatment, as was development of superficial scald and peel yellowing. The duration of 1-MCP-induced responses was dependent on 1-MCP treatment concentration. When 1-MCP-treated fruit began to ripen, softening and production of volatile compounds proceeded similar to that of untreated fruit. Post-storage ethylene exposure did not consistently stimulate ripening of fruit previously treated with 1-MCP. Efficacy of ethylene treatment depended on 1-MCP concentration and storage duration.     

Oxidation products of alpha-farnesene associated with superficial scald development in d'Anjou pear fruits are conjugated trienols

Conjugated triene (CT) oxidation products of the acyclic sesquiterpene (E,E)-alpha-farnesene are thought to induce development of the physiological storage disorder superficial scald in apple and pear fruits of susceptible cultivars. CTs that accumulate in peel tissues of Granny Smith and Delicious apples after several weeks of cold storage are known to be conjugated trienols (CTols) rather than the corresponding hydroperoxides produced by in vitro autoxidation of alpha-farnesene. Here, it is shown that CTols are also the predominant in vivo oxidation products of alpha-farnesene in cold-stored pear fruit of the highly scald-susceptible d'Anjou cultivar. Analysis by octadecylsilane reversed phase high-performance liquid chromatography with diode array detection, gas chromatography with flame ionization detection, gas chromatography-mass spectrometry, and proton nuclear magnetic resonance spectroscopy identified 3,7,11-trimethyldodeca-1,3(E),5(E),10-tetraen-7-ol as the major CT in hexane extracts of peel tissue from d'Anjou pears stored for 3-5 months in air at -1 degrees C. The possible origins of CTols in apples and pears and the hypothesized role of these oxidation products of alpha-farnesene in the induction of scald are discussed. .     

Peroxidase activity and superficial scald development in apple fruit

The relationship between soluble peroxidase (EC 1.11.1.7; POX) activity and the development of a chilling-related disorder, superficial scald, was studied in three apple fruit (Malus x domestica Borkh.) systems: a White Angel x Rome Beauty population with progeny with different scald susceptibilities; Delicious from three harvests with progressively declining scald susceptibility; and the scald-resistant Idared and the scald-susceptible Law Rome. Differences in incidence and severity of scald in progeny from White Angel x Rome Beauty progeny tended to show relationships with POX activity at harvest, but, overall, associations were not consistent. However, greater scald incidence and lower POX activity were found in less mature Delicious fruit than in later harvested fruit. Also, the scald-resistant Iotadared had a much higher POX activity compared with the scald-susceptible Law Rome. A general hypothesis that POX activity is related to scald susceptibility was generally supported, but exceptions were observed.     

Interactive responses of gala apple fruit volatile production to controlled atmosphere storage and chemical inhibition of ethylene action

Gala apples exposed to the ethylene action inhibitor 1-methylcyclopropene (1-MCP) for 12 h at 20 degrees C were stored at 1 degrees C in air or a controlled atmosphere (CA) maintained at 1 kPa O2 and 2 kPa CO2. Volatile compounds were measured after 4, 12, 20, and 28 weeks plus 1 or 7 days at 20 degrees C. Treatment with 1-MCP and then storage in air or CA or storage in CA without 1-MCP treatment reduced volatile production as compared to apples not treated with 1-MCP stored in air. The reduced production of esters, alcohols, aldehydes, acetic acid, and 1-methoxy-4-(2-propenyl)benzene was observed. Ester production by fruit stored in CA decreased throughout the storage period regardless of previous 1-MCP treatment. The production of esters, alcohols, aldehydes, acetic acid, and 1-methoxy-4-(2-propenyl)benzene by 1-MCP-treated fruit stored in air plus 7 days at 20 degrees C increased after 20 or 28 weeks of storage. Continuous exposure to 417 micromol m(-3) ethylene for 7 days at 20 degrees C after 12 or 28 weeks of storage stimulated production of many volatile compounds, primarily esters and alcohols, by fruit stored in CA or 1-MCP-treated apples stored in air. However, exposure to ethylene had no effect on the production of aldehydes or acetic acid.     

Diphenylamine metabolism in 'braeburn' apples stored under conditions conducive to the development of internal browning

Diphenylamine metabolism and ethylene action were evaluated as factors influencing the development of 'Braeburn' apple internal browning and cavitation during cold storage. Apples treated with the antioxidant diphenylamine (DPA) and/or the ethylene action inhibitor 1-methylcyclopropene (1-MCP) were held at 1 degrees C for up to 6 months in air or a controlled atmosphere (CA) containing 1 kPa of O2 and 3 kPa of CO2. Cortex tissues from fruit without disorders as well as from symptomatic and asymptomatic areas of fruit with disorders were analyzed for DPA and DPA derivative content. Internal browning and cavities developed in control and 1-MCP-treated fruit stored in CA, whereas air-stored and CA fruit treated with DPA or with DPA and 1-MCP prior to storage did not develop disorders. Depending on the storage regimen and duration, less DPA was detected in 1-MCP-treated fruit. The 4-hydroxydiphenylamine (4OHDPA) content of control fruit decreased during air storage duration but increased between 2 and 4 months in CA storage. 4OHDPA content in 1-MCP-treated fruit increased with storage duration in CA but not air. N-Nitrosodiphenylamine (NODPA) was detected after 2 months in control fruit stored in air or CA and in 1-MCP-treated fruit stored in CA, and NODPA content in control fruit was higher compared to that in 1-MCP-treated fruit. Accumulation of 4-methoxydiphenylamine (4MeODPA) in control fruit stored in air increased with storage duration, but 4MeODPA content did not change in 1-MCP-treated fruit stored in air or CA. 2-Nitrodiphenylamine content was reduced by prestorage treatment with 1-MCP, but storage environment and duration had no effect on its accumulation. The results indicate that CA storage increases the risk of disorder development in 'Braeburn' apples, that DPA can prevent disorder development, and that the content of DPA and DPA derivatives is influenced by storage environment and ethylene action. A clear relationship between DPA derivative formation and storage conditions that promote internal browning was not apparent.     

Influence of ethylene action, storage atmosphere, and storage duration on diphenylamine and diphenylamine derivative content of Granny Smith apple peel

The application of diphenylamine (DPA) to prevent the apple peel disorder superficial scald can result in accumulation of a number of DPA derivatives resulting from C-nitration, C-hydroxylation, O-methylation, and N-nitrosation during fruit storage. As the presence of these compounds may be indicative of metabolic processes leading to superficial scald development, the contents of DPA and DPA derivatives were determined in fruits treated at harvest with DPA or DPA plus the ethylene action inhibitor 1-methylcyclopropene (1-MCP), which also prevents scald development. Influences of fruit maturity, storage environment, storage duration, and a 14 day poststorage ripening period on accumulation of DPA metabolites were also assessed. Poststorage ripening, 1-MCP treatment, and controlled atmosphere storage had varied effects on DPA derivative contents suggesting that reactive oxygen and nitrogen species, such as *OH, *NO, and *NO2, or enzyme-catalyzed reactions may be present during certain ripening and senescence-related physiological processes. Definitive correlations between superficial scald incidence and contents of specific derivatives were not observed.     

Effect of superficial scald suppression by diphenylamine application on volatile evolution by stored Cortland apple fruit

Cortland apple fruit (Malus x domestica Borkh.) stored for 120-140 days in air at 0 degrees C were warmed to 22 degrees C and held for 8 days. A portion of the fruit was dipped in a solution of diphenylamine (DPA) at harvest to prevent scald development. Scald occurred only in those fruit not treated with DPA, and its development was accelerated after transfer to 22 degrees C. Ester production from apple fruit tended to increase from day 0 to day 6 of poststorage holding and declined thereafter in both treatments. However, ester production in scald-developing fruit was reduced by approximately 50%. The reduction in volatile production remained relatively constant during the rapid development of scald symptoms. Furthermore, the reduction in volatile production appeared to be independent of respiration and ethylene production. Production of esters derived from hexanol was most reduced in fruit developing scald, with hexyl 2-methylbutanoate production being reduced approximately 15-fold. Interestingly, the production of methyl butanoate was detected only in scalding fruit. alpha-Farnesene production in fruit developing scald was reduced 43% compared with DPA-treated fruit. In contrast, the primary volatile oxidation product of alpha-farnesene, 6-methyl-5-hepten-2-one (MHO), was present only in fruit developing scald. The data suggest that inhibition of ester production may occur as a result of the physiological changes associated with susceptibility to, rather than expression of, scald symptoms.     

Development of apple superficial scald, soft scald, core flush, and greasiness is reduced by MCP.

1-Methylcyclopropene (MCP) was used to evaluate the role of ethylene in development of apple (Malus x domestica Borkh.) physiological disorders during storage. Granny Smith, Red Chief Delicious, and Fuji apple fruit were treated with MCP at a concentration of 1 microL L(-)(1) for 12 h at 20 degrees C. For all varieties stored at 0 degrees C, ethylene production and respiration rates were reduced for several months following MCP treatment, and firmness and titratable acidity of treated fruit were higher compared to controls. Apples treated with MCP did not develop superficial scald or peel greasiness through 6 months storage plus ripening at 20 degrees C for 7 days. Core flush was not observed in MCP-treated fruit until 6 months after treatment when the incidence was still lower compared to control fruit. MCP delayed the rise in production of alpha-farnesene and reduced accumulation of its oxidation products.     

Influence of ethylene inhibition by 1-methylcyclopropene on apricot quality,volatile production,and glycosidase activity of low- and high-aroma varieties of apricots

Apricots of two varieties, Ceccona with strong aroma and San Castrese with low aroma but good firmness, were treated with 1 microL L(-)(1) 1-methylcyclopropene (1-MCP) for 12 h at 20 degrees C and then kept for shelf life at 20 degrees C and 85% relative humidity. 1-MCP treatment strongly inhibited ethylene production in apricots of both varieties, and softening was delayed. Fruit softening started before the rise of ethylene in air-treated apricots, which softened even when the rise of ethylene production was inhibited by 1-MCP. The softening reduction was more significant in Ceccona apricots than in San Castrese. Pectinmethylesterase (PME) activity declined in Ceccona fruit regardless of the treatment; in San Castrese, PME of air-treated fruit slightly increased, whereas in 1-MCP-treated apricots the activity declined. alpha-d-Galactosidase (alpha-gal) and beta-d-galactosidase (beta-gal) activities in Ceccona apricot were significantly reduced by 1-MCP treatment, whereas in San Castrese apricot no difference in activities was observed between air- and 1-MCP-treated fruit. The pattern of beta-d-xylosidase (xyl) activity in San Castrese apricot was similar to that of beta-gal, showing a peak on day 4 without difference between treatments. alpha-d-Mannosidase (alpha-man) activity of air-treated apricots of both varieties rose slightly, and 1-MCP treatment decreased the enzyme activity in both varieties. alpha-d-Glucosidase (alpha-glu) decreased in air-treated apricots in both varieties, and 1-MCP maintained higher activity in Ceccona fruit but not in San Castrese. Acidity decreased during postharvest ripening regardless of the treatment, whereas soluble solids content (SSC) increased in Ceccona apricot and slightly diminished in San Castrese ones without any effect by 1-MCP treatment. 1-MCP did not show any effect on apricot color; in contrast, it affected the volatiles profile, especially in Ceccona apricot, reducing the synthesis of lactones and promoting the rise of terpenols.     

Stripped corn oil controls scald and maintains volatile production potential in golden supreme and delicious apples

Effects of stripped (alpha-tocopherol < 5 mg L(-)(1)) corn oil on flesh firmness, skin color, acidity, soluble solids content (SSC), scald, and fruit volatiles during 6 months at 0 degrees C were studied using Golden Supreme and Delicious apples. Treatment with 10% oil emulsion reduced production of ethylene, alpha-farnesene, and major volatile esters in the first 3 months of storage, but this trend reversed after 5 months. After 6 months at 0 degrees C plus 7 days at 20 degrees C, oil-treated fruit were firmer and greener and had higher levels of titratable acidity than the controls. In addition, control fruit developed 27% and 42% scald in Golden Supreme and Delicious apples, respectively, whereas oil-treated fruit were free from scald. Soluble solids content and ethanol production were unaffected by oil treatment.     

Benzylglucosinolate, benzylisothiocyanate, and myrosinase activity in papaya fruit during development and ripening

Papaya is a climacteric fruit that has high amounts of benzylglucosinolates (BG) and benzylisothiocyanates (BITC), but information regarding levels of BG or BITC during fruit development and ripening is limited. Because BG and BITC are compounds of importance from both a nutritional and a crop yield standpoint, the aim of this work was to access data on the distribution and changes of BG and BITC levels during fruit development and ripening. BG and BITC levels were quantified in peel, pulp, and seeds of papaya fruit. Volatile BITC was also verified in the internal cavity of the fruit during ripening. The influence of the ethylene in BG and BITC levels and mirosinase activity was tested by exposing mature green fruits to ethylene and 1-methylcyclopropene (1-MCP). The highest BG levels were detected in seeds, followed by the peel and pulp being decreased in all tissues during fruit development. Similarly, the levels of BITC were much higher in the seeds than the peel and pulp. The levels of BG for control and ethylene-treated fruit were very similar, increasing in the pulp and peel during late ripening but not changing significantly in seeds. On the other hand, fruit exposed to 1-MCP showed a decrease in BG amount in the pulp and accumulation in seed. The treatments did not result in clear differences regarding the amount of BITC in the pulp and peel of the fruit. According to the results, ethylene does not have a clear effect on BITC accumulation in ripening papaya fruit. The fact that BG levels in the pulp did not decrease during ripening, regardless of the treatment employed, and that papaya is consumed mainly as fresh fruit, speaks in favor of this fruit as a good dietary source for glucosinolate and isothiocyanates.     

Papaya fruit ripening: response to ethylene and 1-methylcyclopropene (1-MCP)

Ripening affects the quality and nutritional contents of fleshy fruits, and papayas are climacteric fruits very susceptible to postharvest losses due to the fast softening caused by ethylene. This paper reports the changes in respiration, ethylene production, and pulp color and firmness, along with the contents of soluble sugars and major carotenoids, during ripening of 'Golden' papaya, an important Brazilian cultivar that has been exported to North American and European markets. The results obtained for nontreated and ethylene- or 1-MCP-treated papaya suggest that 1-MCP can decrease the quality of treated fruit and that even the use of ethylene for triggering or inducing homogeneous ripening can result in lower quality when compared to that of fruit allowed to ripe naturally.     

Relationship of superficial scald development and alpha-farnesene oxidation to reactions of diphenylamine and diphenylamine derivatives in Cv. Granny Smith apple peel

Cv. Granny Smith apple fruit, treated at harvest with aqueous emulsions containing diphenylamine (DPA) and DPA derivatives, were evaluated for the peel disorder superficial scald (scald) after 6 months of cold storage at 1 degrees C plus 0 or 7 days at 20 degrees C. Metabolism of these derivatives and alpha-farnesene oxidation were also evaluated after 6 months. Derivatives substituted at the para position prevented scald, but scald developed on fruit treated with derivatives substituted in the amino, ortho, or meta positions. The extent of scald control was also dependent on the chemical nature of the functional group used to derivatize DPA. Hydroxylation of DPA and DPA derivatives during storage was not associated with scald control. Methoxylated DPA derivatives produced during storage resulted from O-methylation of C-hydroxylated derivatives rather than C-methoxylation of DPA. N-Nitrosodiphenylamine provided partial scald control, possibly resulting from its degradation to DPA, indicating that the amino hydrogen of DPA may be crucial for scald control. Results suggest that functional group position and chemical properties both contribute to the efficacy of DPA derivatives for scald control.     

Antioxidant activity of apple peels

Consumption of fruits and vegetables has been shown to be effective in the prevention of chronic diseases. These benefits are often attributed to the high antioxidant content of some plant foods. Apples are commonly eaten and are large contributors of phenolic compounds in European and North American diets. The peels of apples, in particular, are high in phenolics. During applesauce and canned apple manufacture, the antioxidant-rich peels of apples are discarded. To determine if a useful source of antioxidants is being wasted, the phytochemical content, antioxidant activity, and antiproliferative activity of the peels of four varieties of apples (Rome Beauty, Idared, Cortland, and Golden Delicious) commonly used in applesauce production in New York state were investigated. The values of the peels were compared to those of the flesh and flesh + peel components of the apples. Within each variety, the total phenolic and flavonoid contents were highest in the peels, followed by the flesh + peel and the flesh. Idared and Rome Beauty apple peels had the highest total phenolic contents (588.9 +/- 83.2 and 500.2 +/- 13.7 mg of gallic acid equivalents/100 g of peels, respectively). Rome Beauty and Idared peels were also highest in flavonoids (306.1 +/- 6.7 and 303.2 +/- 41.5 mg of catechin equivalents/100 g of peels, respectively). Of the four varieties, Idared apple peels had the most anthocyanins, with 26.8 +/- 6.5 mg of cyanidin 3-glucoside equivalents/100 g of peels. The peels all had significantly higher total antioxidant activities than the flesh + peel and flesh of the apple varieties examined. Idared peels had the greatest antioxidant activity (312.2 +/- 9.8 micromol of vitamin C equivalents/g of peels). Apple peels were also shown to more effectively inhibit the growth of HepG(2) human liver cancer cells than the other apple components. Rome Beauty apple peels showed the most bioactivity, inhibiting cell proliferation by 50% at the low concentration of 12.4 +/- 0.4 mg of peels/mL. The high content of phenolic compounds, antioxidant activity, and antiproliferative activity of apple peels indicate that they may impart health benefits when consumed and should be regarded as a valuable source of antioxidants.     

Influence of 1-methylcyclopropene and storage atmosphere on changes in volatile compounds and fruit quality of conference pears

Conference pears (Pyrus communis L.) were treated with 25 and 50 nL L(-1) 1-methylcyclopropene (1-MCP) at -0.5 degrees C for 24 h, then stored for up to 22 weeks in air (NA) and controlled atmosphere (CA). After 7 and 14 weeks of storage, fruits were retreated with 1-MCP. After 7, 14, and 22 weeks of storage, fruits were kept for up to 7 days at 20 degrees C in air for poststorage ripening. The effects of 1-MCP treatment declined with duration of storage in both storage atmospheres, indicating that retreatments had little additional effects on subsequent ripening. Ethylene production was lower and firmness was higher in 50 nL L(-1) fruits, while the 25 nL L(-1) dose was not very different from the control. Development of superficial scald was not prevented by 1-MCP treatments, but the severity of the symptoms was influenced. The 1-MCP effects were perceivable on texture (juiciness) and flavor. Control fruit and 25 nL L(-1) fruit reached their best sensory quality after 14 weeks of storage, while 50 nL L(-1) fruit reached the same sensory quality later, keeping a fresh flavor when the quality of control fruit declined and became watery or grainy. The fresh flavor in 50 nL L(-1) fruit was probably due to the presence below the odor detection threshold concentrations of the volatile compounds responsible for the "ripe pear" aroma, mainly of butanol and ethyl butanoate. CA prolonged or enhanced the effects of 1-MCP; 1-MCP cannot substitute for CA but can reinforce the CA effects.     

1-methylcyclopropene increases storability and shelf life in climacteric and nonclimacteric plums

The effect of 1-methylcyclopropene (1-MCP) at three different doses (0.25, 0.50, and 0.75 microL L(-1)) on the ripening processes of a climacteric, cv. Santa Rosa, and a suppressed climacteric type, cv. Golden Japan, plum was studied. For both cultivars, positive effects were observed in terms of inhibition of ethylene production and delays of the physical, chemical, and biochemical changes associated with ripening. 1-MCP-treated plums were firmer with lower weight loss, reduced degrees Brix/titratable acidity ratios, and lower color changes during cold storage and subsequent shelf life at 20 degrees C than controls. For most factors, the effectiveness of 1-MCP was dose-dependent in Santa Rosa but dose-independent for Golden Japan.     

适宜1-MCP处理保持采后菠萝常温贮藏品质

为了探索1-MCP处理对采后菠萝生理及品质的影响,为菠萝贮藏保鲜措施提供理论依据。以‘巴厘’品种的菠萝果实为试材,采用适宜0.45μL/L体积分数的1-MCP对菠萝进行处理,置于25℃条件下贮藏,采用气相色谱定期测定乙烯释放量,并采用常规理化分析方法测定菠萝品质及相关生理指标。结果表明,1-MCP处理能延缓果实贮藏过程中乙烯的合成速率,与相同贮藏条件下的对照(未处理)果实相比,乙烯释放高峰推迟4 d;1-MCP处理可以延缓果实丙二醛(malondialdehyde,MDA)含量的快速升高,同时对脂氧合酶(lipoxygenase,LOX)酶活性起到抑制作用;与对照相比,1-MCP处理推迟了过氧化物酶(peroxidase,POD)、过氧化氢酶(catalase,CAT)等酶活性高峰的出现,并使POD、CAT、过氧化物歧化酶(superoxide dismutase,SOD)等保持较高的活性,可以有效延缓菠萝在贮藏期间的衰老进程,在贮藏14 d时,分别比对照高出22.30%、32.35%、36.67%,差异显著(P0.05);1-MCP还可减缓果实可滴定酸、维生素C等含量的下降,有助于保持果实的良好品质。1-MCP处理可抑制菠萝贮藏期的果实衰老进程,有利于保持果实品质,提高贮藏效果。研究结果将为菠萝贮藏保鲜措施提供参考。     

Relationship between ethylene response manipulation and volatile production in Jonagold variety apples.

The ripening of Jonagored Jonagold apple fruit (Malus x domestica Borkh.) during development was manipulated with preharvest applications of ReTain or a combination of ReTain plus Ethrel. The fruits, harvested preclimacteric at approximately the same stages of maturity, were stored in refrigerated air (RA) for 45 days or in controlled atmosphere (CA) for 180 days at 0 degrees C. Volatile evolution, ethylene production, and respiration of stored fruit were studied during poststorage holding at 22 degrees C. ReTain reduced volatile production by 19%, but application of Ethrel to ReTain-treated fruit increased production to control levels. The inhibition of volatile production by ReTain appears to be independent of respiration but may be related to the ethylene-producing capacity of the fruit. Although ReTain reduced flavor-related volatile esters, it did not affect levels of the compound responsible for the typical spicy flavor in Jonagored Jonagold fruit, 4-methoxy-2-propenylbenzene. The CA-stored fruit had a much reduced production of volatile compounds compared to RA-stored fruit, with more discernible effects in ReTain-treated fruit. Ethrel application to ReTain-treated fruit improved the volatile production intermediate between the ReTain alone and control in CA-stored fruit. The data collectively suggest that ReTain may have some promise for better scheduling of harvest of apples with no appreciable loss in RA-stored fruit quality. Reduction in production of alpha-farnesene by ReTain may also reduce the potential for scald development in CA-stored fruit.