A simple pretreatment with low O2 to alleviate superficial scald in Granny Smith apples

Sealing Granny Smith apples in a low‐O₂ atmosphere for 7 days at 20 °C (LO₂‐20C) prior to cold storage reduced superficial scald development after 6 and 8 months at 0 °C plus 10 days at 20 °C. This LO₂‐20C treatment reduced the O₂ levels that induce endogenous production of significant amounts of CO₂, acetaldehyde and ethanol, and thereby reduced ethylene production in cold storage, which in turn reduced scald development. Treatment with ethanol vapour (20 mL L^?1) for 1 day at 20 °C plus 6 days at 1 °C or with low O₂ for 1 day at 20 °C plus 6 days at 1 °C (LO₂‐1C) did not reduce scald effectively. 1‐Methylcyclopropene (1‐MCP) treatment at 0.5 µL L^?1 was the most efficient at reducing scald development. In all treatments, superficial scald development proceeded from the distal blossom end towards the proximal stem end of fruits. After 6 months of cold storage at 0 °C, peel browning and membrane leakage, measured as electrical conductivity in situ, were greater at the blossom end than at the stem end of control, ethanol‐ and LO₂‐1C‐pretreated fruits. In LO₂‐20C‐ and 1‐MCP‐pretreated fruits, colour indices (hue angle, lightness and chroma) and electrolyte leakage were similar at both the stem and blossom ends and were associated with less scald development after 6 months at 0 °C. The reduction in scald development was also associated with lower peroxidase and polyphenol oxidase activities in the peel of LO₂‐20C‐ and 1‐MCP‐pretreated fruits. A simple treatment at 20 °C (LO₂‐20C) prior to regular cold storage could also be suitable for organically grown apples that cannot be treated with diphenylamine or 1‐MCP. Copyright © 2007 Society of Chemical Industry     

Pre‐harvest application of calcium to control black heart disorder in Mauritius pineapples during low‐temperature storage

The chill‐sensitive pineapple cv. Mauritius grown in Sri Lanka was subjected to different pre‐harvest calcium treatments in order to determine an effective means of increasing calcium levels in the fruit, thereby reducing the incidence and severity of black heart disorder. Treatments of CaO and CaSO₄ (10 g and 15 g per plant) were applied to soil as side dressing 6 weeks after planting, while CaCl₂ (1.3 g and 2 g per fruit) were applied as a spray treatment to 1‐month‐old fruit (red bud stage). Fruit were harvested at the 10–20% yellow stage of maturity. Incidence of black heart disorder and observations on total acids, °Brix, ascorbic acid content and total calcium levels were recorded on waxed and unwaxed fruit before and after 17 days storage at 10 °C and 85–90% relative humidity, followed by 2 days at ambient temperature 28 ± 2 °C. Combined treatment of pre‐harvest CaCl₂ fruit spray (1.3 g per fruit) followed by post‐harvest wax treatment showed 80% good fruit with no black heart symptoms after low‐temperature storage at 10 °C for 17 days followed by 2 days at ambient temperature of 28 ± 2 °C. However, side dressings of CaO and CaSO₄ were found to be less effective in reducing the symptoms, showing less than 30% of good fruit without black heart symptoms. Both core and flesh regions of pineapples subjected to pre‐harvest fruit spray treatment showed higher total calcium levels compared to controls as well as other calcium treatments. Results obtained from the field experiment confirmed that the calcium chloride fruit spray treatment of 1.3 g per fruit in three split doses at 2‐week intervals could be used to reduce the incidence of black heart disorder in Mauritius pineapples. Copyright © 2005 Society of Chemical Industry     

1‐Methylcyclopropene affects the antioxidant system of apricots (Prunus armeniaca L. cv. Búlida) during storage at low temperature

BACKGROUND: Apricots (Prunus armeniaca cv. Búlida) were treated with 1 mL L^?1 1‐methylcyclopropene (1‐MCP) immediately after harvest and stored in air at 2 °C for 21 days. Antioxidant levels (ascorbic acid and carotenoids), enzymatic antioxidant activities (superoxide dismutase (SOD) and unspecific peroxidase (POX)) and total antioxidant capacity (trolox equivalent antioxidant capacity (TEAC)) were determined. The level of oxidative stress was also established by measuring ion leakage during storage. The changes in the antioxidant potential of apricots were related to the capacity of 1‐MCP to increase their commercial life. RESULTS: 1‐MCP‐treated fruits exhibited higher SOD activity, whereas POX activity was significantly higher only after 21 days at 2 °C. Treated fruits also exhibited better retention of ascorbate and carotenoids and higher TEAC during storage. In accordance with these observations, lower ion leakage values were detected in 1‐MCP‐treated apricots. CONCLUSION: Taken together, these results suggest that 1‐MCP conferred a greater resistance to oxidative stress. This, along with the reduction in ethylene production, could contribute to the increase in commercial life and nutritional value observed in 1‐MCP‐treated apricots. Copyright © 2010 Society of Chemical Industry     

Effect of storage on the bioactive compounds and antioxidant activity of quince nectar

The changes of bioactive components and antioxidant activity of quince nectar were determined during 9 months of storage at 5, 20, 30 and 40 °C. The amount of total phenolics, flavonoids and antioxidant activity was significantly declined during storage at all temperatures. Loss of L‐ascorbic acid at 5, 20, 30 and 40 °C was 32.08%, 43.69%, 65.21% and 88.82%, respectively. L‐ascorbic acid degradation was in accordance with the first‐order reaction kinetics, and activation energy was found as 43.65 kJ mol^?1. After 9 months of storage, Hydroxymethylfurfural (HMF) contents of quince nectars were 15.01, 16.64, 21.69 and 57.89 mg kg^?1 at 5, 20, 30 and 40 °C, respectively. HMF accumulation fitted a zero‐order kinetic model, and activation energy was found as 88.30 kJ mol^?1. A significant correlation was found among L‐ascorbic acid, total phenolics, flavonoids and antioxidant activity.     

An integrated strategy to control post-harvest decay of Embul banana by combining essential oils with modified atmosphere packaging

Mature Embul (Musa, AAB) bananas were treated with emulsions of either cinnamon bark or leaf (Cinnamomum zeylanicum) or clove (Syzygium aromaticum) oils to control post‐harvest diseases, packed under modified atmosphere (MA) using low‐density polyethylene (0.075 mm, LDPE) bags, and stored in a cold room (14 ± 1 °C, 90% RH) or at ambient temperature (28 ± 2 °C). The effects of the essential oils on post‐harvest diseases; physico‐chemical properties and organoleptic properties were determined and compared with controls and bananas treated with benomyl. Treatments with cinnamon bark and leaf oils controlled crown rot, whereas clove oil treatment did not affect crown rot development. Treatment with emulsions of cinnamon oils combined with MA packaging can be recommended as a safe, cost‐effective method for extending the storage life of Embul bananas up to 21 days in a cold room and 14 days at 28 ± 2 °C without affecting the organoleptic and physico‐chemical properties.     

Improving the application of gibberellic acid to prolong dormancy of yam tubers (Dioscorea spp)

With the aim of reducing the cost and time needed to treat yam tubers with gibberellic acid (GA₃), this study compared several new methods of application with the established dipping procedure (150 mg kg^?1 for 1 h). Both GA₃‐containing soil paste (25 mg kg^?1) and gelatinized starch (860 mg kg^?1) were applied to tuber heads of Dioscorea alata and D cayenensis‐rotundata in the Ivory Coast. Soil paste, gelatinized starch and dipping consistently prolonged dormancy and reduced fresh matter losses by 23–39% in D cayenensis‐rotundata 3‐year means. Although dipping reduced the storage losses most efficiently, soil paste and gelatinized starch used considerably less GA₃. Both new treatments were easily prepared and quickly applied. Soil paste was most effective when the treatment was repeated before the end of dormancy. The third new method, spraying the tubers with a GA₃ solution (150 mg kg^?1), was not effective. In general, the optimal time of application was immediately post‐harvest. For D alata, treatment only 1 month after harvest was particularly ineffective, whereas D cayenensis‐rotundata tubers could be treated with some effect up to the end of dormancy. To achieve extended storage periods of healthy tubers of D cayenensis‐rotundata, GA₃ application may be recommended as post‐harvest practice. Copyright © 2003 Society of Chemical Industry     

1-MCP Treatment Prolongs Postharvest Life of 'Santa Rosa'Plums

'Santa Rosa’plums were treated with concentrations of 0‐ (control), 0.5‐, or 0.75‐μL/L 1‐methylcyclopropene (1‐MCP) for 24 h at 1°C and stored at 1 °C for up to 40 d. Ethylene and CO₂ production, firmness, weight loss, Brix, acidity, color evolution, and ethanol and acetaldehyde concentrations were determined periodically after cold storage and after subsequent shelf life of 5 and 8 d at 20 °C. 1‐MCP strongly inhibited ethylene and CO₂ production. Higher values of firmness were observed in 1‐MCP‐treated plums compared with control. 1‐MCP treatment delayed color evolution, reduced acidity loss, and inhibited ethanol and acetaldehyde production. 1‐MCP did not affect weight loss or sugar content.     

Effects of Growth Regulators on Quality of Ripe Peach Fruit: Discoloration of Canned Peaches

Harvester and Alred Elberta peach trees (Prunus persica (L) Batsch) were sprayed with either daminozide [butanedioic acid mono (2,2-dimethylhydrazide)], ethephon [(2-chloroethyl)phosphonic acid] or GA₄₊₇ (gibberellin GA₄₊₇). Following harvest, treatments were sorted subjectively on the basis of ground color and surface firmness. Firm ripe fruit were placed in 4°C storage, green fruit were held at 23–27°C until ripe (usually 2–3 days). Ripeness was therefore removed as a factor of chemical composition. No differences in skin color were found by instrumental measurements, confirming uniformity of that parameter of ripeness. There were no significant differences among fresh fruit treatments in soluble solids, ascorbic acid content, flesh color, or rate of browning. However, canned product from the ethephon treatment lot was markedly discolored.     

Postharvest response of ‘Brown Turkey’ figs (Ficus carica L.) to the inhibition of ethylene perception

The potential use of 1‐methylcyclopropene (1‐MCP) alone or as a supplement to cold storage to delay the softening of ‘Brown Turkey’ figs (Ficus carica L.) was studied. Figs were treated with 0, 0.25, 0.5 or 5 µl l^?1 1‐MCP at 25 °C for 8 h and stored at 20 °C until evaluated. Figs treated with 0.5 or 5 µl l^?1 1‐MCP had higher ethylene production and respiration rates but slower softening than untreated fruit and those treated with 0.25 µl l^?1 1‐MCP. Early‐harvested firm figs and late‐harvested soft figs were untreated or treated with 0.5 or 5 µl l^?1 1‐MCP at 25 °C and stored at 0 °C for 19 days. Firm figs treated with 1‐MCP showed an early peak in ethylene synthesis, higher respiration rate and were firmer than control fruit. In contrast, soft figs did not respond to 1‐MCP except for a late increase in respiration rates of fruit treated with 5 µl l^?1 1‐MCP. 1‐MCP appeared to have a relatively limited effect on slowing ripening of ‘Brown Turkey’ figs and its effect was influenced by ripening stage. Copyright © 2005 Society of Chemical Industry     

Maintaining quality and bioactive compounds of broccoli by combined treatment with 1‐methylcyclopropene and 6‐benzylaminopurine

BACKGOUND: Broccoli deteriorates very quickly after harvest at ambient temperature due to the loss of green colour and the consequent yellowing of florets. To search for an effective method to control quality deterioration, the effect of 1‐methylcyclopropene (1‐MCP) combined with 6‐benzylaminopurine (6‐BA) treatment on visual quality, antioxidant enzymes and bioactive compounds in broccoli florets were investigated. RESULTS: A combined treatment of 2.5 µL L^?1 1‐MCP and 200 mg L^?1 6‐BA significantly reduced the increase of lightness (L*) value, and retained a high level for the hue value (H) and chlorophyll content. Superoxide dismutase, ascobate peroxidase and catalase activities increased while the activity of peroxidase decreased during storage in treated samples in comparison with the controls. The combined treatment enhanced the biosynthesis of glucosinolate and the formation of the anticarcinogen sulforaphane, which improved the health benefit of broccoli. CONCLUSION: These results indicate that a combined treatment of 1‐MCP and 6‐BA could be a good candidate for maintaining the visual quality and enhancing the nutritional value in broccoli during storage at 15 °C. © 2012 Society of Chemical Industry     

Formulation of monodisperse oil‐in‐water emulsions loaded with ergocalciferol and cholecalciferol by microchannel emulsification: insights of production characteristics and stability

Nutritional deficiencies of ergocalciferol (VD₂) and cholecalciferol (VD₃) cause skeletal deformations. The primary aim of this study was to encapsulate VD₂ and VD₃ in food‐grade oil‐in‐water (O/W) emulsions by using microchannel emulsification (MCE). Silicon asymmetric straight‐through microchannel (MC) array consisting of 10 313 channels, each having an 11 × 104 μm microslot connected to a 10 μm circular microholes. 1% (w/w) sodium cholate or Tween 20 in water was used as the continuous phase, while 0.5% (w/w) of each VD₂ and VD₃ in different oils served as the dispersed phase. Monodisperse O/W emulsions with Sauter mean diameters of 28 to 32 μm and relative span factor widths below 0.3 were formulated via an asymmetric straight‐through MC array under appropriate operating conditions. The monodisperse O/W emulsions stabilised with Tween 20 remained stable for >30 days with encapsulation efficiencies (EEs) of VD₂ and VD₃ of above 70% at 4 and 25 °C. In contrast, those stabilised with sodium cholate had stability of >30 days with their EEs of over 70% only at 25 °C.     

Effect of pre‐ripening chilling temperatures on ripening,shelf life and quality of bananas treated with 1‐methylcyclopropene

Ethylene production, shelf life and fruit quality of Cavendish bananas (cv. Williams), held at different pre‐ripening storage temperatures (5 °C, 10 °C or 15 °C) prior to ethylene and/or 1‐methylcyclopropene (1‐MCP) application, were determined and compared. Levels of ethylene production during ripening were highest for control fruit that had been stored at 5 °C followed by 10 °C and then 15 °C. 1‐MCP treatment (at 300 nL L^?1) had no effect on ethylene production of fruit that had been stored at 10 °C by day 10 of storage, but ethylene production was significantly higher for fruit that had been stored at 15 °C and lower for those stored at 5 °C before 1‐MCP treatment. 1‐MCP also increased shelf life to a greater extent when applied to fruit that had been stored at 10 °C or 15 °C. Even though 1‐MCP had no significant effect on under peel chilling injury, it increased discolouration significantly, regardless of storage temperature. Firmness of 1‐MCP‐treated fruit decreased significantly compared to the control when fruit were held at 5 °C or 15 °C prior to ripening (and 1‐MCP application) but had no effect on fruit stored at 10 °C before ripening. These results indicate that pre‐ripening storage temperature affects ripening, shelf life and quality in both ethylene and 1‐MCP‐treated bananas.     

Effect of heat treatment on internal atmosphere and leaf extension of minimally processed leek stalks

Leeks trimmed at 20 cm from their base were immersed in a 55 °C hot water bath. During the heat treatment (HT), the internal gases released from each stalk were collected, and their volume as well as CO₂ and O₂ concentrations were determined. After HT, cooling and storage at 10 °C for 8 days, the weight, maximum leaf extension and internal atmosphere (volume and gas composition) were measured. It was found that HT inhibited leaf extension during storage at 10 °C for 8 days and induced significant modification of the stalk internal atmosphere, both immediately after HT and after storage. Therefore, in heat‐treated leek stalks, the growth zone of the innermost leaves was subjected to an environment of elevated CO₂ concentration, which was accompanied by the inhibition of leaf extension growth.     

Antifungal activity of chitosan and its application to control post‐harvest quality and fungal rotting of Tankan citrus fruit (Citrus tankan Hayata)

In this study, the antifungal activity of chitosan A (MW = 92.1 kDa) and B (MW = 357.3 kDa), with 94.2% N‐deacetylation were examined at various concentrations against fungi including Penicillium digitatum, Penicillium italicum, Botrydiplodia lecanidion and Botrytis cinerea. The effectiveness of these chitosans to control the post‐harvest quality of Tankan fruit, a popular sub‐tropical citrus fruit, was investigated. It was found that chitosan, depending on type and concentration, caused 25.0–90.5% growth inhibition on test organisms after 5 days of cultivation at 24 °C. Chitosan treatment significantly reduced (P < 0.05) the percentage decay of Tankan fruit during storage at 24 °C. After 42 days of storage at 13 °C, chitosan‐coated Tankan fruits were firmer, exhibited less decay and weight loss, and showed higher titratable acidity, ascorbic acid, and total soluble solids than the control fruit. Weight loss of Tankan fruits decreased as the concentration of chitosan was increased. On the other hand, chitosan A, regardless of concentration tested, was found to be more effective in retaining the firmness, titratable acidity and water content, total solid content and ascorbic acid content of Tankan fruits than chitosan B. Copyright © 2006 Society of Chemical Industry     

Short anaerobiosis period prior to cold storage alleviates bitter pit and superficial scald in Granny Smith apples

BACKGROUND: Californian Granny Smith apples are very susceptible to bitter pit (BP) and superficial scald symptoms that develop during cold storage. The main preventive means are diphenylamine dipping and/or gaseous application of the ethylene inhibitor 1‐methylcylclopropene (1‐MCP), which is effective against superficial scald but not against BP. This study investigated the efficacy of a non‐chemical alternative, low‐O₂ (LO2) stress, in preventing these two physiological disorders. RESULTS: Application of LO2 stress at 20 °C for 10 days prior to cold storage of Granny Smith apples reduced superficial scald and BP incidence and severity during 8 months at 0 °C. LO2 treatments induced volatile alcohols and reduced ethylene and 6‐methyl‐5‐hepten‐2‐one (MHO‐on) production, thereby reducing superficial scald development after 4 months at 0 °C. In addition, LO2‐treated fruits had higher pectin methyl esterase (MdPME) gene expression, similar to that of 1‐MCP‐treated fruits, associated with their higher firmness. Conversion of MHO‐on to 6‐methyl‐5‐hepten‐2‐ol (MHO‐ol) in LO2‐treated fruits may explain the lower scald development. CONCLUSION: The ratio between MHO‐on and MHO‐ol might serve as an index of superficial scald severity. Reduction of BP symptoms in LO2‐treated fruits could be due to accumulation of volatile alcohols in the peel tissue. Copyright © 2010 Society of Chemical Industry     

Stability of anthocyanins and ascorbic acid in sonicated strawberry juice during storage

The stability of anthocyanins and ascorbic acid in sonicated strawberry juice during storage was investigated. Strawberry juice was sonicated at varying acoustic energy densities (AEDs) ranging from 0.33 to 0.81 W/mL and treatment times of 0–10 min. The degradation kinetics of sonicated samples followed first-order kinetics. Degradation rate constants were linearly correlated with AED (R ² > 0.91). Selected samples were stored for 10 days at 4 and 20 °C. A second-order polynomial model was employed to investigate the effects of storage time and processing variables. During storage higher loses were observed at a storage temperature of 20 °C compared to 4 °C. Predictive models developed for anthocyanins and ascorbic acid content were highly significant (P < 0.0001) and closely correlated to the experimental data (R ² > 0.91). Degradation mechanisms for anthocyanins and ascorbic acid due to sonication and storage are proposed.     

Acid hydrolysis of kappa‐carrageenan as a way of gaining new substances for freezing process modification and protection from excessive recrystallisation of ice

The effects of κ‐carrageenan and its hydrolysates on modification of the freezing process and also on inhibition of excessive recrystallisation of ice in sucrose solutions during storage were compared. Acid hydrolysis of κ‐carrageenan was carried out using sulphuric (H₂SO₄) and hydrochloric acid (HCl). Most effective in the hydrolysis process turned out to be H₂SO₄, which degraded κ‐carrageenan to a molecular mass of around 3 × 10⁶ Da, after 1.5 h of hydrolysis. Addition of 0.005% of the new poligeenan (degraded carrageenan), to a sucrose solution (30%), frozen at ?20 °C, caused a nearly 50% reduction in the phase‐change stages, and consequently, the total time of freezing was shorter. Significant retardation of recrystallisation was observed for both types of poligeenan, but a stronger effect was observed for the oligosaccharides obtained after HCl hydrolysis, and after 96 h of storage at ?8 °C, the equivalent diameter of ice crystals was not greater than 11 μm.     

Combined effect of microwave and ultrasonication treatments on the quality and stability of sugarcane juice during cold storage

The main objective of this study was to investigate the combined effect of microwave (MW) treatment (2450 MHz for 120 s), ultrasonication (US) (24 KHz, 20 °C for 20 min) and combined treatment (MW-US) on the quality and stability of sugarcane juice (SCJ) during 21 days of storage at 4 °C. The effect of the treatments and storage time on physicochemical, bioactive compounds (total phenolic, flavonoids and ascorbic acid content) and microbial analysis of SCJ. No significant (P < 0.05) changes were observed in °Brix, while there was an increase in pH and a decrease in titratable acidity in all treatments. Compared to US and MW, MW-US treatments was more effective in preserving colour attributes, total phenolic and flavonoids contents, ascorbic acid and antioxidant capacities of the SCJ during storage. The results regarding the microbial count indicate that more microbial safety and longer shelf life was achieved by MW-US. MW-US treatment is an effective technology for improving the safety and shelf life of SCJ by minimising quality changes, retaining bioactive compounds and reducing microbial growth during storage.     

Effects of initial low oxygen and perforated film package on quality of fresh‐cut cabbages

The effects of perforated film packages (PFP) with different oxygen partial pressures (5, 8 and 10 kPa) and a barrier package (BP) at 21 kPa of O₂ on the quality of fresh‐cut cabbages were studied at 5 and 20 °C. The microbial growth, appearance, flavor, ascorbic acid content and polyphenol oxidase activity were determined during storage. The results indicated that fresh‐cut cabbages had better color retention and quality in PFP. Oxidation of ascorbic acid (AA) and browning of fresh‐cut cabbage were inhibited effectively using a PFP and an initial oxygen partial pressure equal to 5 kPa. Analysis of microbial growth also showed that the total count on fresh‐cut cabbage was relative lower in PFP with an initial low O₂ content. Loss of total ascorbic acid was much lower in PFP than that in BP by suppressing AA oxidation. The results of sensory evaluation showed that flavor and appearance were maintained effectively at 5 °C and significant differences in flavor were found between PFP and BP both at 5 and 20 °C, while significant differences in appearance were found between PFP and BP only at 20 °C. Copyright © 2007 Society of Chemical Industry