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.     

Modified atmosphere packaging of ‘Kolikuttu’ bananas at low temperature

Summary

Mature `Kolikuttu' bananas were packed under modified atmosphere (M.A.) conditions using low density polyethylene (LDPE) bags and stored at 14°C and 94% r.h. The effect of ethylene scavengers on storage life of banana was examined. The in-package concentrations of oxygen, carbon dioxide and ethylene were measured during storage. Percentage weight loss, changes in firmness, total soluble solids (TSS), pH and sugar: acid during storage were also determined. Based on the in-package gaseous composition, the optimum storage period was defined. After termination of storage, bananas were allowed to ripen naturally, and the physico-chemical properties of ripened banana were analysed. `Kolikuttu' bananas could be packed in LDPE (0.075 mm) and stored at 14°C and 94% r.h. for 24.d. Storage life could be further extended up to 30.d by using ethylene scavengers. Physico-chemical properties of M.A. stored banana after ripening were similar to those held under ambient conditions. Therefore, packaging of `Kolikuttu' banana as individual hands in LDPE (0.075.mm) bags of 1:1 surface to weight ratio (cm² g^-1) with 50 ml of saturated potassium permanganate absorbed onto suitable porous matrices could be recommended to increase storage lifeat 14°C.     

Storage performance of clementines treated with hot water,sodium carbonate and sodium bicarbonate dips

Summary

The potential of using hot water (2.5 min at 45°C), 2% sodium carbonate or 2% sodium bicarbonate solutions alone or combined with hot water, for control of Penicillium digitatum (green mould) was investigated on commecially ripe clementines. The effect of such treatments on the post-harvest storage life of clementines was determined during two months analysing weight loss, increase in rind deformation and internal maturity. Carbonate and bicarbonate solutions effectively control green mould during storage but hot water does not. Compared with the control and hot-water treated fruits, clementines treated with carbonate and, to a lesser extend with bicarbonate, showed higher weight loss and lower firmness during storage. In contrast, lower increase in ripening index was found when the fruits were treated with carbonate or bicarbonate. Fruits treated with hot water alone or combined with carbonate exhibited no change in ripening during the first month of storage. Rinsing the fruit significantly reduces weight and firmness loss in the fruits treated with carbonate and bicarbonate, but did not change the ripening index. The primary finding of this work was that carbonate and bicarbonate treatments might significantly increase the loss in weight and firmness during storage. Rinsing the fruit immediately after treatment appeared to be a simple solution to avoid these losses in quality.     

Changes in volume and specific gravity of cucumber fruits after harvest in relation to the recovery from a flaccid appearance

Detached fruits of cucumber (Cucumis sativus L.) developed a flaccid appearance at first, but showed a recovery while stored at a temperature of 12.5°C or above. The recovery occurred in spite of the decline of fresh weight during storage. The higher the storage temperature, the sooner the fruits regained a turgid appearance.After harvesting of cucumber fruits, both their fresh weight and their volume decreased initially, while the specific gravity increased slightly. Accompanying the recovery from a flaccid appearance, however, the specific gravity of the fruits decreased and the rate of decrease in volume was retarded until eventually the fruits began to swell. The increase in volume occurred at any part of a fruit, although in a slightly different manner at the distal quarter.Fruits held at a temperature of 10°C and below, however, remained in a flaccid state during storage. In this case, fruit volume as well as fruit weight continued to decrease, but specific gravity increased gradually.Developed seeds with ivory colored seed coats were found in fruits at the end of storage at 15.0° or 17.5°C, but not in those stored at 12.5° or 10.0°C.     

The effect of temperature and humidity on the ripening of durian fruits

Summary

Fruits of ‘Chanee’ durian (Durio zibethinus Murr.) were exposed to temperature of 30°C and 33°C under low (70%) and high (90%) humidity. Typical climacteric patterns were recorded under each of the tested conditions, but at 33°C and 70% relative humidity (r.h.), low amounts of carbon dioxide and ethylene were produced. Fruits held at 30°C and 70% r.h., and at 33°C at both 70% and 90% r.h. ripened to full eating quality with a good pulp colour during the four-day exposure, while fruits held at 30°C at 90% r.h. did not. Fruits held at 33°C at 70% r.h. had the greatest total sugars, weight loss and dehiscence.     

不同气调保鲜袋对番茄采后保鲜效果的影响

为研究不同包装材料对番茄货架期品质的影响,以聚丙烯打孔袋（PPP）、双向拉伸聚丙烯保鲜袋（BOPP）、自发气调保鲜袋（MA）、聚乳酸保鲜袋（PLA）、聚乙烯保鲜袋（PE）5种保鲜袋为材料,分析了在常温条件下贮藏8 d,不同保鲜袋内O₂和CO₂体积分数、果实失重率、果实硬度、可溶性固形物含量、VC含量和感官评价等指标变化情况。结果表明：与对照组PPP保鲜袋相比,在贮藏期间,MA保鲜袋可以更有效地减少番茄质量损失,使果实的VC含量和可溶性固形物含量维持在较高水平;贮藏第8 d,番茄VC含量为0.11 mg/g,可溶性固形物含量为9.0%,仍能够保持较好的番茄果实硬度和商品性,硬度仍能达到2.2 kg/cm²,较对照高38.2%,感官评分显著高于其他处理。总之,与其他保鲜袋相比,MA保鲜袋保鲜效果最好。     

Effects of high-humidity storage on quality,decay and storage life of cherry,lemon and peach fruits

Sweet cherries (Prunus avium (L.) ‘Lambert’ and ‘Blackboy’), lemons (Citrus limon (L.) Burm. f. ‘Lisbon’) and peaches (Prunus persica (L.) Batsch, ‘Summerset’) were stored at 77–83, 90–94 and 95–99% RH (high humidity) at near-optimal storage temperatures after harvest and treatment with fungicides. High-humidity storage did not increase the storage life of peaches held at 0°C, but the life expectancy of cherries (both cultivars) was extended by 7–10 days at 0°C, and of lemons by at least 4 weeks at 10°C when fruit were stored at 95–99% RH compared with levels below 95%. The beneficial effects of high humidity were attributed to retardation of peel desiccation and associated reductions in fruit deformation, peel de-greening, chilling-injury and decay in lemons and to the maintenance of a fresher stalk and a firmer, less shrivelled fruit in cherries. High humidity had no effect on decay in cherries or peaches, but it significantly reduced weight loss and delayed the appearance of shrivel in peaches stored at 0°C. However, after storage at high humidity for 4 weeks, peaches ripened with low rates of C₂H₄ evolution and showed severe low-temperature injury, slight peeling-injury and a poor flavour ex-store.     

Induction of resistance to Penicillium digitatum and chilling injury in ‘Star Ruby’ grapefruit by a short hot-water rinse and brushing treatment

Summary

Postharvest heat treatments have been used for many years as alternatives to chemical control of fungal diseases and insect infestation of fruits and vegetables. In this study, the effects of a new hot-water brushing (HWB) treatment on the resistance of red grapefruit (C. paradisi cv. Star Ruby) to green mould decay caused by Penicillium digitatum (Pers.: Fr.) Sacc. and on the development of chilling injury (CI) symptoms during cold storage were examined. The HWB treatment comprises rinsing hot water on the fruits as they move along a belt of brush rollers. A twenty second HWB treatment at 59 or 62° reduced decay, after arti®cial inoculation of wounded fruit, by 52 or 70%, respectively, compared with control unwashed fruit, whereas rinsing and brushing the fruit with tap water (~20°) or with hot water at 53 or 56°, were ineffective. HWB treatments applied 1–3 d prior to inoculation were most effective in enhancing the disease resistance of fruit, but were much less effective when the fruit were inoculated on the same day or 7.d later. HWB treatments at 59 or 62° for 20.s also significantly reduced the CI index and the percentage of fruit displaying CI symptoms by 42 and 58%, respectively, after six weeks’ storage at 2° and an additional week at 20°. Furthermore, HWB treatments cleaned the fruit and improved its general appearance without causing any surface damage, and did not influence fruit weight loss, percentage of total soluble solids (TSS) in the juice, juice acidity or fruit colour.     

Shelf-life and quality of ber (Ziziphus mauritiana Lamk) fruits after postharvest water dipping treatments and storage

Summary

An experiment was conducted to study the effect of postharvest water dipping treatments and storage conditions on shelf life and quality of ber (Ziziphus mauritianaLamk). Fresh fruits of ber ‘Umran ’ were dipped in either cold (128C) or hot (50?C) water for 5 min and packed under different storage containers i.e. corrugated fibre board boxes, sealed polythene bags and perforated polythene bags. Control fruits were packed without dipping treatment. Result showed that postharvest water dipping at 508C for 5 min significantly increased the shelf life and maintained the quality of ber fruits, particularly late in the storage period. Fruits packed in sealed polythene bags significantly lowered the loss in fruit weight, spoilage and ripening with consequent increase in acidity and organoleptic score. Interactive results showed that hot-water treated fruits stored in modified atmospheric bags (sealed polythene bags) were qualitatively better than control fruits in terms of colour, taste and appearance. The organoleptic score reveals the acceptability of these fruits even after day 8 of storage. The control fruits were not found acceptable after day 4 of storage. It is suggested that postharvest fruit dipping in hot water (508C) forfive minutes followed by packaging in sealed polythene bags can enhance the shelf life and quality of ber fruits.     

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.     

Einfluss von Erntezeitpunkt und Lagerverfahren auf die Druckstellenempfindlichkeit von Äpfeln

The influence of harvest date and storage method on bruises sensitivity of apples was investigated. The cultivars ‘Braeburn’, ‘Jonagold’ and ‘Golden Delicious’ were harvested at three times in an interval of 10 days. Fruits have been stored at 2°C in normal atmosphere (cold storage) or in film bags (CA-/ULO-storage; CA?=?Controlled Atmosphere, ULO?=?Ultra Low Oxygen) for three months. Monthly fruits were bruised by a penetrometer applying a range of pressures. One day later the appearance of bruises were evaluated. Increasing pressures resulted in bruises of increasing severity. Early harvest led to less severe bruises. No differences were observed in storage conditions, but duration of storage increased bruise sensitivity of ‘Braeburn’. In comparison of the three cultivars ‘Braeburn’ was less sensitive than ‘Jonagold’ and ‘Golden Delicious’.     

Storage conditions and ripening of the custard apple Annona squamosa L.

Annona squamosa is a climateric fruit in which maximal carbon dioxide production preceeds that of ethylene during post-harvest storage. Normal ripening occurred at temperatures between 15 and 30° C, although the fruits were susceptible to fungal attack at temperatures above 25° C. Storage temperatures below 15° C caused chilling-injuries. Ripening was enhanced by removal of carbon dioxide and by addition of oxygen to the storage atmosphere, and delayed by the addition of carbon dioxide or removal of oxygen. Ethylene had no apparent effect on ripening. Fruits maintained under low relative humidities ripened faster than those stored under high-humidity conditions. Dipping the fruits in a solution of indole acetic acid at concentrations between 10^?4 and 10^?2 M accelerated ripening. Levels of both ascorbic acid and glucose increased to a maximum at the climacteric, but decreased as the fruits became over ripe. The stage of “eating” ripeness occurred at the climacteric. Recommended conditions for storing custard apple are: temperatures between 15 and 20° C, low oxygen and ethylene tensions coupled with 10% carbon dioxide and a relative humidity of 85%–90% in the storage atmosphere.     

The ripening of gamma irradiated fruits of jujube

Mature green jujube fruits of cv. Zaytoni were subjected to gamma radiation doses of 0, 10, 30 and 50 krad. The irradiated and unirradiated fruits were then kept at 20°C and 85-90% r.h., and changes in weight loss, total soluble solids, titratable acidity and ascorbic acid content were determined. Fruits subjected to 30 krad were firmer and greener than unirradiated control fruits after six days of storage, and this treatment delayed ripening by three days. There was no significant loss in the nutritive value of the fruit due to irradiation.     

Prevention of hot-water treatment damage in narcissus bulbs by pre-warming

Summary

Hot-water treatment (HWT) used to control stem nematode in narcissus bulbs can lead to yield loss through damage to flower, leaf and root initials. Warm storage of bulbs, usually at 30°C, reduces this damage. The effects of two pre-warming treatments (18°C for two weeks or 30°C for one week before HWT) were investigated in bulbs hot-water treated at a range of dates (from early-July to late-September). Experiment 1 was conducted on bulbs of cv. Carlton lifted on three dates. In the year after HWT, flower numbers were much reduced when HWT was applied after mid-August following storage at ambient temperatures, or after late-August following storage at 30°C, but numbers were only slightly reduced even with late-September HWT when given after 18°C storage. Pre-warming was somewhat more effective after early lifting. Late HWT reduced yields of bulbs harvested after two years' growth, but 18°C treatment largely prevented these losses. In Experiment 2, the beneficial effects of 18°C treatment were confirmed in cvs Carlton and Golden Harvest but not in cv. Barrett Browning. These findings are discussed in terms of growth retardation by warm temperatures.     

Light distribution in apple orchard systems in relation to production and fruit quality

Summary

The effect of tree density (2000, 2667, and 4000 trees per ha) and the ratio of between to within-row distance (1:1, 2:1, and 3:1) on light interception, fruit production, colour and individual fruit weight was evaluated in a ten-year comparative field study with apple at two sites in The Netherlands (51° 30′ and 52°0′ N) and one site in Denmark (55°30′). For each combination of tree density and rectangularity, trees were pruned at three heights (1.50, 1.88, or 2.25 m). Fruit production over nine years and seasonal incoming radiation between bloom and harvest were 20 and 15% greater in The Netherlands. Climate-based estimates of potential production as provided by a crop-growth model, predicted 18% higher fruit production in The Netherlands. Production was proportional to light interception and increased with tree density, but the amount of well-coloured fruit per ha in later years did not increase with planting density. With more than 70% light interception in later years, a large proportion of shade within the canopy was found. Fruits were smaller and less coloured at the Danish site. Fruits were more coloured in the taller and more open trees, even at the highest tree densities. Plantings with 1:1 and 2:1 between-to within-row distances intercepted more light and had a more uniform light distribution than 3:1 designs. This led to higher fruit production and better fruit colour. Fruit weight was not influenced by tree density, rectangularity, or tree height.     

Use of low-pressure storage to improve the quality of tomatoes

Freshly harvested vine-ripened tomatoes (Solanum lycopersicum cv. Neang Pich) were stored at low pressure (4 kPa) at 10°C for 11 days with 100% RH. Fruit quality was examined upon removal and after being transferred to normal atmosphere (101 kPa) at 20°C for 3 days. Weight loss was significantly lower in fruits which were stored at low pressure (4 kPa) than in fruits that were stored at regular atmosphere (101 kPa) at 10°C. Fruits that were stored at low pressure (4 kPa) reduced calyx browning by 12.5%, and calyx rots by 16%, compared to fruits that were stored at regular atmosphere (101 kPa) at 10°C. Fruit firmness was not significantly different between fruits stored at low pressures (4 kPa) and the normal atmosphere (101 kPa), with an average firmness of 14 N after fruits were stored at 10°C for 11 days. There was no difference in the SSC/TA ratio. The results suggest that a low pressure of 4 kPa at 10°C has potential as an alternative, non-chemical postharvest treatment to improve tomato quality during storage.     

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.     

Extending the postharvest life of unrefrigerated avocado (Persea americana Mill.) fruit by storage in polyethylene bags

Mature ‘Hass’ avocado (Persea americana Mill.) fruit were enclosed in sealed polyethylene bags and stored at ambient temperatures for different times. Modified atmospheres developed inside the bags and fruit stayed firm and apparently non-ripening while they remained enclosed. Storage time and temperature influenced ripening of fruits after they were removed from bags. Most storage treatments resulted in an extension to the total postharvest life of fruits compared to control fruits which were not stored in such bags. Abnormal ripening characteristics were observed when storage temperature was high and storage time exceeded 8 days.     

Post-Harvest Studies on Autumn-Drilled Bulb Onions. The Effect of Harvest Date,Conditioning Treatments and Field Drying on Skin Quality and on Storage Performance

Overwintered onion cvs Express Yellow and Senshyu Semi-globe Yellow were harvested at 80% foliar fall-over (early June) and two and four weeks later, in 1975 and 1976. Plants were conditioned for one (1975) or two weeks (1976) at 20°C, 70% RH or 30°C,60% RH or field dried, and then stored at ambient temperature. Measurements of fresh weight loss during the first six weeks after harvest in 1976 indicated that drying was slow and was incomplete after 14 days conditioning at 30°C. Skin staining and splitting generally increased with delay in harvest date. Skin colour improved with delay in harvest date and with conditioning at 20°C. Wastage due to both rotting and sprouting during storage was generally lower when plants from the first two harvest dates were conditioned at 30°C. These bulbs are likely to be useful for long-term storage as total wastage levels of only 20% were reached in both cultivars after 3-5 months storage. Good field drying of the bulbs could not be consistently obtained and consequently storage performance was more variable than for bulbs conditioned at 20 °C and 30 °C before storage.     

The germination of watercress (Rorippa nasturtium- aquaticum) seeds. II. The relationship between seed colour and germination

Freshly-harvested seeds of green watercress were pale yellow, rapidly turning to pale brown under ambient laboratory conditions. Older seeds ranged from pale to very dark brown, the darker seeds losing more electrolyte than the pale ones when immersed in water. Dark seeds germinated more readily than pale ones when the seeds were freshly harvested, but with old seeds germination was generally greater with paler seeds than darker ones. The results suggested that darkening of the seed coat was associated initially with a loss in dormancy and ultimately a loss in viability. Darkening of the seeds was enhanced by moisture. It could be induced by high humidity storage at 40°C, a treatment which resulted in increased electrolyte leakage from the seeds, or by holding individual seeds dormant at 35°C, although only the former treatment reduced germination. The results suggest that the ability of the seeds to germinate and the colour of the seed coat are not directly linked but that both are influenced by RH and temperature during storage.