Postharvest Temperature Research Articles

Genotypic Variability in Tomato for Total Carotenoids and Lycopene Content during Summer and Response to Post Harvest Temperature

Lycopene is the major carotenoid responsible for fruit colour in tomato (Lycopersicon esculentum Mill.). However, colour of the fruit is greatly affected by high temperature prevailing during fruit growth in the summer crop. To select a genotype suitable for summer conditions that can maintain colour better, a set of 52 tomato genotypes were evaluated for lycopene, total carotenoids and for TSS during summer in Bengaluru. Among the genotypes screened, IIHR 2892 recorded very high lycopene content (328.4mg/100g dry weight) and IIHR 2866 recorded very low lycopene content (25.2mg/100g dry weight). TSS values ranged from 2.6° Brix in cv. Vybhav to 7.0° Brix in IIHR 2866. In addition, study was carried out to determine the effect of postharvest temperature on biosynthesis of lycopene in five selected tomato cultivars (Arka Rakshak, Arka Samrat, Arka Ananya, Lakshmi and Abhinava). Tomatoes harvested at breaker stage were stored at 27° C, 35° C and 40° C for ripening. High temperature reduced lycopene content in tomato fruits. Lycopene synthesis in fruits was completely inhibited above 35°C. In this study, mean lycopene content in tomatoes stored at 27° C was 3-4 times higher than that in tomatoes stored at 40° C. This indicates that in tomatoes, temperature at which the fruits are stored after harvest, is a more important factor for colour development.

Effects of Mechanical Harvesting and Physical Compression, in Combination with a Storox® Postharvest Dip, on Internal Quality Attributes of ‘Colossal’ Chestnuts (Castanea sativa x C. crenata)

<abstract><title><italic>Abstract. </italic></title> Chestnut (Castanea spp.) cultivation in established growing regions around the world, including the United States, is challenged with internal quality degradation. As the industry grows, more mechanical harvesting will be required. Concerns of physical damage to chestnuts during mechanical harvesting, leading to internal disorders, prompted a study to evaluate such effects. Chestnuts were subjected to three harvest methods including a commercial harvester, a research prototype harvester, and hand harvesting. Additionally, chestnuts were physically stressed under three controlled compression forces. Samples were held under optimal postharvest temperatures for 130 days following treatment. No significant differences in quality or void spaces within chestnuts was found between mechanical harvesting methods and hand harvesting, indicating that mechanical harvesting, under the standard and representative practices used within this study (300 s Storox^® dip and rapid transport and cooling at 4°C), did not induce internal quality degradation. As expected, some significant (P < 0.05) decrease in chestnut internal quality was observed with the increase of controlled compression forces.

Effect of Different Postharvest Temperatures on the Accumulation of Sugars, Organic Acids, and Amino Acids in the Juice Sacs of Satsuma Mandarin (Citrus unshiu Marc.) Fruit

To elucidate the effect of different postharvest temperatures on the accumulation of sugars, organic acids, and amino acids and to determine the best temperature to minimize their postharvest change, their content after harvest was investigated at 5, 10, 20, and 30 °C for 14 days in the juice sacs of Satsuma mandarin (Citrus unshiu Marc. cv. Aoshima-unshiu) fruit. In all sugars, the changes were negligible at all temperatures. Organic acids decreased slightly at all temperatures, with the exception of malic acid at 30 °C, which increased slightly. Two amino acids, ornithine and glutamine, increased at 5 °C, but they did not increase at other temperatures. In 11 amino acids (phenylalanine, tryptophan, tyrosine, isoleucine, leucine, valine, threonine, lysine, methionine, histidine, and γ-amino butyric acid), the content was higher at 20 and 30 °C than at other temperatures. Thus, the content of amino acids was more variable than that of sugars and organic acids in response to temperatures. Moreover, amino acids responded to temperature differently: two amino acids were cold responsive, and 11 were heat-responsive. The best temperature to minimize the postharvest changes in amino acid profiles in the juice sacs of Aoshima-unshiu was 10 °C. The responsiveness to temperatures in two cold-responsive (ornithine and glutamine) and five heat-responsive (phenylalanine, tryptophan, valine, lysine, and histidine) amino acids was conserved among three different Satsuma mandarin cultivars, Aoshima-unshiu (late-maturing cultivar), Silverhill (midmaturing cultivar), and Miyagawa-wase (early-maturing cultivar). The metabolic responsiveness to temperature stress was discussed on the basis of the changes in the amino acid profile.

Molecular analysis of the bacterial communities in the live Pacific oyster (Crassostrea gigas) and the influence of postharvest temperature on its structure

To evaluate the effect of postharvest temperature on bacterial communities in live Pacific oysters (Crassostrea gigas) using nonculture-based methods. Live oysters were compared before and after storage at 4, 6, 15, 20 and 30°C using terminal restriction fragment length polymorphism (T-RFLP). Bacterial communities in freshly harvested (control) vs stored oysters were significantly different. Changes in bacterial communities at 4, 15 and 30°C observed by T-RFLP were further investigated by clone library analysis. Members of the Proteobacteria predominated (43·0-57·0% of clones) in control oysters, while storage altered the bacterial profile. At 4°C, Psychrilyobacter spp. (phylum Fusobacteria) predominated (43·8% of clones), while at 15 and 30°C, members of the phylum Bacteroidetes represented 63·0 and 60·2% of clones, respectively. High microbial diversity in oysters was observed, with at least 73 different genera-related clones among all samples. Changes in the overall bacterial community of Pacific oysters were influenced by storage temperature and would likely not be detected by standard culture-based methods currently used to assess oyster quality. Certain dominant genera, such as Psychrilyobacter, Polynucleobacter and a bacterial group related to Alkaliflexus, should be further studied as possible indicators for postharvest temperature control. This work is the first report describing the effect of different storage temperatures on bacterial diversity in postharvest live Pacific oysters using molecular-based methods.

Changes in quality and phenolic antioxidants in dark purple American eggplant ( Solanum melongena L. cv. Lucía) as affected by storage at 0 °C and 10 °C

Many beneficial effects associated with fruit and vegetable consumption are related to the presence of antioxidants, which could be greatly affected by postharvest storage conditions. Eggplants or aubergines ( Solanum melongena L.) are among the top vegetables in terms of antioxidant content. In this work, we evaluated the effect of two postharvest temperature regimes on deterioration and antioxidants of dark purple American eggplants (cv. Lucía). Fruit were stored at 0 or 10 °C for 0, 3, 5, 10 or 14 d and weight loss, electrolyte leakage, chilling injury, and pulp browning were evaluated. We also followed DPPH and Folin–Ciocalteu reacting substances and the content of chlorogenic and quinic acid by HPLC. Although weight loss was reduced in fruit held at 0 °C, higher electrolyte leakage and chilling injury manifested as surface scalds and pulp browning were found. Antioxidants (AOX) measured with the DPPH radical and with the Folin–Ciocalteu reagent increased during the first 3 d of storage at 0 °C, but afterwards significant degradation was found. In contrast, a gradual but continuous accumulation of AOX was detected in fruit stored at 10 °C. The slow rate in the reaction between DPPH and eggplant samples suggested that the main changes during postharvest storage were due to modifications in phenolic compounds. The major phenolic detected by HPLC was chlorogenic acid (ChA), an ester between caffeic (CA) and quinic acids (QA), which accumulated in fruit maintained at 10 °C, increasing by 60% after 14 d of storage. No free CA was found at any storage temperature or time, suggesting that its biosynthesis is activated simultaneously with the production of ChA. Free QA showed minor changes at 0 °C as pulp lightness decreased, indicating that ChA rather than CA may be the main substrate for browning reactions. Changes in eggplant fruit antioxidants during storage at chilling and non-chilling temperatures are discussed.

Retention of iceberg lettuce quality by low temperature storage and postharvest application of 1-methylcyclopropene or gibberellic acid.

This study was conducted to evaluate the changes in quality of iceberg lettuce during storage at different temperatures and the effects of postharvest treatments of 1-methylcyclopropene or gibberellic acid at high temperature. The results showed that quality of the lettuce was remarkably retained during storage at 0°C, but significantly declined at 20°C. However, quality of the vegetable at shelf-temperature (20°C, 85 ~ 95% RH) was effectively delayed by the treatment with 1-methylcyclopropene (1-MCP) or gibberellic acid (GA). Browning of the lettuce leaves was significantly inhibited by the storage at low temperature and by treatment with1-MCP and GA. The biochemical analysis further indicated that the reduction of soluble protein and sugar, decrease in activity of polyphenol oxidase (PPO) and peroxidase (POD) and accumulation of free amino acids in the lettuce leaves during storage could be remarkably prevented by low temperature, treatment with1-MCP or GA. Our result suggested that 1-MCP or GA treatment would provide a potential way for controlling quality of the lettuce under suboptimal postharvest temperature conditions.

Postharvest temperature influences volatile lactone production via regulation of acyl‐CoA oxidases in peach fruit

The biosynthesis of volatile compounds in plants is affected by environmental conditions. Lactones are considered to be peach-like aroma volatiles; however, no enzymes or genes associated with their biosynthesis have been characterized. White-fleshed (cv. Hujingmilu) and yellow-fleshed (cv. Jinxiu) melting peach (Prunus persica L. Batsch) fruit were used as materials in two successive seasons and responses measured to four different temperature treatments. Five major lactones accumulated during postharvest peach fruit ripening at 20 °C. Peach fruit at 5 °C, which induces chilling injury (CI), had the lowest lactone content during subsequent shelf life after removal, while 0 °C and a low-temperature conditioning (LTC) treatment alleviated development of CI and maintained significantly higher lactone contents. Expression of PpACX1 and activity of acyl-CoA oxidase (ACX) with C16-CoA tended to increase during postharvest ripening both at 20 °C and during shelf life after removal from cold storage when no CI was developed. There was a positive correlation between ACX and lactones in peach fruit postharvest. Changes in lactone production in response to temperatures are suggested to be a consequence of altered expression of PpACX1 and long-chain ACX activity.

Predictive models for the effect of storage temperature on Vibrio parahaemolyticus viability and counts of total viable bacteria in Pacific oysters (Crassostrea gigas).

Vibrio parahaemolyticus is an indigenous bacterium of marine environments. It accumulates in oysters and may reach levels that cause human illness when postharvest temperatures are not properly controlled and oysters are consumed raw or undercooked. Predictive models were produced by injecting Pacific oysters (Crassostrea gigas) with a cocktail of V. parahaemolyticus strains, measuring viability rates at storage temperatures from 3.6 to 30.4°C, and fitting the data to a model to obtain parameter estimates. The models were evaluated with Pacific and Sydney Rock oysters (Saccostrea glomerata) containing natural populations of V. parahaemolyticus. V. parahaemolyticus viability was measured by direct plating samples on thiosulfate-citrate-bile salts-sucrose (TCBS) agar for injected oysters and by most probable number (MPN)-PCR for oysters containing natural populations. In parallel, total viable bacterial counts (TVC) were measured by direct plating on marine agar. Growth/inactivation rates for V. parahaemolyticus were -0.006, -0.004, -0.005, -0.003, 0.030, 0.075, 0.095, and 0.282 log₁₀ CFU/h at 3.6, 6.2, 9.6, 12.6, 18.4, 20.0, 25.7, and 30.4°C, respectively. The growth rates for TVC were 0.015, 0.023, 0.016, 0.048, 0.055, 0.071, 0.133, and 0.135 log₁₀ CFU/h at 3.6, 6.2, 9.3, 14.9, 18.4, 20.0, 25.7, and 30.4°C, respectively. Square root and Arrhenius-type secondary models were generated for V. parahaemolyticus growth and inactivation kinetic data, respectively. A square root model was produced for TVC growth. Evaluation studies showed that predictive growth for V. parahaemolyticus and TVC were "fail safe." The models can assist oyster companies and regulators in implementing management strategies to minimize V. parahaemolyticus risk and enhancing product quality in supply chains.

Quality of Strawberries Shipped by Truck from California to Florida as Influenced by Postharvest Temperature Management Practices

Commercial shipments of strawberries (Fragaria ×ananassa) were evaluated from the harvest point to the distribution center (DC). Simulated retail conditions were afterward imposed on the fruit. Commercially harvested ‘San Juan’ strawberries in California were instrumented in the field for temperature and relative humidity (RH) monitoring during handling and distribution. At the cooling facility, five different treatments were imposed on five pallets of strawberries: prompt precooling to a final temperature of 1.7 or 10.0 °C, 4-hour delayed precooling to a final temperature of 1.7 or 10.0 °C, and no precooling. Immediately before being loaded into the trailer, all pallets were wrapped in a modified atmosphere (MA) pallet shrouds. Upon arrival at the DC in Florida, fruit from the same five pallets were exposed to three simulated retail temperatures (0, 6, and 21 °C) for 3 days. Results from this study showed that the refrigerated trailer was unable to maintain the temperature of any of the pallets during transport. In addition, upon arrival at the DC in Florida, strawberries from the partial precooling (cooled to 10.0 °C), 4-hour delayed precooling, and no precooling treatments had higher water loss and lower visual quality compared with fruit that were immediately precooled to a final temperature of 1.7 °C. On the basis of the quality control standards of the cooling facility in California, most of the fruit from the no precooling treatment were considered unacceptable for shipment 1 day after harvest. During simulated retail display, quality of the fruit held at 21 °C was inferior to that of fruit maintained at 0 or 6 °C, particularly that of fruit from the partial and delayed precooling treatments. Strawberries from the prompt precooling to a final temperature of 1.7 °C treatment had acceptable visual quality after simulated retail display for 3 days at 0 °C, whereas visual quality of the fruit from the delayed or partial precooling treatments ranged from slightly poor to poor after the same period of time. The presence of bruises due to mechanical damage shortened the shelf life of the fruit because of accelerated development of decay. Overall, results obtained from this study highlight the importance of prompt precooling and the use of optimum storage temperature (i.e., 0 °C) throughout the distribution chain and during retail display.

Influence of Packaging on Quality Retention of Longans (Dimocarpus longan) Under Constant and Fluctuating Postharvest Temperatures

Longan (Dimocarpus longan) fruit production and global exports are rapidly expanding. Consumer acceptance of this high value crop requires that fruit arrive in excellent condition. Pericarp browning and fungal diseases are the main postharvest problems for longans. Research was conducted to establish optimum storage temperatures and packaging systems to retain fruit quality of ‘Biew Kiew’ longans. Average respiration rates for longans stored at 20 °C (61.6 mg CO2/kg/h) were about twice the rate as those stored at 10 °C (32.7 mg CO2/kg/h) and triple the rate for those stored at 5 °C (21.1 mg CO2/kg/h). Ethylene rates were below 0.4 μg·kg−1·h−1. Fruit quality and shelf life were greatest when stored at 10 °C. Longans held at 20 °C were unmarketable after 10 d, and fruit stored at 5 °C exhibited chilling injury (CI). After storage at 10 °C, longans packaged in microperforated (MP) bags, clamshell (CL) containers, or Peakfresh® film (PF) had the highest visual quality ratings, lowest disease incidences, and longest shelf life when compared with fruit in Lifespan® film (LS) or fiberboard boxes. The most promising packages (MP, CL, PF) were evaluated further under constant 10 °C or simulated shipping (SS) conditions with fluctuating temperatures (22 °C/10 °C/22 °C). Longans in CL containers had the highest visual quality and lowest disease incidence when stored at 10 °C, but there were no differences among package treatments under SS conditions. Also, sensory ratings were greatest for fruit packed in CL or PF when stored at 10 °C but all sensory scores decreased under SS temperatures. When longans were stored under fluctuating temperatures, aril texture and flavor ratings were highest for CL packages. CL, PF, and MP are suitable packages for longans stored under optimal temperatures. However, for longans stored under SS conditions, sensory quality was highest when packaged in CL containers.

Effect of Postharvest Temperature and Ethylene on Carotenoid Accumulation in the Flavedo and Juice Sacs of Satsuma Mandarin (Citrus unshiu Marc.) Fruit

The effect of postharvest temperature (5, 20, and 30 degrees C) and ethylene at different temperatures (20 and 5 degrees C) on carotenoid content and composition and on the expression of the carotenoid biosynthesis-related genes was investigated in the flavedo and juice sacs of Satsuma mandarin ( Citrus unshiu Marc.) fruit. Under an ethylene-free atmosphere, storage at 20 degrees C rapidly increased the carotenoid content in flavedo and maintained the content in juice sacs. In contrast, storage at 5 and 30 degrees C gradually decreased the content in juice sacs but slowly increased that in flavedo. Under an ethylene atmosphere, storage at 20 degrees C enhanced the carotenoid accumulation in flavedo more dramatically than found under an ethylene-free atmosphere with distinct changes in the carotenoid composition but did not noticeably change the content and composition in juice sacs. In contrast, storage at 5 degrees C under an ethylene atmosphere repressed carotenoid accumulation with changes in the carotenoid composition in flavedo but did not clearly change the carotenoid content in juice sacs. Under an ethylene-free atmosphere, differences in the gene expression profile among the temperatures were observed but were not well-correlated with those in the carotenoid content in flavedo and juice sacs. Under an ethylene atmosphere, in flavedo, the gene expression of phytoene synthase (PSY) and phytoene desaturase (PDS) was slightly higher at 20 degrees C but lower at 5 degrees C than under an ethylene-free atmosphere. At 20 degrees C, the gene expression of several carotenoid biosynthetic enzymes promoted by ethylene seemed to be responsible for the enhanced accumulation of carotenoid in flavedo. In contrast, at 5 degrees C, the repressed gene expression of PSY and PDS by ethylene seemed to be primarily responsible for the repressed accumulation of carotenoid in flavedo. In juice sacs, the small response of the gene expression to ethylene seemed to be responsible for small changes in carotenoid accumulation under an ethylene atmosphere.

Neural Network Modeling to Predict Shelf Life of Greenhouse Lettuce

Greenhouse-grown butter lettuce (Lactuca sativa L.) can potentially be stored for 21 days at constant 0°C. When storage temperature was increased to 5°C or 10°C, shelf life was shortened to 14 or 10 days, respectively, in our previous observations. Also, commercial shelf life of 7 to 10 days is common, due to postharvest temperature fluctuations. The objective of this study was to establish neural network (NN) models to predict the remaining shelf life (RSL) under fluctuating postharvest temperatures. A box of 12 - 24 lettuce heads constituted a sample unit. The end of the shelf life of each head was determined when it showed initial signs of decay or yellowing. Air temperatures inside a shipping box were recorded. Daily average temperatures in storage and averaged shelf life of each box were used as inputs, and the RSL was modeled as an output. An R2 of 0.57 could be observed when a simple NN structure was employed. Since the "future" (or remaining) storage temperatures were unavailable at the time of making a prediction, a second NN model was introduced to accommodate a range of future temperatures and associated shelf lives. Using such 2-stage NN models, an R2 of 0.61 could be achieved for predicting RSL. This study indicated that NN modeling has potential for cold chain quality control and shelf life prediction.

Different postharvest conditions modulate ripening and ethylene biosynthetic and signal transduction pathways in Stony Hard peaches

Stony hard (SH) peaches are characterized, at ripening, by the maintenance of flesh firmness and the lack of ethylene production due to a reduced expression of Pp-ACS1. In a trial comparing melting flesh (MF, cv. ‘Summer Rich’) and SH (‘IFF331’ selection) fruit at two different postharvest temperatures (10 and 20 °C), unexpected behaviour was observed in SH peaches that displayed an increase in ethylene production and a decrease in flesh firmness when stored at 10 °C, a temperature regime basically ineffective in delaying ripening in MF fruit. This appeared to be the result of an induction of Pp-ACS1 transcription, making this genotype of particular interest for studying temperature stress physiology and ethylene-related ripening processes in peaches. Comparative expression analyses of genes involved in cell wall metabolism pointed out the presence of a negative ( Pp-EG4), positive ( Pp-endoPG) or no (one member of the PL family) relationship with ethylene at ripening. Results clearly showed that the last stage of firmness decrease (melting) only occurs in fruit producing ethylene and is associated with Pp-endoPG transcript accumulation. The expression of genes involved in ethylene biosynthesis and signalling pathways was evaluated using QRT-PCR. Pp-ACO1 appeared to be induced in SH kept at 10 °C but not at 20 °C. Transient increases in Pp-CTR1 and Pp-EIN2like gene expression have only been detected at the early stages of ripening in samples producing ethylene, indicating that a causal relationship might exist between ethylene and elements of its transduction pathway during peach fruit ripening.

Postharvest conditioning of Satsuma mandarins for reduction of acidity and skin puffiness

Postharvest temperature and relative humidity (RH) treatments were tested for their capacity to increase the soluble solids content:titratable acidity ratio (SSC:TA ratio) and/or reduce skin puffiness of New Zealand grown ‘Miho’ Satsuma mandarin. Fruit of low SSC:TA (approximately 6.8:1) harvested in 2001 and 2002 were held at 18 or 30 °C at low (approximately 65%) or high (>95%) RH for 3 or 5 days, followed by 2 days at 10 °C (88–92% RH). In 2002, an additional treatment of high and low RH at 10 °C was examined. Treatments at 30 °C, irrespective of RH, resulted in increased SSC:TA ratios in the fruit as a result of a decrease in titratable acidity, largely a decrease in citric acid. There was little effect of temperature on SSC and the levels of individual sugars. There was no significant effect of RH on either TA or SSC. The altered metabolism was also seen in an elevated respiratory CO 2 output at 30 °C, but a decreased CO 2 output once these fruit were transferred to 10 °C, in comparison with fruit treated at lower temperatures. At 30 °C, weight loss was up to 8.5% after 5 days under low RH, but <4% under high RH. Fruit with >4% weight loss tended to have an unacceptable level of dehydration of the skin. After 5 days at 30 °C and low RH, skin puffiness, quantified from magnetic resonance images taken before and after treatment, was reduced, although fruit tended to have soft skin that could be more prone to damage. It is concluded that short high temperature treatments such as 3–5 days at 30 °C can significantly raise the SSC:TA ratio in Satsuma mandarin through a reduction in TA, and conducting these treatments under a RH >90% minimises the risk of excessive weight loss and softening of the skin.

Acibenzolar-S-methyl and methyl jasmonate treatments of glasshouse-grown freesias suppress post-harvest petal specking caused by Botrytis cinerea

SummaryCompounds that activate host plant defence responses potentially offer socio-environmentally sound alternative methods for disease control. In a series of glasshouse trials over 2 years, pre-harvest sprays with acibenzolar-S-methyl (ASM) and methyl jasmonate (MeJA) were tested for suppression of post-harvest infection of cut Freesia hybrida L. flowers by Botrytis cinerea. For the ASM treatments, variability in reducing the incidence of B. cinerea disease was observed between years, freesia varieties, incubation temperatures and ASM concentrations. In the first year, the greatest reductions in lesion numbers on ASM-treated var. ‘Cote d’Azur’ were recorded using 2.86 mM ASM. For three different post-harvest temperature regimes, the relative reductions in lesion numbers, compared to untreated controls, were 45% at 5°C, 40% at 12°C and 30% at 20°C, respectively. In the second year, lesion numbers were most reduced using 1.43 mM ASM to treat freesia var.‘Dukaat’ flowers. Here, the relative reductions were to 44% at 5°C, 26% at 12°C and 51% at 20°C. MeJA treatments were, in general, more consistently effective than ASM treatments in reducing lesion numbers and lesion diameters on cut freesia flowers. MeJA-treated (0.2 mM) freesia flowers (var. ‘Dukaat’) incubated at 20°C showed relative reductions of 62%, and 45% for lesion number and lesion diameter, respectively.The differing efficacy between ASM and MeJA treatments could be attributed to their differential abilities to induce the salicylic acid (SA)-mediated vs. the jasmonic acid (JA)-mediated host defence pathways, respectively.

Modeling of Active Modified Atmosphere Packaging of Endives Exposed to Several Postharvest Temperatures

ABSTRACTEndives were sealed in low‐density polyethylene flexible pouches containing or not containing individual oxygen or carbon dioxide scavenger sachet and stored at 5 °C and 20 °C. A mathematical model has been applied to predict gas changes for these passive and active modified atmosphere packaging (MAP). The model took into account the respiration rate of endives, the transmission rate of gases through the film, the absorption kinetics of gas scavengers, and the temperature influence of all these parameters. Whatever the temperature, the model was successfully validated with root mean square error values still lower than 1 kPa and thus represented a real tool to improve the design of MAP for fresh fruits and vegetables. Oxygen scavengers reduced by half the transient period duration (50 h compared with 100 h without scavengers) and did not modify the gas equilibrium composition, suggesting a beneficial influence on keeping the quality of the product. The carbon dioxide scavengers’ influence was limited and needs further study with carbon dioxide‐sensitive products.

NEW STRATEGIES IN TRANSPORTATION FOR FLORICULTURAL CROPS

In the past century, the centers of production and consumption of ornamentals increasingly have become widely separated. A cut flower bouquet purchased today in a Verona florist could easily combine Italian foliage with flowers grown in Kenya, Colombia, Holland and Thailand. The extended transportation infrastructure and delays between harvest and consumption implicit in this separation can easily result in significant reduction in quality and vase life. Geography plays an important role in selection of transportation mode, and most “long distance” flowers still are transported by air. Air transport typically results in quality loss due to poor temperature control, accelerated water loss, and airport delays and interventions. The high Q10 for respiration in cut flowers (as much as 7!) implies a substantial premium for careful temperature control during transportation. Innovative systems for temperature control could be important tools for maintaining freshness during air transport. The primacy of postharvest temperature control has driven the continued search for ways to use surface transportation - sea containers and trucks are an important tool in this effort. The lack of response of cut flowers to controlled atmospheres (apart from ethylenesensitive flowers) has frustrated this effort, but careful temperature control and monitoring of container temperatures and the use of faster ships has resulted in successful out-turn of flowers transported from Central America to North America. Temperature control also frustrates efforts to direct-market flowers using the Internet. Innovative packaging concepts will be essential to success in this field. THE CONSUMPTION OF CUT FLOWERS IN THE U.S. IS LOW The world market for cut flowers is a dynamic one, with major changes in consumption and production in relatively short time-scales. Of particular interest has been the evolution of the market in the United States, which is illustrated by statistics provided by the USDA Market Research Service (Fig. 1). In brief, the data show: • In the early 70’s, with the entry of significant quantities of imported flowers, consumption rose. • U.S. production was static until the early 90’s, while consumption increased with steady increase in imported product. • During the 90’s the unfavorable comparative economics of production in the U.S. (primarily California) resulted in a rapid decline in local production, which now represents less than 30% of all the flowers consumed in this country. • From the mid-90’s, consumption of cut flowers fell steadily, and by 2000 was less than three quarters of that at the peak (1993). PER CAPITA CONSUMPTION OF FLOWERS IN THE U.S. LAGS BEHIND THAT IN OTHER COUNTRIES Comparison of U.S. and international statistics show the nature of the problem for the cut flower industry in the U.S. Per capita consumption of cut flowers in the United States is very low compared to other developed, and even some developing nations (Table 1). For example, consumption in Holland is 24 times higher, and even in Britain, a nation that historically has had relatively low cut flower sales, present consumption is 16 times that in the U.S. Despite the high standard of living and historically high levels of disposable income in the U.S., cut flower consumption is lower than that in Poland and

INFLUENCE OF DRYING CONDITIONS AND STORAGE TEMPERATURE ON DESICCATION AND LOSS OF TUBERS DURING STORAGE AND SUBSEQUENT GROWTH OF ZANTEDESCHIA TUBERS

After lifting Zantedeschia tubers in autumn severe losses of tubers occur during storage and the subsequent growing season caused by soft rot (Erwinia carotovora) and calcification of tubers. In this study the effects of post-harvest drying conditions and storage temperature were investigated. After lifting early November tubers were dried at 17°C without air circulation, with moderate air circulation and with strong air circulation. After one week tubers were placed at different temperatures (9, 13, 17, 20°C) for storage with moderate air circulation during the rest of the storage period until planting in April. No air circulation at 17°C during the first week after lifting caused losses of tubers by bacterial rot during that week and calcification during subsequent storage. Hardly any rot or calcification was observed after moderate and strong air circulation. The temperature during subsequent storage had a great influence on desiccation of the tubers. Remarkably, in the period from cleaning the tubers in December until planting in April, weight loss increased with decreasing temperature. The big loss of weight at 9°C resulted in calcification during storage or severe losses of tubers during the subsequent growing season. It is suggested that drying or storage at temperatures higher than 13°C are necessary to form a skin that prevents desiccation of the tuber.

Dynamics of Rabbiteye Blueberry Fruit Quality in Response to Harvest Method and Postharvest Handling Temperature

Abstract Research was conducted to understand the effect of harvesting method and postharvest temperature on fruit quality of ‘Brightwell’ and ‘Tifblue’ rabbiteye blueberries (Vaccinium ashei Reade). Mass loss, firmness and fruit respiration were measured under refrigerated (1°C) and ambient (22°C) conditions for both machine harvested (MH) and hand harvested (HH) berries of each cultivar. Few differences were found between cultivars for the various postharvest quality parameters. Firmness of MH blueberries was diminished by an overall average of 36.2% as compared to HH berries. MH berries placed at 22°C had a mass loss rate of 2.6% per day as compared to 0.2% per day at 1°C during the first two days of storage. Respiration rate of MH berries at ambient temperature was 31.1% higher than HH berries. Refrigeration reduced respiration rates by an overall average of 79%. Refrigerated HH blueberries had the best overall fruit quality after storage, and firmness measures suggested that HH berries had an extende...

Increasing ‘Blackamber’ plum (Prunus salicina Lindell) consumer acceptance

‘Blackamber’ plum (Prunus salicina Lindell) consumer acceptance and market life were highly dependent on harvest date. For fruit within the most common industry ripe soluble solids concentration (RSSC) range (10.0–11.9%), ripe titratable acidity (RTA) played a significant role in consumer acceptance. Plums within this RSSC range combined with low RTA (≤0.60%) were disliked by 18% of consumers, while plums with RTA ≥1.00% were disliked by 60% of consumers. Plums with RSSC ≥12.0% had ∼ 75% consumer acceptance, regardless of RTA. Fruit harvested between 35.6 and 17.8 N had high consumer acceptance because of lower RTA and higher RSSC than earlier harvested fruit. Ripening plums before consumption decreased TA by approximately 30% from the TA measured at harvest. In some cases, this decrease in TA during ripening may increase the acceptability of plums that would otherwise be unacceptable. Development of chilling injury (CI) symptoms limited market life of fruit harvested early (44.5–35.6 N) and late (17.8–13.3 N). Late harvested fruit were more likely to develop flesh translucency (overripe or bladderiness) when stored at 5 ◦ C, whereas early harvested fruit had low consumer acceptance and were more prone to develop flesh bleeding/browning during storage at 0 or 5 ◦ C. Based on this work, ‘Blackamber’ plums are well adapted to late harvest but proper postharvest temperature management, including ripening, and marketing within its market life potential are necessary to avoid the onset of storage disorders and maintain flavor. © 2004 Elsevier B.V. All rights reserved.