Intermittent Warming Treatments Research Articles

Postharvest behavior and chilling injury in avocado (Persea americana Mill) fruit cv. Hass treated with 1-methylcyclopropene, ethylene, and intermittent warming

Persea americana, cv. Hass has become an important crop in Colombia due to increased exports to European markets; however, the avocado is a climacteric fruit sensitive to chilling injury, reducing its shelf-life and affecting commercialization abroad. This research aimed to evaluate the effect of 1-methylcyclopropene, ethylene, and intermittent warming on chilling injury and postharvest behavior of avocado cv. Hass. Five treatments were evaluated: Control; Intermittent warming cycles of 4 days at 2 °C + 1 day at 18 °C; Intermittent warming cycles of 7 days at 2 °C + 1 day at 18 °C; 1-methylcyclopropene, and ethylene. The fruits were stored for 29 days at 2 °C and then up to 14 days in the shelf-life period. The intermittent warming treatment 4-days cycles reduced chilling injuries. However, this treatment increased weight loss, respiration, epidermal color index, and electrolyte leakage during the storage period at 2 °C. Intermittent warming showed that Hass avocado fruit ripens faster, regardless of the application of ethylene in the shelf-life period. The results indicated that intermittent warming reduced the chilling injury, the treatment with 1-methylcyclopropene delayed ripening but it is not recommended for avocado cv. Hass when stored at 2 °C because the chilling injury is not reduced.

Integral evaluation for intermittent cold storage of apples by using mathematical modeling

AbstractThis study proposes an integrated approach to evaluate the efficiency of intermittent warming (IW) on cooling rate, uniformity, energy efficiency, mass loss, and the development of CIs by combining experiment and computational fluid dynamics (CFD) modeling. The results show that the cooling homogeneity and mass loss increases with increasing the warming duration and frequency, although the incidence of chilling injuries (CIs) and energy consumption decrease under these conditions. Near the bottom of the pallet, CIs increased and mass loss decreased because of the higher cooling rate of fruit in this zone. The accuracy of the CFD simulations was confirmed by a good agreement with experiments. The root‐mean‐square error and mean absolute percentage error for fruit temperature were 0.879°C and 21.42%, respectively.Practical applicationsReducing energy consumption and chilling injuries (CIs) is vital for improving the overall economic benefits of the cold chain and maintaining poststorage quality in fresh fruit. This research provides a reliable theoretical and experimental basis for improving the efficacy of IW and for ensuring optimum IW treatment and thereby minimizing energy consumption and CIs during fruit storage.

Effect of Intermittent Warming on Aroma-Related Esters of ‘Nanguo’ Pears Through Regulation of Unsaturated Fatty Acid Synthesis After Cold Storage

Cold storage can effectively delay the ripening of ‘Nanguo’ pears (Pyrus ussuriensis Maxim.). However, the aroma-related esters of ‘Nanguo’ pears decreased after cold storage. In this study, we aimed to investigate the effect of intermittent warming (IW) treatment on the formation of aroma-related esters and unsaturated fatty acid synthesis from cold stored pears. IW-treated pears were exposed to 20 ± 1 °C for 1 day every 20 days during storage at 0 ± 0.5 °C, every 21 days was a cycle and a total of 90 days. The pears in control group were stored at 0 ± 0.5 °C for 90 days. After this 90-day storage, both groups of pears (control and IW-treated) were transferred to a shelf life of 12 days at room temperature. The results showed that, compared with the pears in control group, the productions of aroma-related esters and the expression levels of PuLOX1, PuADH3, and PuAAT1 in IW-treated pears were significantly higher during the shelf life (P < 0.05). At the same time, IW-treated pears maintained significantly higher contents of linoleic acid and linolenic acid (P < 0.05), which were precursors of aroma compounds. We also found that the expression of PuFAD2 and PuFAD3 had significant positive correlation with the contents of unsaturated fatty acids (P < 0.05). The significantly higher expression levels of PuFAD2 and PuFAD3 in IW-treated pears may have played an important role in the improvement of ester contents (P < 0.05). It could be inferred that IW treatment had an impact on the aroma-related esters of cold-stored ‘Nanguo’ pears through regulation of unsaturated fatty acid synthesis.

Effects of thermal treatments on chilling injury and shelf life time of Citrus reticulata Blanco1

ABSTRACT The ‘Arrayana’ mandarin (Citrus reticulata Blanco) is considered the variety most widely grown in Colombia. Despite being a non-climacteric fruit, it has a short postharvest life. In order to evaluate the effects of thermal treatments on the chilling injury and shelf life time of this cultivar, ripe fruits were selected and submitted to the following treatments: non-treated fruit (control); hot water at 50 ºC for 5 min; hot water at 53 ºC for 3 min; intermittent warming in 8-day cycles at 2 ºC + 1 day at 18 ºC; and intermittent warming in 12-day cycles at 2 ºC + 1 day at 18 ºC. The fruits were stored at 2 ºC for 40 days and then left for one week at room temperature. The thermal treatments decreased the chilling injury in the mandarin fruits during the shelf life time, with the intermittent warming treatments being the most favourable ones (mainly in cycles of 12 days at 2 ºC + 1 day at 18 ºC), because, besides decreasing the chilling injuries and electrolytes leakage, they promoted a higher carotenoid biosynthesis and epidermis colouring, without negative effects on the fruit internal quality.

Effect of intermittent warming on alleviation of peel browning of ‘Nanguo’ pears by regulation energy and lipid metabolisms after cold storage

Refrigeration slows postharvest ripening of ‘Nanguo’ pears (Pyrus ussuriensis Maxim.), but the peel of the pears is prone to browning when the fruit are returned to room temperature. Intermittent warming (IW), in which the fruit were exposing to 20 ± 1 °C for 1 day every 20 d during storage at 0 ± 0.5 °C, retarded the occurrence of peel browning (PB) of the pears in this study. IW-treated pears showed higher firmness and ethylene production in peel of fruit during the early stage of shelf life. An increase in ATP concentration and energy charge (EC) was detected in IW-treated fruit. The concentration of malondialdehyde (MDA) and the electrolyte leakage were lower in IW-treated fruit. Higher enzyme activity and increased gene expression of transcripts for ATP synthase (ATPase), NADH dehydrogenase (NDA) and vacuolar proton-inorganic pyrophosphatase (VPP), which were associated with oxidative phosphorylation, were found in IW-treated fruit during the shelf life. Lower enzyme activity and down-regulated gene expression levels of phospholipase D (PLD) involved in glycerophospholipid metabolism were found in fruit under IW treatment. These results indicate that the PB of ‘Nanguo’ pears can be effectively alleviated by IW treatment and the possible mechanisms are discussed.

Perlakuan Panas untuk Mengurangi Gejala Kerusakan Dingin pada Mangga (Mangifera indica L.) var. Gadung selama Penyimpanan pada Suhu Rendah

Mango (Mangifera indica L.) is perishable horticulture product. Commercially, mango fruits are harvested at the mature-green stage of development and are handled at low temperatures to facilitate shipping. However, long term low temperature storage of mature-green mango fruits is currently risky because of chilling injury (CI). The ojective of this study was to examine quality changes of mango during storage at 8 oC after heatshock treatment. Heatshock treatment consist of hot water treatment (HWT) at temperature of 55 oC in 3 and 10 minutes and intermittent warming (IW) at temperature 20 oC for 1 day after 2 and 3 days of low temperature storage. The result showed that HWT of 55 oC in 3 minutes could decrease of weight loss and maintain the quality and chemical content of mango during storage at low temperatures. While IW treatment after 2 and 3 days at low temperature storage in this study was not effective in reducing chilling injury and maintaining quality of mango.Keywords: chilling injury, hetshock treatment,low temperature storage, mango

Determining the physiochemical changes and time of chilling injury incidence during cold storage of pomegranate fruit

Intermittent warming (IW) is a good postharvest technique to prevent or alleviate chilling injuries during cold storage. Performing the warming treatment at the period of time before chilling injury is irreversible during storage, and it is the first prerequisite for a successful IW treatment. In order to determine the fruit physiochemical changes and time of irreversible chilling injury incidence during cold storage of pomegranate fruit (cv. Rabab-e-Neyriz), this research was conducted. Fruits were stored at 2 ? 0.5?C and 90 ? 5% relative humidity for 90 days. At 15-day intervals, 40 fruits (four replicates and 10 fruits in each replicate) were sampled and further stored at 20?C for 3 days (shelf life). Chilling injury (CI) index and weight loss (WL) in intact fruits, electrolyte leakage (EL) and K leakage (KL) in peel samples, total soluble solids (TSS), titratable acidity (TA), TSS/TA ratio and pH in fruit juice were measured. With respect to quality parameters, TSS did not change significantly under cold storage. According to TA changes, the TSS/TA ratio was decreased up to 30 days but subsequently increased and the highest ratio was detected at the end of storage, which was significantly higher than the TSS/TA ratio at the harvest time. Results related to CI index, WL, EL and KL showed that pomegranate fruits could be stored cold without significant chilling damages up to 30 days. It was suggested that performing the IW treatment during this period could be concomitant with desired effects in long-term storage of this commercial cultivar.

Ripening, storage temperature, ethylene action, and oxidative stress alter apple peel phytosterol metabolism

The chilling conditions of apple cold storage can provoke an economically significant necrotic peel disorder called superficial scald (scald) in susceptible cultivars. Disorder development can be reduced by inhibiting ethylene action or oxidative stress as well as intermittent warming. It was previously demonstrated that scald is preceded by a metabolomic shift that results in altered levels of various classes of triterpenoids, including metabolites with mass spectral features similar to β-sitosterol. In this study, a key class of phytosterol metabolites was identified. Changes in peel tissue levels of conjugates of β-sitosterol and campesterol, including acylated steryl glycosides (ASG), steryl glycosides (SG) and steryl esters (SE), as well as free sterols (FS), were determined during the period of scald development. Responses to pre-storage treatment with the ethylene action inhibitor, 1-methylcyclopropene, or an antioxidant (diphenylamine), rapid temperature elevation, and cold acclimation using intermittent warming treatments were evaluated. Diphenylamine, 1-MCP, and intermittent warming all reduced or prevented scald development. ASG levels increased and SE levels decreased in untreated control fruit during storage. Removing fruit from cold storage to ambient temperature induced rapid shifts in ASG and SE fatty acyl moieties from unsaturated to saturated. FS and SG levels remained relatively stable during storage but SG levels increased following a temperature increase after storage. ASG, SE, and SG levels did not increase during 6months cold storage in fruit subjected to intermittent warming treatment. Overall, the results show that apple peel phytosteryl conjugate metabolism is influenced by storage duration, oxidative stress, ethylene action/ripening, and storage temperature.

Physico−chemical, respiratory and fungicide residue changes in wax coated mandarin fruit stored at chilling temperature with intermittent warming

Influence of chilling temperature, intermittent warming (IW) and fungicidal wax coating was evaluated during storage of 'Nagpur' mandarins (Citrus reticulata Blanco). Fruits were light green coloured with slight colour-break at the start of storage. Waxed and non-waxed fruits were stored at 3.5°C (constant), 2weeks at 3.5°C followed by IW for 1week at 19.5°C (cycle) and at 6.5°C (constant), and were evaluated immediately after 30, 45, 60, 75days and also after 1week holding at ambient condition (24 ± 2°C, 60-70% RH). There was no chilling injury to fruit under IW treatment irrespective of coating. At 3.5°C (constant) chilling injury appeared after 45days during 1week holding and thereafter increased at each storage interval. Wax coated fruit had lower chilling injury. Fruit under IW treatment and at 6.5°C (constant) developed yellow-orange colour while at 3.5°C (constant) fruit remained green during storage. Juice content, titratable acidity and ascorbic acid contents were not affected by temperature regimes and waxing while total soluble solids content was higher with IW treatment. Reducing and total sugars were higher in fruits stored at IW treatment and at 6.5°C (constant) than at 3.5°C (constant). Total peel phenols content were not significantly affected by waxing and temperature regimes. However, loss of phenols content was higher at 3.5°C (constant). Phenol content decreased during storage. At 3.5°C (constant), chlorophyll ('a', 'b' and total) content in peel was maximum while total carotenoids were minimum with little colour development. Rapid colour development was recorded under IW and also at 1week holding. Wax coating delayed colour development at 3.5°C (constant). Initially carbendazim residues were higher in peel (4.0ppm) and pulp (3.2ppm) of waxed fruit than in non-waxed (3.2ppm in peel and 3.1ppm in pulp) fruit. Overall drop in residues till storage up to 75days+ 1week over the initial values was 80.2-85.6% in peel and 56.2-75.8% in pulp of waxed and non-waxed fruit, respectively. Respiration was lower in waxed fruit. Respiratory rate was lowest at 3.5°C (constant) and it changed with IW. At 3.5°C and 6.5°C (constant), range of respiration was 4-6mgCO2/kg/h and 7-9 mgCO2/kg/h, respectively in waxed and non-waxed fruit. Respiratory rate increased as the fruit was removed to warmer temperature. Chilling injury caused considerable rise in respiration rate of fruit. Present findings indicated that storage life of 'Nagpur' mandarin can be extended up to 75days at 3.5°C with IW.

Effect of coating and intermittent warming on enzymes, soluble pectin substances and ascorbic acid of Prunus persica (Cv. Zhonghuashoutao) during refrigerated storage

The effect of 1% chitosan coating + polyethylene (PE) package, 1% chitosan + 0.5% CaCl 2 coating + PEpackage, and 1% chitosan + 0.5% CaCl 2 coating + PEpackage + intermittent warming on the enzymes and quality of Zhonghuashoutao fruits ( Prunus persica) was studied during refrigerated storage (1 °C). The results showed that, compared to the control (CK) of water dip + PEpackage, all treatments had positive effectiveness on the inhibition of polyphenol oxidase, peroxidase (POD), ascorbic acid oxidases (ASA-POD) and polygalacturonase (PG) activities to some extent, and reduced the increase of soluble pectinefic substance. Results also showed that 1% chitosan + 0.5% CaCl 2 + PEpackage + intermittent warming treatment significantly inhibited ASA-POD and PG activities, kept vitamin C at a high level, and reduced fruit sensitivity to chilling injury at the later stage of storage.

EFFECT OF SOME POSTHARVEST TREATMENTS AND CONTROLLED ATMOSPHERE (CA) STORAGE ON BASIC QUALITY CRITERIA OF PEACHES AND NECTARINES

The peach (Flavorcrest and Red Top) and nectarine (Fantasia and Fairlane) cultivars used in the study were stored in normal and controlled-atmosphere conditions. Peaches and nectarines were subjected to some treatments (fungicide solution, low O2 and intermittent warming treatment) either before or during storage. Physical and chemical changes (weight loss, respiration rate, fruit flesh firmness, titratable acidity, total sugar, overall appearance) were recorded at 15-day intervals during 45 days storage and after 10 days shelf life at the end of the storage. Results are given.

Intermittent warming of peaches reduces chilling injury by enhancing ethylene production and enzymes mediated by ethylene

SUMMARYPeaches (Prunus persica ‘Hermoza’) were ripened at 208>C after harvest and either stored at 08C for four weeks (control) to induce chilling injury or given intermittent warming (IW) on the twelfth day of storage (28C for 24.h) to alleviate chilling injury (CI). Continuously stored fruit from control developed wo olliness, a CI disorder, during ripening at 208C after cold storage while only a small percentage of IW fruit developed woolliness. CI fruit produced less ethylene during ripening after storage, and this inhibited ethylene production was closely tied with woolliness development. The IW treatment caused enhanced ethylene production in the fruit when returned to 08C and the ethylene remained higher than control fruit until the end of the storage period. IW also induced the messages for 1-aminocyclopropane-1-carboxylic acid oxidase (ACO) and 1-aminocyclopropane-1-carboxylic acid synthase (ACS) in the ethylene synthesis pathway. IW also elevated the mRNA of the cell wall degrading enzymes polygalacturonase (PG) and endo-1,4-gluconase (EGase). The mRNAs of the cell wall enzymes and the enzymes in the ethylene synthesis pathway remained higher even after 5.d at 08 C following the IW treatment. It is suggested that IW maintained the fruit tissue capacity to ripen normally by preventing inhibition of the ethylene synthesis pathway which occurred in the control fruit after extended storage.

Thermal postharvest treatments for improving pomegranate quality and shelf life

Sweet pomegranates (Punica granatum L. cv Mollar de Elche) were cold-stored for 90 days. Curing at 33°C and 95% RH for 3 days before continuous storage at 2 or 5°C and 95% RH was tested for reducing chilling injuries. Alternatively, cycles of intermittent warming (IW) of 1 day at 20°C every 6 days at 2 or 5°C were tested. Control fruits were conventionally stored at 2 or 5°C and 95% RH, and a shelf life of 6 days at 15°C and 75% RH was included in the trials. At the end of the storage and shelf life periods, IW fruits showed the highest anthocyanin concentrations and titratable acidity, and the best visual appearance. After shelf life, IW during 2°C storage was the only treatment that resulted in fruit with flavor similar to that at harvest. Main losses were due to decay (Penicillium spp.) in treatments at 5°C, with the least loss being in the IW2°C treatment. Chilling injuries (pitting and husk scald) were strongly reduced by curing at 2°C but only after cold storage. The lowest chilling injuries were found in the IW treatments. Severity of husk scald development was not directly related to low storage temperature. IW during 2°C storage has proved to be the best treatment for minimizing chilling injuries and maintaining pomegranate fruit quality.

Intermittent warming effects on superficial scald development of ‘Cortland’, ‘Delicious’ and ‘Law Rome’ apple fruit

Abstract ‘Cortland’, ‘Delicious’ and ‘Law Rome’ apples were intermittently warmed to 20°C for 24 h every 1, 2, or 4 weeks during cold storage for 16 weeks, not warmed, or treated with diphenylamine (DPA) at harvest. The effects of these treatments on fruit ripening and on the accumulation of α-farnesene and its oxidation products in hexane extracts of the peel, were assessed throughout storage. Incidence and severity of superficial scald were assessed after 22 weeks. Warming treatments, especially the weekly regime, advanced fruit ripening. Without warming, scald incidence in ‘Cortland’, ‘Delicious’ and ‘Law Rome’ was 70, 14 and 85%, respectively. Intermittent warming treatments reduced scald but the magnitude of effects varied among cultivars. In ‘Cortland’, scald was reduced only by the weekly warming treatment, which was less effective than DPA treatment. In ‘Delicious’, all warming treatments were equally effective but less so than DPA. In ‘Law Rome’, weekly warming controlled scald better than DPA, but less frequent warming was proportionately less effective in controlling the disorder. Concentrations of conjugated trienes measured at 281 nm were not related consistently to scald incidence after storage, but ratios of measurements at 258 and 281 nm in crude hexane extracts were. The results are discussed in relation to the α-farnesene hypothesis of scald development and chilling injury.

Intermittent Warming Reduces Tomato Fruit Quality Deterioration during Cold Storage

Mature green tomatoes (cv. Vibelco) were stored at 2°C for 2, 3, and 4 weeks. Intermittent warming treatments for 12, 24, and 36 hours at 24°C were applied at the end of every week. Control Fruit were held continuously at 2°C. All fruit were subjected to poststorage ripening at 24°C for 7 days. Fruit decay, chlorophyll and lycopene content, fruit firmness, pH, TSS and TA were detected after storage or 7 days after transfer to 24°C. Results were compared between control and intermittently warmed fruit when stored at 2°C for 2, 3, and 4 weeks. Compared to fruit kept continuously at 2°C, intermittent warming at 24°C for 12, 24, and 36 hours reduced decay, increased chlorophyll disappearance, lycopene synthesis, and fruit firmness, enhanced pH and TSS, and declined TA. Fruit intermittently warmed for 36 hours/week showed the least decay, higher chlorophyll disappearance, and lycopene synthesis; retention of fruit firmness, pH, and TSS; and lower TA than fruit intermittently warmed for 12 and 24 hours/week. Decay percentage, lycopene content, pH, and TSS were increased from 2 to 4 weeks, but chlorophyll content, fruit firmness, and TA were declined.

Intermittent Warming Effects on Superficial Scald of Apple Fruit

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