THESIS .. w , .g I 'f" 'I. .. C iiiilllliiliiliglii 3 1293 ‘0096 This is to certify that the thesis entitled The Application of Calcium to Jonathan Apples by fiydrocooling presented y Steven Alonzo Sargent has been accepted towards fulfillment of the requirements for M. S . degree inHQLtiantnne J fo; o / Major professor 6” ~ 0 Date 7 2W / 4- / / 0-7639 w: 25¢ per day per item RETURNING LIBRARY MTERIALS: Place in book return to remove charge from circulation records THE APPLICAIION 0! CALCIUH.TO JOIAIHAI’APPLIS BY EIDIOCOOLIIG By Steven Alonzo Sargent A.IEZSIS Subaitted to Michigan State University in partial fulfill-ant of the require-ante for the degree of MASTER.OF SCIEICB Depart-ant of Horticulture 1979 VJ. L‘ ABSTIACT THE APPLICATION OF CALCIUH.TO JONATHAN APPLES BY HYDROCOOLIHG 3! Steven Alonso Sargent Postharvest physiological disorders of 'Jonsthan' apples favored by low fruit calcium can be reduced or retarded by prestorsge treatment of harvested apples with calciua chloride (CsClz). Drench hydrocooling with a calcium solution should increase fruit calcium since fruit cooling aide the infiltration of the drenching solution into the fruit. Cold solutions (3°C) of 0, 2 or 62 CaCl2 with surfactant L-77 were applied for 20 minutes at a rate of 9 gallons per minute per square foot of surface area to warm apples (25°C) held in field crates of l-bushel capacity. These apples were compared.with similar fruits that had been drenched with cold solutions for 1 minute, or drenched with warm solutions for l or 20 minutes, and with initially cold apples that had been drenched with warm or cold solutions for l or 20 minutes. The apples were not rinsed prior to subsequent storage at 3°C and approximately 902 relative humidity. Total calcium in the fruit cortex after treatment plus 13 weehs of storage was measured by atomic absorption procedures. The mean for apples hydrocooled with 22 CaCl2 was 3.85 mg of calcium per 100g fresh weight and was equivalent to the fruit calcium of all the 42 CaClz treat- ments except where 42 CaCI2 was applied as a cold solution to cold fruits which was markedly lower in calcium. All other 22 0:1612 treatments were less effective for increasing fruit calcium than 61 applied in a similar manner. The development of internal breakdown, Jonathan spot and lenticel Steven Alonzo Sargent spot in apples stored for 17 weeks was generally reduced by calcium application. Surface injury to the fruit by CaCl2 was negligible. The results indicate that commercial hydrocooling with a 21 CaCl2 solution containing surfactant would be equivalent to the current practice of applying 6! CaCl as a brief prestorage drench at 2 ambient temperature. It.weuld serve to precool the apples prior to storage as well as to reduce the hazard of storage disorders. Dedicated to my parents, Alonso and Grace Sargent, for their love and encouragement. ii Sincere appreciation is expressed to Dr. D.H. Dewey for his valuable guidance and concern during my course of study. I am grateful to Drs D.R. Dilley, H.J. Dukovac and 0.". Laughlin for their helpful discussions and for serving on my guidance committee. Special thanks are given to Dr. D.D. Harnche for the use of facilities at the Soil Testing Laboratory and his suggestions as well as to Loreen Cedarstaff, Steve Skrobak, Dave Pivorunas and Kris Willimenn for their dependable technical assistance. iii LIST OF TABLES . . . . LIST OF FIGURES . . . LIST OF APPENDICES . 0 INTRODUCTION . . . . . LITERATURE REVIEW . . MATERIALS AND METHODS RESULTS . . . . . . . DISCUSSION . . . . . . SUMMARY AND CONCLUSION APPENDIX . . . . . . . LITERATURE CITED . . . TABLE OF iv CONTENTS Page . . . . . . . . . . . . l . . . . . . . . . . . . 3 . . . . . . . . . . . . 8 . . . . . . . . . . . . 18 . . . . . . . . . . . . 36 . . . . . . . . . . . . 40 . . . . . . . . . . . . 41 . . . . . . . . . . . . 44 LIST OF TABLES Table Page 1. Summation of variation sources and degrees of freedom for M’.1.0£"m¢.eeeeeeeeeeeeeeeeeeee 17 2. The effect of treatment on total calcium in the cortex of Jonathan apples after 13 weeks of storage in air at 3°C . . . l9 3. Mean total calcium in the cortex of Jonathan apples after 13 weeks of storage at 3° C as affected by prestorage tmmt..........................20 4. The effect of treatment on the incidence of internal breakp down in Jonathan apples stored for 17 weeks at 3°C plus 2 weeks at 22°C . . . . . . . . . . . . . . . . . . . . . . . 21 5. Prestorage treatment effects on the incidence of internal breakdown in Jonathan apples after l7 weeks of storage et3°Clnd2w¢eksat22C .o...............23 6. The effect of treatment on the incidence of Jonathan spot after 17 weeks of storage in air at 3°C. . . . . . . . . . . 25 7. Prestorage treatment effects on incidence of Jonathan spot after 17 weeks storage in air at 3°C. . . . . . . . . . . . . 25 8. The effect of treatment on the incidence of lenticel spot after 17 weeks of storage in air at 3°C . . . . . . . . . . . 26 9. Prestorage treatment effects on incidence of lenticel spot after 17 weeks of storage in air at 3°C . . . . . . . . . . . 28 10. The effects of treatment on the percentage of calyx injury after 17 weeks storage in air at 3°C . . . . . . . . . . . . 29 11. The effects of treatment factors on the percentage of "other injury" after 17 weeks of storage in air at 3°C . . . . . . . 29 12. Prestorage treatment effects on flesh firmness of Jonathan apples after 13 weeks of storage in air at 3°C . . . . . . . 30 13. The effects of treatment on the percentage of sound apples after 17 weeks of storage . . . . . . . . . . . . . . . . . . 32 16. Prestorage treatment effects on the percentage of sound apples after 17 weeks of storage in air at 30 C . . . . . . . 33 LIST OF FIGURES Figure Page 1. 2. The experimental drench hydrocooling unit being prepared for treatment. The circulating pump, foreground, and heater, left, are connected to the system with rubber hoses. . . . . . 9 Solution dispersion during drenching as achieved by the use of a plastic pen with 0.125 inch diameter perforations positioned over each of the crates of apples during tn‘Mte eeeeeeeeeeeeeeeeeeeeeeeee10 Appendix l. ”mu 3e LIST OP APPENDICES Page Calculations for the cooling requirements of treatments utilising 3°C drench solutions . . . . b1 Calculations for conversion of ppm fruit Ca to Isa/1008EICChmghteeeeeeeeeeeeee‘2 Comparison of cortex Ca after 13 weeks of storage to occurrence of disorders, flesh firmness, and amount of sound Jonathan apples ‘ft.t17".h0f8t°t.8¢eeeeeeeeeeeee 63 Vii INTRODUCTION Jonathan apples accounted for approximately 212 of the total Michigan apple production in 1978 (12). The availability of this cultivar for long-term.marketing, however, is limited by the development of the poetharvest disorders of internal breakdown, Jonathan spot and lenticel spot (28). High levels of fruit calcium (Ca) retard the development of these disorders and since the concentration of Ca within the fruit varies markedly with cultural practices and environmental conditions, the incidence of these disorders varies (26). Reduction of internal breakdown has been achieved by the applica- tion of Ca sprays in the orchard (ll; 17), and by direct postharvest application to the fruit (1). Although these physiological or functional disorders are best controlled by the latter method, some epidermal injury occasionally occurs. Lee (15) has shown that a higher initial amount of Ca could be introduced into Jonathan apples by submersion hydrocooling of the apples in 22 calcium.chloride (CaClz) than by momentarily dipping them in 61 CaCl2 solution. Commercial-scale drench hydrocoolers capable of precooling apples are already used in Michigan for highly perishable commodities such as cherries, peaches and asparagus. Apples, however, are normally placed directly into storage rooms and cooled by forced-air circulation (9). The use of hydrocooling with 22 CaCl2 as a means of increasing fruit Ca as well as for precooling apples seems worthy of consideration where hydrocoolers are available, particularly in view of the current interest in energy conservation. This experiment was designed to examine the feasibility of hydrocooling as a method for increasing fruit calcium in.Jonathan apples for control of storage disorders, and to evaluate the effectiveness of 2 and b2 CaClz concentrations applied in this manner. Literature Review The relationship between the calcium level in the fruit and the development of fruit storage disorders has been verified by a number of researchers (2, 6, 22, 36). Disorders currently associated with low Ca include internal breakdown, bitter pit, corkspot, cracking, lenticel blotch, lenticel breakdown, low temperature breakdown, and watercore (40). Calcium.has been determined to be quite mobile within the fruit. As much as 502 of that accumulated in the core region during the growing season migrates outward through the cortex after the first 1-2 months of storage (7). However, it is during the first month of storage that many of the disorders develop in low-Ca regions of the fruit. For example, internal breakdown usually appears as a light brown discolora- tion in the cortical cells immediately below the epidermis, and during storage this disorder may develop as far as the core, causing mealiness and loss of flavor (A2). The functions of Ca in delaying senescence include the maintenance of membrane integrity and semi-permeability and cell rigidity due to the formation of calcium pectate in the middle lamella (5, lb). Bangerth _e_t_ _a_l_.. (1) found that postharvest infiltration of CaClz in 'Jonathsn' apples inhibited internal breakdown, reduced the respiration rate and metabolism of endogenous substrates, and increased the oxidation of exogenous substrates. They suggested that Ca might retard respiration indirectly by limiting the amount of substrates diffusing from the vacuole into the cytoplasm. Similar effects on respiration were obtained by Faust and Shesr'(10), who cited the respiration rate to be inversely related to the Ge content or the fruit. Bramlage _e_t_ L1, (6) demon- strated that Ca affects the respiration.rate, but independently of maturity and ripening since respiration climacterics for apples with varying Ca levels occurred simultaneously. This independence of Ca and ripening could be species-dependent, however, since Cs application delayed the onset of the climacteric in avocado fruit (66). Cellular disorganization is retarded by Ca, as evidenced by better preservation of organelles in apple tissue high in Ca when compared to tissues which were deficient in fruit Ca (19). The delay in the progress of senescence processes reduces the development of storage disorders (29, 38). The endogenous Ca level varies greatly with crop loads, orchard location, cultural practices and environmental conditions during the growing season, so it is not unexpected that the severity of disorders fluctuates widely. A comprehensive review of the factors affecting fruit Ca has been compiled by Shear’ (40). iAlthough methods for increasing the Ge content of apples have been extensively examined, soil applications of Ca sources such as calcium carbonate have not been advantageous due to problems encountered with Ca uptake and translocation by the tree (61). The direct application of Ca salts to the fruit has met with greater success in that Ca can diffuse into the fruit through the direct connection between open lenticels and the intercellular air surrounding the loosely-bound cortical cells. The epidermis and its cuticular layer are the major barriers to Ca entry into the fruit according to Van Coot (65) and Mitchell :5 31. (24) have shown the nuaber of open lenticels and the thickness of the lipophilic cuticle to vary with apple variety. Since Ca ions are hydrophilic, maximum coverage of the fruit surface by the applied Ca solution is essential. Repeated preharvest sprays of CeCl2 hays increased Ca levels of apples and reduced the incidence of internal breakdown (11), as has a single spray of S2 CaClz prior to harvest (17). The former treatment is expensive due to the number of spray applications required, whereas the latter revealed nonuniform.distribution.of spray droplets on the fruit surface and inconsistent control of breakdown, especially for apples on uppermost branches. The 52 concentration of CeCl2 also caused moderate to severe damage to the foliage. fostharvest Ca applications hays yielded more consistent control of internal breakdown and other disorders than.either soil or preharvest spray applications. Rapid.aovement of Ca into the flesh resulted from fruits being dipped in a ‘2 CaClz solution at ambient temperature, with a significant Ca increase after the first week.of storage (21). During subsequent storage for 32 weeks, the Ca continued to migrate toward the core area. This inward movement sufficiently raised the Ca level so as to reduce breakdown.in 'Spartan' apples and retard flesh softening (22). The increase in the Ca level during long-term storage under high humidity (85-902) conditions is attributed by Lidster g; _a_l_. (16) to the hygro- scopic properties of CaC1 Surface-adhering CaClz molecules bind with 2. water vapor, forming a thin layer of solution which diffuses through the epidermis to the cortex region. Ca uptake is enhanced by the addition of food thickeners plus surfactants to the b2 CaCl2 dip solutions (20). The thickeners apparently increase the viscosity of the solution resulting in greater adhesion of the solution to the fruit surface. Solutions of 62 CaC12 may cause severe necrosis to the fruit surface of 'Jonathan' apples (1). Some injury from ‘2 CaCl2 treatments during long-term storage of 'Jonathen' has been reported (8). Vacuum infiltration of CaCl2 has reduced the incidence of bitter pit (37) and tripled the fruit Ca level in 'James Crieve' apples (13). Ten to 20 pounds per square inch of pressure was employed by Poovaiah (30) to force a 32 solution into the fruit during a 10-minute treatment period. Both methods, vacuum and pressure, substantially increased the amount of Ca infiltrated during a brief period of time so that the remaining surface-adhering Ca could be washed off, thereby preventing the hazard of skin injury during storage. Hydrocooling has served for many years as a rapid means of precooling highly perishable fruits and vegetables (3S). Chilled water (0-3°C) is utilized as a medium to transfer field heat from.the commodity to refrigeration coils or crushed ice. Depending upon the capacity of the refrigeration system and the size of the fruit, a temperature reduc- - tion of 20°C can be accomplished in 15-30 minutes of hydrocooling (3). Many hydrocooling systems drench water by gravity flow over the commodity as individual items, in crates or in bulk bins, permitting maximal heat transfer at the fruit surface. Other systems use spray nozzles or submergence in agitated water (5). Schomer and Patches (35) , using 3 apple varieties, showed that hydrocooling and air-cooling were equiva- lent cooling methods, provided the fruits were air-cooled to storage temperature within 7 days. Apples which‘were slowly airbcooled were of lower quality. The cooling time in many commercial storagee may be several weeks due to inadequate refrigeration capacity or air movement. Under these circumstances, the rapid cooling of apples by hydrocooling could permit maximal storage life and a greater percentage of marketable fruits following storage. Bydrocooling by submergence of the fruit in cold CeClz solution has been demonstrated as a means for introducing substantially higher amounts of Ca into 'Jonathan' apples than by dips in CaCl2 solutions at ambient temperature (15). Apples which‘were hydrocooled a minimum of 10°C in a 22 CaCl2 solution containing 0.12 LP77 surfactant increased in Ca by approximately 6 mg/100g fresh‘weight per individual fruit. This gain in Ca has been considered to be sufficient for control of internal breakdown and other Ca-related storage disorders of 'Cox's Orange Pippin' (25). A pressure differential between the external solution and the intercellular airspace is created as the volume of intercellular air contracts during fruit cooling, drawing the calcium solution into the fruit via open lenticels, surface breaks, and the calyx canal. Such an increase in Ca could possibly permit the use of the 22 CaCl2 solution instead of 62 which would reduce the incidence of internal breakdown without the hazard of fruit injury (8, 33). Important considerations in using a CaClz hydrocooling solution according to Lee (15) are that a minimum of 10°C reduction in fruit temperature be achieved and that a surfactant be employed to reduce surface tension so as to maintain continuous contact of the solution with the waxy cuticular layer surrounding the epidermis during the treatment period. Materials and Methods Commercial drench hydrocooling parameters were considered in the design of equipment for use in this study. Since apples are normally handled in bulk.bins, a fruit depth of approximately 26 inches was simm- 1ated by placing apples in two vertically-stacked bushel crates which measure 16.75 x 14 x 11.75 inches in height. The drench unit (Pigure l) was constructed of 0.5 inch plywood over a.wood frame, with hinged top and front panels and an open bottom. The wood covering provided some insula- tion from.ambiont temperature and protection fromnwind evaporation for the drenching solutions. Plastic drench pens with perforations in the bottom (0.125 inch diameter and spaced 0.5 inch apart) provided a drench pattern identical in area to the top surface of the crate. One drench pen was placed above the top crate and another between the 2 crates. The drench solution flow rate was restricted by the perforations in the drench pans to 9 gallons/minute/square foot of top surface area with sufficient head pressure for adequate dispersion over the fruits as in Figure 2. An open-top steel tank of about 100 gallons capacity was used to collect the drench solution which was pumped to the top of the drench unit positioned above the collection tank. Six clean 55-gallon steel drums served as storage containers for drench solutions and were located in either a 25°C storage room.for warm treatments of 0, 2 and 62 CaClz or in a 3°C storage room for the cold treatments of 0, 2 and 62 CaClz. Since fruit cooling of at least 10°C is required for a substantial uPtake of Ca (15), calculations (Appsndix 1) revealed that 50 gallons of Figure l. The experimental drench hydrocooling unit being prepared for treatment. The circulating pump, foreground, and heater, left, are connected to the system with rubber hoses. 10 Figure 2. Solution dispersion during drenching as achieved by the use of a plastic pan with 0.125 inch diameter perforations positioned over each of the crates of apples during treatment. w 5.. .2 :4 w. tit: ll 3°C solution would be more than sufficient to remove this amount of heat during a 20-minute hydrocooling drench, when used in combination with ice. Three gallons each of the 0, 2 and 62 CaCl2 drench solutions were frozen, crushed and added to the appropriate solution in the collec- tion tank during treatment. With this procedure, cold drenching solutions warmed only 2-3°c during the 20-minute hydrocooling period. To maintain warm (25°C) solutions during a 20-minute treatment to cold fruits, solutions were circulated through a water heater _1_/ . Temperatures were held at 25-30%. The drench solutions were formulated as follows: 50 gallons of tap water, 0.05 gallon L-77 surfactant 24 0.08 ounces/gallon of benomyl 2", and either 0, 10.7 lbs. or 21.6 lbs. of CaCl2 3’ for a final concentration of 0, 2 or 42 CaClz. After mixing, each drench solution was stored in the appropriate storage tank for temperature equilibration prior to truant. s l’Comfort zone LP gas heater, 80,000 D.t.u. Lochinvar Water Heater Corp. , Nashville, TN z’L-n, organo-modified silicone: surface tension - 20 dynes/cm in 12 solution at 25°C. Application Information Sheet F-“lO'I, Dec. 1972, Union Carbide Corp., 270 Park Ave., New York, N! 10017. linenlste, A. 1. - benomyl (502), F. I. duPont de Nemours and Co., Inc., Wilmington, DE 4/ -' Dowflake, 77-802 CaCl Dow Chemical Co., Midland, MI 2. 12 To determine the effectiveness of the drench treatments for coverage of the fruit surfaces, a solution containing 12 Migrisine dye, tap water and 0.12 L-77 surfactant was drenched over apples in two crates for 1 minute. After air drying, each fruit was visually inspected for the percentage of its surface not covered by dye. For a cold drench applied to warn fruits, 952 of the fruits in the top crate had greater than 902 of their surfaces covered with dye, whereas those in the lower crate had 912 with greater than 902 of the surface covered. The greatest amount of solution channeling and the poorest coverage appeared to be for fruits positioned against the sides or corners of the crates. At these locations 60-702 of a fruit's surface was occasionally found covered by the dye. The points of fruit contact with other fruits resulted in small areas not covered with dye. The apples were harvested according to the ideal harvest date for long-term storage, based on the M.S.U. system utilizing minimum tapers- ture during the first 15 days after full bloom for each orchard. Sixty bushels of 'Jonathan' apples from the MSU Horticulture Research Center at East Lansing (Orchard 1), were harvested, randomized, labeled and placed at 3 or 25°C overnight for teqerature conditioning on October lo, 1978. Each holding room was provided with adequate air circulation to aid temperature conditioning. Treatments were run the following day. Apples from the Graham Experimental Station at Grand Rapids (Orchard 2) were harvested on October 8, 1978 and handled similarly except they were treated 2 days after harvest. There were nrked differences in fruit quality at harvest between the two orchards. Fruits from Orchard 1 had numerous scab infections, which were included in the treatments mless cracked open, as well as 12.52 watercore based upon a random sample of 13 60 fruits. Apples from Orchard 2 were relatively free from scab and showed no watercore. fruits from both locations had an average flesh fir-tees of 18.7 pomds. Flesh fir-less determinations were made on AO fruits (with a press-mounted Effgi tester), with 2 tests performed on opposite sides of each fruit with the epidermis removed prior to testing. Branching procedures involved puwing-s-l a given solution from the storage dn- (agitated manually) to the collection tank, where it was then pumped to the upper drench pan for application to the fruits. Agitation as a result of the drenching operation maintained solute suspension in the solutions. Depending on the treatment, either the appropriate concentra- tion of frosen solution was added to the cold solutions or the warm solu- tions were heated to ensure constant temperature of the solution during drenching. Treatments were rm beginning with the cold solutions of O, 2 and 62 (zeal2 and within each concentration the cold fruits were treated first for l or 20 ninutes. This was followed by treating the warm fruits for the same drench periods. This entire procedure was reversed for the warm drench solution concentrations. Initial and final temperatures were recorded for each treatment for the drench solutions and from the core region of an apple from the lower crate. After treatment, crates were individually wrapped with perforated polyethylene to provide a high relative haidity environment for the fruits and placed in storage at 3°C. I 2 'reel centrifugal pun, 1 inch suction and discharge, mutated on a Dayton 1/3 h.p. 3450 rpm 120v motor. Dayton Electric Mfg. Co., Chicago, IL 60688 16 After 13 weeks of storage, on January 2, 1979, 20 medium-sised fruits were selected from each crate in Orchard 1, labeled and allowed to equili- brats to 22°C overnight in the laboratory. The next day, they were rinsed with 0.52 acetic acid solution, rinsed in tap water to remove surface- adhering Ca and air dried. Flesh firmss mean values were determined for each sample of 20 fruits using the previously described method. The following day each fruit was sliced twice longitudinally. One slice was made on each side of the core, parallel with the pressure test holes. The center slice containing the core region was discarded and an 8- diameter cylinder was removed from each apple half with a cork borer. These flesh cylinders were angled away from surface cuts or holes which say have permitted abnormal Ca entry and contamination. Bach cylinder was tri-ed to 9- 1ength i-ediately below the epidermis so as to sample the Ca only in the cortex. Approxinately 10 g of cortex tissue cylinders from each treatment sample was weighed and placed in a 25 ml crucible. The crucibles were covered with plastic to prevent air contamination during tissue saqling and afterward, the tissues were air dried for 70 hours at 82°C. Upon drying, the tissues were ashed in an electric oven at 560°C for 13 hours. Ash from each crucible was extracted with 5 ul 0.5N 8C1 with 12 La(liO3)3 (wt/wt) and the aliquot stored in an air-tight vial (11). If the solution contained any visible carbon due to carnelisation of fruit sugars, it was filtered through Whatnsn #6 paper. The equipment was rinsed and air-dried after each sample was extracted. Fruits from Orchard 2 were sampled in the sane manner the following week (January 8, 1979). 15 A Varian Techtron AA6 spectrophotometer was used for Ca determina- tions. .A standard reference curve for Ca of O, 10, 20, 30, 60 and 50 ppm was made by dilution of Reference Stock Solution (lOOO ppm)2!'with distilled water. Aliquots free the 2 and 62 CaCl drench treat-ants were diluted 2 152*with the extracting solution to fit the 0-50 ppm range of the Varian unit, prior to detersinations. Calculations for conversion from ppm Calaliquot to mg CallOO g fresh.weight are reported in Appendix 2. After 16 weeks of storage (February 6, 1979) the crates of fruit from Orchard 1 were removed and placed in the laboratory at 22°C. I-ediate examinations of the fruit were node for incidence of the following disor- ders according to these synptome: a. Internal Breakdown - fruit soft when hand squeesed, may show brown to dark brown discoloration on epidermal tissues (28) b. Jonathan Sggt - necrosis not originating fromhthe lenticel, dark blue to black in color (36). c. Lenticel Sggt - any necrosis radiating from the lenticel (36). d. Calyx Injury - necrosis not related to preharvest indury (e.g. scab, mechanical damage, mite injury) located within the calyx cavity or at the calyx shoulder of the fruits; e. Other Injury - lesions on the epidernis other than Jonathan spot or lenticel spot, but obviously arising during storage. Noted especially were small brown streaks at the calyx and, notably on fruits from Orchard 2, possibly an aggravation of preharvest mite injury. f. Sound Fruit - not having any of the above storage disorder synptoes. 2’ Fisher Scientific Co., Fairlawn, NJ 07510. llInjury symptoms, D. R. Dewey, personal communication. 16 All fruits with pathological decay were discarded and not included in final counts. After a 2-week holding period, to simulate the marketing period, the remaining fruits were examined internally by slicing latitu- dinally for incidence of internal breakdown. Apples from Orchard 2 were examined in the sane manner. Statistical evaluations of the data after transformation by sin’1~f§'(43) were performed by Analysis of Variance (ADV) using the STAT program of the CDC 6500 computer. An initial analysis showed there were no significant differences for fruits in the upper or lower crates as to values for any of the treatment effects (flesh firmness, fruit Ca, disorders, injuries or sound fruits). A second ADI was performed utilis- ing orchard locations as blocks and the crate positions as replicates. The ADV summary for this analysis in Table 1 shows main treatments, inter- actions, error terms and the corresponding degrees of freedom (df). Main treatment and interaction effects were compared by Least Significant Difference (lsd) according to the significance of the Fbtest, using transformed data. Individual treatments were compared by Duncan's Multiple Range Test at the 52 level. The error mean squares used in these means separation tests were based on the sum of Orchard (block) df multiplied by each main treatment and interaction df for a total df of 23. The remaining error consisted of the sum of crate position df multiplied by the df's for block, main treatments and interactions, totalins 48 df. This latter term was not used in the calculations for means separations. Transformed means were converted back to percentage values for data presentation. 17 TABLE 1 Summation of \eriation sources and degrees of freedom for analysis of variance Degrees of Source. Freedom Main Treatments Orchard (Block) Solution Temperature (ST) Fruit Temperature (FT) Drench Duration (DD) CaCl2 Concentration (Ca) Z-Way Interactions ST FT ST DD FT DD ST Ca FT Ca DD Ca Nt‘h‘Hb‘ saunas NEQBJHPJF‘ 3-Way Interactions ST x FT x DD ST x FT x Ca ST x DD x Ca FT x DD x Ca NNNH 4-Way Interaction ST x FT x DD x Ca 2 Total 24 Error (Orchard x Main treatments and interactions) 23 Remaining error (Crate position x all other main treatments and interactions) TOTAL |‘° l“ U! as Results The total calcium of the fruit cortex after the apples had been stored for 13 weeks was greater for apples which were warm (25°C) when subjected to prestorage drenching than those which were cold (3°C) , Table 2. The drench period of 20 minutes was more effective for increasing cortex Ca than the l-minute drench, and as CaCl2 concentration in the drench solu- tion was increased from O to 2 and 62, the fruit Ca was increased (Table 2). Comparisons of individual treatment means in Table 3 reveal that all treatments of 62 CaCl2 caused significant increases in cortex Ca over the 02 controls, except when cold solutions were applied to cold fruits for l or 20 minutes or when a warm solution was applied to cold fruits for 1 minute. Rydrocooling for 20 minutes with 42 CaCl2 (Cold! Warm/20M) resulted in the highest Ca (6.81 mgllOOg fresh weight); it was significantly greater than the l-minute warm drench of 42 CaCl2 applied to warm fruit (Harm/Harmlllb, 3.63 mgllOOg) which is the treatment currently race-ended for the field treatment of Jonathan apples for long- term storage (8). The most effective treatments containing 22 CaCl2 (Table 3) were those applied to warm fruits for 20 minutes with either warm or cold solutions. Hydrocooling for 20 minutes with 22 CaCl2 (Cold/Warm] 20/ 2) was equivalent to hydrocooling for 20 minutes with 42 CaCl2 and to the 1-minute warm drench of 42 CaCl2 applied to warm fruit for increasing fruit Ca. The incidence of internal breakdown in fruit which had been stored for 17 weeks at 3°C plus 2 weeks at 22°C was less prevalent in apples from Orchard 2 than from Orchard 1, Table lo. Harm treatment solutions, the 18 19 TABLE 2 The effect of treatment on total calcium in the cortex of Jonathan apples after 13 weeks of storage in air at 3°C. 2 Mean Treatment (mgllOO g fresh.wt.) l.s.d. Fruit Temperature 3% 2.39 a 0.35“ 25°C 2.90 b Drench Duration 1 Minute 2.45 a O.3S** 20 Minutes 2.85 b CaCl2 Concentration 02 1.82 a 22 2.81 b O.43** 42 3.31 c zMeans not followed by the same letter are significantly different by lsd, 12 level. 20 TABLE 3 Mean total calcium in the cortex of Jonathan apples after 13‘weeks of storage at 3°C as affected by prestorage treatment Solution Fruit Drench Meanz Temperature Temperature Duration 2 CaClz (mg/100g fr. wt.) cold warm 20 4 4.81 warm warm 20 4 3 . 93 cold warm 20 2 3.85 warm. cold 20 4 3.69 warm warm 1 4 3.43 cold warm 1 4 3.01 warm warm. 20 2 3.01 warm cold 1 4 2.93 warm cold 20 2 2.82 warm warm 1 2 2.69 cold warm 1 2 2.68 cold cold 1 2 2.67 warm cold 1 2 2.41 cold cold 20 4 2.37 cold cold 20 2 2.35 cold cold 1 4 2.31 cold warm 20 O 1.93 warm warm 1 O 1.88 cold cold 1 O 1.85 warm cold 20 0 1.83 cold warm, 1 0 1.82 cold cold 20 0 1.81 warm warm 20 0 1.78 warm cold 1 O 1.69 zMeans not connected by the same line are significantly different according to Duncan's Multiple Range Test, 52 level. 21 TIBLE 4 The effect of treatment on the incidence of internal breakdowg in Jonathan apples , stored for 17 weeks at 3 C plus 2 weeks at 22°C. Treatment Mean.(2)z l.s.d. Orchard 1 25.9 l.9*** 2 6.3 Solution Temperature 3°C 18.5 l.1** 25°C 11.3 Fruit Temperature 3°C 23.7 1.9*** 25°C ' 7.5 CaCl2 Concentration oz 38.1 1.6*** 22 10.5 42 3.4 'zMeans not followed by the same letter are significantly different. 22 treatment of warm fruits, and increased concentrations of CaCl2 reduced the occurrence of breakdown. The individual treatment means presented in Table 5 show that all of the 42 CaCl2 treatments were equivalent to each other in reducing breakdown. All of these, except when applied as a cold solution to cold fruits for l or 20 minutes or as a warm.solution to cold fruit for 1 minute, caused significant decreases in.breakdown.ower the O2 CaCl 2 treatments. The 22 CaCl applications reduced breakdown as well as the 2 42 treatments in most instances. The exceptions were when warm or cold solutions were applied to cold fruits for 1 minute, and when a cold solu- tion was applied to cold fruits for 20 minutes. The data in Table 6 show less incidence of Jonathan spot after 17 weeks of storage for apples from Orchard 2 than from Orchard 1. Fruits which were cold prior to treatment developed less Jonathan spot than those that were treated while warm. Drenching for 20 minutes reduced the inci- dence over the l-minute drench. As CaCl2 concentration of the drenching solution increased, the occurrence of Jonathan spot in storage decreased, ranging from 12.72 for 02, down to 3.4 and 0.82 for 2 and 42 CaClz, lrespectivaly. Comparisons of the individual treatment means in Table 7 reveal that Jonathan spot occurred most extensively for the 02 CaCl2 treatments of cold or warm solutions applied to warm fruits for 1 minute and warm solution applied to warm fruits for 20 minutes. The incidence of lenticel spot after 17 weeks of storage varied by orchard location, with a lower percentage occurring in apples from Orchard 2 than from Orchard 1, Table 8. Increasing the drench period to 20 minutes 23 TABLE 5 Prestorage treatment effects on the incidence of internal breakdown in.Jonathan apples after 17 weeks storage at 3°C and 2 weeks at 22°C. Solution Fruit Drench Temperature Taperature Duration 2 CaCl.2 Mean (2)2 warn warm 20 4 0.1 cold warm 20 4 0.5 warn warm; 1 4 0.6 cold warm 1 4 1.0 warn warm 20 2 1.5 warm cold 20 4 1.6 were warm; 1 2 2.2 cold warm 20 2 2.2 cold warm 1 2 5.3 warm cold 1 4 9.4 mm cold 20 2 10.6 cold cold 1 4 13.3 cold cold 20 4 14.1 warm warm 1 0 23.1 warm cold 1 2 25.6 warn warm, 20 0 27.8 cold cold 1 2 28.6 cold warm, 1 0 29.2 cold cold 20 2 29.8 warm cold 20 O 36.9 warm cold 1 O 43.0 cold cold 1 0 45.1 cold warm 20 0 49.5 cold cold 20 0 52.5 zMeans not connected by the same line are significantly different according to Duncan's Multiple Range test, 52 level. 24 TABLE 6 The effect of' treatment on the incidence of 1 Jonathan spot after 17 weeks of storage in air at 3°C. Treatment Mean (2)2 1.s.d. Orchard 1 7.5 a O.9*** 7- 2.2 b Fruit Temperature 3°c' 3.1 a o.5** 25°C 6.0 b Drench Duration 1 Minute 6.0 a 0.5M. 20 Minutes 3.1 b CaCl2 Concentration 01 12.7 a 1.4*** 22 3.4 h 41 0.8 c zMeans not followed by the same letter are significantly different. 25 TABLE 7 Prestorage treatment effects on incidence of o Jonatfnn spot after 17 weeks storage in air at 3 C. Solution Fruit Drench Temperature Temperature. Duration 2 CaCl2 Mean (2)2 warm earn. 20 4 0.1 cold warm 20 4 0.1 cold warm 20 2 0.6 cold cold 20 4 0.6 warm cold 20 4 0.7 cold cold 1 4 0.9 warm, cold 1 4 1.5 cold warm, 1 4 1.8 warm. warm. 1 4 2.0 warm cold 20 2 2.2 cold cold 1 2 2.3 cold cold 1 0 3.1 warm warm 20 2 3.7 cold cold 20 2 3.7 warm cold 1 2 4. 3 cold warm, 1 2 5.7 cold cold 20 0 6.1 cold warm 20 0 7.0 warm warm 1 2 7.3 warm cold 20 0 9.1 warm cold 1 0 9.7 warm warm 20 0 22.3 warm wave 1 O 26.7 cold warm 1 0 28.6 zMeans not connected by the same line are significantly. different according to Duncands Multiple Range.Test, 52 level. 26 TABLE 8 The effect of treatment on the.incidence of lenticel spot after 17 weeks of storage in air at 3°C. Treatment Mean (2)2 1.s.d. Orchard 1 12.1a l.l** 2 317b Drench Duration 1 Minute 8.9a 0.3* 20 Minutes 5 . 9f) CaCl2 Concentration 02 16.4a l.O** 22 4.7h 4; 3.5c zMeans not followed by the same letter are significantly different. ' 27 reduced lenticel spot over the l-minute period, as did increasing the CaClz concentration from 0 to 22 and to 42. The individual treatments means in Table 9 show that the highest incidence of lenticel spot resulted from treatments without Ca, especially when applied as warm or cold solutions to warm fruits for 1 minute, or as cold solution.to cold fruits for 1 minute, or as a warm.solution to warm fruits for 20 minutes. All other treatments were of similar effect in significantly reducing lenticel spot over the above treatments. Although fruit injury at the calyx end of the apples was relatively slight after 17 weeks of storage, fruits from.Orchard 2 were damaged more than those free Orchard 1, Table 10. Comparison of the individual means by Duncan's Multiple Range Test showed there was no significant effect of the individual treatments on occurrence of calyx injury. Damage classified as ”other injury“ developed on apples during storage. It occurred most frequently on fruits which were cold when treated and on apples receiving the higher CaCl2 concentrations, Thble 11. The indiwidual treatments were of no significant effect on this type of injury. Apples treated with 42 CaCl had a mean flesh firmness of 9.8 pounds 2 when examined after 13 weeks of storage, a decrease of 4.9 pounds from the firmness at treatment of 14.7 pounds. They were significantly firmer than the 9.4 pounds firmness for apples receiving 02, but not for the 9.6 pounds of those treated with 22 CaCl Pirmness of fruit for the O 2. and 22 CaCl2 treatments were not significantly different. Comparisons of individual treatment means in Table 12 show there was a relatively narrow range of values, and that significantly higher firmness occurred only for 28 TABLE 9 Prestorage treatment effects on incidence of lenticel spot after 17 weeks of storage in air at 3°C. Solution Fruit Drench Temperature» Temperature Duration 2 CaClz ‘Mean (z)z. warm warm 20 4 0.81 cold cold l~ 4 1.5 cold warm 20 2 1.8 warm cold 1 4 3.1 cold cold 1 2 3.7 cold cold 20 4 3.7 cold warm 1 4 3.9 warm warm 1 4 4.0 warm warm 20 2 4.3 warm cold 20 4 4.4 warm cold 20 2 4.5 cold cold 20 2 4.8 warm. cold 1 2 4.9 warm warm 1 2 5.6 .cold warm 20 0 6.0 cold warm 20 4 9.1 cold cold 20 0 9.3 cold warm. 1 2 9.5 warm cold 1 0 12.1 warm cold 20 0 12.9 warm warm 20 0 17.3 cold cold 1 o 19.4 II warm. warm 1 0 28.3 cold warm. 1 0 32.2 zMeans not connected by the same line are significantly different according to Duncan's Multiple Range Test, 52 level. 29 TABLE 10 The effects of treatment on the percentage of calyx injury after 17 weeks storage in air at 3° C Treatment Meanz 1.s.d. Orchard 1 0.004 a 0.130*** 2 0.160 b CaCl2 Concentration 02 0.004 a 0.060* 22 - 0.052 a 42 0.071 b zMeans not followed by the same letter are significantly different. TABLE 11 The effects of treatment,factors on the percentage of other injury after 17 weeks of storage in air at 3 C Treatment Meanz 1.s.d. Fruit Temperature 3°C 2.8 a 0.4* 25°C 0.8 b CaCl2 Concentration 02 0.4 a l.l*** 22 1.7 b 42 3.8 c zMeans not followed by the same letter are significantly different. 3 0 TABLE 12 Prestorage treatment effects on flesh firmness of Jonathan apples after 13 weeks of storage in air at 3°C. Solution Fru it Drench Tanperature Tenperamre Duration 2 CaClz Mean (lbs . ) 2 cold warm 20 4 O. 47 - warm cold 20 4 0. 02 , cold cold 20 2 9. 95 warm warm 1 0 9. 94 warm cold 1 4 9. 91 cold warm 20 2 9. 90 cold cold 20 4 9. 77 warm warm. 20 4 9. 77 cold cold 1 2 9. 67 cold cold 1 4 9. 61 warm warm 1 2 9. 60 warm warm 1 4 9. 59 warm cold 1 2 9. 59 mm warm 20 0 9. 58 warm cold 20 0 9. 56 cold warm 1 4 9. 53 warm warm 20' 2 9. 52 cold cold 20 0 9. 50 cold warm 1 0 9. 49 warm cold 20 2 9. 43 cold warm .1 2 9. 28 warm cold 1 O 9. 18 cold warm 20 O 9. 17 cold cold 1 0 9. l6 zMeans not connected by the same line are significantly different according to Duncan's Multiple Range Test, 52 level. 31 apples which had been hydrocooled for 20 minutes with 42 CaCl This 20 treatment yielded firmer fruits than any of the 02 CaCl treatments, with 2 the exception of warm solution applied to warm fruit for 1 or 20 minutes. Hydrocooling with 42 CaCl2 for 20 minutes also maintained fir-aces over treatments in which 42 CaCl: was applied as a cold solution to warm fruits for 1 minute, and in which 22 CaCl2 was applied as a warm solution to warm or cold fruits for 20 minutes, or as a cold solution to warm fruits for 1 minute. Sound apples were so classified when free from internal breakdown, Jonathan spot, lenticel spot, and calyx and other injuries when removed from storage 17 weeks after treatment. Table 13 su-erizes the results that show there was a greater nufler of sound fruits for Orchard 2 than for Orchard 1 and that the application of 22 CaClz significantly increased the percentage of sound fruits over the 02 Control, whereas, 42 CaCl2 gave significant increases over both of the 0 and 22 concentrations. The means for individual treatments in Table 14 show the highest percentages of sound fruits to have resulted from all of the 42 and most of the 22 CaCl treatments. For the latter, CaClz applied as a 2 cold solution to cold fruits for 1 or 20 minutes was the least effective. 32 TABLE 13 The effects of treatment on the percentage of sound apples after 17 weeks of storage Treatment Meanz 1.s.d. Orchard 1 71.4 a 1.8*** 2 86.1 b CaCl2 Concentration 02 60.2 a 1.5** 22 85.7 b 42 88.3 c zMeans not followed by the same letter are significantly different. 33 TABLE 14 Prestorage treatment effects on the percentage of sound Jonathan apples after 17 weeks of storage in air at 3°C. Solution Fruit Drench Temperature Temperature Duration 2 CaClz Mean- 2 cold warm 20 2 95 , 6 warm warm 20 4 94, 9 cold warm 1 4 91 , 8 cold cold 1 4 91. 4 warm warm 20 2 91 . 3 I warn: cold 20 4 90. 9 [ warm cold 20 2 89. 5 warm warm 1 4 88 . 0 warm warm 1 2 88 . 0 { cold warm 1 2 35 . 1 cold cold 2 0 4 83 , 8 cold warm 20 4 82 _ 2 warm co 1d 1 2 so. 5 warm cold 1 4 80, 3 1 cold warm 20 O 74 . 0 cold cold 2 0 2 73 , 7 cold cold 1 2 71 , 7 warm warm 20 O 63 . 5 warm cold 1 O 53, 5 cold cold 1 0 6 3 , o warm cold 20 0 62 , 1 cold cold 20 0 58 , 3 warm warm 1 O (.8 , 2 cold warm 1 0 47 , 7 zMeans not connected by the same line are significantly different according to Duncan's Multiple Range Test, 52 level. Discussion The results of this study show that total fruit Ca is increased by the peetharvest application of CaCl to fruit in agreement with the 2 findings of Mason and Drought (21), Millikan and danger (23) and van Coor (457. The range of Ca values from 1.69 to 4.81 mgllOOg fresh.weight is similar to those obtained by Lee (15) for the 'Jonathan’ variety, Perring (26) for 'Cox's Orange Pippin,‘ and Sharples and Johnson (33) for 'James Grieve'. Although there were treatment dif- ferences in total fruit Ca, the increase in Ca induced by a particular drenching treatment is not known since the determinations were made after the apples had been stored for 13 weeks with CaCl adhering to the surface. 2 As demonstrated by Lidster ggngl, (16) high humidity conditions in storage favor the migration of Ca from the surface through open lenticels and into the cortex region during the storage period. It is assumed that Ca con- tinued to migrate into the fruits during this 13-week storage period and that this migration was similar for all fruits treated with a given CaCl; concentration. Therefore, the values for fruit Ca as determined after 13 weeks of storage are the sum.of Ca accumulated in the fruits during the growing season, plus the Ca induced during treatment, plus the Ca which moved into the fruits from the surface during the storage period. The 42 CaCl: concentration, application to warm fruits and the 20—minute treatment period were the most favorable factors for increas- ing fruit Ca. The application of 22 CaCl by hydrocooling for 20 minutes 2 yielded fruit Ca values similar to those of the commercial method currently practiced, which is the brief drenching with 42 CaCl2 as a warm 34 35 solution to warm fruits. Levels of fruit Ca were significantly higher when 42 CaCl2 was applied as a hydrocooling treatment for 20 minutes then when applied by the simulated commercial method. The decision as to which of the above treatments would be the most appropriate for co-ercial use would be determined by the level of Ca desired in the fruits after treat- ‘ment, the possibility of CaClz injury to fruit surfaces, and the feasibility of hydrocooling to precool the apples. The higher Ca levels in fruits which were hydrocooled with 2 or 42 CaCl2 solutions is explained by the work of Lee (15) whereby cooling reduces the pressure of the intercellular air below that of the surrounding drench solution. This causes an intake of the solution into the fruit via open lenticels and breaks in the epidermis. Lee considered a minimal decrease of 10°C as necessary for the immediate Ca uptake to be signifi- cantly greater than that induced by nonehydrocooled Ca applications. In the experiment reported here the fruits were cooled approximately 10-15°C. The CaCl2 applied as cold solutions to cold fruits resulted in only a slight increase in total fruit Ca over the non-Ca (02 CaClz) treatments (Table 3), probably because there was no reduction in the volume of inter- cellular :1: and hence, 11::1. c. uptake during the treatment. Lee (15) in measuring Ca uptake by fruit weight gain immediately after treatment, obtained similar results and attributed this ineffectiveness to the fruits being in equilibrium with the drenching solution. Another factor which no doubt affected Ca infiltration during treatment was coverage of the apples by the drench solution. The use of Nigrisine dye to evaluate coverage revealed that as much as 102 of the surface of 5-102 of the apples was not covered after a 19minute drench with either were or cold solution. 36 Channeling of the solution between the fruits appeared to be the major source of incomplete coverage, especially for apples which rested against the side or corners of the crate. During hydrocooling treatments, the exposed surfaces allowed the uptake of air rather than solution since pressure in the fruit equilibrated with atmospheric pressure, negating the driving force for solution uptake by the apples. Incowlete coverage could have reduced Ca uptake during non-hydrocooling treatments as well, but this appears to be less a factor due to Ca movement into the fruits during long-term storage. Correlations between fruit Ca and disorders, flesh fir-less and sound fruits were calculated to aid in the explanation of these relation- ships. There was a highly significant linear but inverse correlation between fruit Ca and the incidence of internal breakdown (y-3.37-0.38x; r-0.8l; P-0.01). Breakdown is a senescence disorder and it is known that increased Ca delays semscence, since fruit respiration is suppressed with increased fruit Ca levels (1, 10, 6). This reduced respiration is related to better maintenance of cellular integrity so as to retard the develop- ment of storage disorders (10). Another hypothesis is that sufficient fruit Ca may maintain proper substrate metabolism so as to prevent the emulation of toxic products which cause the breakdown disorder (1, 46). Sufficient Ca may also preserve cellular integrity by maintaining protein synthesis (10). It was found that with a mean Ca level above 3.0 mgllOOg fresh weight per fruit, the incidence of internal breakdown was less than 22 (Appendix 3). This is consistent with the results of Perring (25) who reported that Cox's Orange Pippin apples with a collective sample mean greater than 37 4.5 mgllOOg should remain free of senescent breakdown during long-term storage. The threshold level for an individual fruit was lower at 3.0 mg/ 100g. 8e (26) also showed that the threshold levels for fruit Ca fluc- tuate with orchard location as well as seasonally, and postulated that high concentrations of phosphorus, potassium, magnesium and dry matter may off- set the otherwise detrimental effects of low Ca. This may partially explain why apples from Orchards 1 and 2 in this studyVhad similar means for fruit Ca, and yet those from.Orchard 1 developed significantly more internal breakdown, Jonathan.spot and lenticel spot (Tables 2, 4, 6, and 8). Differences in orchard management such as pruning, water relations and nutrition program most likely had a bearing on overall fruit nutrition, as reported by Redmond (32) . Another reason for the more frequent occurrence of disorders in fruits from.Orchard 1 may have been over- maturity, since 12.52 of the fruits showed watercore at harvest. Apples from Orchard 2 were free from this disorder which, according to Smock (42) is an indication of advanced maturity. Fruits drenched with 02 CaCl, which remained warn until placement in storage had significantly less breakdown (23.12 in Table 5, for’warll warm/110) than those which were either cooled prior to treatment (52.52, cold/cold/ZOIO) or which were cooled during treatment as a result of hydro- cooling (49.52, coldfwarIIZOIO). Similarly, breakdown was significantly reduced in 'Spartan' apples by holding the fruits for 3 days at 21°C prior to cold storage (31). The retardation of flesh softening as a result of increased fruit Ca has been reported by other workers (1, 22). In this study, firmness values were significantly correlated to fruit Ca determinations 38 (y-12.28+1.55x; r-0.57; P-0.05). APPCBdix 3. The possible preservation of cellular organisation.by Ca would have contributed to the reduced amount of softening. Significant negative linear correlations as determined from the data in Appendix 3 existed between fruit Ca and Jonathan spot (y-3.03-0.06x; r-0.58; P-0.01) and between fruit Ca and lenticel spot (y-3.08-0.05x; r-0.57; P-0.0l). .As with internal breakdown, this inverse relation- ship of physiological disorders to fruit Ca appears to be more a conse- quence of delayed senescence due to a higher fruit Ca than to any direct effect of Ca on the development of the disorder (38). The incidence of Jonathan spot was reduced significantly by cooling the fruit prior to drenching without Ca application (Table 7). Fruits which did not receive Ca during treatment, but remained warm until placement into cold storage had the greatest amount of Jonathan spot. Studies by Richmond and Dewey (34) found this disorder was favored by overmaturity at harvest and low fruit nitrogen. Additionally, storage at temperatures below 21°C sometime during the holding period was necessary before Jonathan spot would develop. Calyx injury to fruits from CaCl was less than 12 (Table 10) and 2 of little effect on overall fruit quality. Other injury (Table 11) occurred with greater frequency, but whether it was caused by CaCl penetration at 2 points of preharvest injury or by the slow development of damage during storage is unknown. The percentage of sound apples was correlated to fruit Ca (y'-O.45+0.04x; r-O.71; P-0.01). Significant increases in the amount of sound fruits resulted for all treatments involving the application of Ca over the non-Ca treatments, except for 22 CaCl applied to cold fruits 2 (Table 14). 39 Total fruit Ca and, hence, reduction of internal breakdown was generally affected more by the concentration of CaCl2 applied during treatment than by solution temperature, fruit temperature, or drench duration. Even so, a drench of 22 CaCl with proper surfactant applied 2 as by commercial hydrocooling procedure would likely serve the dual purpose of precooling Jonathan apples prior to storage while increasing the fruit calcium level sufficiently to control the development of internal breakdown. 51-111 and Conclusion Drench hydrocooling was examined as a possible means of post- harvest CaCl2 application to 'Jonathan' apples for the control of storage disorders. Experimental conditions utilised to assure maxim effective- ness of the hydrocooling treatments were the inclusion of the surfactant L-77 in the drench solution, a solution flow rate of 9 gallons per minute per square foot of surface area, and a 10°C or greater decrease in fruit temperature during the 20-minute treatment period. Hydrocooling for 20 minutes with 42 CaClz significantly increased total fruit Ca over the current practice of drenching apples momentarily with 42 CaCl2 at adient temperature, whereas hydrocooling for 20 minutes with 22 CaClz was equivalent to both of the above 42 treatments. Reductions in the occur- rence of internal breakdown, Jonathan spot and lenticel spot after 17 weeks of storage in air at 3°C were related to the increase in fruit Ca. Fruit injury from CaCl treatment was of minor inortance. 2 40 APPENDIX 41 APPENDIX.1 Calculations for the cooling requirements of treatments utilizing 3°C drench solutions. 1) Field heat - (specific heat of apple) x (temperature differential) x ‘ (sample‘weight) [Lutz and Hardenburg, 1968] - (0.87) x (20°F) x (40 lbs/crate) x (2 crates/treatment) - 1392 B.t.u. 2) Heat loss due to poor insulation - 502 [Mitchell 3; £1, I972} - 1392 x .50 - 2784 B.t.u. 3) Vital heat (heat of respiration) and field heat of crates were negligible sources of heat 4) 1 gallon - 8.33 lbs. 5) Acceptable solution temperature increase - 60F. 6) Heat capacity of water - 8.33 x 60F - 50 B.t.u./gallon 7) Heat capacity for 40 gallons of solution - 50 x 40 gal - 2000 B.t.u. 8) Heat capacity of ice (32°F) - 144 B.t.u./lb. 9) Heat capacity of 25 lbs. ice - 144 x 25 - 3600‘ B,t;u. 10) Total heat capacity of 40 gallons solution with 25 lbs. crushed ice - 2000 + 3600 - 5600 B,t,u‘ The safety range of 2816 B.teu. (5600-2784) should have been more than sufficient for maintaining the drench solution within the range of 3 - 6‘C during the 45 minutes necessary for running all of the cold solutions. 42 APPENDIX 2 Calculations for conversion of ppm fruit Ca to mg Ca/lOOg fresh weight. 1) mg Ca in 55ml aliquot 5mg g-l) x (ppm aliquot) x (10-6) x (15 dilution factor, if applicable) - (Sml) x (10 2) mg Ca/lOOg fresh weight - [(mg Ca in aliquot) / (g fresh weight)] x (100g) Comparison of cortex C's after. 13 weeks of storage to occurrence of disorders, 43 APPENDIX 3 flesh firmness, and amount of sound Jonathan apples after 17 weeks of storage Dimnflbrs _. ' Intmnmd .kmaflum. lentkmd Plan: 2 Treatment Cortex Ca Breakdown Spots Spots Firmness Sound c/w/20-4 14.81 2 0.5 2‘0.1 16 911 110.47 1282.2 wIw/20—4 23.93 1 0.1 10.1 1 0.8 8 9.77 294.9 c/w/zo-z 33.85 T2.2 3 0.6 3.1.8 5 9.90 196.6 w/c/20-4 43.69 6 1.6 9773 0.7 104.4 210.02 690.9 wvw/ 1.4 53.43 3 0.6 9 2.0 8 4.0 115 9.59 888.0 c/wl 1-4 63.01 4 1.0 8 1.8 7 3.9 16 9.53 391.8 w/w/zo-z 73.01 5 1.5 13 3.7 9 4.3 17 9.52 591.3 w/c/ 1-4 82.93 1° 9.4 7 1.5 4 3.1 5 9.91 1480.3 w/c/zo—z 92.82 1110.6 1° 2.2 11 4.5 2° 9.43 789.5 w/w/ 1-2 102.69 7 2.2 19 7.3 14 5.6 11 9.60 988.0 c/W/ 1-2 112.68 .315-3 16 5.7 18 9.5 21 9.28 1086.1 c/c/ 1-2 122.67 1728.6 11 2.3 5 3.7 9 9.67 1771.7 w/c/ 1-2 132.41 1525.6 15 4.3 13 4.9 13 9.59 1380.6 c/c/20-4 142.37 1314.1 4 0.6 6 3.7 7 9.77 1183.8 c/c/20-2 152.35 1929.8 14 3.7 12 4.8 3 9.95 1673.7 c/c/ 1-4 162.31 1213.3 6 0.9 2 1.5 1° 9.61 491.4 c/w/zo-o 171.93 2349.5 18 7.0 15 6.0 23 9.17 1574.0 wIWI 1-0 181.88 1423.1 2326.7 2328.3 4 9.94 2348.2 c/c/ 1-0 191.85 x 2245.1 12 3.1 2219.4 24 9.16 2063.0 w/c/zo-o 261.83 2036.9 2° 9.1 2012.9 15 9.56 2162.1 C/WI 1-0 211.82 1829.2 2428.6 2432.2 19 9.49 2447.7 0/0/20-0 221.81 2452.5 17 6.1 17 9.3 18 9.50 2258.8 wig/2040 231.78 1627.8 2222.3 2111.3 14 9.58 1863.5 w/c/ 1-0 2"1.69 2143.0 21 9.7 1912.1 22 9.18 1963.5 zRank‘within each classification - ascending for disorders, descending for firmness and sound fruit. LITERATURE CITED l. 2. 3. 4. 5. 6. 7. 9. 10. 11. Literature Cited Bangerth, F., Dilley, D. R., and Dewey, D. H. (1972). Effect of postharvest calcium treatments on internal breakdown and respiration of apple fruits. J. Amer. Soc. Bert. Sci. 97(5) 679-682. , (1973). Investigations upon calcium-related physiological disorders. Phyto. Zeits. 77(1) 20-37. Bennett, A. 8., Smith, R. 8., and Fortson, J. C. (1965). hydrocooling peaches, a practical guide for determining cooling require- ments and cooling times. 0.5. Dept. Agr. Info. Bull. 293, 11 pp. Bennett, A. E. (1970). Principles and equipment for precooling fruits and vegetables. Symposium: Precooling of fruits and vege- tables, Jan. 19-22, 1970. ASERAE, New York, pp. 5-10. Bidwell, R. C. S. (1974). Plant Physiology, MacMillan Publ. Co., Inc., New York, 643 pp. Bramlage, H. J., Drake, M., and Baker, J. B. (1974). Relationships of calcium content to respiration and postharvest condition of apples. J. Amer. Soc. Hort. Sci. 99(4) 376-378. , and . (1979). Changes in calcium level in apple cortex tissue shortly before harvest and during post- harvest storage. Comn. Soil Sci. Plant Anal. 10(1, 2) 417-426. Dewey, D. I. and Dilley, D. R. (1974). Increasing storage and market life of Jonathan apples. Extension Bulletin E-627, Michigan State University. and Earner, R. C. (1970). Frecooling in the Great Lakes region. Symposium: Precooling of Fruits and Vegetables, .7“. 19-22. “M. N." York’ pps 14-17e Faust, M. and Shear, C. B. (1972). The effect of calcium on respiration of apples. J. Amer. Soc. Hort. Sci. 97(4) 437-439. Fukuda, I. (1972). Effect of calcium sprays on physiological disorders of Jonathan apples. 1. Jonathan breakdown. (In Japanese, English abstract); J. Japan. Soc. Hort. Sci. 41(1) 11-16. 44 12. 13. 14. 16. 17. 18. 19. 20. 21. 22. 23. 24. O 45 Bolko,'M. and Krafft, P. A. (1979). Michigan Agricultural Statistics for 1979. Michigan Agricultural Reporting Serv., Lansing, 80 pp. Johnson, D. S. (1979). New techniques in the portharvest treatment of apple fruits with Ca salts. Comm. Soil Sci. Plant Anal. 10(1,2) 373-382. Jones, R., Wynn, 0., and Lunt, O. R. (1967). Function of calcium in plants. Bot. Bev. 33:407-426. Lee, J. J. L. (1979). The effects of temperature differential and surfactant on the postharvest infiltration of calcium solution into Jonathan apple fruit. Unpublished Ph.D. thesis, Michigan State University, 71 pp. Lidster, P. D., Porritt, S. N., and Eaton, G. W. (1977). The effect of storage relative humidity on calcium uptake by 'Spartan' apple. J. Amer. Soc. Mort. Sci. 102(4) 394-396. Looney, N. E. (1977). 4A four-year study of single CaCl; and growth regulator tree sprays to control storage breakdown of 'Spartam' apples. J. Amer. Soc. Hort. Sci. 102(1) 85,88. Lute, J. M. and Bardenburg, R. E. (1968). The commercial storage of fruits, vegetables, and florist and nursery stocks. U.S. Dept. Agr., Handbook 66, 94 pp. Mahanty, E. K. and Fineran, B. A. (1975) . Effects of calcium on the intrastructure of Cox's Orange Pippin with reference to bitter pit. Austr. J. Bot. 23(1) 55-65. Mason, J. L. (1976). Calcium concentration and firmness of stored 'McIntosh' apples increased by calcium chloride solution plus thickener. Bortscience 11(5) 504-505 , and Drought, 8. G. (1975). Penetration of calcium into 'Spartan apple fruits from a post-harvest calcium chloride dip. J. Amer. Soc. Hort. Sci. 100(4) 413-415. , and McDougald, J. M. (1974). Effect of a calcium chloride dip on senescent breakdown, firmness and calcium con- centration in 'Spartan’ apple. Bortscience 9(6) 596. Millikan, C. R. and Ranger, 8. “5 (1965). surface applications of Ca into Mr. An. Hush. 58479-481. Penetration of postharvest apple fruits. Austr. J. Mitchell, F. 6., Cuillou, R., and Persons, R. A. (1972). Commercial cooling of fruits and vegetables. Manual 43, 44 pp. University of California, 25. 26. 27. 28. 29. 31. 32. 33. 35. 36. 37. 46 Perring, M. A. (1968a). 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