Internal quality and antioxidants content of cold-stored red sweet peppers as affected by polyethylene bag packaging and hot water treatment

Physical (weight, firmness) and compositional (sugars, organic acids, ascorbic acid, phenolic compounds and carotenoids) changes of red sweet peppers (Capsicum annuum L.) were monitored during 21 days of cold storage (at 7.5 °C); fruits were stored without packaging, packaged in low density polyethylene bags, or after hot water dipping (53 °C for 4 min) and packaging. Packaging prevented water loss, and preserved the firmness of the fresh product. Sugars (fructose and glucose) content was practically constant throughout the whole storage time, for all treatments. A moderate accumulation of citric acid was observed during storage, but no marked effects of packaging and hot water dipping on citric and malic acid content. Ascorbic acid content slightly increased in unpackaged and packaged fruits, but not in treated+packaged peppers. Hydroxycinnamics total content seemed not to be affected by cold storage, packaging or hot water treatment, whereas glycosylated flavonoids showed somewhat lowered levels during storage, particularly in the case of unpackaged and packaged+treated fruits. Regarding carotenoids content, the effect of the considered storage conditions seemed to be much smaller than that due to ripening stage. Provitamin A content showed an increasing trend in unpackaged and packaged fruits; packaged+treated peppers were characterised by a lower retention of provitamin A and a higher level of capsanthin and cucurbitaxanthin A with respect to not treated fruits. On the whole, packaging and hot water treatment did not produce noticeable adverse effects on the majority of the examined compositional quality parameters.     

Phenolic and carotenoid profiles of papaya fruit (Carica papaya L.) and their contents under low temperature storage

BACKGROUND: Tropical fruits are rich in phenolic and carotenoid compounds, and these are associated with cultivar, pre‐ and postharvest handling factors. The aim of this work was to identify major phenolics and carotenoids in ‘Maradol’ papaya fruit and to investigate their response to storage temperature. RESULTS: Ferulic acid, caffeic acid and rutin were identified in ‘Maradol’ papaya fruit exocarp as the most abundant phenolic compounds, and lycopene, β‐cryptoxanthin and β‐carotene were identified in mesocarp as the major carotenoids. Ranges of contents of ferulic acid (1.33–1.62 g kg^?1 dry weight), caffeic acid (0.46–0.68 g kg^?1 dw) and rutin (0.10–0.16 g kg^?1 dw) were found in papaya fruit, which tend to decrease during ripening at 25 °C. Lycopene (0.0015 to 0.012 g kg^?1 fresh weight) and β‐cryptoxanthin (0.0031 to 0.0080 g kg^?1 fw) were found in fruits stored at 25 °C, which tend to increase during ripening. No significant differences in β‐carotene or rutin contents were observed in relation to storage temperature. CONCLUSION: Phenolics and carotenoids of ‘Maradol’ papaya were influenced by postharvest storage temperature with exception of β‐carotene and rutin. Ripe papaya stored at 25 °C had more carotenoids than those stored at 1 °C. Low (chilling) temperature (1 °C) negatively affected the content of major carotenoids, except β‐carotene, but preserved or increased ferulic and caffeic acids levels, as compared to high (safe) temperature (25 °C). Copyright © 2010 Society of Chemical Industry     

Effects of gamma irradiation and storage temperature on carotenoids and ascorbic acid content of mangoes on ripening

Synthesis and accumulation of carotenoids in the flesh of Alphonso mangoes on ripening was found to be maximal in fruits stored at tropical ambient temperatures (28–32°C). Gamma irradiation of preclimacteric fruits at 25 krad did not affect the formation of carotenoids. Storage of preclimacteric fruits either irradiated or unirradiated at 7–20°C for 16–43 days caused a substantial reduction in carotenoid formation even when these fruits were subsequently ripened under optimal conditions. Regardless of storage temperature, carotenes always exceeded xanthophylls in the ripe fruits and, in general, irradiated fruits showed higher levels of carotenes in comparison with unirradiated samples. Ascorbic acid loss during ripening was maximum at ambient temperatures while lengthy storage at low temperatures caused a net increase in ascorbic acid levels. Irradiation seemed to accentuate the loss in ascorbic acid during ripening.     

Changes in Bioactive Compounds, Antioxidant Activity and HMF Formation in Rosehip Nectars During Storage

In this study, reaction kinetics of ascorbic acid degradation and hydroxymethylfurfural (HMF) formation in glass-bottled and cardboard-packaged rosehip nectars stored at 25, 35 and 45 °C were evaluated. Variations of total phenolics, total carotenoids, and antioxidant activity of samples were also evaluated. HMF formation followed a zero-order reaction, while a first-order reaction model was fitted to ascorbic acid degradation. The activation energies for ascorbic acid degradation and HMF formation were found as 56–63.9 and 42.9–53.0 kJ mol^?1, respectively. During storage, total phenolics content of rosehip nectars were decreased significantly. However, changes in the total carotenoids of rosehip nectars during storage were not statistically significant. Decreases in the antioxidant activity of glass-bottled rosehip nectars during storage at all applied temperatures were found statistically significant, whereas no significant variations were observed in the antioxidant activities of cardboard-packaged rosehip nectars.     

Phytochemical composition and antioxidant activity of peach as affected by pasteurization and storage duration

Fruit are very perishable and are often preserved as heat-processed foods. Clingstone peach [Prunus persica (L.) Batsch ‘Catherine’] fruit were heat-treated at 90 °C for 5 min and stored under aseptic conditions at room temperature (ca. 22 °C) for 90 days. Significant reductions in total carotenoids were observed immediately after pasteurization but total antioxidant activity and the concentration of total phenolics were unaffected. Pasteurization induced significant reductions in the concentration of protocatechuic acid (from 10.2 to 5.8 μg/g fw), zexanthin and β-cryptoxanthin. Significant reduction in antioxidant activity, expressed as ascorbic acid equivalents, from 0.52 to 0.25 mg/g fw, was observed during storage of pasteurized peach for 90 days. Total phenolics, expressed as gallic acid equivalents, decreased during storage from 0.57 to 0.28 mg/g fw and total carotenoids decreased from 4.0 to 1.3 μg/g fw. Procyanidin B1 increased from 15.8 to 26.8 μg/g fw and chlorogenic acid and neochlorogenic acid increased 35 and 43%, respectively. (?)-Epicatechin decreased during storage from 13.1 to 4.0 μg/g fw and quercetin-3-glucoside from 7.3 to 4.4 μg/g fw. All carotenoids decrease significantly with the exception of zeaxanthin, which increased during storage. Storage duration strongly affected the concentration of phenolics and carotenoids in pasteurized peach.     

Total Phenolics,Carotenoids, Ascorbic Acid,and Antioxidant Properties of Fresh‐cut Mango (Mangifera indica L., cv. Tommy Atkin) as Affected by Infrared Heat Treatment

Abstract: Mango (Mangifera indica L.) is a major tropical fruit that has not been exploited for fresh‐cut or minimally processed products on a scale similar to apples, pineapples, or melons. The objective of this study was to investigate the effect of infrared (IR) treatment on total phenolics, carotenoids, ascorbic acid, and antioxidant properties of fresh‐cut cubes from ‘Tommy Atkin’ mangoes. Mango cubes were IR treated (5, 10, 15 min) and evaluated at 4‐d intervals during 16‐d storage at 4 ± 1 °C. Total phenolics, carotenoids, and ascorbic acid content in fresh‐cut control mango cubes were 43.33, 1.37, and 15.97 mg/100 g FW, respectively. IR treatments increased total phenolics (59.23 to 71.16 mg/100 g FW) and decreased ascorbic acid (12.14 to 15.38 mg/100 g, FW). Total carotenoids showed a mixed trend (1.13 to 1.66 mg/100 g, FW). The IR treatment showed a significant positive impact on antioxidant properties (μM TE/100 g, FW) of mango cubes, as assayed by ABTS (261.5 compared with 338.0 to 416.4), DPPH (270.5 compared with 289.4 to 360.5), and ORAC (6686 compared with 8450 to 12230). Total phenolics, carotenoids, ascorbic acid, and antioxidant capacity decreased over 16‐d storage. However, IR treated samples had consistently higher ABTS, DPPH, and total phenolics during storage. It was demonstrated that IR treatment can be effectively used in improving antioxidant properties of fresh‐cut mangoes with minimal effect on the visual appearance. Practical Application: Various methods/treatments are in use for extending the quality of fresh‐cut fruits, including mild heat treatment. This study explored the application of infrared (IR) heat for processing fresh‐cut mango cubes and evaluated its effect on vitamin C and antioxidant capacity during 16‐d storage. This is the first study reporting on the use of IR heat in fresh‐cut fruits. IR treatment was shown to be effective in retaining antioxidant properties of fresh‐cut mango cubes with minimal effect on the visual appearance.     

Quality of Gamma Irradiated California Valencia Oranges

California Valencia oranges were irradiated at 0.30, 0.50, 0.75 and 1.0 kGy for quality evaluation and potential use of gamma-radiation as an alternative quarantine treatment and for fresh market life extension. Fruits were ocean-freighted to Honolulu, irradiated at the Hawaii Research irradiator 8 days after harvest, then stored for 7 wk at 7°C or 4 wk at 7°C and 2 wk at 21°C (6 wk total). Treatments of 0.75 kGy maintained fruit qualities at low storage temperature (7°C) up to 7 wk while 0.50 kGy retained qualities when fruits were stored at 21°C. Gamma irradiation of Valencia oranges at 0.26–0.30 kGy can achieve fruit fly disinfestation at probit 9 security level while preserving market qualities including organoleptic qualities, ascorbic acid, total acids, and total soluble solids.     

The effects of washing treatment on antioxidant retention in ready-to-use iceberg lettuce

The influence of washing treatment on the retention of key antioxidants in minimally processed iceberg lettuce was examined. Shredded iceberg lettuce was subjected to one of three washing treatments: a domestic wash (tap-rinsed), immersion in distilled water (water-dipped) or immersion in chlorinated water (chlorine-dipped). Lettuce was subsequently packed in oriented polypropylene bags and flushed with 100% nitrogen and stored at 4 °C. Vitamin C (ascorbic acid and dehydroascorbic acid), total phenols, total antioxidants, individual phenols, individual carotenoids, colour measurements and pH were quantified on production day and throughout the storage period (8 days). Different groups of antioxidants were found to differ in their response to washing treatments. No significant ( P  > 0.05) effects of washing treatment were observed on total antioxidant activity, total phenolics and on the levels of individual phenolics (chicoric acid, chlorogenic acid and caffeic acid). Individual carotenoids were initially affected by washing treatment, with higher levels of lutein and beta-carotene retained with domestic washed lettuce. Ascorbic acid was the antioxidant most affected by washing treatments with domestic washing resulting in significantly ( P  ≤ 0.05) higher retention of ascorbic acid throughout the storage period compared with the chlorine-dipped lettuce.     

Effect of calcium on the storage life of oro (Antiaris africana)

The effects of calcium on the ascorbic acid, chlorophyll, titratable acidity and texture (firmness) of stored oro (Antiaris africana (Mill)) friuits (average weight 100 g ) were studied. Three groups of the fruits were dipped in 20 g litre^?1, 40 g litre^?1 CaCl₂ solutions and deionised water respectively for I0 min. The fourth group, which was untreated, served as the control and was also packaged in heat-sealed cellophane bags. The fruits were displaced and stored at ambient temperature (28 ± 2°C). The calciumtreated fruits which kept better were firmer and had a slight colour change (chlorophyll) which also produced a progressive increase in ascorbic acid level during storage. The titratable acidity of the fruits did not fluctuate as signijcantly as that of the untreated (control) fruits.     

Effects of Modified Atmosphere Packaging on the Physicochemical Characteristics of Ciku ( Achras sapotaL) at Various Storage Temperatures

The physicochemical changes in ciku during storage at various temperatures and the effect of various techniques of modified atmosphere packaging (MAP) at 5, 10, 15°C and ambient were examined by monitoring fruit texture, weight loss, soluble solids content, pH, sucrose, fructose, glucose, pectin, tannin, ascorbic acid and microbial infection. Under MAP, ciku could be stored for 4 weeks at 10°C and 3 weeks at 15°C, while without MAP the storage life was shorter by 1 week. Packaging in low-density polyethylene film (LDPE) was highly effective in maintaining the texture and weight of cold-stored fruits. Fruits stored at 5°C experienced chilling injury, observed as their inability to ripen properly, even after 3 days at room temperature in the presence of 50 g kg⁻¹ calcium carbide. The ascorbic acid content was highest in vacuum-packed fruits followed by the other LDPE packagings. LDPE packaged fruits also received the highest sensory scores for taste, colour, texture and overall acceptability in cold-stored ciku. The unsealed nature and heating involved in shrink wrapping did not favourably affect the storage life of ciku. MAP alleviated the chilling injury which occurred in ciku stored at 10°C but not at 5°C.     

Fruit rots of Capsicum annuum L. and C. frutescens L. in Nigeria. Part III. Effect of post-harvest infection by two Fusaria species on a few nutrients

The effects of temperature on rot infections produced by Fusarium oxysporum and F. equiseti on the sugars and ascorbic acid levels in pepper fruits were investigated. There was a gradual decrease to a total loss of ascorbic acid in infected fruits (at 25 °C) with increase in incubation period (14 days). In infected fruits stored at 30 °C during the 8 days of incubation, a total loss of this acid was also recorded. There were fluctuations in the levels of reducing sugars in diseased fruits stored for 8 days at different temperatures while a gradual decrease in amount of sugars was recorded in infected fruits at a temperature of 25 °C during 14 days of incubation.     

Postharvest Physiology and Quality Maintenance of Sliced Pear and Strawberry Fruits

Sliced strawberries (cvs.‘Pajaro’ and 'G-3′) and partially ripe pears (cv.‘Bartlett’) were dipped in various solutions (citric acid, ascorbic acid, and/or calcium chloride) and stored in air or in controlled atmospheres (CA) for 7 days at 2.5°C followed by one day at 20°C. Fruit slices respired at a higher rate than whole fruits at both temperatures. CA storage suppressed respiration and ethylene production rates of sliced fruits. Firmness of strawberry and pear slices was maintained by storage in air + 12% CO₂ and in a 0.5% O₂ atmosphere, respectively, or by dipping in 1% calcium chloride. These treatments also resulted in lighter colored pear slices than the air control treatment.     

Hot water and curing treatments reduce chilling injury and maintain post-harvest quality of 'Valencia' oranges

‘Valencia’ oranges [Citrus sinensis (L.) Osbeck] were harvested at optimal maturity and either dipped in hot water at 53 °C for 3 or 6 min or at 48 °C for 12 min or cured at 53 °C for 1 or 6 h or at 48 °C for 12 h. The fruits were not degreened, waxed or treated with any post‐harvest fungicides. All fruit samples were stored at 4 °C for 6 months following the treatments. Both hot water dip and curing treatments reduced chilling injury and decay when compared with the untreated control. The most effective treatments were curing of fruit at 53 °C for 6 h and at 48 °C for 12 h. Weight loss and juice yield were higher in cured fruits than those from other treatments, but the heat treatments had no consistent effects on titratable acid, soluble solids, ascorbic acid and peel colour. It was concluded that a pre‐storage hot water dip and curing at high temperatures might be beneficial in preventing chilling injury and decay of ‘Valencia’ oranges for 6 months of storage at 4 °C.     

Controlling Temperature and Water Loss to Maintain Ascorbic Acid Levels in Strawberries During Postharvest Handling

‘Chandler’, ‘Oso Grande’ and ‘Sweet Charlie’ strawberries were stored for 8 days at 1 or 10°C, or 4 days at 20°C, either unwrapped or wrapped in PVC film to retard were conducted during the 1 water loss. Total ascorbic acid (AA) content was expressed on a dry weight basis to correct for water loss differences between treatments. Loss of AA was low and did not differ between wrapped treatments at 1 and 10°C, but was much greater at 20°C. Wrapping reduced AA loss by 5-fold at 1 and 10°C and by 2-fold at 20°C. The effect was not due to modification of O₂ and CO₂ levels in wrapped treatments, which was minimal. The results indicate that water loss had a greater effect on AA levels than temperature. Combining wrapping with storage at 1 or 10°C reduced AA loss by 7.5-fold compared to unwrapped strawberries stored at 20°C.     

Shelf Life of Pretreated Dried Tomato

Determining the shelf life has become a factor of major importance in the development of foods designed to meet consumer demands in terms of quality and safety. The goal of the present study was to investigate the shelf life of vacuum-packed dried tomatoes, stored at both room and refrigeration temperature (4 °C) for a period of 180 days. The following determinations were performed during the storage period studied: microbiological analysis, instrumental color, lycopene, and ascorbic acid. Sorption isotherms were determined at both temperatures (room temperature and 4 °C). The microbiological quality of vacuum-packed dried tomatoes remained unchanged during 180 days for the refrigerated samples and 90 days for the samples stored at room temperature. The rate constant (k) of lycopene degradation of the refrigerated samples and the samples stored at room temperature was 3.209 × 10⁻⁵ and 12.994 × 10⁻⁵/day, respectively. The rate constant (k) of ascorbic acid degradation was 3.339 × 10⁻⁴/day for cold storage and 76.655 × 10⁻⁴/day for storage at room temperature. The tomatoes stored at room temperature were subjected to analysis over 90 days of storage, period after which both the appearance and sensory characteristics of the product fell below the levels of consumer acceptability. As for the tomatoes stored at refrigeration temperature, the original sensory characteristics were maintained throughout the entire storage period of 180 days.     

Effects of storage condition and domestic cooking on the quality and nutrient content of African leafy vegetables (Cassia tora and Corchorus tridens)

BACKGROUND: The main objective of this research was to determine changes in nutrient content of two African leafy vegetables, Cassia tora and Corchorus tridens, on cooking and storage under different temperature conditions, i.e. room storage (20 °C), refrigerated storage (4 °C) and frozen storage (?18 °C). RESULTS: The leafy vegetables were analysed for moisture, colour (Hunter L, a, b), texture, total chlorophyll, ascorbic acid, dehydroascorbic acid and total phenolics. Results indicated that the degradation of ascorbic acid was highest as a result of frozen storage, followed by room temperature storage. The dehydroascorbic acid content was correspondingly high in frozen stored leafy vegetables, whereas it was undetectable in the room temperature and refrigerated stored materials. The total phenolic content of the leaves increased with storage time while the total chlorophyll content decreased under all storage conditions. Domestic cooking resulted in significant additional losses of ascorbic acid following storage under all temperature conditions, with only 1–10% retention in the leaves and 50–60% retention in the cooking water. The green colour of the leafy vegetables was retained best under refrigerated and frozen storage, while the peak force and toughness of the leaves increased upon storage under all conditions. The moisture content of the leafy vegetables did not show any significant difference on storage. CONCLUSION: This study is one of few to report nutrient content changes on the same raw material stored under various temperature conditions and cooked domestically. Refrigerated storage resulted in the highest retention of ascorbic acid and green colour in the leafy vegetables. Copyright © 2009 Society of Chemical Industry     

Influence of moderate heat pre-treatments on physical and chemical characteristics of kiwifruit slices

The effect of mild heat treatments, applied to whole kiwifruit, on physical characteristics and chemical composition of minimally processed fruit was studied. Fruits were subjected to heat treatments at 45 °C for 25 and 75 min, cooled for 24 h, minimally processed and stored at 4 °C for 12 days. Heat-treated fruits showed increased respiration rates in the first 2 days of storage. Samples colour was marginally affected either by heat treatments or by minimal processing. The application of heat treatments leads to an increment of slices firmness due to cross linking between demethylated galacturonic acid chains and endogenous calcium. An increment in sucrose, L-malic, citric, quinic and ascorbic acids was observed as a consequence of applied heat treatments. Heat treatment at 45 °C for 25 min applied to whole fruits allows quality retention of minimally processed fruit during 9 days at 4 °C.     

Effect of Pretreatments on Quality Characteristics of Dehydrated Ivy Gourd (Coccinia indica L.)

Ivy gourd (Coccinia indica L.) is an important tropical vegetable cultivated in India. It belongs to the Cucurbitaceae family and is attributed with neutraceutical properties such as hypoglycemic effect and contained a fair amount of ascorbic acid. The effect of blanching and different pretreatments on the quality characteristics of dehydrated ivy gourd slices was optimized. The treated ivy gourd slices were dehydrated in a cross flow hot air drier at 50 ± 1 °C to a final moisture content of 4.6%. The dehydration ratio of dried ivy gourd slices ranged from 17.1:1 to 18.7:1. Ivy gourd slices blanched at 98 °C in water, dipped in 0.2% potassium metabisulphite (K₂S₂O₅) solution and dried at 50 ± 1 °C for 5–6 h resulted in best product. Dehydrated ivy gourd slices obtained from the optimized treatment had good color, texture with rehydration ratio of 1:8.6. Equilibrium relative humidity of dehydrated slices was 34.18% with an initial moisture content of 4.6% at 28 ± 1 °C. Dehydrated slices were packed in low density polyethylene (LDPE) and metallized polyester polyethylene (MPP) pouches and stored at room temperature (27–35 °C) for 6 months. The dehydrated slices were analyzed for changes in physicochemical composition and sensory quality characteristic such as color and appearance, texture and overall quality during storage. Dehydrated ivy gourd slices remained acceptable during storage of 4 and 6 months in LDPE and MPP pouches, respectively, at room temperature.     

Effect of ripeness on the shelf-life of fresh-cut melon preserved by modified atmosphere packaging

Fresh-cut ‘Piel de Sapo’ melon was processed at different ripeness stages and stored under modified atmosphere packaging for 35 days at 5 °C. Raw material firmness and soluble solids content ranged from 6.5 to 3.9 N and 11.1 to 14.3 °Brix, respectively. The effects of a 2.5 kPa O₂+7 kPa CO₂ packaging atmosphere and a dip of 1% ascorbic acid and 0.5% calcium chloride on physiology, microbiological stability as well as color and firmness were evaluated. An intermediate stage of ripeness at processing was the most suitable to extend the shelf-life of fresh-cut ‘Piel de Sapo’ melon. Green-mature fresh-cut melon reduced CO₂ accumulation and ethanol production. In addition, a treatment with ascorbic acid and calcium chloride in combination with modified atmosphere packaging, contributed to a greater extension of the shelf-life of fresh-cut melon than that reported for fruits stored under non-modified atmosphere, slowing down the growth of microbial populations, maintaining the original color and reducing softness. Thus, the shelf-life of green-mature fresh-cut ‘Piel de Sapo’ melon dipped in an ascorbic acid and calcium chloride solution and packaged under modified atmosphere was about 10 days.     

Protection of vessel permeability by genistein against lipopolysaccharide induced acute inflammation in a chick embryo chorioallantoic membrane model

Effects of dip treatments on nutritional quality preservation during the shelf life of fresh-cut tomato (Licopersicum esculentum Mill.) cv. Eufrates were investigated. Fresh-cut tomatoes were dipped in solutions of 2% ascorbic acid, citric acid, and calcium lactate for 2 min, then stored at 4°C for 20 days. Color (L*, a*, and b*), firmness, °Brix, phenolics, ascorbic acid content, antioxidant activity (DPPH), and sugars were measured during storage. Pathogen development was monitored, and a sensory evaluation was performed. Ascorbic acid was better in maintaining firmness. No treatments significantly affected °Brix, color, or sugars. Ascorbic acid maintained a higher antioxidant capacity, phenolics, and ascorbic acid content, and was better at reducing bacterial growth, while citric acid treatment was better at prevention of yeast and molds proliferation. Fresh-cut tomatoes showed good quality after 10 days of shelf life, except for flavor with the calcium lactate treatment. Ascorbic acid treatment better preserved the general and nutritional quality parameters.