Progress 10/01/98 to 09/30/03
Outputs
This project addressed fruit softening as part of the Post Harvest Physiology of Fruits. We have devised a genetic based strategy to interfere with the softening of McIntosh apples. A 1.1 kb segment of one of the ACS (1-aminocyclopropane-1-carboxylate synthase) genes, MdACS2, was isolated from ripening McIntosh fruit and characterized by Northern analysis as part of the fruits ethylene producing system during ripening and storage. An antisense probe was constructed with this gene under the control of the CAMV35S promoter and kanamycine resistance as selectable marker. Using an Agrobacterium transformation system, transgenic plants were obtained. Evaluation of the transgenic McIntosh fruit resulted in the selection of four transgenic trees which we characterized for ethylene production, ACS activity, soluble solids and firmness during several growing seasons. The best performing fruit was obtained from the transformation line TM503. Apples from this tree showed a 70 %
down regulation in ethylene production and had a 10.75 lb firmness after 41 days storage at laboratory temperature (25-28oC). With this we have fulfilled the projects objectives to produce McIntosh apples with an extended shelf life. We are presently addressing regulatory issues in order to make these plants available to commercial growers.
Impacts
Ethylene down regulated McIntosh apples have an extended shelf life, can be stored in a cold chamber without chemical treatment or controlled atmospheric storage.
Publications
- Hrazdina G. 2000. ed. Use of Agriculturally Important Genes in Biotechnology. IOS Press, Amsterdam, The Netherlands.
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Progress 01/01/02 to 12/31/02
Outputs
Twenty nine new transgenic McIntosh trees harboring the antisense-ACS-2 construct produced fruit in addition to the twenty two trees which fruited last year. Fruit production was somewhat better than last year, and this time we were able to evaluate all trees for ethylene production and softening. Two transgenic lines, TM-503 and TM 597 resulted in individual trees producing fruit that was approximately 65 percent down regulated in ethylene production. One day after harvest the firmness of these fruits was 23, respectively 17.5 lb/sq.inch, and it decreased to 17.75 lb/sq.inch after three months of storage at room temperature and atmosphere.
Impacts
The ethylene and softening down regulated apples provide a viable alternative to controlled atmospheric storage.
Publications
- No publications reported this period
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Progress 01/01/01 to 12/31/01
Outputs
Twenty two new transgenic McIntosh trees harboring the antisense ACS-2 construct produced fruit during the last growing season and were evaluated for ethylene production. Changes in ethylene production in the apples from these trees ranged from 39 to 251%. The low number of fruits produced did not permit us a more detailed investigation.
Impacts
Down regulated ethylene synthesis in apples results in the extension of shelf life and hence the preservation of fruit quality.
Publications
- No publications reported this period
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Progress 01/01/00 to 12/31/00
Outputs
We have been measuring ethylene production, amount of soluble solids, firmness, ACC synthase and polygalacturonase activity in transgenic McIntosh fruits of different transgenic transformation lines containing the ACC synthase antisense construct. Soluble solids content varied between 12.9 and 15.3 Brix in the control and transgenic fruits. Other parameters showed a linear correlation with the ethylene production by the transgenic fruits.
Impacts
Down regulated ethylene synthesis in apples results in the extension of their shelf life, and hence their preservation of their quality.
Publications
- Hrazdina G. (2000) ed. Use of Agriculturally Important Genes in Biotechnology. IOS Press, Amsterdam, The Netherlands.
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Progress 01/01/99 to 12/31/99
Outputs
We have measured ethylene production in fruits on non-transgenic Royal Gala and McIntosh trees to characterize these as background for the transgenic studies. Ethylene production in non-transgenic Royal gal fruit varied between 130 and 240 nmol/g/hour, while that in the non-transgenic McIntosh fruit was around 300-400 nmol/g/hour.
Impacts
Down regulation of ethylene production in transgenic apples will significantly extend their shelf life.
Publications
- No publications reported this period
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Progress 01/01/98 to 12/31/98
Outputs
We have observed the production of the first transgenic fruit of Royal Gala that contains the antisense ACS(MdACS-2) gene. The fruit appears to be normal in its morphology. The fruit was harvested in October and stored at 4oC. We have analyzed the ethylene production of this and three control Royal Gala apples that did not contain the antisense ACS-2 gene. Our results indicate that the control non-transgenic apples produced ethylene at the 80-160 microM/g tissue basis. The transgenic fruit had ethylene production in the same range. Ethylene production in individual fruits seem to be varying much, therefore, we don not know presently the reason for the high ethylene production in the single transgenic fruit we measured. We have also checked textural changes of the control and transgenic apples. The penetrating force of the control apples ranged between 93 and 115 Newtons, that of the transgenic apple was 110. Measurement of the soluble solids (16.3 to 19.3 oBrix)
showed that the apples were in a similar maturity stage. The McIntosh plants that are being grown in the field did not form any transgenic fruit to date. However, the tree developmental stage indicates that we can expect fruit formation in 1999.
Impacts
(N/A)
Publications
- No publications reported this period
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Progress 01/01/97 to 12/31/97
Outputs
Softening of fruits during storage is the result of cell wall modification by enzymes that are under the control of ethylene. Ethylene is produced in fruits (and plants) from S-adenosyl methionine by a two step pathway, where the first enzyme, ACC synthase, seems to be rate limiting. In the past we have sequenced two ACC synthase genes, MdACS-2 and MdACS-3, made sense and antisense constructs and using Agrobacterium as vector, we have transformed McIntosh plants. During this reporting period we have investigated the expression of these two genes from fruit setting to ripeness. We have sampled developing and maturing apple fruits in weekly intervals, isolated total and PolyA+ RNA and studied the expression of the genes by Northern blotting. Our results to date indicate that the gene MdACS-2 is expressed during ripening. This in turn suggests that this gene is a suitable target in our strategy to extend the storageability of McIntosh apples by interfering with the
expression of this gene.
Impacts
(N/A)
Publications
- No publications reported this period
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Progress 01/01/96 to 12/30/96
Outputs
We have fully sequenced the 1.1 kb ACC synthase gene fragment that we have obtained previously using PCR with the tomato derived OLE 5 and OLE 6 primers and an RNA preparation obtained from ripening McIntosh apples. The gene constructs for the ACS antisense and sense, and for polygalacturonase antisense genes were transferred into Marshall McIntosh apple using Agrobacterium-mediated transformation of excised leaf slices. A total of 55 transgenic lines were regenerated and multiplied in sterile culture. Several of these were micrografted to potted rootstocks in the greenhouse and have produced grafted plants. Four grafted transgenic Marshall McIntosh lines (total of 12 plants) and 12 grafted transgenic Royal Gala lines (total of 56 plants) were planted in the field trial. These plants are in addition to the 4 transgenic Royal Gala lines (total of 5 plants) that were planted in the field trial in 1995.
Impacts
(N/A)
Publications
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Progress 01/01/95 to 12/30/95
Outputs
We have transformed Royal Gala and McIntosh apple shoots and leaves with both the sense and antisense constructs of ACC synthase and and apple polygalacturonase gene construct. Presently we have 24 Royal Gala and 14 McIntosh confirmed transformants that are being propagated. The presence of the antisense ACC synthase construct in the transgenic plants has been ascertained by both ELISA and PCR methods. We are in the process of characterizing the other transformants. Ethylene measurements on Royal Gala and some McIntosh transgenic plantlets indicated a reduced ethylene production in those where the antisense ACC synthase gene was present. We expect that the transgenic apples will have reduced ACC synthase and polygalacturonase activity, hence a better keeping and storage quality. Golden Delicious apples were studied at various harvest and storage conditions including CA and cold storage. Apples were placed into storage after various delays simulating room loading times
and arrival yard delays. After four months of storage, the apples were processed into slices.Various processing and quality parameters were measured. Delay before controlled atmosphere storage had a detrimental effect on the firmness of blanched apple slices. A decrease in the degree of pectin polymerization in the slices was observed with later harvests. The same decreasing trend was observed in the firmness of the blanched slices. Harvest time also had a significant effect on the water-soluble and insoluble pectin content.
Impacts
(N/A)
Publications
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Progress 01/01/94 to 12/30/94
Outputs
We have devised a specific molecular strategy to reduce post- harvest softening in apples. This strategy addresses the down regulation of the ACC-synthase gene that controls the key enzyme of the ethylene biosynthetic pathway. We have devised primers and obtained partial clones of the apple ACC synthase gene. We have sequenced this partial cDNA clone and constructed an antisense ACC synthase gene. We have transformed 'Royal Gala' apple shoots and leaves with this construct. Presently we have 11 confirmed transformants that are being propagated and are in the process of characterizing these. We expect that the transgenic apples will have reduced ACC synthase activity, hence a better keeping and storage quality. Post harvest processing for light raisins were studied. Treatments involving sodium dioxide, honey, erythrobic acid, citric acid and calcium chloride indicated that the honey treatments produced lighter and yellower raisins and these were ranked highest. A
method has been derieved for all four quadrants of thre Hunter color spectrum so that a 360 degrees representation is accommodated and results are expressed as positive signed numbers. We have also developed a new technique for statistical analysis of colorimetery data has been proposed involving a transformation of the hue angle from 361 degrees on up as high as appropriate.
Impacts
(N/A)
Publications
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Progress 01/01/93 to 12/30/93
Outputs
We have devised a specific molecular strategy to reduce post-harvest softening in apples. This strategy addresses the down regulation of the ACC-synthase gene that controls the key enzyme of the ethylene biosynthetic pathway. We have isolated mRNA from immature and mature McIntosh apples and established cDNA libraries. We have devised primers and obtained partial clones of the apple ACC synthase gene. Sequencing of these partial clones showed low homology of the apple ACC synthase gene with ACC synthase genes from other plants. Presently we are constructing sense and antisense probes for transformation of McIntosh. Since the expression of all cell wall degrading enzymes is under the control of ethylene, it is expected that ACC-synthase down regulated apples would show less softening during storage. Orange juice pectin and reducing end groups were measured to determine the degree of polymerization of the pectic substances in fresh squeezed orange juice.
Measurement of these parameters in a freshly squeezed juice and measurement after one week of 5 degrees Centigrade storage elucidate changes occurring during natural enzymatic clarification of the juice. The characteristics of the juice pectic substances influence juice quality such as haze stability and viscosity (mouthfeel), and aid in determining ideal harvesting/processing dates and conditions.
Impacts
(N/A)
Publications
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Progress 01/01/92 to 12/30/92
Outputs
The softening of fruits is the result of cell wall degrading enzymes. It is an integral part of ripening and affects the quality of both fresh and processed products. We have investigated some of the cell wall degrading enzymes, e.g. polygalacturonase and pectinmethylesterase and characterized them. We have also investigated some of the cell wall changes that occur during storage. We have shown by enzymological, immunological and molecular investigations that the enzyme endopolygalacturonase is present in apples during ripening and post-harvest softening. Previously, this enzyme was claimed to be absent in apples. We have devised a specific molecular strategy to reduce post-harvest softening in apples. This strategy addresses the down regulation of the ACC-synthase gene that controls the key enzyme of the ethylene biosynthetic pathway. Since the expression of all cell wall degrading enzymes is under the control of ethylene, it is expected that ACC-synthase down
regulated apples would show less softening during storage. In an attempt to increase awareness and understanding by the processor the effect of post harvest handling and processing methods on product quality, we have co-authored two chapters on this topic. The first chapter dealt with the problems of grape and juice processing. The second chapter focused on the problems of the apple processing industry. In the past year we have also completed the final form of a computerized apple database.
Impacts
(N/A)
Publications
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Progress 01/01/91 to 12/30/91
Outputs
A study has been completed of the effectiveness of electroplasmolysis for enhancement of juice yield with stored apples. Various enzyme treatments, a heat treatment and a control batch were each compared to the electroplasmolysis. A standard method of pressing on a pilot scale pneumatic rack and frame press was used. With a fifteen minute press cycle under identical press conditions, total yields from all methods were identical. Speed of juice expression from the press cake was significantly different between treatments with the heat treated and electroplasmolysis samples the most rapid. When clarified and filtered, the electroplasmolysis treatment produced the lightest color product. The sample with the most brown color was the heated mash. All other treatments fell between these two. These results may indicate that electroplasmolysis inactivated or inhibited expression of the browning enzyme, polyphenoloxidase.
Impacts
(N/A)
Publications
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Progress 01/01/90 to 12/30/90
Outputs
Storage effects on cultivars of apples are being evaluated. A new cultivar selection, NY-674, has been noted to display a large degree of non-browning attributes both as fresh apple as well as processed products. Current studies indicate that the non-browning potential of the selection is reduced upon senescence of the fruit during cold storage.
Impacts
(N/A)
Publications
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Progress 01/01/89 to 12/30/89
Outputs
Cell wall degrading enzymes were prepared from Golden Delicious and MacIntosh apples. Polygalacturonase was extracted at pH 5.5 in 0.5 M NaCl. It was purified and concentrated by ammonium sulfate precipitation, ion-exchange chromatography and gel permeation chromatography to give an enzyme that had an exo-polygalacturonase activity, maximal at pH 4.5. Its molecular weight was 55,000. Its activity was inhibited by 0.2 M NaCl. B-galactosidase was extracted by 0.2-0.5 M NaCl and purified by chromatography. Chromatography indicated two isozymes, both with molecular weights near 45,000 and both active at pH 4.5. Pectin methylesterase was also obtained by extraction with 0.2 M NaCl and had a molecular weight of 28,000 and pH maximum at 7.5. Enzyme levels were followed during storage and softening. Apples softening in common cold storage increased in enzyme levels, but, comparing varieties, the level of enzyme was not related to the degree of softening. The same lack
of correlation was seen with the softness and enzyme levels of 10 varieties whose firmness and enzyme levels were measured at the time of harvest. Cold storage in controlled atmosphere prevented enzyme accumulation and loss of firmness over a 4 month period. Introduction of ethylene did not increase enzyme levels. In well ripened apples there was a large difference in the activities of the different enzymes.
Impacts
(N/A)
Publications
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Progress 01/01/88 to 12/30/88
Outputs
Techniques designed to improve quality measurements need to be upgraded and improved. During a recent study, it was determined that both weight and sample orientation can have a serious impact on textural measurements made using a Kramer Shear Press. Results have been published and are being followed up.
Impacts
(N/A)
Publications
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Progress 01/01/87 to 12/30/87
Outputs
Data analysis is currently being done on controlled atmosphere project. This project was to assess the effect of harvest date and post harvest, pre-CA delays on the quality of processed apple slices. Golden Delicious fruit were harvested at three harvest dates. After each harvest, fruit was delayed going into CA by 0, 2, 4 weeks. After CA storage, fruit were held until 13 lbs pressure and then processed. Early analysis reveals that delays in moving fruit into CA can have a very dramatic result on the firmness of the processed slices. The longer the delay, the less firm will be the slice. This reduction in firmness is not necessarily observed in the raw slices prior to processing.
Impacts
(N/A)
Publications
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Progress 01/01/86 to 12/30/86
Outputs
Two primary projects are underway in which post harvest storage of apples are being studied. The first involves a study of Golden Delicious apples held in CA storage. In this study, time of harvest, delay of fruit into CA and post CA ripening will be evaluated in terms of frozen apple slice quality. A preliminary project in early 1986 indicated no significant differences between the water blanch and a steam blanch for the slices. The second project involves a study of Northern Spys and Red Delicious apples stored under CA conditions for use in the production of applesauce. Two other projects studied the effect of apple storage on the processing of apple juice concentrate and applesauce. Results in both cases indicated measurable and significant storage effects. (See publications listed.
Impacts
(N/A)
Publications
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Progress 01/01/85 to 12/30/85
Outputs
We have initiated study of the processing characteristics of three eastern- grown CA stored apple cultivars for late season processing. Preliminary experiments were conducted in which early harvested CA stored fruit followed by a brief poststorage holding at 0 degrees centigrade regular storage (RS) were processed into sauce. The cultivars utilized for this study were Red Delicious, Empire and Idared. Raw product, processing efficiency and finished product analyses were performed on each cultivar, and the results compared to fruit which had been stored continuously under conventional RS. Although it was found possible to attain a fairly acceptable product from CA stored fruit, there was a poor relation between raw product and finished product quality. The opportunity to improve both the quality and the yield of finished product utilizing poststorage preprocessing temperature tempering of CA fruit appears to be great. We will explore this area during the coming
season. Exploratory experiments into the feasability of extending the fresh market life of Concord grapes utilizing sulfur dioxide generating inserts to the packaged product have been conducted, emphasis being placed on the fate of in-package sodium dioxide relative to damage to the fruit incurred. Further experiments along these lines are anticipated.
Impacts
(N/A)
Publications
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Progress 01/01/84 to 12/30/84
Outputs
For a number of years we have been conducting experiments to relate finished apple product quality to raw product quality attributes following low temperature storage and high temperature ripening. In addition to chemical evaluations, we have also conducted studies on the results of preprocessing treatments to sensory quality of processed applesauce. Despite some variations in response between cultivars, we found the results to be relatively uniform. Preprocessing low temperature storage tended to increase the perceived sweetness and decrease sourness of finished sauce. Storage had no significant effect on the sheen and fruitiness of sauce and no effect on the overall acceptability ratings of flavor and texture. Grain size decreased on storage. Depending on cultivar, color was adversely affected by storage. High temperature ripening tended to darken the sauce but did not adversely affect the overall acceptability ratings of color and flavor. Ripening increased
the fruitiness and decreased the grain size with some interactions between ripening and storage on grain size. Sweetness and sourness were not significantly affected by ripening treatments. The overall rating of texture was decreased with ripening.
Impacts
(N/A)
Publications
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Progress 01/01/83 to 12/30/83
Outputs
Previous studies relating finished apple product quality to raw product quality attributes following low temperature storage and high temperature ripening have been repeated and expanded. Of the five cultivars now tested, Greening and Idared gave inconsistent correlations between fruit firmness following 0 degrees storage and texture (average partical size) of finished sauce made from this fruit. With the former, this inconsistency appears to be directly related to early symptoms of low temperature breakdown and obviously involves cell death. With the latter we observe a progressive and significant increase in particle size in sauce made from fruit with normal appearing tissues which have slowly softened during increasing periods of 0 degrees storage. As yet, the cause of this unusual phenomenon has not been determined. Preliminary results indicate that it continues to increase over 0 degrees storage periods of at least 20 weeks and does not occur at storage
temperatures of 4 degrees and above. It has been shown to be unrelated to pectin quality. This research is continuing. Results of this year's research focused primarily on the effect of maturity (date of harvest) on this response are not yet available.
Impacts
(N/A)
Publications
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Progress 01/01/82 to 12/30/82
Outputs
Study of the effect on quality of various periods of postharvest low temperatureholding and subsequent high temperature ripening of apples for processing into sauce is continuing. Last year's data indicated progressively increasing quality parameters characteristic of increasing degrees of ripening at both temperatures, with rather predictable effects on both raw product analysis and sauce manufacturing efficiency. Effects on the characterization of the resulting sauce were varied, however, depending on cultivar. Particle size (grain) of sauce made from Cortland and Monroe decreased slowly with increasing low temperature holding periods, and more rapidly with subsequent high temperature ripening. However, particle size of sauce made from Idared decreased with high temperature ripening, but increased during low temperature storage. This discrepancy on the effect of storage on particle size was apparent both in physical and sensory evaluations. Results of this
experiment are currently being confirmed and variables such as cultivar, holding temperature and duration are being expanded. This year's experimental results are not yet available.
Impacts
(N/A)
Publications
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Progress 01/01/81 to 12/30/81
Outputs
Study of the effect of severe bruising without skinbreak on the utility of Cortland and Greening apples ripened for processing into sauce was extended this year by varying the intensity of bruising from 5 to approximately 15% of the total fruit volume. Although bruising intensity affected the intensity of the resulting physiological responses, the quality and yield of the finished sauce was essentially unaffected except for a progressive decrease in yield due to the required trimming. Study of the effect of various periods of postharvest low temperature holding and subsequent high temperature ripening of several varieties of apples for processing on the resulting "grain" of the finished sauce has been initiated. Analysis of the sauce is as yet incomplete. Preliminary results show relatively marked changes in grain occurring as a result of both treatments.
Impacts
(N/A)
Publications
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Progress 01/01/80 to 12/30/80
Outputs
It has been proposed that endogenous tissue ethylene production might be a reliable harvest date index for both fresh and processing apples. Various indices of maturity including brix/acid ratio, Magness-Taylor pressure and respiratory acitivity (climacteric), were determined throughout the harvest period and compared to ethylene production rates. Fairly good correlations were found between the initiation of high ethylene production rates and other ripening indices for the cultivars cortland and Greening, but not for the cultivars red Rome and Idared. There relationships will be reexamined in another season.
Impacts
(N/A)
Publications
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Progress 01/01/79 to 12/30/79
Outputs
We investigated the effect of severe bruising without skinbreak on ripening and quality for processing into sauce of both early and conventionally-timed harvested Cortland and Greening apples held at 2 degrees and 18 degrees C until the attainment of processing softness. With early harvested fruit, although the effect of bruising on softening rate was consistently accelerated by bruising, the rate at neither temperature was sufficiently accelerated to be of practical value to the processor. At processing there was no consistent difference in soluble solids, pH, total acid or soluble solids/acid ratio between bruised and unbruised fruit at either temperature for either variety. Although processed sauce quality was relatively unaffected by bruising, processed yield was decreased approximately 4.5% due to excess trimming required in both varieties at both temperatures. With conventionally-timed harvested fruit, the picture was approximately the same except that there
was a more pronounced increase in softening rate with bruising at 2 degrees holding, and at processing softness there was a slight but significant increase in soluble solids/acid ratio with both varieties. Processed yield was decreased approximately 4.7% again due principally to excess trimming with both varieties at both temperatures.
Impacts
(N/A)
Publications
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Progress 01/01/78 to 12/30/78
Outputs
Physiological responses of Cortland and Greening apples to severe bruising followed by holding at 2 degrees and 21 degrees C were reexamined this season. The more conventional responses (increased ethylene production, respiratory activity, softening rate, and decreased soluble solids content and organolyptic quality) were obtained this year. However no similarity to the rapid and complete disintegrative response to wounding noted in small fruit such as the cranberry could be discerned. Completely differing breakdown mechanisms between the two types of fruit are postulated. Idared, Monroe, and Rhode Island Greening apples were ripened at 13 or 18 degrees C for processing into sauce after an initial period of cold storage at 0 or 3-1/2 degrees C. Storage and ripening periods were chosen to provide equal ripening in terms of pressure test drop and the usual, simultaneous increase in Brix: acid ratio. In general, the lower temperatures of storage and ripening provided
better yield an quality of applesauce. Also, hand-picked and "shaken" McIntosh were compared as to storage losses at 2-1/2 and 10 degrees C. Twice as much spoilage occurred in shaken fruit as in hand-picked, and weight loss was 20% greater; storage temperature made little difference to either. However, a post-harvet benomyl drench reduced spoilage in shaken McIntosh by a factor of four.
Impacts
(N/A)
Publications
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Progress 01/01/77 to 12/30/77
Outputs
The effect of severe bruising without skinbreak (infection) on initial ethylene production, respiratory activity, and subsequent ripening rates at 2 degrees and 21 degrees C was studied with early-and commercial-date harvested Cortland and Greening apples. Although ethylene production and respiratory activity were both increased by bruising, no significant alteration in softening rate, soluble solids or organolyptic evaluation following subsequent holding up to a maximum of 2 months was noted with any sample of either variety at either temperature. Bushel lots of three apple cultivars (R.I. Greening, Monroe, and Idared) were subjected to different storage and ripening regimes prior to processing as sauce. The resulting drop in pressure test was held constant among ripening treatments, though strongly influenced by cultivar. Soluble solids: acid ratio increased more and spoilage was greatest for long storage, but weight losses were quite uniform among both treatments
and cultivars. Processing yield parameters were affected by more initial storage temperature than by subsequent ripening. Mixed results were obtained on sauce quality, depending on cultivar.
Impacts
(N/A)
Publications
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Progress 01/01/76 to 12/30/76
Outputs
Post harvest application of ethephon initiates accelerated ripening of all applevarieties tested except R. I. Greenings. Comparative studies of this variety andMcIntosh and Rome Beauty varieties indicate that this difference is due to a differential response to ethylene and not due to differences in penetration and/or breakdown of this chemical to ethylene gas. Samples of six apple cultivars (Wayne, Cortland, Twenty ounce, Golden Delicious, Monroe, and R. I. Greening), in which machine-harvesting damage was simulated by dropping a portion onto a grid of closely-spaced apple branches, were stored in half-bin lots at 36, 48, and 60 F until ripe for processing. Weight losses were greater at high temperature, but spoilage was reduced by half or more depending on variety, by prestorage drenching with benomyl at 300 ppm. Sauce yield was decreased 10-15% by ripening at the highest temperature. Sauce color and grain were also adversely affected, although flavor was
improved.
Impacts
(N/A)
Publications
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Progress 01/01/75 to 12/30/75
Outputs
Over 50 half-ton bulk bins of machine-harvested apples were obatined from processors' yards and stored at Geneva. Four-bin lots of McIntosh, Cortland, Twenty ounce, R.I. Greening, and Golden Delicious were distributed among storages at dry- and wet-bulb temperatures of: 36/34, 46/41, 57/50, and 70/61(0)F. Late-harvested Romes were stored only at 36 and 46(0)F. Fipening was monitored by pressure test, and weight loss during storage was recorded. A bushel-sample drawn from a cross-section of the bin beforehand, then segregated in a burlap bag buried in the bin during storage, was used to determine incidence of spoilage, as well as (VPI) usable material index. The peeled, cored, and trimmed apples were then processed into sauce or slices. Ripening wasmost rapid and spoilage and weight loss greatest at higher storage temperature. This emphasizes that conditions equivalent to outdoor, or yard, storage represent a difficult management problem, with potentially greater
losses of product yield and quality. Product color became less green, but not necessarilymore attractive. Flavor was usually improved, but slice texture was softer and serum separation from sauce greater, though slice drained weight and sauce consistency were otherwise unaffected. The use of post-harvest ethephon dips to bring about rapid and uniform ripening in processing peaches shows promise. Samples of commercially harvested hard-ripe fruit dipped at concentrations as low as 500 ppm ripened a day prior and more uniformly than
Impacts
(N/A)
Publications
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Progress 01/01/74 to 12/30/74
Outputs
Use of post-harvest dips of ethephon to bring about a more rapid and uniform rate of ripening in pears for processing continues to show good promise. Samples of commercially harvested fruit obtained at the receiving docks of localprocessors were made to ripen within 4 days by dips as low as 500 ppm ethephon with more uniformity than fruit which had been subjected to the standard 2 week refrigeration followed by 3 days of high temperature ripening. No breakdown wasfound in any of the treated fruit. Detailed study of R.I. Greening continues toindicate the resistance of this apple variety to chemical ripening. Although ethylene content and respiratory activity are both measurably accelerated by ethephon treatment, softening and other raw-product associated with ripening do not seem to respond as in other varieties.
Impacts
(N/A)
Publications
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Progress 01/01/73 to 12/30/73
Outputs
Post-harvest dips of ethephon have been shown to increase the ripening rate of apples and pears for processing except where ethephon was applied as a pre-harvet spray. Either pre-harvest or post-harvest applications may substitute for 32 storage as an aid to rapid and uniform ripening in pears. Ripening of pears which had been subjected to a pre-harvest application of ethephon was often accompanied by breakdown which can be as high as 50% in some instances. Breakdown was not found in fruit which had been subjected to post-harvest application of ethephon only. Alterations in shipping and ripeningprocedures for a local peach processor have reduced his overall losses from morethan 40% in 1970 to approximately 28% this year.
Impacts
(N/A)
Publications
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Progress 01/01/72 to 12/30/72
Outputs
Pilot-plant-scale experiments conducted with unripe-harvested Cortland apples ripened by post-harvest dips of ethephon and processed into sauce were conducted. The results indicate that sauce manufactured from fruit harvested 42days prior to commercial harvest graded the same as that from tree-ripened fruit, but sauce made from fruit harvested 27 days prior to commercial harvest graded better than that from tree-ripened fruit. Experiments conducted with picking-ripe pears indicated that post-harvest applied ethephon brings about a more rapid and much more uniform rate of softening than that of non-treated fruit.
Impacts
(N/A)
Publications
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Progress 01/01/71 to 12/30/71
Outputs
The post-harvest effect of Ethrel on the physiology of processing apples was studied. It was found that treatment elicits a normal ripening pattern of respiratory activity, ethylene production, softening and changes in ground color. However, soluble solids of the treated fruit did not change appreciably from that at harvest. Thus, early picking and post-harvest ripening is done at the expense of yield and soluble solids. The treatment may be justified in terms of increased maturity of the fruit and less shrinkage. Mechanically-harvested McIntosh apples for processing were given pre- and post-harvest treatment with Captan or thiabenzadole and stored under different conditions. Spoilage in outdoor and common storages was reduced by about a quarter by a pre-harvest spray with Captan at 1,200 ppm and by a half with post-harvest dips with either fungicide at 1,000 ppm. The improvement was proportionately greater in cold storage. Roughly equivalent ripening - in
termsof pressure test and soluble solids:acid ratio - occurred during the following storage regimes: four weeks of outdoor or common storage, four weeks of cold storage followed by an equal period of (by then) cooler outdoor or common storage, or twelve weeks of cold storage. Weight losses ranged from 2% in cold storage up to 6% outdoors.
Impacts
(N/A)
Publications
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Progress 01/01/70 to 12/30/70
Outputs
Half-bushel samples of several varieties of processing apples were stored three different ways, approximating commercial conditions of yard (outdoor), common (protected), and cold storages. Fruit held in cold storage for 79 days ripened less, lost less weight, and experienced only 1/3 as much spoilage as that held in the warmer storages for 30 days. Usable material was 4-8% higher in the cold-storage fruit. Ben Davis apples machine-harvested from small trees showed only 1/3-1/2 as much spoilage as fruit harvested from much larger trees nearby. Machine-harvested R.I.Greenings given a pre-harvest spray of Captan showed less than half as much spoilage in storage with an advantage in usable material of 6%. The effect of Ethrel on ripening of processing apples continues to be most promising. Apples harvested 1-4 weeks prior to commercial picking and dipped into dilute concentrations of Ethrel ripen into fruit producing a completely acceptable sauce in approximately
1/2 the time as fruit permitted to ripen at 70 or at an even greater saving of time over fruit left to ripen on the tree, with a substantial increase in yield in the case of the former through decreasedspoilage.
Impacts
(N/A)
Publications
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Progress 01/01/69 to 12/30/69
Outputs
The object of this study is to test the feasibility of improving the market value of pomological fruits for processing by increasing the quality and yield brought about by improvement in current commercial handling and storage practices. We are currently studying the effect of cold-storage on early harvested apples to control raw product ripening and shrinkage. Experiments have been initiated on both a laboratory and commercial scale in which samples of early-harvest fruit have been held in yard, common, and cold storages with and without postharvest dips of Ethrel. Laboratory samples are now being processed into sauce and slices in our department pilot plant. Yield and quality will be evaluated on the finished product. Incidental raw product variables included in this year's study include machine-harvesting, fungicide treatment, and field freezing on these practices.
Impacts
(N/A)
Publications
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