Characterization of chlorophyll degradation in banana and plantain during ripening at high temperature

Bananas fail to fully degreen when ripening at tropical temperatures, but this abnormal symptom does not occur in plantain. To elucidate the temperature effect on banana degreening, comparison of the colour change and chlorophyll degradation pathway between banana and plantain during ripening at 20 or 30 °C was carried out. Compared to bananas ripening at 20 °C and plantains at 20 °C or 30 °C, bananas at 30 °C contained significantly higher levels of chlorophylls, chlorophyllide a and pheophorbide a at the end of the ripening process, linearly correlating to the colour scores of a^∗, b^∗ and Hue angle. Whilst higher chlorophyllase activity was recorded in both banana and plantain at 30 °C as to the fruits at 20 °C, 30 °C inhibited Mg-dechelatase activity in banana, but not in plantain. The reduction of Mg-dechelatase activity in banana peel at 30 °C may contribute to repressed chlorophyll degradation and lead to uneven degreening.     

Reduction of chilling injury in ripe Alphonso mango fruit in cold storage by temperature conditioning

The influence of ripening temperature and cold conditioning of pre-climacteric fruits on the incidence of chilling injury (CI) in ripe mango fruits cv. Alphonso during refrigerated storage was investigated. Fruits previously held and ripened at tropical ambient temperature (AT, 27–34°C) developed CI (skin staining or browning) when ripe fruits were subsequently stored at 5, 10, or 15°C for shelf-life extension. Fruits held and ripened at 20°C1°C, RH 85–90% showed little evidence of CI when subsequently stored at 5 or 10°C up to 14 days. Chilling injury in ripe mangoes was also avoided by holding pre-climacteric fruits for a minimum period of 30 days at 10°C and then ripening them at 27–34°C. The quality of the ripe mangoes remained good during cold storage for 7 days and were acceptable until 10–14 days with minimal changes in texture, flesh colour, carotenoids, total soluble solids, titratable acids and ascorbic acid. Shelf-life of ripe mangoes can thus be extended under refrigeration by pre-storage conditioning.     

Ripening Associated Phytochemical Changes in Mangos (Mangifera indica) Following Thermal Quarantine and Low-Temperature Storage

ABSTRACT: Fresh mangos entering the United States must be subjected to a thermal quarantine treatment to eliminate invasive pests, commonly followed by cold storage to extend shelf-life. Changes in phytochemicals and their resultant antioxidant capacity after such treatments are unknown. These studies evaluated mature, green mangos subjected to a simulated quarantine treatment using hot water immersion at 50°C for 60 min and subsequent storage at 5°C and 20°C against their respective controls. Fruit held at 5°C were transferred to 20°C after 8 d of storage to complete ripening, whereby symptoms of chill injury were observed. Phytochemical, antioxidant capacity, and quality parameters were then assessed every 4 d as the fruit ripened over the next 20 d. Storage temperature during ripening and not the hot water treatment was the major factor contributing to changes in polyphenolic content, with antioxidant capacity unaffected by either postharvest treatments or ripening. Major polyphenolics identified were free gallic acid and 4 gallotannins that collectively increased in concentration by 34% as the fruit ripened, also independent of postharvest and storage treatments. Carotenoid concentrations were highest in hot water-treated fruit stored at 20°C, whereas storage at 5°C initially delayed ripening. Despite appreciable differences in fruit quality during quarantine treatment or low temperature storage, only minor differences in antioxidant phytochemicals were observed.     

Influence of the ripening environment on the development of finger drop in bananas

‘Finger drop’, which is the dislodgement of individual banana ‘fingers’ from the bunch during ripening and marketing, was shown to be related to the conditions during fruit ripening. At high ripening temperatures fruit are generally softer than those ripened at temperatures of 20°C or lower when they reach eating ripeness. This is reflected in the strength of the fruit pedicel and can result in their having a strength sufficiently low that the fruit can easily be dislodged in handling and transport during marketing. However, ripening at very high temperatures (40°C) did not result in development of finger drop, but fruit ripened at this temperature were unmarketable. No consistent effects of ripening humidity were shown on the development of finger drop. Prolonged exposure of fruit to ethylene gas during ripening could increase finger drop in certain circumstances. Possible reasons as to how finger drop might be related to the ripening physiology of the fruit are discussed, and recommendations are made for further studies.     

高压静电场处理对香蕉果实成熟生理的影响

以香蕉果实为试验材料,在(20±1)℃试验冷库中贮藏21d,贮藏期间用－100kV/m和－200kV/m的高压静电场连续处理并测定果实的呼吸强度、乙烯释放量、硬度、果皮颜色变化以及果肉淀粉和可溶性糖含量的变化。结果表明：连续高压静电场处理可以使香蕉果实的呼吸跃变和乙烯释放高峰提前,淀粉转化为糖的速度快而且比对照早,果皮叶绿素含量明显低于对照,同时处理后的果肉硬度下降,低于对照;并且－200kV/m处理组的效果要优于－100kV/m处理组。说明高压静电场连续处理促进了香蕉果实的成熟,尤以－200kV/m处理组比对照提前成熟4d。     

Effects of 1-MCP on chlorophyll degradation pathway-associated genes expression and chloroplast ultrastructure during the peel yellowing of Chinese pear fruits in storage

The peel yellowing is an important pigment physiological process of green fruit ripening, which mainly results from chlorophyll degradation in the fruit peel. In this work, two typical cultivars with different ripening speed, a slow ripening pear 'Emerald' (Pyrus bretschneideri Rehd. cv. Emerald) and a fast ripening 'Jingbai' (Pyrus ussuriensis Maxim. cv. Jingbai) were used to investigate the molecular mechanism of chlorophyll degradation in pear yellowing/ripening during postharvest storage. The fruits after harvest were treated with 1-methylcyclopropene (1-MCP), an ethylene action inhibitor at 1.0 μLl(-1) to determine its effect on chloroplast ultrastructure and the expression of chlorophyll degradation associated genes in peel tissues. Our results show that the pears treated with 1-MCP had a lower ethylene production rate and higher chlorophyll content compared to those of untreated fruit. The more intact chloroplasts with well-organised grana thylakoids and small plastoglobuli were maintained in the peel of 1-MCP treated fruit for up to 30 and 15 d in 'Emerald' and 'Jingbai', respectively. The expression of chlorophyll degradation associated genes: pheophorbide a oxygenase (PAO), non-yellow colouring (NYC), NYC1-like (NOL), stay-green 1(SGR1), was suppressed, while no significant change was found in chlorophyllase 1 (CHL1) and red chlorophyll catabolite reductase (RCCR) in both cultivar fruits treated with 1-MCP. These results suggest that 1-MCP can delay chlorophyll degradation by inhibiting ethylene production and suppressing the gene expression of PAO, NYC, NOL and SGR1, which are closely associated with chlorophyll catabolic pathway.     

Chlorophyll disappearance and chlorophyllase activity during ripening of Capsicum annuum L fruits

The disappearance of chlorophyll pigments and involvement of chlorophyllase during fruit ripening of seven Capsicum annuum cultivars (Delfin, Mana, Belrubi, NuMex, Agridulce, Bola and Negral) have been studied. Chlorophyll pigments decreased and eventually disappeared from the red cultivars during ripening. In contrast, the green cultivar Negral, a chlorophyll‐retaining variety, showed reduced disappearance of chlorophyll pigments, and the fully ripe fruits retained chlorophylls. Chlorophyllase activity followed a consistent pattern of variation in all the red cultivars which was concomitant with the disappearance of chlorophyll. In the ripe stage the six red cultivars preserved their chlorophyllase activity, reflecting a high rate of chloroplast‐to‐chromoplast transformation. The green cultivar (Negral) showed maximum chlorophyllase activity in the late stages of ripening. Thus increasing activity of chlorophyllase, a constitutive chloroplast enzyme, could be associated with a new genesis of both chloroplast (regreening) and chromoplast constituents. The coexistence of chlorophyll and a high level of chlorophyllase activity in ripe fruits of the Negral cultivar suggests that chlorophyll catabolism may be affected in several ways, eg by the presence of other chlorophyll‐degrading enzymes, by restricted chlorophyll and chlorophyllase contact or by delayed degeneration of chloroplast structures. © 2002 Society of Chemical Industry     

PARTIAL CHARACTERIZATION OF CHLOROPHYLLASE FROM STRAWBERRY FRUIT (FRAGARIA ANANASSA, DUCH.)

In this article we report the existence of chlorophyllase in strawberry fruit (Fragaria ananassa, Duch.). The enzyme was extracted from either fresh fruit or from acetone powder in the presence of Triton X-100 to improve its solubilization. The composition of the reaction mixture as well as the enzymatic activity conditions were optimized. At test conditions the temperature of maximum enzymotic activity was 40C and optimum pH 7.8. The chlorophyllase showed a considerable resistance to thermal treatment. The enzyme was stable for incubation times of 30 min up to 50C. Chlorophyllase showed a preferential action on chlorophyll a at pHs 6.0, 7.0 and 8.0. The specific enzyme activity, just as did chlorophyll level, decreased during ripening.     

EFFECTS OF NITROGEN NUTRITION AND DAY TEMPERATURE ON COMPOSITION, COLOR AND NITRATE IN TOMATO FRUIT

The effects of nitrogen nutrition and day temperature on composition, color and nitrate in VF–145 tomatoes were investigated in growth chambers kept at 20, 25, 30 and 35°C respectively during the days for 14 hr, and at 20° C during the nights for 10 hr. Nitrogen fertilizer application was altered in half the pots in each chamber by supplying them with half-strength −N Hoagland's #1 solution during the fruit growth period. Tomatoes from fertilized plants (+N) were slightly higher in titratable acidity but lower in solids content than those from the −N plants. Fruits ripening at high day temperature were poor in color while those ripening at below 30°C were more attractive in color. The total, amino, ammonium and nitrate nitrogen contents of the tomato fruits were higher in the +N series than those of –N series. Tomatoes from plants receiving +N treatments contained more nitrate than those receiving −N treatments. Day temperature greatly affected the nitrate content in the tomatoes. In the +N series the nitrate content of the tomatoes decreased from 72.9 ppm to 0.37 ppm as the day temperature increased from 20: to 35°C. In the −N series, the nitrate content ranged from 0.35–1.15 ppm. Accumulation of nitrates in tomatoes appears to be related to the level of nitrate in the nutrient solution and the day temperature. Low day temperature results in accumulation of nitrate because of the low nitrate reductase activity.     

The response of unripe Conference pears to modified atmosphere retail packaging

Unripe green Conference pears with initial firmness values of 46–55 N were sealed in modified atmosphere (MA) low density polyethylene (LDPE, 30μ) pillow packs and in perforated control packs on three dates during 1985–1986. Changes in pack atmosphere composition, skin chlorophyll content, flesh firmness and sensory quality were monitored during 14–20 days simulated shelf-life at 20°C. In MA packs, equilibrated atmospheres containing 5–9% CO₂ and < 5% O₂ developed within c. 3 days. Chlorophyll degradation was completely inhibited by MA and resumed when packs were perforated, but MA only partially retarded the rate of flesh softening. Variations in the rate of ripening changes in duplicate MA packs could not be explained simply by differences in pack atmospheres. Furthermore, pears retarded by MA packaging failed to develop the normal sweet, aromatic flavour and succulent, juicy texture of 'eating-ripe' fruit, even when the packs were perforated after 4 days.
The differences in the responses of pears and apples to MA packaging, and the limitations of using this technique for the commercial marketing of English pears are discussed.     

Composition, sensory quality and respiration during ripening and storage of edible wild mango (Irvingia gabonensis)

The effects of tree and room ripening and of storage at chill temperatures and at 26–29°C on the sensory quality, composition and respiration of edible wild mango fruits were investigated.
Fruits harvested at the mature green stage and ripened at 26–29°C were slightly preferred to tree-ripened fruits in colour and texture. Apart from a lower moisture content, room-ripened fruits were comparable in composition with tree-ripened fruits. During storage at 26–29°C, CO₂ production increased sharply from 22 ml kg^-1 h^-1 at the end of the first day, reaching a maximum of 91 ml kg^-1 on day 5 and declining thereafter; O₂ consumption followed a similar trend. The respiratory climacteric coincided with the onset of ripening. Fruits held at 12–15°C developed symptoms of chilling injury including pitting and black spots in mature green fruits, and brownish discoloration, pitting, surface scald, excessive softening and decay in ripe fruits.     

Effect of short‐term anaerobic conditions on the production of volatiles,activity of alcohol acetyltransferase and other quality traits of ripened bananas

Yellow, ripened (yellow with green tips) bananas were treated with nitrogen gas for 12, 24 and 48 h at 20 °C to study the effects of anaerobic conditions on the fruit quality, including the production of volatile compounds and activity of alcohol acetyltransferase (AAT) during the post‐harvest period. Significantly higher concentrations of acetaldehyde and ethanol were found in the treated fruit than in the untreated bananas after removal from the conditions. The 48‐h treatment showed higher levels of ethanol and acetaldehyde after storage. Immediately after releasing the fruit from the anaerobic atmosphere, the amounts of isobutyl acetate and isoamyl acetate decreased. The production of ethyl acetate increased markedly in each treatment unit 1 day after removing the fruit. Regardless of recovery from the production of isobutyl acetate and isoamyl acetate 1 day after treatment, the banana‐like aroma was denatured because of the production of high levels of ethyl acetate and ethanol. The increase in AAT was slightly lower in nitrogen‐treated fruit than untreated fruit. However, the activity in treated fruit was sufficient for ester production in bananas. The endogenous alcohol levels were increased during nitrogen gas treatment in the fruit due to the inhibition of ester production. Colour development of the bananas was greatly inhibited by the treatments, while the sugar content did not show any differences between the treated and untreated fruit. The results suggest that, even if bananas are removed from the short‐term anaerobic conditions, a loss in quality, except sweetness, easily occurs afterwards, especially the characteristic aroma of the fruit during the post‐harvest period. Copyright © 2006 Society of Chemical Industry     

Effects of storage treatments upon the ripening of conference pears

Preliminary work established the pattern of changes in the amounts and properties of soluble pectic polysaccharides in Conference pears during ripening at 10 °C. Conference pears were harvested on three dates and stored in air at ?1 °C and in 2% O₂ at ?1 °C for various periods. They were ripened on removal from store at 18 °C. Chlorophyll and carotenoid concentrations in the fruit peel and soluble polyuronide concentrations in whole fruit as well as general storage data were recorded. The lag in the ripening of pears at 18 °C after harvesting was abolished by storage at ?1 °C. Softening and pectin changes were similar in all stored fruit samples irrespective of picking date, period of storage and whether stored in air or 2% O₂. Storage in 2% O₂ did retard breakdown slightly, however. The main effect of 2% O₂ was that it reduced the rate of destruction of chlorophyll during storage. Higher levels of chlorophyll were found during ripening in fruit which had been stored in 2% O₂ than in fruit stored in air.     

OXALACETATE SYNTHESIS IN APPLES AND BANANAS AT LOW TEMPERATURES

¹⁴CO₂ was applied to apples and bananas that were stored at various temperatures and the incorporation of ¹⁴C into oxalacetate was determined. Apples that were susceptible to internal breakdown showed an initial decrease in incorporation as the storage temperature was reduced but incorporation then increased at temperatures below 10°C (Jonathan) or 5°C (Twenty Ounce). Apples that were not susceptible to breakdown (Delicious and Granny Smith) showed no incorporation at any temperature. Green bananas showed a minimum incorporation at 10°C but in ripe bananas, incorporation markedly increased at all temperatures less than 20°C. The respiration rate of the apple varieties at 20°C was found to be higher in fruit that were more susceptible to breakdown whereas at O°C the higher rates of respiration were from fruit less susceptible to the disorder.     

Changes in Chlorophyll and Pectin After Storage and Canning of Kiwifruit

Kiwifruit were harvested and stored at 0°C. Over a 92-day period fruit were removed from storage, ripened to 13° Brix by holding at 25°C, and canned as slices in a sugar syrup. Changes in the chlorophylls and pectic substances were measured after storage and canning. The concentration of total chlorophyll remained virtually constant during storage and ripening. During the canning process about 90% of the chlorophylls was degraded, the data fitting a first-order model better than a second-order model. The total pectin content increased by over 100% during storage and ripening but decreased significantly during canning. A significant inverse relationship between the firmness of unpeeled kiwifruit and the water-soluble, high-methoxyl pectin content was derived.     

Irradiation Effects on the Ripening of Kent Mangoes

SUMMARY— Kent mango fruit irradiated with 0, 100, 200, and 300 Krad were ripened at 20°C for 0, 4, and 8 days.
Irradiated mangoes were less firm than control fruit immediately after irradiation, but fruit softening due to ripeness was more pronounced than softening induced by irradiation. Irradiated fruit contained higher water-soluble and lower Versene-vinsoluble pectic fractions as compared to unirradiated fruit. NO differences were observed in the content of the Versene-soluble fraction among all irradiation dosages. Higher PE activities were exhibited by the irradiated fruit throughout the ripening period. Irradiated fruit contained higher AIS and lower soluble solids than control fruit. No differences in sucrose content due to irradiation were observed, but there were less reducing and total sugars at the 300 Krad dose as compared to other dosages.
Changes in pectic fractions and PE activity were more pronounced immediately following irradiation in comparison to those occurring during ripening. The increase in soluble solids as well as sucrose, and the decrease in AIS, titratable acidity, reducing sugars and firmness during ripening proceeded at faster rates in control fruit than in the irradiated fruit. These variable rates of change were reflected by the significant irradiation dose and storage duration interactions.
Results suggest that irradiation induces a delay in ripening of Kent mangoes.     

不同条件对‘巴西蕉’和‘南天黄’香蕉后熟的影响

‘南天黄’为性状优良且抗枯萎病的香蕉新品种,其后熟条件与传统栽培品种‘巴西蕉’不同,然而生产中常以统一做法对‘南天黄’进行催熟,易造成生产误判。为提高香蕉品质,延长货架期,本研究以500 mg/L乙烯利喷雾处理后的‘南天黄’与‘巴西蕉’果实为材料,实验分为（22±2）℃处理组（T2）、（22±2）℃＋双向拉伸聚丙烯（biaxially oriented polypropylene,BOPP）薄膜包装处理组（T-2）、17 ℃处理组（T1）、17 ℃＋BOPP薄膜包装处理组（T-1）,观察果皮色差、果肉硬度、果实质量损失率、可溶性固形物质量分数的变化和货架期的特点,以此制定‘南天黄’合理催熟方案。T1、T-1处理组‘南天黄’褪绿转黄（催熟时间）比‘巴西蕉’早1 d,T1处理组‘南天黄’比‘巴西蕉’货架期长2 d;T2处理组‘南天黄’褪绿转黄比‘巴西蕉’迟1 d,货架期长2 d;与T2处理组相比,T1处理组香蕉后熟末期硬度、色差L*值、C*值、a*值更大,货架期长2 d,但后熟后颜色不如T2处理组的鲜黄;BOPP包装延缓了褪绿转黄,使催熟时间延长4 d,货架期缩短。因此前期高温（21 ℃）后期低温（17 ℃）是‘南天黄’获得较好的货架品质和货架期的后熟条件。     

Conditions in banana ripening using the rack and pit traditional methods and their effect on juice extraction

Traditional banana ripening processes for juice extraction, using the rack and pit methods, were carried out on farm to assess and compare the conditions in the respective ripening chambers and the suitability of the resulting ripe bananas for juice extraction. During ripening, high temperatures (23‐32°C) were attained and ethylene was produced. Ethylene reached peak concentrations of 250 and 500 mg kg⁻¹ for the rack and the pit methods respectively. Owing to the continued respiration of the bananas, the oxygen concentration fell and carbon dioxide accumulated, however the bananas attained a bright yellow colour on ripening. There was a significant difference in environmental conditions between the rack and pit ripening chambers. This did not affect ripening and it was possible to extract juice from bananas ripened by either method. However, some juice extraction failures were encountered. These preliminary studies suggest that the success or failure of banana juice extraction depends partly on conditions of ripening, in particular temperature. © 1999 Society of Chemical Industry     

Instrumental based flavour characterisation of banana fruit

Different instrumental techniques are used to evaluate the integrated flavour profile, including taste and volatile components, of a common export banana cultivar (Gran Enano) during ripening. Besides standard techniques to assess fruit quality (firmness, soluble solids content), gas chromatography-mass spectrometry (GC–MS) with headspace solid-phase micro-extraction (HS SPME) was used for the quantification of the different volatile components. The most important taste components with respect to sweetness (d-glucose, d-fructose, sucrose) and sourness (l-malic acid and citric acid) were determined using an enzymatic high-throughput (EHT) method. The different parameters were monitored during a ripening process starting from a green colour stage until fully ripened bananas. Clear differences were observed between bananas at different ripening stages with respect to the main instrumental attributes (total acid and sugar content, total volatile production, SSC, and firmness) and the individual volatile components. In addition, differences in flavour profile were observed between ethylene and non-ethylene treated bananas at the same colour stage and between bananas from different origins.     

Influence of fruit ripening process on the natural antioxidant content of Hojiblanca virgin olive oils

The effect of fruit ripeness on the antioxidant content of `Hojiblanca' virgin olive oils was studied. Seasonal changes were monitored at bi-weekly intervals for three consecutive crop years. Phenolic content, tocopherol composition, bitterness index, carotenoid and chlorophyllic pigments and oxidative stability were analysed. In general, the antioxidants and the related parameters decreased as olive fruit ripened. The phenolics and bitterness, closely related parameters, did not present significant differences among years. Although in general, the tocopherols decreased during olive ripening γ-tocopherol increased. Differences between crop years were found only for total tocopherols and α-tocopherol, which showed higher content in low rainfall year oils. The pigment content decreased during ripening, chlorophyll changing faster. For low rainfall years, the level of pigments was higher, reaching significant differences between yields. Significant differences among years were found for oil oxidative stability; higher values were obtained for drought years. A highly significant prediction model for oxidative stability has been obtained.