Guazatine control of sour rot in lemons,oranges and tangors under various storage conditions

Guazatine (1-17-diguanidino-9-aza-heptadecane acetate) was compared with sodium orthophenylphenate (SOPP), sec-butylamine (2-AB), benomyl and tridemorph for the control of citrus sour rot (Geotrichum candidum) under local marketing, export, and ethylene (C₂H₄) degreening storage conditions. Guazatine at 25–125 mg/l gave better control than 20 g/l SOPP, 10 g/l 2-AB and 250 mg/l benomyl in artificially inoculated ‘Eureka’ lemons stored at 27° C and high humidity for 6 days. At 500 mg/l, guazatine gave better control than 20 g/l SOPP, 10 g/l 2-AB or 500 mg/l benomyl in dip-inoculated ‘Eureka’ lemons, treated and packaged as for export and stored at 7° C for 2 or 10 weeks. At 250 mg/l, guazatine provided better control than 20 g/l SOPP, 5 g/l 2-AB, 250 mg/l benomyl or 1000 mg/l tridemorph in artificially inoculated ‘Washington’ navel oranges held for 4 days under degreening-conditions of 27° C and 90% RH with added C₂H₄.     

Quality of raisins under different packaging and storage conditions

We determined the effect of different storage systems and packaging on the quality of ‘Sultana Seedless’ raisins. The fruit were packed in plastic boxes and kept under controlled atmosphere (1% O₂ and 3% CO₂) at 0°C and 75–85% RH for 12 months (CA), packed in vacuum bags and kept under normal atmosphere (21% O₂–0.03% CO₂) (NA) and packed in thin plastic bags + carton boxes and kept under ambient condition (semi-refrigeration), at 0°C and 90% ± 5 RH for 12 months (AC). Fruit kept under CA or NA had acceptable fruit quality in terms of general appearance and taste for 10 months, whereas fruit quality was unacceptable at that time under AC. Fruit under NA had less weight loss than fruit under the other conditions. Differences in skin colour were relatively small, apart from the h° values. Concentrations of ochratoxin A were generally higher with AC. External appearance and taste were better with CA and NA. As a result, raisins can be stored for 10 months with good quality in vacuum package in NA (0°C and 90% ± 5 RH) and CA (1% O₂–3% CO₂) at 0°C and 75–85% RH.     

Long-term storage of yam pollen

During 1978–1979, viability of mixed hand-collected pollen from 6–10 genotypes of white yam (Dioscorea rotundata Poir.), stored under various combinations of relative humidity (Rh) and temperature, as well as the relation of pollen germination in vitro with fruit set were investigated.Yam pollen stored at 0% RH, ?5°C, remained highly viable for over one year (from one flowering-season to the next). Fluctuations in storage conditions accelerated loss of pollen viability. Pollen germination in vitro was not significantly correlated with the degree of fruit set, and pollen samples with low percent germination did give satisfactory fruit set.     

Storage capability at different temperatures of lemons grown in Israel

For prolonged storage of lemons, the best temperature to avoid rots and physiological disorders such as internal browning and peel pitting, was 14°C; for short periods only, storage at lower temperatures, 2–8°C, did not cause damage. Physiological disorders appeared in storage earlier, the lower the storage temperatures, and in fruit picked at a less ripe stage. The general appearance of the fruit is better when stored at the lower temperature. Color development, chemical changes, weight loss, respiration rate and ethylene evolution during storage of lemons at different temperatures and stages of maturity were examined.     

Leatheriness and mealiness of peaches in relation to fruit maturity and storage temperature

Summary

`Huangjin' peaches (Prunus persica Batsch) were harvested at commercial harvest time (commercial) and 20 d before (early) or after (later) commercial harvest. Fruit from each harvest were stored at three temperature regimes (0, 5 and 10°C) at 95% r.h. After four weeks of storage at 0 or 5°C, early harvested fruit developed more leatheriness but less mealiness and later harvested fruit did not develop leatheriness but developed more mealiness comparedwith fruit from commercial harvest. Overall, fruit stored at 5°C developed more mealiness but less leatheriness than fruitat 0°C for the same period of storage. When stored at 10°C for two weeks, after which fruit were senescent, fruit did not develop any leatheriness or mealiness regardless of harvest times. Fruit with leatheriness were firmer (>30 N) thanjuicy or mealy fruit (<10 N) after the same period of cold storage and 4 d at 20°C. Mealy fruit were as soft as juicy fruit. 1-Aminocyclopropane-1-carboxylate oxidase (ACO) activity, 1-aminocyclopropane-1-carboxylic acid (ACC) content, and polygalacturonase (PG) and galactosidase (GAL) activities were lower, and insoluble pectin content was higher in leathery fruit than that in juicy or mealy fruit. ACO, PG and GAL activity, ACC, and insoluble pectin content were similar between mealy and juicy fruit.     

The effects of storage temperature and fruit size on firmness,extractable juice,woolliness and browning in two nectarine cultivars

Fruit firmness, extractable juice, woolliness and browning of the mesocarp tissue in ‘Independence’ and ‘Flavortop’ nectarines stored at —0.5°, 3°, 5° and 7°C for four weeks were determined during ripening at 15°C. The firmness of both ‘Independence’ and ‘Flavortop’ during ripening decreased as storage temperatures increased. The percentage extractable juice after cold storage and during ripening varied considerably between cultivars and between the storage temperatures. The extractable juice of fruit stored at higher temperatures tended to increase during ripening, whereas fruit stored at lower temperatures tended to decrease first before increasing. At storage temperatures of —0.5° and 3°C both cultivars passed through a stage of woolliness during ripening, while less woolliness occurred after storage at 5° and 7°C. In both cultivars the percentage extractable juice during ripening was higher on average at storage temperatures of 5° and 7°C. Severe browning of mesocarp tissue in both cultivars occurred during ripening after storage at 3°C. The effect of fruit size on changes in firmness, development of woolliness and mesocarp browning in ‘Flavortop’ nectarines stored at — 0.5°C for four weeks and ripened at 15°C was also determined. Larger nectarines lost firmness more rapidly, woolliness occurred sooner and the mesocarp tissue was more prone to browning than smaller fruit during ripening.     

Biochemical and physiological changes during chlorophyll degradation in lime (Citrus aurantifolia Swingle cv. ‘Paan’)

Summary

Lime (Citrus aurantifolia Swingle cv. ‘Paan’) native to South East Asia, has a distinct flavour and quality characteristics. Maintenance of the green colour in the peel of lime is a desirable quality attribute during storage. Post-harvest chlorophyll degradation in lime was studied in fruit stored at room temperature (30°C) at a relative humidity (RH) of 70 – 85%. Within 7 d of storage, the total chlorophyll content decreased to 53.9% of its initial level. The highest chlorophyllase activity (1.68 units mg^–1 protein) was observed after 4 d of storage and declined thereafter. Peroxidase activity differed from chlorophyllase activity and increased significantly to 6.25 units mg^–1 protein after 9 d of storage, (i.e., at the late maturity stage). Respiration rate and 1-aminocyclopropene-1-carboxylic acid (ACC) oxidase activity did not significantly affect the chlorophyll degradation process in lime.The total nitrogen content of lime peel was inversely correlated with its chlorophyll content. A higher soluble protein content was observed in yellow peel than in mature green peel. A colour index chart was developed for maturity stages 1–4 in lime based on peel colour changes from mature green to full-yellow, and its correlation with chlorophyll content and fruit quality attributes.     

Subatmospheric pressure storage of mango fruits

Ripening of mango fruit is markedly delayed when the pressure in the storage chamber is reduced below 100 mm Hg, and fruit storage life is thus prolonged. The prolongation of storage life is inversely related to the pressure; control fruit stored at 760 mm Hg started to ripen after 16 days in storage at 13°C, while fruit stored at 100 and 75 mm Hg after 25 and 35 days, respectively. Fruit stored at 50 mm Hg remained unripe for 35 days. No effect on ripening was recorded at pressures above 250 mm Hg, while at pressures below 50 mm Hg the fruit desiccated. All fruits stored at subatmospheric pressure ripened 3–4 days after transfer to shelf life at 25°C. However, green mango fruits of the colored cultivars like ‘Haden’ and ‘Maya’, stored at subatmospheric pressure for a prolonged period, did not develop the proper red or orange color during shelf-life, but turned pale yellow instead. Treatment with ethylene upon removal from storage slightly improved color development in these fruits.     

A comparison of the response of different citrus fruit cultivars to storage temperature

A comparison was made of the response to storage temperatures (0–17°C) of grapefruit ‘Shamouti’ and ‘Valencia’ oranges, and lemon fruit. There was no chilling injury (CI) and the incidence of rot was relatively low at 12°C or higher for all cultivars. At low storage temperatures, however, pitting and subsequent rot development in grapefruit and in ‘Shamouti’ and ‘Valencia’ oranges were highest at 6°C, while in lemon the incidence of these disorders rose with the decrease in storage temperature, and was highest at 2°C. Grapefruit and ‘Shamouti’ oranges exhibited the highest susceptibility to CI, lemon showed an intermediate susceptibility, and ‘Valencia’ orange a very low one. In grapefruit, severe peel pittings that developed in cold storage were covered by mold rots during cold storage and shelf-life, but in ‘Valencia’ and particularly in ‘Shamouti’ oranges the incidence of decay during cold storage was low. During shelf-life, a pronounced CI-induced increase in the incidence of mold rots was evident. This breakdown during shelf-life may be associated with microscopic peel injuries which are formed during cold storage and covered by mold rots during shelf-life. Increased susceptibility of the cultivar to CI could be correlated with an increase in ethanol content at low temperatures.     

Effect of gibberellic acid and Vapor Gard on ripening,amylase and peroxidase activities and quality of mango fruits during storage

Post harvest application of gibberellic acid at 200 mg 1^?1, Vapor Gard (di-l-p-menthene) at 2.5% and their combination was studied on ‘Mallika’ mangoes (Mangifera indica L.) stored at ambient temperature (37 ± 2° maximum and 34 ± 2°C minimum) and at 15°C. Significant delay in the ripening of mango fruits was observed when gibberellic acid was applied with or without Vapor Gard. Gibberellic acid significantly retarded the degradation of ascorbic acid and chlorophyll in the peel, and reduced a-amylase and peroxidase activities during storage. Loss of weight decreased following treatment with Vapor Gard either alone or with gibberellic acid during storage at both ambient temperature and at 15°C. A pronounced retardation of ripening was observed when fruits were treated with gibberellic acid and Vapor Gard and stored at 15°C. The study thus suggests that mango fruits can be successfully stored for 20 d by application of gibberellic acid (200 mg 1^?1) in combination with Vapor Gard (2.5%) and stored at 15°C.     

Fruit quality and respiration of ‘McIntosh’ apples in response to ethylene,very low oxygen and carbon dioxide storage atmospheres

Storage of ‘McIntosh’ Apples (Malus domestica Borkh.) in a controlled atmosphere (CA) with very low O₂ (1.5% CO₂ + 1.0% O₂, 2.8°C) retained greater fruit firmness and titratable acids during storage and during subsequent air storage than apples stored in conventional CA (5.0% CO₂ + 3.0% O₂, 2.8°C). The rate of firmness loss during subsequent 0°C air storage decreased with length of storage in CA. Storage of apples in very low O₂ for 40 or 80 days decreased the rate of firmness loss in subsequent 0°C air storage as compared to the rate of firmness loss in conventional CA fruit, but the rate of firmness loss in 0°C air storage subsequent to 160 or 320 days of conventional CA was significantly less than the loss in similar fruit stored in very low O₂ atmospheres.A modified atmosphere with 1.0% O₂ decreased the rate of C₂H₄ accumulation in storage, and fruit production of both C₂H₄ and CO₂ after storage opening in comparison with similar fruit in conventional CA. The accumulation of C₂H₄ in storage chambers was increased with increasing O₂ levels, but the rate of increase depended upon the CO₂ level. C₂H₄ storage accumulation was stimulated by the presence of CO₂ at 0.5% O₂, but was suppressed by CO₂ when 3.0% O₂ was maintained.Retention of fruit firmness and titratable acids in apples stored in 1.5% CO₂ + 1.0% O₂ were insensitive to very low (0.231 ml l^?1) or very high (2440 ml l^?1) C₂H₄ levels in storage. Scrubbing C₂H₄ (0.304 ml l^?1) from chambers held at 5.0% CO₂ + 3.0% O₂ resulted in significantly firmer fruit after storage, but this effect was not significant after shelf life of 7 days at 20°C.     

The effect of preharvest calcium sprays on quality attributes,physicochemical aspects of cell wall components and susceptibility to brown rot of peach fruits (Prunus persica L. cv. Andross)

This study was planned to evaluate the effect of preharvest calcium sprays on physicochemical aspects of cell wall components, activity patterns of pectin-modifying enzymes and susceptibility to brown rot (Monilinia fructicola) of peach fruits (Prunus persica L. cv. ‘Andross’). Six or 10 preharvest calcium sprays were applied with two different formulas (calcium chloride and an ethylenediamine tetraacetic acid (EDTA) chelated calcium form) in equimolar calcium concentration (0.12% Ca, w/v). After harvest, peach fruits were cold stored (0 °C, 95% R.H.) up to 4 weeks. Calcium content increased significantly in the calcium-sprayed peaches both in the peel (25–42%) and in the flesh (11–17%), 1 d after harvest. Calcium chloride sprays were more effective than those of chelated calcium, whereas the increase of calcium content in the fruits seems to be unaffected by the 6 or 10 calcium sprays. The increase of cell wall calcium corresponded to increase of calcium in the insoluble pectin fraction, whereas no differences were detected in the calcium of water-soluble pectin fraction. Ethylene production, respiration rate, uronic acid content and activity of pectin-modifying enzymes did not indicate substantial differentiations by preharvest calcium sprays as ripening progressed after harvest or cold storage. Calcium sprays resulted in significant decrease of brown rot development, although no effect on disease incidence was recorded.     

Interaction of Maximum Daily Trunk Shrinkage and Fruit Quality in European Plum

Maximum daily trunk shrinkage (MDS) has been suggested as an appropriate indicator of plant water status because it is closely related to stem water potential. Interaction of MDS and fruit quality was studied in plum (Prunus domestica L. ‘Jojo’/Wavit and ‘Tophit plus’/Wavit) in temperate climate. According to the MDS data, trees were grouped as low MDS (LMDS) and high MDS (HMDS). Fruit quality was analysed during fruit development (95, 103, 117 DAFB for ‘Jojo’ and 99, 112, 121 DAFB for ‘Tophit plus’) before commercial harvest. Fruit picked at commercial harvest (137 DAFB and 140 DAFB for ‘Jojo’ and ‘Tophit plus’, respectively) were stored at 2 ± 0.5?°C (90 ± 2% RH) for 28 days, and 2 days shelf life at 20?°C providing 6 measuring dates postharvest. Results confirmed that MDS was positively correlated with water vapour pressure deficit also in the apparent temperate, semi-humid climate. Transpiration of fruit from high crop load and resulting HMDS trees, which can be assessed as physiologically drought, was low compared to that of fruit from LMDS trees. Furthermore, HMDS tree grown plums had enhanced soluble solids and dry matter contents with a tendency of reduced fruit size.     

Quality of lemons sealed in high-density polyethylene film during long-term storage at different temperatures with intermittent warming

Storage of lemons is designed to extend the marketing of fruit throughout the year, from the main harvest season in the winter until late summer, which is a period of short supply in the market. This work was concerned with physiological and chemical attributes of stored lemons either seal-packaged in high-density polyethylene plastic film (HDPE), or left unwrapped, during storage at 13, 8 and 2°C. Intermittent warming (IW) was used to prevent chilling injury at the lower temperatures. Differences between fruit subjected to the two treatments which produced longest storage (sealed at 13°C and non-sealed at 2°C with IW) are discussed. Both treatments are recommended for adoption in commercial practice.     

Effect of temperature manipulation during storage and ripening on firmness,extractable juice and woolliness in nectarines

‘Independence’ nectarines were stored at — 0.5°C for three or four weeks or at 3°C for four weeks or kept at room temperature for 18 h prior to storage for four weeks at -0.5°C. After cold storage, fruit from all treatments was ripened at 10°, 15°or20°C. In all treatments the percentage woolly fruit initially increased to high values and thereafter decreased with further ripening. The rate of increase and decrease in woolliness depended on the ripening temperature. A storage period of four weeks at — 0.5°C resulted more woolliness during subsequent ripening. Woolliness persisted longer after a four-week cold storage period than after a three-week one. When fruit was delayed at room temperature prior to cold storage, woolliness generally developed earlier and to a lesser extent during ripening. At all ripening temperatures initial storage at 3°C resulted in most woolliness extending over the longest period. In addition, browning of the meso- carp tissue occurred only in fruit cold stored at 3°C.-The delay period before cold storage decreased fruit firmness by 15.7 to 17.6 N. Except for fruit subjected to the delay period, the extractable juice in fruit of all treatments first decreased during ripening to low values then increased.     

贮藏环境湿度对采后杨梅果实品质的影响

以荸荠、东魁和炭梅3个品种杨梅果实为试材,研究了不同贮藏环境湿度对果实腐烂率、硬度、失重率、出汁率、糖和酸等品质指标的影响。结果显示,0℃条件下,高湿(100%RH)处理果实的腐烂率最高;低湿[(71.0±1.85)%RH]处理导致失重率增加,出汁率减少,果实品质显著下降;中湿[(84.1±1.84)%RH]处理可明显减少腐烂发生,有效维持采后果实品质。     

Effects of polyethylene bags,ethylene absorbent and 1-methylcyclopropene on the storage of Japanese pears

Summary

Storage of the ‘Nijisseiki’ cultivar of Japanese pears was studied over three seasons for periods up to 36 weeks at 0°C. Storage in 50 μm thick low-density polyethylene (LDPE) bags at 0°C considerably delayed yellowing in all experiments, even after fruit was removed to 20°C for 1 week at the end of storage. The addition of an ethylene absorbent made from potassium permanganate on aluminium oxide (Purafil II) further delayed yellowing. Carbon dioxide levels in both treatments varied, but were generally in the range 2–3%. Oxygen levels remained high, generally 16–19%. In bags without Purafil, ethylene levels rose slightly during storage and were generally about 0.15 μl l^–1. When Purafil was included in the bags, the ethylene level was reduced 10-fold or more. A sensory test indicated that the use of LDPE bags and ethylene absorbent resulted in fruit with better eating quality than fruit stored in air. Disorders over the 3-year investigation were low even after long-term storage. The use of polyethylene bags reduced the severity of flesh browning, and flesh spot decay was virtually absent. The use of bags increased the severity of core browning. Inclusion of an ethylene absorbent in bags reduced the severity of disorders, particularly core browning. Treatment of the fruit with 1-methylcyclopropene (1-MCP), before or during storage, resulted in higher ethylene levels in the polyethylene bags. At the concentrations used, 1-MCP did not improve the storage of ‘Nijisseiki’ compared to the use of polyethylene bags with Purafil II.     

Effect of low-pressure storage on the quality of green capsicums (Capsicum annum L.)

Green capsicums (Capsicum annum L.) were stored under low pressure (4 kPa) at 10°C for 5 and 11 days with 100% RH. The results showed that the incidence of stem decay under low-pressure storage for 5 and 11 days and storage at ambient atmosphere at 20°C for 3 days was lower compared to fruits that were stored at regular atmosphere at 10°C. Fruit that had been stored at low pressure at 10°C had no symptoms of flesh rots for up to 11 days, whilst fruit which had been stored at regular atmosphere at 10°C had 6% flesh rots after 11 days storage at 10°C.There was no difference in flesh firmness and colour retention between fruits stored at low pressure and regular pressure at 10°C. Capsicums stored at low pressure had higher overall acceptability compared to fruit that were stored at regular atmosphere at 10°C. These results demonstrate the potential of low pressure storage as an effective technique to manage capsicum fruit quality, however, there was no additional benefit when fruits were stored at low pressure for more than 5 days.     

Involvement of 1-methylcyclopropene in ripening of harvested mei (Prunus mume) fruit

Summary

Harvested mei (Prunus mume) fruit were stored at 20°C after exposure to 500 nl l^–1 1-methylcyclopropene (1-MCP) for 8 h. Firmness, peel colour, chlorophyll content, chlorophyllase activity, soluble solids content (SSC), titratable acidity (TA), respiration and ethylene production, and cell wall hydrolysis enzyme activities were monitored to determine the efficacy of 1-MCP treatment in delaying mei fruit ripening compared to untreated control fruit. Results showed that control ‘daqinghe’ mei fruit displayed typical climacteric patterns of respiration and ethylene production. Peak CO₂ production and ethylene production were observed after 6 d. Fruit softening was accompanied by a progressive decrease in colour parameters expressed as hue angle (h°), chlorophyll content, SSC, TA and increases in chlorophyllase, pectin methylesterase (PME) and polygalacturonase (PG) activities. 1-MCP treatment prior to the climacteric increase significantly delayed the onset of the climacteric peaks of CO₂ and ethylene production. These delays were associated with reductions in fruit softening, consistent with delaying the activities of PME and PG. Fruit treated with 1-MCP exhibited less peel colour change from green-to-yellow because of their lower levels of chlorophyllase activity and less chlorophyll breakdown. Moreover, 1-MCP treatment also significantly retarded reductions in SSC and TA compared with control fruit. The shelf-life of mei fruit ripening was increased by 4 d following 1-MCP treatment. Thus, 1-MCP treatment can markedly extend the post-harvest life of ‘daqinghe’ mei fruit.     

Storage of some local and introduced mango cultivars grown in Trinidad

The fruit characteristics and storage potential of some local and introduced mango cultivars grown in Trinidad were compared. At ambient temperature (28–32°C), fruit could be stored satisfactorily for between 3 and 8 days, after which ripening rapidly occurred. At 14°C, storage life was increased to as much as 18 days (cultivar ‘Graham’). Enclosure of fruits individually in polythene bags increased storage life at either ambient or 14°C temperature, while treatment with 3% Sta-fresh wax increased storage at ambient but not at 14°C. In the case of ‘Doodooth’, which was highly susceptible to anthracnose, treatment of fruit with hot water (52 ± 2°C) containing 500 or 1000 mg l^?4 benomyl for 5 min reduced the incidence of disease. Results are discussed in relation to the export potential of mangoes.