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1.
In order to examine the influence of preharvest nitric oxide (NO) treatment on ethylene biosynthesis and soluble sugar metabolism in ‘Golden Delicious’ apples, apple trees were sprayed with 50 μM sodium nitroprusside (SNP) (a donor of NO) 14 days before harvest. The results indicated that preharvest SNP treatment can increase the NO content and the NOS activity in apple fruit, therefore, delay the accumulation of ethylene due to its inhibition on the activities of 1-aminocyclopropane-1-carboxylate synthase (ACS) and 1-aminocyclopropane-1-carboxylate oxydase (ACO). Fructose is the main sugar in ‘Golden Delicious’ apple. The synthesis of sucrose was stimulated and the decomposition of sucrose was inhibited by this treatment, thus causing the accumulation of sucrose. We can draw a conclusion that pre-harvest SNP (50 μM) treatment can increase the NO content of fruit during storage, while higher NO content can further regulate fruit ripening through its effect on ethylene and sugar metabolism in ‘Golden Delicious’ apple fruit during storage at 18 °C.  相似文献   

2.
‘Raf’ tomato fruit were harvested at the mature-green stage and treated with 1-methylcyclopropene (1-MCP) at 0.5 (for 3, 6, 12 or 24 h) or 1 μl l−1 for 3 or 6 h. Fruit were stored at 10 °C for 7 days and a further 4 days at 20 °C for a shelf life period. All 1-MCP treatments reduced both ethylene production and respiration rate and in turn retarded the changes in parameters related to fruit ripening, such as fruit softening, colour (a*) change, and increase in ripening index (TSS/TA ratio). These effects were significantly higher when 1-MCP was applied at 0.5 μl l−1 for 24 h. In order to obtain the maximum benefit from 1-MCP, this treatment would be the most suitable for commercial purposes.  相似文献   

3.
We investigated the effects of nitric oxide (NO) fumigation on fruit ripening, chilling injury, and quality of Japanese plums cv. ‘Amber Jewel’. Commercially mature fruit were fumigated with 0, 5, 10, and 20 μL L−1 NO gas at 20 °C for 2 h. Post-fumigation, fruit were either allowed to ripen at 21 ± 1 °C or were stored at 0 °C for 5, 6, and 7 weeks followed by ripening for 5 d at 21 ± 1 °C. NO-fumigation, irrespective of concentration applied, significantly (P ≤ 0.5) suppressed respiration and ethylene production rates during ripening at 21 ± 1 °C. At 21 ± 1 °C, the delay in ripening caused by NO-fumigation was evident from the restricted skin colour changes and retarded softening in fumigated fruit. NO treatments (10 and 20 μL L−1) delayed the decrease in titratable acidity (TA) without a significant (P ≤ 0.5) effect on soluble solids concentration (SSC) during ripening. During 5, 6, and 7 weeks of storage at 0 °C, NO-fumigation was effective towards restricting changes in the ripening related parameters, skin colour, firmness, and TA. The individual sugar (fructose, glucose, sucrose, and sorbitol) profiles of NO-fumigated fruit were significantly different from those of non-fumigated fruit after cold storage and ripening at 21 ± 1 °C. CI symptoms, manifest in the form of flesh browning and translucency, were significantly lower in NO-fumigated fruit than in non-fumigated fruit after 5, 6, and 7 weeks storage followed by ripening for 5 d at 21 ± 1 °C. NO-fumigation was effective in reducing decay incidence in plums during ripening without storage and after cold storage at 0 °C for 5, 6, and 7 weeks. In conclusion, the postharvest exposure of ‘Amber Jewel’ plums to NO gas (10 μL L−1) delayed ripening by 3–4 d at 21 ± 1 °C, and also alleviated chilling injury symptoms during cold storage at 0 °C for 6 weeks.  相似文献   

4.
Ethylene production is enhanced by wounding during fresh-cut processing and the accumulation of this gas within the packages of fresh-cut fruit can be detrimental to their quality and shelf-life. The effect of 1-methylcyclopropene (1-MCP), an ethylene action blocker, applied before or after processing, on the quality of fresh-cut kiwifruit, mangoes and persimmons was evaluated during storage at 5 °C. Fresh-cut ‘Hayward’ kiwifruit slices softened at a slower rate and their ethylene production rate was decreased in response to 1-MCP application (1 μL L−1 for 6 h at 10 °C) either before or after processing. A 2-min dip in 0.09 M (1%, w/v) CaCl2 synergistically increased the effect of 1-MCP on firmness retention and 1-MCP did not affect the color (L* value) of fresh-cut kiwifruit slices. Softening and browning (decreasing L* value) were delayed when 1-MCP was applied directly on fresh-cut ‘Kent’ and ‘Keitt’ mango slices. Respiration rate of mango slices was not influenced by 1-MCP whereas the ethylene production was affected only towards the end of their shelf-life. Fresh-cut ‘Fuyu’ persimmons treated with 1-MCP after processing presented higher ethylene production rate, slower softening rate and slower darkening of color (decrease in L* value), whereas the respiration rate was not affected.  相似文献   

5.
After three months storage at 0.5 °C one quarter of a lot of ‘Anjou’ pears (Pyrus communis L.) were treated with 1 μL L?1 of 1-methylcyclopropane (1-MCP) for 8 h at 20 °C and three quarters of the fruit were left untreated at 20 °C for the same time. Treated and untreated pears were then sliced, dipped in a commercial anti-browning solution and packaged in modified atmospheric bags. Packages, containing slices from 1-MCP treated fruit, were labelled as MCP1. Slices from two thirds of the untreated fruit had one of two secondary treatments applied: (1) multi-functional co-release sachets added to the package at the time of sealing (NT), or (2) an injection of 1-MCP to sealed packages to achieve a final concentration of 1 μL L?1 (MCP2). The last third of the slices from the untreated lot of pears were sealed into packages with no further treatment (CK). The packages were kept at 5 °C. In-package ethylene concentrations were significantly lower for the NT treated slices. NT also significantly delayed and reduced net oxygen consumption in the package headspace compared with other treatments. The NT treatment also reduced incidence of browning induced by enzymes of microbial origin, termed secondary browning (SB), and better maintained the measured juiciness of slices. In contrast, the CK, MCP1 and MCP2 treatments showed a more rapid appearance and severity of SB. Slices in packages treated with NT retained higher tissue levels of butyl, hexyl and pentyl acetate, 6-methyl-5-hepten-2-one, butanol and hexanol during storage than any of the other three treatments.  相似文献   

6.
Fresh-cut banana slices have a short shelf-life due to fast browning and softening after processing. The effects of atmospheric modification, exposure to 1-MCP, and chemical dips on the quality of fresh-cut bananas were determined. Low levels of O2 (2 and 4 kPa) and high levels of CO2 (5 and 10 kPa), alone or in combination, did not prevent browning and softening of fresh-cut banana slices. Softening and respiration rates were decreased in response to 1-MCP treatment (1 μL L−1 for 6 h at 14 °C) of fresh-cut banana slices (after processing), but their ethylene production and browning rates were not influenced. A 2-min dip in a mixture of 1% (w/v) CaCl2 + 1% (w/v) ascorbic acid + 0.5% (w/v) cysteine effectively prevented browning and softening of the slices for 6 days at 5 °C. Dips in less than 0.5% cysteine promoted pinking of fresh-cut banana slices, while concentrations between 0.5 and 1.0% cysteine delayed browning and softening and extended the post-cutting life to 7 days at 5 °C.  相似文献   

7.
The potential of 1-MCP for controlling ripening in ‘Angeleno’ plum fruit under air and controlled atmosphere (CA) storage was explored, and the possibility that 1-MCP can inhibit development of brown rot caused by Monilinia laxa and internal breakdown in ‘Fortune’ and ‘Angeleno’ plums tested. After harvest, fruit were exposed to 300 and 500 nl l−1 (in 2003) and 500 nl l−1 1-MCP (in 2004) at low temperatures (0–3 °C) for 24 h. After treatment the plums were stored in air at 0 °C and ‘Angeleno’ fruit were also stored in CA storage (1.8% O2 + 2.5% CO2). Following storage, fruit were kept at 20 °C. In ‘Angeleno’ fruit, 1-MCP was effective in delaying the loss of firmness and colour changes during holding at 20 °C. 1-MCP reduced brown rot in fruit stored in CA but no significant reduction was found in air storage. Internal breakdown, a major physiological storage disorder in plums, was inhibited by 1-MCP treatment. Furthermore, since 1-MCP applied in air storage showed better results than the control in CA conditions, an application of 1-MCP before air storage could be the best way to reduce the ripening process for short or medium storage periods (40 and 60 days). CA storage plus 1-MCP treatment could be used for long periods (80 days).  相似文献   

8.
Surface browning is an important cause of deterioration of fresh-cut apples during postharvest handling. ‘Granny Smith’ apple slices treated with NO gas (10 μL/L) and the NO donor compound 2,2′-(hydroxynitrosohydrazino)-bisethanamine (diethylenetriamine nitric oxide (DETANO) (10 mg/L) dissolved in phosphate buffer (pH 6.5) showed delayed development of surface browning during storage at 5 °C and also resulted in a lower level of total phenols, inhibition of PPO activity, reduced ion leakage and reduced rate of respiration but had no significant effect on ethylene production or lipid peroxide level as measured by malondialdehyde (MDA) and hydrogen peroxide levels. The two control treatments of phosphate buffer (pH 6.5) and water dips also had significant effects compared to untreated slices. The relative effectiveness of treatments in extending postharvest life and reducing total phenols, PPO activity, ion leakage and respiration was DETANO > NO gas > phosphate buffer > water > untreated. Apple slices dipped in chlorogenic acid dissolved in water showed surface browning soon after application but dipping in DETANO solution negated the effect of chlorogenic acid whether applied before or after dipping in chlorogenic acid solution while the buffer and NO gas were also effective. It is suggested that an increase in phenols occurs on the apple surface soon after cutting, possibly as a defensive mechanism of the apple to limit damage to surface cells. The effectiveness of the applied treatments to inhibit development of surface browning may relate to their ability to minimize the level of phenols active on the cut surface possibly in conjunction with a reduced PPO activity.  相似文献   

9.
Factors that affect the efficacy of 1-methycyclopropene (1-MCP) treatment of apples [Malus sylvestris (L.) Mill var. domestica (Borkh.) Mansf.] include cultivar and maturity. In this study, ‘McIntosh’, ‘Cortland’ and ‘Empire’ apples were categorized by internal ethylene concentrations (IECs) at harvest, treated with 1 μL L−1 1-MCP, and the IECs of individual fruit followed at 30 d intervals during air storage at 0.5 °C for 90 d. IECs at harvest ranged from <0.5 μL L−1 to ≥100 μL L−1, 51 < 100 μL L−1, and 10 < 50 μL L−1 for ‘McIntosh’, ‘Cortland’ and ‘Empire’, respectively. 1-MCP treatment resulted in a decrease of IECs in fruit of all cultivars by day 30 after harvest. During subsequent storage IECs remained low in fruit with <1 μL L−1 at harvest, but in ‘McIntosh’, ‘Cortland’ increased in proportion to IECs at harvest, but not in ‘Empire’. The importance of initial IECs in fruit on the persistence of 1-MCP inhibition of ethylene production was confirmed in a further experiment, in which IECs in untreated and 1-MCP treated ‘McIntosh’ and ‘Empire’ apples were measured for up to 194 d. 1-MCP also decreased 1-aminocyclopropene-1-carboxylic acid (ACC) concentrations in fruit. The results of our study are consistent with the hypothesis that IEC modulates the sensitivity of climacteric fruit to 1-MCP.  相似文献   

10.
The curative antifungal activity of postharvest sodium methylparaben (SMP) treatments against citrus green (GM) and blue (BM) molds was characterized on different citrus species and cultivars artificially inoculated with Penicillium digitatum or Penicillium italicum and incubated at 20 °C and 90% RH for 7 d or stored at 5 °C and 90% RH for 8 weeks plus 7 d of shelf-life at 20 °C. Effective concentrations were selected in in vivo primary screenings with ‘Valencia’ oranges. SMP at 200 mM was tested at 20, 50 or 62 °C for 30, 60 or 150 s in small-scale trials to determine the best dip treatment conditions. Dips of 200 mM SMP at 20 °C for 60 s were selected and applied alone or in combination with 25 μL L−1 of the conventional fungicide imazalil (SMP + IMZ 25). Imazalil at the very low concentrations of 25 (IMZ 25) or 50 μL L−1 (IMZ 50) were also tested. Effectiveness of SMP alone at 20 °C for 60 s was significantly higher on oranges (cvs. ‘Valencia’ and ‘Lanelate’) than on mandarins (cvs. ‘Clemenules’, ‘Nadorcott’ and ‘Ortanique’), with GM and BM incidence reductions of up to 88% after 7 d at 20 °C. SMP was compatible with IMZ 25 and consistently improved its performance, irrespective of citrus cultivars and storage conditions. All treatments were less effective on ‘Clemenules’ mandarins. On ‘Valencia’ oranges stored for 8 weeks at 5 °C and 7 d at 20 °C, the combined treatment was significantly more effective than the single treatments (reductions of GM and BM incidence of about 50–60% and 90–95%, respectively). In additional tests, 200 mM SMP dips at 20 °C for 60 s did not prevent GM on ‘Valencia’ oranges wounded, treated, inoculated with P. digitatum 24 h later, and incubated at 20 °C for 7 d. In contrast, the treatments IMZ 25 and SMP + IMZ 25 showed significant preventive activity. It can be concluded from these results that SMP aqueous solutions, especially applied at room temperature, might be an interesting nonpolluting control alternative to be included in citrus postharvest disease control programs in the future.  相似文献   

11.
Four cultivars of tomato fruit (‘Cherry’, ‘Daniela’, ‘Patrona’ and ‘Raf’) were harvested at two ripening stages (S1 and S2), treated with 0.5 μl l−1 of 1-methylcyclopropene (1-MCP) for 24 h and stored at 10 °C for 28 days. For all cultivars, control fruit deteriorated very rapidly (due to weight loss, softening, colour changes and decay) with an estimated shelf life of 7 days (‘Cherry’ and ‘Patrona’) and 14 days (‘Daniela’ and ‘Raf’), independently of the ripening stage at harvest. All quality parameters for all cultivars were delayed and/or inhibited in treated fruit, the efficacy of 1-MCP being higher in tomatoes harvested at the S2 ripening stage. At this stage, the organoleptic properties had already developed in fruit on the plant and tomatoes could thus reach consumers with optimal postharvest quality.  相似文献   

12.
Separate experiments were conducted with three major commercial avocado (Persea americana Mill.) cultivars grown in Florida: ‘Simmonds’ (early-season, West Indian race); ‘Booth 7’ (mid-season, Guatemalan-West Indian hybrid); and ‘Monroe’ (late-season, Guatemalan-West Indian hybrid). Fruit were harvested at preclimacteric stage and left untreated (Control) or treated 24 h after harvest with aqueous 1-methylcyclopropene (1-MCP) at 1.39 (treatment M1) or 2.77 μmol L−1 a.i. (treatment M2) (75 or 150 μg L−1) for 1 min at 20 °C. Whole fruit ripening was monitored at 20 °C/92% ± 3% R.H. and based on whole fruit firmness, respiration and ethylene evolution. Fruit volatiles were assessed at preclimacteric (24 h after harvest), mid-ripe (half of initial fruit firmness) and ripe maturity stages, from 100 g of chopped pulp using a purge and trap system. Untreated, firmer fruit ‘Monroe’ (268 N at harvest) ripened within 12 d of harvest while softer fruit ‘Simmonds’ (118 N) ripened within only 6 d. 1-MCP treatment extended ripening time from 33% (M1) to 83% (M2). All fruit softened normally, indicating the potential benefits of aqueous 1-MCP as a postharvest treatment for avocado when applied at these concentrations. Volatile profiles differed among the three cultivars with several compounds detected in only one cultivar, results that may contribute to a potential identification of the origin of the cultivar based on fruit volatile composition. The West Indian cultivar ‘Simmonds’ had much higher emission of hexanal (preclimacteric fruit) and cis-3-hexenal and cis-3-hexen-1-ol (ripe fruit) than the Guatemalan-West Indian hybrids ‘Booth 7’ and ‘Monroe’. On the other hand, these latter hybrids had much higher levels of alkanes than ‘Simmonds’. Treatment with 1-MCP increased emissions of alkanes during ripening of ‘Booth 7’ and ‘Monroe’. Total volatiles of avocado decreased during ripening mainly due to the significant reduction of sesquiterpenes, the main group of volatiles in all cultivars at harvest (‘Simmonds’, 53%; ‘Booth 7’, 78%; ‘Monroe’, 66%). β-Caryophyllene was the major compound at harvest, but decreased to less than 2% in ripe fruit, at which point most sesquiterpenes were not detected. Among the 10 sesquiterpenes commonly found in the avocado cultivars in this study, only α-Copaene had significantly higher emissions in mid-ripe fruit treated with the higher concentration of 1-MCP (2.77 μmol L−1 a.i.), suggesting that ethylene participates in the regulation of this sesquiterpene.  相似文献   

13.
‘Galia’ (Cucumis melo var. reticulatus L. Naud. cv. Galia) fruit were harvested at the three-quarter slip stage and treated with 1 μL L−1 1-methylcyclopropene (1-MCP) at 20 °C for 24 h. The fruit were processed and stored as fresh-cut cubes and intact fruit for 10 d at 5 °C. Ethylene production of fresh-cut cubes was approximately 4–5-fold higher than intact fruit at day 1. Afterward, the ethylene production of fresh-cut cubes declined significantly whereas that of intact fruit remained relatively constant at about 0.69–1.04 ng kg−1 s−1. 1-MCP delayed mesocarp softening in both fresh-cut and intact fruit and the symptoms of watersoaking in fresh-cut fruit. Continuously stored fresh-cut cubes and cubes derived from intact fruit not treated with the ethylene antagonist softened 27% and 25.6%, respectively, during 10 d storage at 5 °C while cubes derived from 1-MCP-treated fruit softened 9% and 17%, respectively. Fresh-cut tissue from 1-MCP-treated fruit exhibited slightly reduced populations of both total aerobic organisms and Enterobacterium, although the differences did not appear to be sufficient to explain the differences in keeping quality between 1-MCP-treated and control fruit. Based primarily on firmness retention and reduced watersoaking, 1-MCP treatment deferred loss of physical deterioration of fresh-cut ‘Galia’ cubes at 5 °C by 2–3 d compared with controls.  相似文献   

14.
‘Superior seedless’ table grapes were stored for 7 days at 0 °C followed by 4 days at 8 °C + 2 days at 20 °C under modified atmosphere packaging (MAP). Two polypropylene films (PP) were used to generate the MAP, the micro-perforated PP-30 and an oriented PP (OPP). The OPP film was applied with and without fungicide (10 μL of trans-2-hexenal or 0.4 g Na2S2O5 kg−1). As control a macro-perforated PP was used. PP-30 packages reached the lowest O2 and the highest CO2 levels. Control clusters showed the highest weight losses and decay while almost no losses occurred under MAP treatments. No changes in softness, skin and/or pulp browning, or cluster shatter were found. After shelf life MAP-treated clusters showed slight to moderate stem browning, except under SO2 where practically no browning occurred while control clusters showed an extreme stem browning. After shelf life, MAP treatments showed good visual appearance and crunchiness, while control fruits were unmarketable. No off-flavors were detected for MAP treatments except for hexenal-treated berries. No remarkable changes for color, firmness, soluble solids content, pH, titratable acidity and maturity index were detected. Total sugars content at harvest was 200 g L−1 and only slight decreases were found after shelf life for most treatments. Total organic acids content at harvest was 15.4 mg 100 mL−1, which remained quite constant after cold storage and shelf life. The main phenolic compounds were flavan-3-ols (over 85% from the total content), hydroxycinnamic acid derivatives and flavonols, whose total amount at harvest was 140 mg kg−1 in a fresh weight basis. After shelf life only slight decreases in total phenolics occurred in all treatments. As a main conclusion, SO2-free MAP kept the overall quality of clusters close to that at harvest, with few differences when SO2 was added.  相似文献   

15.
A continuing challenge for commercializing 1-methylcyclopropene (1-MCP) to extend the storage life and control superficial scald of ‘d’Anjou’ pear (Pyrus communis L.) is how to initiate ripening in 1-MCP treated fruit. ‘D’Anjou’ pears harvested at commercial and late maturity were treated with 1-MCP at 0.15 μL L−1 and stored either at the commercial storage temperature −1.1 °C (1-MCP@−1.1 °C), or at 1.1 °C (1-MCP@1.1 °C) or 2.2 °C (1-MCP@2.2 °C) for 8 months. Control fruit stored at −1.1 °C ripened and developed significant scald within 7 d at 20 °C following 3–5 months of storage. While 1-MCP@−1.1 °C fruit did not develop ripening capacity due to extremely low internal ethylene concentration (IEC) and ethylene production rate for 8 months, 1-MCP@1.1 °C fruit produced significant amounts of IEC during storage and developed ripening capacity with relatively low levels of scald within 7 d at 20 °C following 6–8 months of storage. 1-MCP@2.2 °C fruit lost quality quickly during storage. Compared to the control, the expression of ethylene synthesis (PcACS1, PcACO1) and signal (PcETR1, PcETR2) genes was stable at extremely low levels in 1-MCP@−1.1 °C fruit. In contrast, they increased expression after 4 or 5 months of storage in 1-MCP@1.1 °C fruit. Other genes (PcCTR1, PcACS2, PcACS4 and PcACS5) remained at very low expression regardless of fruit capacity to ripen. A storage temperature of 1.1 °C can facilitate initiation of ripening capacity in 1-MCP treated ‘d’Anjou’ pears with relatively low scald incidence following 6–8 months storage through recovering the expression of certain ethylene synthesis and signal genes.  相似文献   

16.
The efficacy of three antagonistic yeasts, Metschnikowia pulcherrima strain MACH1, M. pulcherrima strain GS9, and Metschnikowia fructicola strain AL27, against Penicillium expansum and patulin accumulation was evaluated on apples stored at room (22 ± 1 °C for 7 days) and cold temperatures (1 ± 1 °C for 56 days). To increase the potential range of application of the biocontrol agents (BCAs), their efficacy was evaluated on four cultivars of apple, i.e. ‘Golden Delicious’, ‘Granny Smith’, ‘Red Chief’ and ‘Royal Gala’. AL27 was more effective than MACH1 and GS9 in the control of blue mold rot and in the reduction of patulin accumulation. The efficacy of AL27 was in most cases similar to the chemical control used, making the antagonist as competitive as chemical fungicides. In vitro experiments showed that AL27 reduced the conidial germination and germ tube length of P. expansum more than the other strains. The three BCAs were more effective in the control of blue mold rot on ‘Golden Delicious’ apples than on the other tested cultivars.  相似文献   

17.
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18.
Highbush blueberries (Vaccinum spp.) are a major export fruit crop of Chile which is stored at 0 °C and transported to markets in Asia, Europe, and the USA, using more than 15 d of maritime transportation. Under these conditions, gray mold caused by Botrytis cinerea can produce important economic losses. The effectiveness of sulfur dioxide (SO2) concentration × time treatments on gray mold control was determined in the laboratory and validated prior to refrigerating the fruit, using pallet scale SO2 fumigation treatment on the following blueberry cultivars: ‘Brigitta’, ‘Legacy’, ‘Liberty’ and ‘O’Neal’. In inoculated ‘Brigitta’ and ‘Liberty’ blueberries, gray mold prevalence varied from 97.2% to 97.5% in non-treated fruit, and this value was reduced from 7.9% to 6.1% in blueberries that were exposed to a SO2 concentration × time (Ct) product of 400 (μL L−1) h. The relationship between SO2 Ct products and gray mold prevalence under laboratory conditions was best explained by exponential models, which had a determination coefficient (R2) that ranged from 0.88 to 0.96. The estimated EC90 values varied between 245 and 400 (μL L−1) h, and the SO2 Ct between 250 and 350 (μL L−1) h was validated using a pallet scale application treatment to obtain the best control and minimal variation. No visual phytotoxicity symptoms of SO2 were observed with the Ct that was tested in this study. Therefore, SO2 fumigation was demonstrated to be an effective and practical technology for reducing the risk of blueberry gray mold decay during storage, and further effort should be given to register the use of this product for blueberries in the main Chilean export markets.  相似文献   

19.
Rachis browning of table grapes after harvest is a significant problem, and water loss is considered the primary factor in browning. The major rachis desiccation and browning occurs during marketing at ambient temperatures and relative humidity (RH) which create high water vapor pressure deficits (WVPD). In this study the effect of WVPD and its components on rachis browning were examined on the two white seedless cultivars ‘Superior’ and ‘Thompson’. The grape clusters were stored at 20 °C or at 10 °C with low (70%) or high (>95%) RH, thus creating 4 WVPD levels. At each WVPD the clusters were held in open punnets, punnets sealed with low density polyethylene film or microperforated polyethylene, and examed every 2 or 3 d for weight loss, berry firmness, rachis dry weight and subjective rachis index. In addition, the rachis were photographed and image analysis employed to identify the level of browning. The results show that image analysis gave very similar patterns to subjective evaluation of rachis browning with correlation coefficients up to 0.90. However, image analysis detected an increase in browning before subjective evaluation. There was poor overall correlation between cluster weight loss and rachis dry weight to browning for ‘Superior’ grapes but a good correlation for ‘Thompson’. Rachis of ‘Superior’ suffered extensive browning at 20 °C even at high RH while rachis of ‘Thompson’ remained relatively green under similar conditions. ‘Thompson’ grape rachis remained green during the entire examination period (11 d) when held at high RH in either 10 °C or 20 °C. At high WVPD, microperforated packaging offered better control of browning in ‘Superior’ grapes than closed packaging, while clusters of ‘Thompson’ retained green rachis after 4 d in open punnets, and after 7 d in covered punnets. In summary, detailed analysis of rachis browning shows that water loss is an important but not the only factor in browning. Quantitative and objective measurement of rachis browning is likely to facilitate better communication of experimental data and higher resolution of processes which lead to browning.  相似文献   

20.
The antifungal activities of cinnamon extract (CE), piper extract (PE) and garlic extract (GE) were evaluated on banana crown rot fungi (Colletotrichum musae, Fusarium spp. and Lasiodiplodia theobromae) in vitro. The assay was conducted with extracts of CE, PE and GE with concentrations of 0, 0.1, 0.5, 1.0, 5.0, 10.0 and 0.75 g L−1 of carbendazim (CBZ) on potato dextrose agar at room temperature. CE completely inhibited conidial germination and mycelial growth of all fungi at 5.0 g L−1. PE totally suppressed mycelial growth of all fungi at 5.0 g L−1 and conidial germination at 10.0 g L−1 except for Fusarium spp. GE had no significant effects but low concentrations (0.1 and 0.5 g L−1) enhanced germ tube elongation of the three fungi. The ED50 values were higher for mycelial growth than for conidia except for Fusarium spp. Combined treatments were investigated on crown rot development in banana fruit (Musa AAA group ‘Kluai Hom thong’). Treatments included 5.0 g L−1 CE, 1% (w/v) chitosan solution, hot water treatment (HWT, 45 °C for 20 min), CE plus chitosan, CE plus HWT and 0.75 g L−1 of CBZ, applied before and after inoculation of the fruit. Crown rot development was assessed during storage at 13 °C for 7 weeks. Disease development was least (25%) on CE treated fruit after inoculation compared to CBZ but was higher when CE was applied before inoculation. Chitosan significantly delayed ripening as in terms of peel color, firmness, soluble solids and disease severity. CE showed no negative effects on quality of fruit. CE plus HWT caused unacceptable peel browning.  相似文献   

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