Enclosing apple fruit in bags during development is widely practiced in Japan. Bags create a barrier that reduces damage from insects and fungal pathogens as well as treatments to control these problems. Bags also reduce the incidence of sunburn and change fruit appearance by altering peel pigmentation composition, two features that have prompted northwestern United States producers to bag `Fuji' apples. Fruit maturity and quality of bagged and nonbagged Fuji apples grown in Washington state were evaluated at harvest and after refrigerated storage in air or controlled atmosphere. Bagged fruit had less watercore and lower ethylene production at harvest compared to non-bagged fruit with similar starch ratings. Bagged fruit had lower soluble solids content, titratable acidity and firmness at harvest and during storage. Emission of ester and alcohol volatiles was consistently lower for bagged fruit. Postharvest volatile emissions were negatively correlated with bagging duration during development. Bagged fruit had no incidence of a peel disorder with similarity to delayed sunscald.
J.P. Mattheis, D.A. Buchanan, and J.K. Fellman
J.P. Mattheis, D.A. Buchanan, and J.K. Fellman
Quantitative and qualitative changes in net production of volatile compounds by apples occurs during fruit development with a major transition to ester production occurring as fruit ripening begins. Ester production during fruit ripening is an ethylene-mediated response; however, differences in maturation patterns among apple cultivars led us to examine the relationship between ester production and onset of the ethylene climacteric in several commercial apple cultivars. Emission of volatile esters as a function of apple fruit development was evaluated for `Royal Gala', `Bisbee Delicious', `Granny Smith', and `Fuji' apple fruit during two harvest seasons. Apples were harvested weekly and analyses of harvest maturity were performed the day after harvest. Non-ethylene volatiles were collected from intact fruit using dynamic headspace sampling onto Tenax traps. Fruit from each harvest was stored at 1°C in air for 5 months (3 months for `Royal Gala') plus 7 days ripening at 20°C, then apples were evaluated for the development of disorders. The transition to ester production occurred after internal ethylene exceeded 0.1 μL for `Royal Gala', `Bisbee Delicious', and `Fuji'. Ester emission by `Granny Smith' apples remained low throughout the harvest period. Increased ester emission occurred after the optimum harvest date (as determined by the starch index and internal ethylene concentration) for controlled-atmosphere storage of `Bisbee Delicious' and prior to optimum maturity for `Royal Gala' and `Fuji'. A relationship between the potential for development of superficial scald and ester production at harvest was evident only for `Bisbee Delicious' apples.
J.P. Mattheis, D.A. Buchanan, and J.K. Fellman
Fruit quality and volatile compounds produced by apple fruit (Malus ×domestica Borkh. `Gala') were characterized following regular atmosphere (RA) or controlled atmosphere (CA) storage at 1°C. Static CA conditions were 1, 1.9, 2.8, or 3.7 kPa O2. Fruit stored under dynamic CA conditions were exposed to ambient air 1, 2, or 3 days per week for 8 hours then returned to 1 kPa O2. All CA treatments included 2 kPa CO2. Ethylene production was reduced following CA storage plus 1 day at 20°C compared with apples stored in RA. Apples stored in static 1 kPa O2 and the dynamic treatments had lower ethylene production compared with apples stored in 1.9 to 3.7 kPa O2 after 90 and 120 days. Ethylene production by apples from all CA treatments recovered during a 7-day poststorage ripening period at 20°C. Ester production was reduced following CA at 1 kPa O2 after 60 days compared with RA-stored fruit. Production of butyl acetate by apples stored in 1 kPa O2 static CA was 29%, 30%, and 7% of that produced by RA-stored fruit after 60, 90, and 120 days storage plus 7 days at 20°C. Amounts of 2-methylbutyl acetate were not affected by CA storage, however, production of other 2-methylbutyrate esters was reduced following 1 kPa O2 storage. Ester production increased with O2 concentration after 90 days in storage. The dynamic treatments resulted in greater ester emission after 120 days storage plus 7 days at 20°C compared with apples stored in static 1 kPa O2. Production of 1-methoxy-(2-propenyl) benzene by apples subjected to dynamic treatments was also higher after 120 days storage plus 7 days at 20°C compared with apples stored in RA or static CA. No differences in firmness, titratable acidity or soluble solids content were observed between apples stored in 1 kPa O2 and the dynamic treatments. Firmness and titratable acidity were maintained better by dynamic treatments compared with static atmospheres containing > 1 kPa O2.
Loretta J. Mikitzel, Max E Patterson, and John K. Fellman
Walla Walla Sweet onions (Allium cepa L.) have a short storage and marketing season. Studies to determine viable shelf life and to extend post-harvest life with controlled atmosphere (CA) storage were conducted. Onions were exposed to various CA gas mixtures in combination with heat curing (35°C) and/or chlorine dioxide (ClO2) fumigation, to control disease. Preliminary results indicated Botrytis was the primary cause of post-harvest losses. A 1% O2, 5% CO2 atmosphere appeared to maintain onion quality better than other gas mixtures tested during 15 weeks of CA storage (0°C). Carbon dioxide series above 5% show promise in reducing the 35% storage loss that occurred with the 5% CO2 treatment. Curing for at least 72 hours followed by a 1-hour ClO2 fumigation resulted in the least bulb decay and after 15 weeks of storage (1% O2, 5% CO2), 75% of the bulbs were in marketable condition. Onions stored 15 weeks in air (0°C, 70% RH) were unmarketable. Shelf life of freshly harvested onions was 18 days, after which the onions rapidly decayed. After CA storage, shelf life was reduced to 10-14 days due to rapid sprouting. To enjoy a 30-day market window, disease control is necessary for freshly harvested onions and sprouting must be controlled in post-storage onions.
J.P. Mattheis, J.K. Fellman, P.M. Chen, and M.E Patterson
Synthesis of non-ethylene volatiles (NEV) undergoes significant alterations during the transition from vegetative growth to senescence in apple fruit. This change results in a substantial increase in the production of esters characteristic of ripe apples. The relationship between changes in NEV synthesis and other indicators of physiological and horticultural maturity were investigated using `Bisbee Delicious' apples. Analysis of NEV was conducted using headspace sampling and GC-MS. Aldehydes and alcohols were the largest NEV components from pre-climacteric fruit although several esters were detected. The concentration of all NEV components declined to a minimum prior to the onset of the climacteric rise in ethylene synthesis. Initial detection of 2-methyl butylacetate, the major ester in ripening `Bisbee Delicious' fruit, occurred several weeks prior to the onset of the climacteric. The increase in ester synthesis accelerated during the post-climacteric period and the amount of total aldehydes also increased.
Xuetong Fan, J.P. Mattheis, M.E. Patterson, and J.K. Fellman
Several strains of Fuji apples were harvested weekly from September through October in 1990 and 1991, and evaluated for maturation and quality after 1 and 7 days at 20 °C following harvest and storage in atmospheres of 0.5%, 1.0%, 2.0% O2 and air. Results showed that Fuji apples have very low ethylene production rates and little firmness loss during maturation. A change in the postharvest respiration pattern preceded the increase ethylene synthesis. Oxygen concentration during storage directly affected apple respiration rate after removal from storage. Ethylene production rates and internal ethylene concentrations indicated that the apples were still in the preclimacteric stage after 7 to 9 months storage at 0.5%, 1.0%, or 2% O2. Fuji apples develop watercore and tend to have a particular type of corebrowing during maturation on the tree, or during and after storage. The cause is unknown.
X. Fan, J.P. Mattheis, M.E. Patterson, and J.K. Fellman
Total starch and amylose (AM) concentration and a starch index (SI) were determined in `Fuji' apple (Malus domestica Borkh.) fruit from weekly harvests in 1990 and 1991. As apples matured, SI scores increased and total starch and amylose content decreased. The percentage of AM in the total starch decreased as the apples matured. Because KI solutions interact efficiently only with AM, the SI is less reliable in representing total starch during later stages of `Fuji' apple maturation.
D.R. Rudell, D.S. Mattinson, J.K. Fellman, and J.P. Mattheis
`Fuji' apple (Malus ×domestica Borkh.) fruits were harvested periodically prior to and during fruit ripening. Ethylene evolution and respiration rates of skin, hypanthial, and carpellary tissue was determined in each fruit. Additionally, whole fruits were used for analyses of internal ethylene concentration, volatile evolution, starch content, flesh firmness, and soluble solids content. Ethylene production was greatest in the carpellary tissue at all sampling dates except the one occurring just before the rise in whole fruit internal ethylene concentration, when production in the skin and carpellary tissue was similar. Respiration was always highest in the skin, in which the climacteric rise was most drastic. Higher ethylene production in the carpellary tissue of pre- and postclimacteric fruit and higher respiration in the skin tissue, including a noticeable climacteric rise, is indicative of a ripening initiation signal originating and/or transduced through the carpels to the rest of the fruit.
J.K. Fellman, T.W. Miller, D.S. Mattinson, and J.P. Mattheis
D.R. Rudell, J.P. Mattheis, X. Fan, and J.K. Fellman
Effects of artificial ultraviolet-visible light and methyl jasmonate (MJ) treatment on `Fuji' apple [Malus sylvestris (L.) Mill. var. domestica (Borkh.) Mansf.] fruit peel anthocyanin, phenolic, carotenoid, and chlorophyll production were examined using tristimulus color analysis and reverse-phase high performance liquid chromatography. Anthocyanin synthesis was enhanced by light and MJ treatment. Chlorogenic acid and most cyanidin, quercetin, and phloretin glycosides increased with MJ treatment concentration. Light alone also promoted increased production of most of these compounds. Production of catechin, (-)epicatechin, quercetin, and quercetrin was not enhanced by either light or MJ treatment. Light and MJ enhanced ß-carotene and chlorophyll b, synthesis but not xanthophyll or chlorophyll a synthesis. The chlorophyll a/b ratio decreased with MJ dosage. Results suggest MJ may provide a viable means of enhancing apple fruit coloration and other photoprotective mechanisms. Chemical name used: methyl 3-oxo-2-(2-pentenyl)cyclopentane-1-acetate (methyl jasmonate).