Days Of Cold Storage Research Articles

Changes in the content of water-soluble vitamins in Actinidia chinensis during cold storage

We assessed the effects of cold storage on nine water-soluble vitamins in 7 cultivars of Actinidia chinensis (kiwifruit) using high-performance liquid chromatography. Samples were collected at three time points during cold storage: one day, 30 days, and when edible. We found that vitamin C in most cultivars was raised with cold storage, but there was no consistent increased or decreased trend for other water-soluble vitamins across cultivars in storage. After one day of cold storage, vitamins B1 and B2 were the most prevalent vitamins in Control (wild) fruit, while vitamins B5 and B6 were most prevalent in the Hongyang and Qihong cultivars. However, B12 was the most prevalent vitamin in the Qihong cultivar after 30 days of cold storage. Vitamins B3, B7, B9, and C were detected at the edible time point in Huayou, Hongyang, Jinnong-2, and Control fruit. Vitamin contents varied significantly among cultivars of kiwifruit following different durations of cold storage. Out of the three durations tested, a period of 30 days in cold storage was the most suitable for the absorption of water-soluble vitamins by A. chinensis.

Lactobacillus plantarum strains for multifunctional oat-based foods

Fermented oat-based foods offer attractive prospects within the market of non-dairy functional products, since they are suitable substrates for the delivery of probiotic microorganisms, and are significant sources of dietary fiber, both insoluble and soluble such as β-glucan, good quality fat and other phytochemicals important for human health.In the present work, whole oat flour was fermented with probiotic Lactobacillus plantarum strains to produce new functional foods with improved nutritional and technological features. Viability of the probiotic and the main technological, physico-chemical, nutritional and sensorial parameters were monitored at 7, 14 and 21 days of cold storage. The microbial survival was higher than 5x108 cfu g-1 at the end of the shelf life. After the fermentation step, viscosity was higher in products inoculated with the exopolysaccharide-producing L. plantarum strain Lp90. However, a subsequent viscosity reduction was detected in all the samples throughout the storage period, consistent with the observed concentration decrease of the oat β-glucan. Vitamin B2 content was about two-fold higher in products fermented by the riboflavin-overproducing LpB2, and in these samples the riboflavin concentration further increased during cold storage. (Less)

Impact of staggered treatments of novel molecules and ethylene absorbents on postharvest fruit physiology and enzyme activity of ‘Santa Rosa’ plums

The present investigation was conducted to study the effect of staggered removal of cold stored (2°C) plums at 7, 14 and 21 days interval and their subsequent treatment with salicylic acid (SA), nitric oxide (NO) and ethylene absorbent (EA) sachets. The fruit were then stored at supermarket conditions (20±1°C and 90±5% RH) with the objective to know whether delayed EA, SA and NO treatments still have significant beneficial effects on the plum fruit quality. The observations on different physiological and biochemical parameters were taken at 2 days interval. The results showed that staggered treatments enhanced postharvest life and maintained fruit quality. We observed that SA-treated plums showed the highest fruit firmness and lowest decay losses when plums were either removed on 7th, 14th or 21st days of cold storage. Furthermore, SA-treated fruit exhibited lowest rates of respiration and ethylene evolution; phenylalanine ammonia lyase and pectin methyl esterase activities; minimum malondialdehyde content and lowest electrolyte leakage in comparison to those treated either with NO or packed with EA sachets or control fruit. In conclusion, ‘Santa Rosa’ plum removed after 7th (staggered-I), 14th (staggered-II) and 21st day (staggered-III) from cold storage maintained a shelf life of 10, 6 and 4 days, respectively at subsequent supermarket storage conditions. The overall results submit that even if the plums are not treated immediately or within few days after harvest and placed as such in cold store, they can be still treated with SA, NO or in-package ethylene absorbent (EA) treatment for beneficial postharvest influences.

Quality Characterization of Processed Cheese Inoculated by Bacillus coagulans During Cold Storage: Compositional and Sensorial Attributes and Probiotic Microorganism Viability

The effect of the addition of probiotic spores (107 and 108 colony-forming unit [cfu]/g) of Bacillus coagulans ATCC 7050 on the critical quality attributes of an Iranian processed cheese including chemical composition, pH, titratable acidity (TA), survival rate and sensory features was studied during 60 days of cold storage. No significant difference was found in the chemical composition by the increasing spore count. A low pH value and a high TA quantity in the cheese inoculated by Ba. coagulans spores in comparison with the control sample were observed (P < 0.05). Results showed that the viability of probiotic cells was mentioned more than 106 cfu/g during the cold storage. The color, odor and texture sensory scores were insignificantly affected by the addition of probiotic spores during storage. However, a significant difference was found for the flavor and overall acceptability among different samples as these sensory attributes decreased with an increase in spore count. Practical Applications Incorporation of probiotic bacteria has been successfully performed in whey cheese matrices. However, probiotic-processed cheese inoculated by Bacillus coagulans spores have not been before made according to the data found in the literature. The use of this microbial source in producing processed cheese led to the improved critical quality attributes during 60 days of storage at refrigerator temperature. This study demonstrated that the processed functional cheese can be a potential carrier for the delivery of probiotic cells.

Effects of hot air and methyl jasmonate treatment on the metabolism of soluble sugars in peach fruit during cold storage

Soluble sugar metabolism affects the quality and chilling resistance of postharvest peach fruit. Although hot air (HA) and methyl jasmonate (MeJA) treatments are often effective in reducing chilling injury (CI), little is known about the relationship between sugar metabolism and HA or MeJA treatments in peach fruit. In this study, peach fruit was treated with hot air at 37°C for 3 days or MeJA vapor at 10μmol/L for 24h before storage at 5°C. Soluble sugar content, gene expression and enzyme activities associated with sugar metabolism were measured. Both treatments resulted in an initial increase, then a decrease in sucrose content over the course of storage time. Sucrose levels at every time point, but one, throughout the experiment were significantly higher than in control fruit, paralleled by higher gene expression and activity of SPS (sucrose phosphate synthase) and lower expression and activity of AI (acid invertase). HA-treated fruit had the highest sucrose content at the end of storage and the mildest CI symptoms. All treated fruit had higher sorbitol content and lower levels of SDH (sorbitol dehydrogenase) gene expression than control fruit. After 21 days in cold storage, sucrose content had decreased sharply in the control group, hexose content was not markedly affected, perhaps due to the increased expression of PFK (phosphofructokinase), resulting in more glucose entering the Embden–Meyerhof–Parnas pathway (EMP). These results suggest that the increase in sucrose observed during cold storage, associated with higher SPS and lower AI levels, enhances the chilling tolerance observed in HA- and MeJA-treated fruit.

Seabuckthorn as a novel prebiotic source improves probiotic viability in yogurt

It was aimed to i) investigate if seabuckthorn whole fruit (S), and seabuckthorn purified mucilage (SP) addition into yogurt enhance bacterial viability, by measuring total bacterial counts of different yogurt trials on selective media, pH and total titratable acidity (TTA) during 28 day cold storage at 4 °C, as well as ii) measure antioxidant activities of microwave extracted seabuckthorn crude mucilage (SC) and SP using oxygen radical absorbance capacity (ORAC) and DPPH scavenging activity. After 21 days of cold storage, yogurts with S and SP maintained higher viable bacteria counts in both of probiotics, Lactobacillus acidophilus (9.3 log cfu/mL) and Bifidobacterium lactis (9.2 log cfu/mL), higher TTA (0.8%), and lower pH (5.0) compared to the controls (P < 0.05). SC exhibited strong antioxidant activity with an ORAC value of 138.9 μmol Trolox equivalents/100 g, and a %DPPH scavenging activity value of 37.0%. Results of this study suggest S may serve as a new prebiotic source for functional foods and nutraceutical applications.

Exogenous Application of Oxalic Acid Delays Pericarp Browning and Maintain Fruit Quality of Litchi cv. “Gola”

The present study was conducted to investigate the influence of oxalic acid on pericarp browning, biochemical quality, antioxidative and enzymatic changes in litchi cv. “Gola” fruit under extended cold storage, which has not been studied extensively. Postharvest application of 2 mM oxalic acid reduced fruit weight loss and delayed pericarp browning by maintaining higher anthocyanin contents, as compared with control. Activities of polyphenol oxidase and peroxidase enzymes in litchi peel as well as pulp tissues were reduced in fruit treated with 2 mM oxalic acid during 28 days of cold storage. Activities of antioxidative enzymes (superoxide dismutase and catalase) and level of total phenolic contents and total antioxidants in litchi peel as well as pulp tissues were significantly higher in 2 mM oxalic acid-treated fruit. In conclusion, postharvest application of 2 mM oxalic acid significantly delayed pericarp browning and maintained better quality of litchi cv. “Gola” fruit during cold storage. Practical Applications Pericarp browning of litchi fruit is associated with postharvest oxidative stress, which deteriorates its quality, long-term storability and commercial value. Postharvest application of oxalic acid has been found to be a useful strategy to overcome the issue of pericarp browning and enhance antioxidative potential of litchi under low temperature storage; thereby, applicable to commercial supply chains for domestic and export markets. Furthermore, this study may facilitate in understanding the changes in antioxidative potential and enzymatic activities during cold storage with gradual browning in pulp as well as peel tissues of litchi.

Influence of a chitosan coating on the quality and nutraceutical traits of loquat fruit during postharvest life

Chitosan coating has been used for improving the postharvest life of fruits and vegetables. Loquat is a non-climacteric-fruit with a short postharvest life and a susceptibility to browning, chilling injury, purple spot and microbial decay. The effectiveness of a chitosan coating treatment (1%) on the quality and nutraceutical traits of three loquat cultivars and three selections stored at 7°C for 21 days were investigated. It was found that chitosan treatment provided an effective control in reducing fruit weight loss and delaying changes in the soluble solids concentration, titratable acidity and skin colour during 21 days of cold storage in a cultivar-dependent manner. Furthermore, in chitosan-coated fruits, losses of the total polyphenol, flavonoid, carotenoid, ascorbic acid content and the antioxidant capacity were reduced. Principal component analysis was used to track the effect of different parameters on the effectiveness of the chitosan coating on loquat fruit. It showed that with the cold storage increasing time, the uncoated fruits exhibited a higher deterioration than chitosan-coated fruits.The chitosan coating could be used commercially to extend the postharvest life, improve the storability and enhance the nutraceutical value of loquat fruits up to 21 days of cold storage.

Postharvest trans-resveratrol and glycine betaine treatments affect quality, antioxidant capacity, antioxidant compounds and enzymes activities of ‘El-Bayadi’ table grapes after storage and shelf life

The effect of exogenous trans-resveratrol (1.6×10−5M, 1.6×10−4M and 1.6×10−3M) and glycine betaine (GB) (10, 15 and 20mM/L) treatments on quality, antioxidant capacity, antioxidant compounds and enzymes activities of ‘El-Bayadi’ table grapes after 30 days of cold storage plus 2 days of shelf life were evaluated. trans-resveratrol especially at medium and high rates decreased decay after storage compared to control. GB, only at the high rate, decreased decay. Weight loss was higher at the low rate of trans-resveratrol than control. However, GB had no effect on weight loss. TSS, acidity and pH slightly changed during storage and were not affected by trans-resveratrol and GB. Firmness decreased after storage compared to initial, but was higher at trans-resveratrol and GB treatments than control. Both trans-resveratrol and GB retained higher total phenols concentration after storage than control. The high rate of trans-resveratrol and GB retained higher total flavonoids concentration than control. Vitamin C concentration was not affected by the applied treatments. Both trans-resveratrol and GB increased peroxidase (POD) and polyphenoloxidase (PPO) activities compared to control. Polygalacturonase (PG) activity greatly decreased by trans-resveratrol treatments. Xylanase activity increased by the medium rate of trans-resveratrol and the high rate of GB. Antioxidant capacity measured by DPPH assay decreased after storage in control compared to initial, but was higher at trans-resveratrol than other treatments. GB at low rate showed higher antioxidant activity than control. Also, antioxidant capacity measured by ABTS assay decreased after storage in control compared to initial, but was higher at the high rate of trans-resveratrol than other treatments. It is concluded that exogenous trans-resveratrol and GB treatments retained quality of ‘El-Bayadi’ table grapes after cold storage and shelf life and being suggested as natural alternatives to synthetic chemicals.

Efficacy of lactoferricin B in controlling ready-to-eat vegetable spoilage caused by Pseudomonas spp.

The microbial content of plant tissues has been reported to cause the spoilage of ca. 30% of chlorine-disinfected fresh vegetables during cold storage. The aim of this work was to evaluate the efficacy of antimicrobial peptides in controlling microbial vegetable spoilage under cold storage conditions. A total of 48 bacterial isolates were collected from ready-to-eat (RTE) vegetables and identified as belonging to Acinetobacter calcoaceticus, Aeromonas media, Pseudomonas cichorii, Pseudomonas fluorescens, Pseudomonas jessenii, Pseudomonas koreensis, Pseudomonas putida, Pseudomonas simiae and Pseudomonas viridiflava species. Reddish or brownish pigmentation was found when Pseudomonas strains were inoculated in wounds on leaves of Iceberg and Trocadero lettuce and escarole chicory throughout cold storage. Bovine lactoferrin (BLF) and its hydrolysates (LFHs) produced by pepsin, papain and rennin, were assayed in vitro against four Pseudomonas spp. strains selected for their heavy spoiling ability. As the pepsin-LFH showed the strongest antimicrobial effect, subsequent experiments were carried out using the peptide lactoferricin B (LfcinB), well known to be responsible for its antimicrobial activity. LfcinB significantly reduced (P≤0.05) spoilage by a mean of 36% caused by three out of four inoculated spoiler pseudomonads on RTE lettuce leaves after six days of cold storage. The reduction in the extent of spoilage was unrelated to viable cell density in the inoculated wounds. This is the first paper providing direct evidence regarding the application of an antimicrobial peptide to control microbial spoilage affecting RTE leafy vegetables during cold storage.

Synergism of defatted soybean meal extract and modified atmosphere packaging to preserve the quality of figs (Ficus carica L.)

The effect of the natural antimicrobial compounds from soybean meal in combination with packaging under a passive equilibrium modified atmosphere was studied with the ‘Cuello Dama Blanco’ (BS) and ‘Cuello Dama Negro’ (NS) fig cultivars during postharvest cold storage at 0°C. Soybean meal extract was applied by dipping the NS and BS cultivars, in combination with microperforated M50 film (1/50mm; ø=100μm) as well as with macroperforated films. In addition, microperforated and macroperforated film packaging (without natural antimicrobial compounds) were also used and served as the control. The gas composition, weight loss, percentage of fruits with disorders, microbial counts, physicochemical parameters and sensory quality were monitored during cold storage for 21 days. The use of these compounds allowed for the extension of cold storage, reducing decay as well as yeast and fungal infestation. Moreover, the combination of natural compounds with M50 film showed good performance in terms of maintaining fig fruit quality for both cultivars, and was a useful tool to extend storability with optimal quality properties for the NS cultivar as well as the BS cultivar treated with soybean meal extract, allowing cold storage for 21 and 14 days, respectively, while the use of M50 film without natural compounds application allowed the shelf-life extension up to 14–17 and 7 days of cold storage respectively.

Preservation of different fig cultivars (Ficus carica L.) under modified atmosphere packaging during cold storage.

The effect of modified atmosphere packaging (MAP) on the stability of 'Cuello Dama Blanco' (CDB), 'Cuello Dama Negro' (CDN) and 'San Antonio' (SA) figs during post-harvest cold storage was evaluated by using three different films with a diverse number of microperforations (diameter, ø = 100 µm): M10 (16 holes), M30 (five holes) and M50 (three holes). A macroperforated film was used as control (five holes, ø = 9 mm). Gas composition, weight loss, percentage disorder, microbial counts and physico-chemical parameters were monitored during cold storage for 21 days. Furthermore, sensory quality was also evaluated. MAP has allowed the extension of cold storage and distribution time for the three different cultivars of figs, minimising weight loss and delaying pathological disorders related to endosepsis, smut, and souring. Of the three cultivars, the M50 batch (one hole per 50 mm) showed the best efficiency in terms of physico-chemical quality and delay of post-harvest decay, although the M30 batch was also found to be suitable for delaying the post-harvest decay, especially for the CDB cultivar. MAP is a useful tool to extend the storability with optimal quality properties for CDN and SA during 21 days of cold storage and 14-17 days of cold storage for CDB.

IRRIGATION AFFECTS POSTHARVEST DISCOLOURATION AND YIELD IN ICEBERG LETTUCE

Fresh produce is highly perishable and significant wastage can occur from producer to consumer. Lettuce heads and other leafy salads can often suffer non-infectious discolouration disorders, such as pinking. Pinking of lettuce butts and leaves can occur within only a few days of harvest, and this can limit product shelf life and contribute to retail consumer dissatisfaction. It has already been shown that preharvest water stress can have an impact on the yield and postharvest quality of ‘Batavia’ lettuce. Our aim was to investigate the sensitivity of ‘Iceberg’ lettuce to water stress pre- and postharvest. A lettuce crop was grown in a polytunnel at Harper Adams University; soil was amended with peat to give two defined uniform soil types; 25% (high OM soil) or 5% (low OM soil) in containers of 180 L volume. By alternating the amount of irrigation a range of different water stress treatments were imposed. Increased irrigation led to greater biomass production, with heads containing a greater proportion of water. Analysis also showed that soil type and irrigation significantly affected the total amount of N (%) in lettuce head dry matter, whilst postharvest scoring revealed that the pinking score after 20 days in cold storage was significantly greater in treatments with increased irrigation.

A modified form of Myzithra cheese produced by substituting the fresh cheese whey by dried whey protein concentrate and ovine milk and cream

A modified form of Myzithra cheese (M) was produced by substituting the fresh cheese whey by dried whey protein concentrate 65% (WPC 65%). The proportion of the materials used in the production of the modified Myzithra cheese blend was: 16.1% WPC, 49.9% water, 8.0% ovine milk and 26.0% ovine cream. The mixture was placed in polyethylene package before being subjected to heat treatment at 90°C for 30min. A control Myzithra cheese (C) was also produced in the traditional way. Both cheeses were submitted to microbiological, physicochemical and rheological analyses as well as organoleptic tests 1 day after production and following 25 days in cold storage. The modified Myzithra cheese (M) had a higher lactose, potassium and sodium content and lower total bacteria, protein, ash, calcium, hardness and adhesiveness than C-Myzithra cheese, while yeasts and moulds were absent. Also, M-Myzithra cheese remained unchanged organoleptically and texturally during cold storage, whereas C-Myzithra cheese deteriorated. Sensory evaluation revealed that M-Myzithra cheese was of good quality and can cover the annual consumption demand for Myzithra cheese, thus helping to resolve the problem of seasonal production of C-Myzithra cheese while simultaneously exploiting the WPC.

Individual Shrink Wrapping of Zucchini Fruit Improves Postharvest Chilling Tolerance Associated with a Reduction in Ethylene Production and Oxidative Stress Metabolites.

We have studied the effect of individual shrink wrapping (ISW) on the postharvest performance of refrigerated fruit from two zucchini cultivars that differ in their sensitivity to cold storage: Sinatra (more sensitive) and Natura (more tolerant). The fruit was individually shrink wrapped before storing at 4°C for 0, 7 and 14 days. Quality parameters, ethylene and CO2 productions, ethylene gene expression, and oxidative stress metabolites were assessed in shrink wrapped and non-wrapped fruit after conditioning the fruit for 6 hours at 20°C. ISW decreased significantly the postharvest deterioration of chilled zucchini in both cultivars. Weight loss was reduced to less than 1%, pitting symptoms were completely absent in ISW fruit at 7 days, and were less than 25% those of control fruits at 14 days of cold storage, and firmness loss was significantly reduced in the cultivar Sinatra. These enhancements in quality of ISW fruit were associated with a significant reduction in cold-induced ethylene production, in the respiration rate, and in the level of oxidative stress metabolites such as hydrogen peroxide and malonyldialdehyde (MDA). A detailed expression analysis of ethylene biosynthesis, perception and signaling genes demonstrated a downregulation of CpACS1 and CpACO1 genes in response to ISW, two genes that are upregulated by cold storage. However, the expression patterns of six other ethylene biosynthesis genes (CpACS2 to CpACS7) and five ethylene signal transduction pathway genes (CpCTR1, CpETR1, CpERS1, CpEIN3.1 and CpEN3.2), suggest that they do not play a major role in response to cold storage and ISW packaging. In conclusion, ISW zucchini packaging resulted in improved tolerance to chilling concomitantly with a reduction in oxidative stress, respiration rate and ethylene production, as well as in the expression of ethylene biosynthesis genes, but not of those involved in ethylene perception and sensitivity.

Microbiological, functional and rheological properties of low fat yogurt supplemented with Pleurotus ostreatus aqueous extract

Pleurotus ostreatus aqueous extract was incorporated to milk aiming to produce a yogurt with different functional and rheological characteristics. Viable counts of Streptococcus thermophilus and Lactobacillus bulgaricus, pH, lactic acid production, changes in rheological and structural properties (syneresis, texture profile analyses, color and microstructure), antioxidant capacity and total phenolic were followed throughout 28 days of cold storage. Addition of POE increased S. thermophilus and L. bulgaricus CFU counts. Low fat yogurts with POE exhibited lower syneresis and firmness, but more adhesiveness, springiness and cohesiveness than control. Supplemented yogurts were darker, contained more polyphenols and exhibited higher antioxidant activity than controls in cold storage. Overall, the results indicated that POE can be used to manufacture low fat yogurt with functional activity and at the same time modifies rheological properties.

EFFECT OF LASER BEAM EXPOSURE ON THE QUALITY OF CATTLE MEAT DURING COLD STORAGE

The aim of this research is to study effect of laser exposure on the fresh cattle meat quality during cold storage with respect to survival and growth of bacteria, shelf-life and physiochemical properties. Fresh cattle meat samples were exposed to three doses (9, 18 and 27 W.s/cm2) of laser beam with wavelength 450 nm. The obtained results were indicated that: 1) the total account of microorganisms of samples weren’t changed at 0 (control) and 9 W.S/cm2 of laser exposure dose for 5 days of cold storage period. Meanwhile, it was decreased 8.1 x106 and 8.3 x106 CFU/g. of 18 and 27 W.s/cm2 laser exposure dose of meat sample, respectively, at extended shelf life of 10 and 15 days of cold storage period, comparing in control sample which was 3.6 x106 CFU/g. at 5 days of cold storage period. Also, the physiochemical properties of samples were taken the same trend, 2) the samples were rejected of 0 (control), 9, 18 and 27 W.s/cm2of laser exposure dose at 10, 15, and 20 days of cold storage period, because of the total account of microorganisms of meat was higher than within the acceptable limits. 3) the total account of microorganisms and physiochemical properties of sample at 18 and 27 W.s/cm2 laser dose were within the acceptable limits, and these results lead to increase the beef meat shelf life about 10 and 15 days, comparing with control sample at 5 days of cold storage period., and 4) laser beam exposure can be used to increase shelf life and inspection of meat quality.

Sweet cherries from farm to table: A review

ABSTRACTIn order to enable long-distance transportation and ensure that the fruit presents the requisite quality on arrival at markets, the cherry industry for direct consumption needs to prolong post-harvest shelf life. Sweet cherries are highly perishable, non-climacteric fruits with shelf life of 7–14 days in cold storage. Their shelf life is shortened by loss of firmness, color and flavor, stem discoloration, desiccation and mould growth. Various factors such as harvest time, proper handling and cooling practices and above all packaging, greatly influence the shelf life of cherries. One of the areas of research that has shown promise, and had success, is modified atmosphere packaging (MAP). It is one of the fastest growing packaging technologies and has many advantages for different food products. Properly designed modified atmosphere packs can be exploited to lower respiration rates and thus ripening of fruits which results in least changes in physiochemical parameters of sweet cherries during postharvest storage. This paper intended to review a broad spectrum of studies dealt with the use of MAP for preservation of sweet cherries cultivars with an interest for future research work.

Influence of postharvest chitosan treatment on enzymatic browning and antioxidant enzyme activity in sweet cherry fruit

The effectiveness of chitosan fruit coating to delay the onset of senescence in three sweet cherry (Prunus avium L.) cultivars “Ferrovia”, “Lapins”, and “Della Recca” as well as its effect on antioxidant enzymes involved in the balancing of the reactive oxygen system (ROS), were evaluated. Fruit were dipped for 60s into a 0.5% chitosan solution, stored at 2°C for 14 days and sampled at harvest, 7 and 14 days of cold storage. At each sampling date, subsamples were maintained for 3 days at 24°C to assess the shelf life of the fruit. Malondialdehyde content and some enzymatic activities such as superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), polyphenol oxidase (PPO), guaiacol peroxidase (POD) and lipoxygenase (LOX) were evaluated. Chitosan treatment enhanced the activity of some antioxidant enzymes, including SOD and APX. The treatment inhibited PPO and POD activities, preventing flesh-browning and extending storage life of sweet cherry fruit. In addition, chitosan treatment also maintained membrane integrity by delaying LOX activity LOX and malondialdehyde accumulation. A multivariate statistical approach including a principal component analysis provided a global view of the response of the three sweet cherry cultivars to chitosan coating and storage temperature. Chitosan-coated fruit showed a lower decay both at 2°C and 24°C than the uncoated fruit. In “Della Recca” fruit, membrane preservation and antioxidant enzyme system resulted higher than in “Ferrovia” and “Lapins”.

Changes in phenolic compounds and antioxidant activity of sour–sweet pomegranates cv. ‘Hicaznar’ during long-term storage under modified atmosphere packaging

This study was carried out to evaluate the effects of modified atmosphere packaging (MAP) on phenolic compounds and antioxidant activity of sour–sweet pomegranates cv. Hicaznar during long-term storage. Pomegranate fruit were harvested at commercial harvest maturity and packed in two different commercial types of MAP (MAP1, sealed in packages made of Xtend® film; MAP2, sealed in bags made of ZOEpac). Unpacked fruit stored in plastic boxes were used as control. After packaging, all fruit samples were stored at 6±0.5°C at 90±5% relative humidity for up to 210 days, and removed from storage at 60 days intervals for assessing phenolic compounds and antioxidant activity, as well as other quality parameters. After each storage period, fruit were removed and kept at 20°C for 3 days to simulate a period of shelf life. Total phenolic, total anthocyanin contents and antioxidant activity increased slightly until the first 120 days of storage, and then decreased during the rest of the storage. Ascorbic acid, titratable acidity and total soluble solids decreased after cold storage and shelf life, and no significant differences were found among treatments except for total soluble solids. Contents of organic acids were decreased in all treatments during storage, and no significant differences were found among treatments except for tartaric acid. During long-term storage, CO2 levels increased and O2 levels decreased inside both MAPs systems. MAPs significantly reduced weight loss, maintained visual appearance, retarded skin discoloration compared to control fruit. There was no statistical difference in decay incidence between MAPs and control fruit at 210 days of cold storage, while more decay developed on fruit packed in MAPs than on control fruit at 210+3 days SL period. The results indicated that 180 days storage of fruit in the modified atmosphere packaging at 6°C maintained physiological and biochemical properties of pomegranate fruit.