Relationships of antioxidants in apple peel to changes in α-farnesene and conjugated trienes during storage, and to superficial scald development after storage

1994 ◽  
Vol 4 (1-2) ◽  
pp. 23-33 ◽  
Author(s):  
Cynthia L. Barden ◽  
William J. Bramlage
Keyword(s):  
Superficial Scald ◽  
Apple Peel ◽  
Conjugated Trienes

scholarly journals Accumulation of Antioxidants in Apple Peel as Related to Preharvest Factors and Superficial Scald Susceptibility of the Fruit

1994 ◽  
Vol 119 (2) ◽  
pp. 264-269 ◽  
Author(s):  
Cynthia L. Barden ◽  
William J. Bramlage
Keyword(s):  
Ascorbic Acid ◽  
Low Temperature ◽  
Light Intensity ◽  
Phosphonic Acid ◽  
Malus Domestica ◽  
Water Soluble ◽  
Total Water ◽  
Superficial Scald ◽  
Apple Peel ◽  
Conjugated Trienes

Antioxidants are believed to protect against the oxidation of α-farnesene to conjugated trienes in apple (Malus domestica, Borkh.) peel, thus providing resistance against superficial scald development. We conducted three experiments in which apples were a) harvested weekly, during which they were exposed to increasing hours at <10C during ripening; b) induced to ripen with no hours at <10C by applying ethephon; and c) enclosed in paper bags as they ripened. Inducing ripening with ethephon increased total water-soluble reducing compounds and percentage inhibition of lipid oxidation of peel extracts, increased concentrations of α-tocopherol, carotenoids, and ascorbic acid in peel, but only slightly reduced scald. Delayed harvests increased all of these antioxidants except ascorbic acid and greatly reduced scald development. Bagging fruit before ripening decreased α-tocopherol, carotenoid, and ascorbic acid concentrations, decreased total water-soluble reducing compounds, and increased scald development. We conclude that changes in these antioxidants probably are affected more by ripening and light intensity than by low temperature before harvest. Chemical name used: (2-chloroethyl)phosphonic acid (ethephon).

Synthesis of Conjugated Trienes and Related Oxidation Products of α-Farnesene

1994 ◽  
Vol 47 (11) ◽  
pp. 1979 ◽  
Author(s):  
MA Brimble ◽  
DD Rowan ◽  
JA Spicer
Keyword(s):  
Ring Opening ◽  
Room Temperature ◽  
Oxidation Products ◽  
Epoxide Ring ◽  
Epoxide Ring Opening ◽  
Superficial Scald ◽  
Conjugated Trienes ◽  
Conjugated Triene ◽  
Cyclic Peroxide

The synthesis of conjugated trienes and related oxidation products of α- farnesene (1), principally from the epoxides of α- farnesene (1), is reported. Base-promoted ring opening of 6,7-epoxide (4) by KOBut/LiNPri2 affords the conjugated triene (2), whilst the 3,4-epoxide (5) affords trienol (7). In contrast, 10,11-epoxide (6) fails to undergo epoxide ring opening; it rearranges to the conjugated triene epoxide (8). Base-promoted ring opening of bisepoxide (9) afforded trienol epoxide (11) at -30°C, whilst cyclization to tetrahydrofurans (10a,b) occurred at room temperature. Photosensitized oxidation of 10,11-epoxide (6) followed by in situ treatment with acid gave the cyclic peroxide (3) and on reduction triol (12). Bisallylic alcohol (13) was prepared by alkylation of 3-methylsulfolene with geranial. Trienes (2) and (3) have been isolated previously as autoxidation products of α- farnesene (1) and are implicated as the causal agents of superficial scald of stored apples.

scholarly journals Intermittent Warming Effects on Superficial Scald of Apple Fruit

HortScience ◽  
1996 ◽  
Vol 31 (4) ◽  
pp. 605b-605
Author(s):  
Thair F. Alwan ◽  
Christopher B. Watkins
Keyword(s):  
Fruit Ripening ◽  
Marked Reduction ◽  
Apple Fruit ◽  
Oxidation Products ◽  
Superficial Scald ◽  
Cooperative Agreement ◽  
Postharvest Treatments ◽  
Conjugated Trienes ◽  
Hexane Extracts ◽  
Intermittent Warming

Fruit of `Cortland', `Delicious' and `Law Rome' were warmed for 24 hours at 20°C either weekly, once every 2 weeks, or once every 3 weeks during storage. The effect of these treatments on fruit ripening and concentrations of alpha-farnesene and conjugated trienes in hexane extracts of the skin were measured during storage. Without warming, scald incidence of the cultivars was 70%, 14%, and 85%, respectively. Intermittent warming treatments resulted in a marked reduction of scald though effectiveness was affected by cultivar. In `Cortland', scald was reduced only by the weekly warming treatment (10%) as was less effective than DPA (1%). In `Delicious', all warming treatments were equally effective. In `Law Rome', weekly warming resulted in better control of scald (3%) than DPA (14%) and less frequent warming was proportionately less effective in controlling the disorder. Concentrations of conjugated trienes at 281 nm did not relate consistently to scald incidence after storage. However, ratios of conjugated trienes of 258 nm or 269 nm with 281 nm strongly support a hypothesis that non-toxic and toxic oxidation products of alpha-farnesene interact and influence the effectiveness of postharvest treatments on scald control (Du and Bramlage, 1993; JASHS 118:807-813). A hypothesis relating the interactions between ripening and scald development will be presented. Supported in part by USDA Specific Cooperative Agreement 58-1931-5-017.

scholarly journals 140 DEVELOPMENT OF SUPERFICIAL SCALD ON `D'ANJOU' PEARS DURING COLD STORAGE AS INFLUENCED BY GROWING ELEVATION

HortScience ◽  
1994 ◽  
Vol 29 (5) ◽  
pp. 448f-448
Author(s):  
Paul M. Chen ◽  
Diane M. Varga
Keyword(s):  
Cold Storage ◽  
Threshold Level ◽  
Pyrus Communis ◽  
River Valley ◽  
Superficial Scald ◽  
Flesh Firmness ◽  
Pyrus Communis L ◽  
Conjugated Trienes

`D'Anjou' pears (Pyrus communis, L.) growing in 3 locations with the elevation at 150 meters, 380 meters, and 610 meters respectively in Hood River valley, Oregon were harvested at the commercial maturity with the flesh firmness of 62.3 Newton (±2.2 N) and stored in air at -1°C. Regardless of different growing elevations, the incidence of superficial scald became noticeable after 2.5 months of storage and became substantial after 3 months. The rate of scald development was higher on the fruit from 150 meters elevation than those from higher elevations. Alpha-farnesene and conjugated trienes in the peel tissue accumulated at faster and higher rates in the fruit from 380 meters and 610 meters elevations than those from 150 meter elevation. The threshold level of conjugated trienes which causes superficial scald disorder was different from the fruit grown at different elevations.

scholarly journals Superficial Scald Development on Apples at Chilling and Nonchilling Temperatures

HortScience ◽  
1995 ◽  
Vol 30 (4) ◽  
pp. 782E-782
Author(s):  
William J. Bramlage
Keyword(s):  
Superficial Scald ◽  
Conjugated Trienes ◽  
High Concentrations

`Cortland' and `Delicious' apples were stored at 0C for up to 25 weeks, and at 20C in either open boxes or non-sealed poly bags for up to 8 weeks. At 20C, lesions occurred mostly around lenticels, but with some calyx bronzing and scald-like symptoms on shaded areas. At 0C, typical scald symptoms occurred. At both temperatures, high concentrations of alpha-farnesene and conjugated trienes occurred in conjunction with symptom appearance, and both these concentrations and discolorations decreased with later harvest of fruit. Scald development appeared to be chilling-enhanced, but not chilling-dependent.

scholarly journals CHARACTERISTICS OF UV ABSORBANCE BY HEXANE EXTRACTS OF APPLE SURFACES SUGGEST A MODIFIED HYPOTHESIS ON THE ROLE OF CONJUGATED TRIENES IN SCALD DEVELOPMENT ON APPLES

HortScience ◽  
1992 ◽  
Vol 27 (11) ◽  
pp. 1159d-1159
Author(s):  
Zhanyuan Du ◽  
William J. Bramlage
Keyword(s):  
Hexane Extract ◽  
Uv Absorbance ◽  
Superficial Scald ◽  
Data Support ◽  
Conjugated Trienes ◽  
Hexane Extracts ◽  
Fruit Surface

Much correlative data support the hypothesis that superficial scald on apples results from oxidation of α farnesene to conjugated trienes (CT) in the coating of apples. However, these associations are poorly defined both chemically and physiologically. α Farnesene and CT are measured as OD 232 and OD 281-290, respectively, of a hexane extract of the fruit surface. During assays, we observed anomalies in absorbance characteristics of extracts from fruit with different scald potentials, particularly in the region of 258 nm. Results suggest that absorbance near 258 nm might represent a metabolite of CT, which may be further metabolized. It appeared that under different conditions, CT metabolism could be altered, resulting in changed ratios of OD 258/OD 281. Higher ratios correlated with lower scald development, regardless of CT concentration. Thus, CT metabolism, rather than its concentration, may determine if scald occurs.

scholarly journals Expression of Alpha-farnesene Synthase Gene AFS1 in Relation to Levels of Farnesene and Conjugated Trienols in Peel Tissue of Scald-susceptible `Law Rome' and Scald-resistant `Idared' Apple fruit

HortScience ◽  
2004 ◽  
Vol 39 (4) ◽  
pp. 782B-782
Author(s):  
Steven W. Pechous ◽  
Bruce D. Whitaker* ◽  
Christopher B. Watkins
Keyword(s):  
Sharp Increase ◽  
Biosynthetic Pathway ◽  
Apple Fruit ◽  
Oxidation Products ◽  
High Rate ◽  
Subsequent Increase ◽  
Transcript Levels ◽  
Superficial Scald ◽  
Apple Peel ◽  
Apple Cultivars

Fruit of different apple cultivars vary widely in susceptibility to superficial scald. The genetic and biochemical factors involved in this variation are unknown. Conjugated trienol (CTol) oxidation products of alpha-farnesene have been linked with scald induction, and a high rate of farnesene synthesis in peel tissue of scald-prone apples early in storage is often associated with development of the disorder. Pre-storage treatment of apple fruit with 1-methylcyclopropene (1-MCP) inhibits the early burst of farnesene production and prevents scald, suggesting that ethylene induces transcription of genes involved in farnesene synthesis. We recently cloned a gene from apple peel tissue, AFS1, which encodes alpha-farnesene synthase, the last enzyme in the farnesene biosynthetic pathway. In this study, expression of AFS1 was compared in scaldsusceptible Law Rome (LR) and scald-resistant Idared (IR) apples at harvest and over 20 weeks of storage at 0.5 C. AFS1 transcript levels were closely correlated with accumulation of farnesene and CTols. In fruit of both cultivars, a sharp increase in AFS1 mRNA during the first 4 to 8 weeks of storage preceded a proportional rise in farnesene and a subsequent increase in CTols. However, maximum levels of AFS1 transcript, farnesene, and CTols were, respectively, 2.5-, 4-, and 33-fold greater in LR than in IR apples. Treatment of fruit with 1-MCP at harvest suppressed the increases in AFS1 transcript and farnesene early in storage, but AFS1 expression and farnesene synthesis recovered in LR fruit after 20 weeks. Scald incidence in LR apples after 20 weeks at 0.5 °C plus 1 week at 20 °C averaged 86%, whereas IR fruit had no scald. 1-MCP treatment reduced scald incidence in LR to <1%.

scholarly journals Volatile Cuticular Components Involved in Superficial Scald

HortScience ◽  
1996 ◽  
Vol 31 (4) ◽  
pp. 605a-605
Author(s):  
S. Wee ◽  
R.M. Beaudry
Keyword(s):  
Gas Chromatography ◽  
Mass Spectroscopy ◽  
Malus Domestica ◽  
Apple Fruit ◽  
Superficial Scald ◽  
Conjugated Trienes ◽  
Gas Chromatography Mass Spectroscopy

Autoxidation products alpha-farnesene of have been implicated in superficial scald induction for apple (Malus domestica cv. Cortland Apple) fruit. We suspect the apple cuticle acts as a sink where α-farnesene can accumulate and eventually autoxidize into hydroperoxides, conjugated trienes, 6-methyl-5-hepten-2-one (ketone), and other compounds. These oxidized byproducts may diffuse back into the peel, thereby initiating the scald process. Cortland apples were stored at 0.8°C. Volatile cuticular components were analyzed at 2-week intervals by gas chromatography–mass spectroscopy. Only two scald-related volatiles were found, 6-methyl-5-hepten-2-one and α-farnesene. The identification of these compounds may allow the determination of cuticular involvement in superficial scald, as well as a possible correlation between the volatiles and apple scald development. α-farnesene concentrations initially increased and was followed by a decline, possibly due to its autoxidation.

scholarly journals A Modified Hypothesis on the Role of Conjugated Trienes in Superficial Scald Development on Stored Apples

1993 ◽  
Vol 118 (6) ◽  
pp. 807-813 ◽  
Author(s):  
Zhanyuan Du ◽  
William J. Bramlage
Keyword(s):  
Absorption Spectra ◽  
Malus Domestica ◽  
Ultraviolet Absorption ◽  
Superficial Scald ◽  
The Poor ◽  
Metabolic Products ◽  
Conjugated Trienes ◽  
Conjugated Triene ◽  
Experimentally Induced

Three experiments were conducted using `Cortland' and `Delicious' apples (Malus domestica Borkh.). Fruit varying widely in superficial scald susceptibility, because of either endogenous or experimentally induced conditions, were stored for various intervals at 0C and evaluated for scald development at 20C. Samples were extracted periodically in hexane, and ultraviolet absorption spectra of the extracts were used to evaluate α-farnesene and conjugated triene (CT) relationships to scald development. CT concentrations were calculated using each of the three CT absorption maxima (258-290 nm, 269-290 nm, and 281-290 nm) and expressed accordingly as CT258, CT269, and CT281. The poor association of CT281 concentrations with scald development led us to propose that metabolic products of CT281 species are more likely to be associated with scald development than the species themselves.

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