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1.
Three preservation techniques, chemical treatment, modified atmosphere packaging (MAP) and low temperature storage were used to improve physico-chemical attributes of oyster mushrooms. Mushrooms were treated with a solution of sorbitol (0.05%, w/v), citric acid (3%, w/v) and CaCl2 (1%, w/v). Chemically treated mushrooms were packed under two different gas compositions. Physico-chemical, textural and sensory properties of the samples were assessed during storage at 4 °C for 25 d. Chemical treatment of mushrooms followed by modified atmosphere packaging using 10% O2 and 5% CO2 provided better retention of quality characteristics and received higher sensory ratings compared to other samples, resulting in a storage life of 25 d. Material with this treatment underwent minimal changes in weight, pH and TSS. Radical scavenging activity and total polyphenol contents were retained at 85 and 91% levels, respectively. Control samples without chemical treatment and with chemical treatment, kept under similar packaging conditions, underwent spoilage after 5 and 15 d, respectively.  相似文献   

2.
Satsuma mandarins (Citrus unshiu Marc., cv. Gungchun) of an early harvesting cultivar were treated by hot water dipping at 52 °C for 2 min, 55 °C for 1 min, and 60 °C for 20 s, and then stored at 5 °C for 3 weeks and subsequently at 18 °C for 1 week (simulated shelf-life) to examine the possible use of hot water treatment (HWT) as an environmentally benign method to maintain mandarin quality characteristics during postharvest storage and sale. The initial respiration rate, just after heat treatment, was significantly higher in the treated fruit than in the untreated controls. During storage, however, the respiration rate was at a similar level in all treatments. HWT also had no adverse effects on quality attributes, including pH, titratable acidity, soluble solids contents, weight loss, firmness and peel color. The development of stem-end rots, mold decay, and black rots was manifestly lower in heat-treated fruit than in untreated controls. Sensory evaluation showed that HWT at 60 °C for 20 s markedly improved fruit appearance, making them cleaner and glossier. The results confirmed that hot water dipping could be applied to satsuma mandarin as an effective pretreatment to maintain postharvest quality during storage and marketing.  相似文献   

3.
Potato cultivars Premier Russet, GemStar Russet, Defender and Russet Burbank differ substantially in resistance to low temperature sweetening (LTS) and associated metabolism. ‘Gemstar Russet’ and ‘Premier Russet’ have moderate and high resistances, respectively, while ‘Defender’ loses processing quality progressively during storage at 9 °C, and similar to ‘Russet Burbank’, has virtually no resistance to LTS at 4 °C. The different mechanisms of LTS resistance or susceptibility in these cultivars were indicated by changes in sucrose (Suc), fructose (Fru) and glucose (Glc) concentrations in relation to tuber respiratory profiles during wound healing (9 °C), LTS (4 °C) and reconditioning (16 °C). At 4 °C, ‘Premier Russet’ tubers maintained low levels of Suc and reducing sugars (RS, Glc + Fru), while ‘GemStar Russet’ tubers accumulated Suc with little inversion to RS. ‘Defender’ and ‘Russet Burbank’ tubers accumulated RS during LTS but only moderate levels of Suc. Changes in RS content reflected the combined activities of acid invertase and its endogenous inhibitor. In response to an immediate drop from 9 °C to 4 °C, tuber respiration decreased to a minimum and then increased to a new maximum over the next approximately 5 days, before decreasing to a constant basal rate at 4 °C. Relative changes in respiration from the minimum to maximum rate during cold acclimation (respiratory acclimation response, RAR) were 80% for ‘GemStar Russet’ and ‘Defender’, 51% for ‘Russet Burbank’ and 26% for ‘Premier Russet’. The RARs correlated with total sugar (Suc + Glc + Fru) accumulation during LTS and likely reflected the metabolic energy required to catabolize starch to Suc, Glc and Fru. The relative ratio of Fru/Glc was also demonstrative of LTS-resistance, discriminating genotypes that accumulated Suc versus RS under LTS conditions. Changes in carbohydrates, invertase, respiration rates and RARs in response to temperature over the wound healing, LTS and reconditioning phases of storage characterized the LTS phenotypes unique to each cultivar, and revealed different mechanisms of resistance to LTS.  相似文献   

4.
‘Black Splendor’ (BS) and ‘Royal Rosa’ (RR) plums were treated preharvest with methyl jasmonate (MeJA) at three concentrations (0.5, 1.0 and 2.0 mM) along the on-tree fruit development: 63, 77 and 98 days after full blossom (DAFB). Both control and treated fruit were harvested at the commercial ripening stage and stored in two temperature conditions: 9 days at 20 °C or at 2 °C + 1 day at 20 °C for 50 days. Preharvest MeJA at 2.0 mM significantly accelerated whereas 0.5 mM delayed the postharvest ripening process for both cultivars, since ethylene production, respiration rate and softening were reduced significantly at the two storage conditions for 0.5 mM. In these fruit, total phenolics, total antioxidant activity (hydrophilic fraction, HTAA) and the antioxidant enzymes peroxidase (POD), catalase (CAT) and ascorbate peroxidase (APX) were found at higher levels in treated than control plums during postharvest storage, which could account for the delay of the postharvest ripening process and the extension of shelf-life.  相似文献   

5.
The effect of exogenous oxalic acid treatment on ripening attributes of banana fruit during storage was investigated. Banana fruit were dipped into solutions of 0 (control) or 20 mM oxalic acid for 10 min and then stored at room temperature (23 ± 2 °C) and 75–90% relative humidity. The application of oxalic acid reduced fruit deterioration during storage. The oxalic acid treatment also reduced the rates of respiration and ethylene production, and delayed the decreases in firmness, hue angle, and maximal chlorophyll fluorescence (Fv/Fm) of banana fruit during storage. Furthermore, fruit treated with oxalic acid exhibited higher superoxide dismutase activity and antioxidant capability with a lower production of reactive oxygen species at the late storage period compared with non-oxalic acid-treated fruit. Overall, the oxalic acid treatment was effective in inhibiting postharvest ripening of banana fruit and exhibited the potential for commercial application to store the bananas at room temperature. It can be concluded that the delay in banana fruit ripening associated with oxalic acid treatment could be due to inhibition of respiration and ethylene production rates, and reduction of oxidative injury caused by reactive oxygen species through increased antioxidant activity.  相似文献   

6.
Most sweet cherries produced in the US Pacific Northwest and shipped to distant markets are often in storage and transit for over 3 weeks. The objectives of this research were to study the effects of sweet cherry storage O2 and CO2 concentrations on the respiratory physiology and the efficacy of modified atmosphere packaging (MAP) on extending shelf life. Oxygen depletion and CO2 formation by ‘Bing’ and ‘Sweetheart’ cherry fruit were measured. While respiration rate was inhibited linearly by reduced O2 concentration from 21% to 3–4% at 20 °C, it was affected very little from 21% to ∼10% but declined logarithmically from ∼10% to ∼1% at 0 °C. Estimated fermentation induction points determined by a specific increased respiratory quotient were less than 1% and 3–4% O2 for both cultivars at 0 and 20 °C, respectively. ‘Bing’ and ‘Sweetheart’ cherry fruits were packaged (∼8 kg/box) in 5 different commercial MAP box liners and a standard macro-perforated polyethylene box liner (as control) and stored at 0 °C for 6 weeks. MAP liners that equilibrated with atmospheres of 1.8–8.0% O2 + 7.3–10.3% CO2 reduced fruit respiration rate, maintained higher titratable acidity (TA) and flavor compared to control fruit after 4 and 6 weeks of cold storage. In contrast, MAP liners that equilibrated with atmospheres of 9.9–14.4% O2 + 5.7–12.9% CO2 had little effect on inhibiting respiration rate and TA loss and maintaining flavor during cold storage. All five MAP liners maintained higher fruit firmness (FF) compared to control fruit after 6 weeks of cold storage. In conclusion, storage atmospheres of 1.8–14.4% O2 + 5.7–12.9% CO2 generated by commercial MAP, maintained higher FF, but only the MAP with lower O2 permeability (i.e., equilibrated at 1.8–8.0% O2) maintained flavor of sweet cherries compared to the standard macro-perforated liners at 0 °C. MAP with appropriate gas permeability (i.e., equilibrated at 5–8% O2 at 0 °C) may be suitable for commercial application to maintain flavor without damaging the fruit through fermentation, even if temperature fluctuations, common in commercial storage and shipping, do occur.  相似文献   

7.
8.
Button mushrooms (Agaricus bisporus) were dipped for 2 min in different concentrations (1%, 2% and 3%) of alginate, then placed in jars and ventilated continuously with 100% O2 for up to 16 d at 4 °C. Mushroom respiration rate, weight loss, texture, color, percent open caps, chemical properties and activities of polyphenol oxidase (PPO), and peroxidase (POD) were measured. The results indicate that treatment with alginate coating (2%) + 100% O2 maintained a high level of firmness, and delayed browning and cap opening. In addition, alginate coating (2%) + 100% O2 also delayed changes in the soluble solids concentration, total sugars and ascorbic acid, and inhibited the activity of PPO and POD throughout storage. Our study suggests that the use of alginate coating under a high oxygen modified atmosphere has the potential to maintain button mushroom quality and extend its postharvest life to 16 d.  相似文献   

9.
Shiitake (Lentinus edodes) mushrooms were exposed to UV-C light (4 kJ/m2) and stored in modified atmosphere packaging (MAP) prior to 15 days at 1 ± 1 °C and 95% relative humidity plus 3 days at 20 °C. Mushroom firmness, total phenolics, total flavonoids, ascorbic acid and H2O2 contents, superoxide anion (O2) production rate and activities of catalase (CAT), superoxide dismutase (SOD), ascorbate peroxidase (APX) and glutathione reductase (GR) were measured. UV-C treatment resulted in maintenance of a high level of firmness during 15 days at low temperature and reduced the decrease in firmness during shelf-life storage. Furthermore, treated samples showed higher total flavonoids, ascorbic acid, and delayed the increases in both O2 production rate and H2O2 contents. However, no clear treatment effects were seen in total phenolics contents. The treatment also increased the antioxidant enzyme activities of CAT, SOD, APX and GR throughout the storage period. These results indicate that postharvest application of UV-C radiation can delay softening and enhance antioxidant capacity in shiitake mushrooms.  相似文献   

10.
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   

11.
Hexanal vapour and intact tomatoes were used as models to assess the opportunities for control of Botrytis cinerea rots by controlled release of organic vapours. Hexanal vapour concentrations in the ranges 5–270 μL L−1 were applied continuously or as a single dose at the start of storage. The postharvest microbiological, physiological and quality attributes of control and hexanal treated tomatoes were investigated during storage for 7 days at 20 ± 1 °C and ∼99% RH. Continuous hexanal exposure effectively suppressed grey mould with the minimum inhibitory concentration (MIC) being 40–70 μL L−1; the single-dose treatment showed minimal antifungal activity. During continuous exposure at the MIC the fruit respiration rate was increased ∼50% and reddening was slowed. No clear trend was observed in ethylene production and treated fruit did not differ from the controls in firmness or mass loss. The controlled release of low concentrations of hexanal vapour into a packaging headspace appears a feasible mechanism for prolonging tomato storage life.  相似文献   

12.
This article studies the efficacy of an edible coating based on Aloe vera gel at four different concentrations (0, 1, 5, 15% (v/v)) in maintaining the quality of fresh-cut kiwifruit. The kiwifruit slices were packaged under passive atmosphere and stored at 4 ± 1 °C. Quality attributes such as colour and texture (firmness and texture profile analysis), titratable acidity, total soluble solids, pectin content, microbial load and sensory parameters were evaluated during storage. In general, Aloe vera coating reduced respiration rates and microbial spoilage in sliced kiwifruit. After seven days of storage, the mesophilic load dropped by approximately one logarithmic unit for slices coated with 15% and 5% Aloe vera. Total pectin depolymerization was also lower in the treated samples and the texture of the uncoated samples deteriorated more rapidly than the treated slices during storage. Furthermore, due to the atmospheric composition and the microbial load, the quality of the control samples declined after six days of storage. Our results show that an Aloe vera coating improved the quality of stored kiwifruit slices. The best results obtained in the instrumental texture profile and in the preference panel test were with the 5% coating, indicating that this may be a healthy alternative coating for fresh-cut kiwifruit.  相似文献   

13.
Burdock roots were stored for six weeks at three temperatures, 0, 15 and 20 °C, and activity of sucrose hydrolase (SH), 1-kestose hydrolase (1-KH), inulin hydrolase (InH), sucrose:sucrose 1-fructosyltransferase (1-SST) and fructan:fructan 1-fructoslytransferase (1-FFT) were assessed. Simultaneously, total fructooligosaccharides (FOS), total inulooligosaccharides (IOS) and inulin were also assessed during storage. During storage, SH showed an irregular variation at 15 and 20 °C, and was significantly higher at 0 °C showing a continuous increase during the storage period. 1-KH decreased progressively at 15 and 20 °C, but showed a sharp increase at 0 °C after two weeks and decreased afterwards. InH showed a different although more regular pattern by decreasing progressively at 0, 15 and 20 °C. However, the decrease was more significant at 15 and 20 °C during the first two weeks, while at 0 °C the decrease was significant after four weeks storage. 1-SST and 1-FFT activities decreased progressively in a pseudo-linear regression during storage, and showed similar patterns. At 15 and 20 °C, total FOS increased during the first three weeks then decreased, while at 0 °C FOS increased progressively during storage. Total IOS increased during storage, however, this increase was much higher at 0 °C than that observed at 15 and 20 °C. Inulin content decreased during storage and final content was lower at 20 °C. The inulin to total FOS plus total IOS ratio decreased sharply during the first two weeks of storage, then progressively during the last four weeks, while the ratio of hydrolyzing to synthesizing activities was quite stable at 15 and 20 °C, but showed a peak at 0 °C after two weeks. The results suggest that carbohydrate metabolism in stored burdock depends partly on temperature and other physiological factors.  相似文献   

14.
15.
The influence of light on fresh-cut vegetables during storage is controversial, since both positive and negative effects on shelf-life and quality of such products have been observed. In this work, the effect of low-intensity light treatments on lamb's lettuce, a fresh-cut leafy and ready-to-eat vegetable, was investigated during storage at low temperature (6 °C), in comparison with conventional storage (in the dark at 4 °C). Although continuous light treatment (1 cycle of 8 h per day) was deleterious, cycles of light treatments (8 cycles of 1 h per day; 16 cycles of 0.5 h per day) showed positive effects, assessed by evaluating the content of chlorophylls, carotenoids, ATP, glucose and ascorbate. These analyses were performed at the beginning and after 6 days of storage, in comparison with samples stored in the dark at 4 °C. Under low-intensity light treatments, even if performed at a higher temperature (6 °C), the content of such bioactive compounds increased or was at least similar to that found in samples stored in the dark at the same temperature. We suggest that continuous low-intensity light treatments during cold storage of lamb's lettuce are able to promote photosynthesis but, at the same time, induce photo-damage. On the contrary, under intermittent low-intensity light cycles, photosynthesis is only partially activated, while the metabolism of the green tissues is still able to provide carbon moieties for the synthesis of bioactive molecules involved in delaying senescence. Therefore, low-intensity light cycles at 6 °C could contribute to maintain quality of lamb's lettuce, with respect to samples stored in the dark at both 6 and 4 °C. Finally, setting the temperature at 6 °C allows reduction of refrigerator energy consumption during storage.  相似文献   

16.
The main problem affecting the quality of fresh-cut sunchoke tubers is cut surface discoloration. Pre- and post-cutting hot water and ethanol treatments were evaluated for their potential to inhibit discoloration, color changes, and associated phenolic metabolism in tuber slices stored in air at 5 °C. Some of the treatments tested inhibited discoloration and changes in a* and hue color values. Slices that were post-cut treated with hot water at 50 °C for 6–8 min or 55 °C for 3–4 min and pre-cut treated with water at 50 °C for 20–25 min maintained good color for 8–12 days at 5 °C. Post-cut ethanol fumigation (150–750 μL/L for 5 h at 5 °C) can prevent discoloration for 30 d at 5 °C. Post-cut dips with ethanol solutions (3, 5, 8 or 10% for 5 min) increased shelf-life twofold or longer compared to untreated slices. Ethanol fumigation retarded the onset of wound-induced respiration rates as well as reducing maximum rates. A post-cut 10% ethanol dip also reduced respiration rates and reduced PAL activity and total phenolics. Ethanol dips had no effect and hot water treatments had no persistent effect on microbial loads over 12 d.  相似文献   

17.
The influence of the first and second cutting at harvest on the physiological response of four baby leaf Brassica species was studied. The species were salad rocket (Eruca vesicaria), wild rocket (Diplotaxis tenuifolia), mizuna (Brassica rapa L. ssp. nipposinica) and watercress (Nasturtium officinale) stored at 1, 4, 8 and 12 °C. In addition, the microbial and metabolic behaviours of baby leaves were evaluated after different washing treatments including water, ozonated water (10 mg L−1 total dose), ozonated water activated with ultraviolet C light (UV-C) and heat shock wash (50 °C, 1 min). Temperature had a significant effect on both respiration rate and post-cutting life. The production of CO2 increased between 2- and 4-fold when temperature increased from 1 to 12 °C. Minor differences in leaf respiration rate between the first and second leaf cutting were observed for salad rocket and wild rocket, while leaves from the second cutting of mizuna and watercress leaves had a higher respiration rate than from the first cutting. Ozone, and ozone combined with UV-C, were the most efficient washing treatments in reducing total mesophilic counts, while heat shock treatment did not affect them. Additionally, naturally occurring Listeria spp. were controlled well in wild rocket and mizuna (<1 log cfu g−1) when the ozone treatments were applied. On the other hand, respiration rates of the Brassica species were not substantially affected by the washing treatments when stored at 4 °C. Maximum CO2 production was observed immediately after washing but decreased during the first 24 h of storage. Baby leaves washed with cold water consistently showed a lower respiration rate than the other washing treatments. Heat shock was the washing treatment that most influenced the increase in the respiration rate of baby leaves during storage at 8 °C.  相似文献   

18.
Experiments were conducted to examine softening and quality responses of harvested banana fruit to cold shock treatment intended to extend shelf-life. Fruit were immersed in ice-water for 1 h, then treated with or without 100 μL L?1 ethylene for 24 h at 24 °C, and finally stored at 20 °C. Fruit firmness, chlorophyll content, ethylene production, respiration rates, contents of pectin, starch and sugar, and the activities of the cell wall modifying enzymes polygalacturonase (PG), pectin methylesterase (PME) and CMCase (cellulase, endo-1,4-β-glucanase) were analyzed. Total amylase activity was also measured. Immersion in ice-water for 1 h effectively inhibited ripening-associated processes, including peel de-greening and pulp softening during storage or ripening. The delay in ripening was also manifest in reduced ethylene production and respiration rates. The inhibition of softening by cold shock treatment was related to decreased PG and PME activities, that is, retardation of pectin solubilization/degradation. Reduced activities of CMCase and total amylase and conversion of starch to sugar by ice-water immersion also contributed to the delay in softening of harvested banana fruit.  相似文献   

19.
Ethylene action can be counteracted by 1-methylcyclopropene (1-MCP), which has been used during postharvest storage to maintain quality. In this work, we evaluated the effect of 1-MCP treatments on eggplant quality and phenolic metabolism during refrigerated storage. Eggplants (cv. Lucía) were harvested at commercial maturity, treated with 1-MCP (1 μL/L, 12 h at 20 °C), stored at 10 °C for 21 d and subsequently held at 20 °C for 2 d. Corresponding controls were stored at 10 °C and then transferred to 20 °C for 2 d. During storage calyx color, damage and chlorophyll content, fruit weight loss and firmness, pulp sugar content, acidity, browning and total phenolics were measured. In addition, polyphenol oxidase (PPO), pyrogallol peroxidase (POD), and phenylalanine ammonia-lyase (PAL) activities were evaluated. Fruit calyxes showed reduced damage and remained greener in 1-MCP treated than in control fruit. 1-MCP treated eggplants showed lower weight loss. Pulp browning was clearly prevented as a consequence of 1-MCP exposure, and this was associated with delayed senescence, lower accumulation of total phenolics and reduced activity of PAL. The activity of the enzymes PPO and POD involved in the oxidation of phenolics compounds was also decreased in 1-MCP treated fruit. Results suggest that 1-MCP treatments delay senescence, prevent browning and are beneficial to complement low temperature storage and maintain quality of non-climacteric eggplant fruit.  相似文献   

20.
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   

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