Improving antioxidant capacity of fresh-cut mangoes treated with UV-C

ABSTRACT:  The effect of UV-C irradiation time on total phenol, flavonoids, β-carotene, ascorbic acid contents, and antioxidant capacity (ORAC, DPPH^•) of fresh-cut "Tommy Atkins" mango stored for 15 d at 5 °C was investigated. Fresh-cut mango was irradiated for 0, 1, 3, 5, and 10 min prior to storage at 5 °C. UV-C irradiation for 10 min induced a hypersensitive defense response resulting in the phenols and flavonoids accumulation which was positively correlated with ORAC and DPPH^• values. However, β-carotene and ascorbic acid content of fresh-cut mangos decreased with irradiation time during storage. Antioxidant capacity (ORAC, DPPH^•) was increased in fresh-cut mangoes treated with UV-C irradiation. In conclusion, UV-C irradiation appears to be a good technique to improve the total antioxidant capacity of fresh-cut mango.     

GAMMA IRRADIATION, HOT WATER AND IMAZALIL TREATMENTS ON DECAY ORGANISMS AND PHYSICAL QUALITY OF STORED NETTED MUSKMELON FRUIT

Nonchemical treatments of gamma irradiation (2 Kilograys) and hot water (57°C) and the fungicide imazalil (1000 ppm) were compared with and without shrink-film wrap for effects on decay and physical quality of netted muskmelon fruit stored at 4°C for 0 through 60 days. Gamma irradiation was ineffective in controlling decay and surface molds, and injurious to physical quality by decreasing firmness, increasing fresh weight loss, membrane leakage and vein track browning. Hot water treatment coupled with shrink-film wrap was effective in controlling decay activity and maintaining physical quality up to 20 days storage. Imazalil coupled with shrink-film wrap controlled the incidence and severity of decay and maintained fruit firmness, moisture loss, membrane permeability and vein track browning for almost 60 days storage.     

Effect of Hot Water Treatments on Quality of Highbush Blueberries

ABSTRACT:  Highbush blueberries, cv 'Burlington', were treated with 22, 45, 50, or 60 °C water for 15 or 30 s along with an untreated control. Fruit were then stored for 0, 1, 2, or 4 wk at 0 °C and 2 or 9 d at 20 °C prior to evaluation of microbial population and fruit quality. After 4 wk of storage, the hot water treatment at 60 °C resulted in 92% marketable berries, followed by 90% at 50 °C, 88% at 45 °C, and 83% at 22 °C compared with 76% in untreated controls. Decay incidence was reduced to 0.6%, 1.2%, 1.4%, or 2.8% with 60, 50, 45, or 22 °C water treatments, respectively, compared with 5.1% in controls following 4 wk at 0 °C and 2 d at 20 °C. After an additional 7 d at 20 °C, decay in fruit treated at 60 °C for 15 or 30 s remained at 1.8% and 0.4%, respectively, compared to 37.4% in controls. Weight loss of berries treated with hot water was 0.4% against 3.8% in controls, and shriveled and split berries were also reduced compared to controls ( P < 0.001). Aerobic plate count and yeast and mold count were reduced by 0.45 to 0.7 log at 60 °C for 30 s. Botrytis cinerea and Colletotrichum sp. were the dominant fungal pathogens causing decay of Burlington blueberries during storage. Hot water treatments also immediately induced an increase in ethanol and reduced fruit titratable acidity and soluble solids content, but had no significant effect on fruit firmness, pH, or most flavor volatile concentrations.     

Preservation and shelf-life extension of shrimps and clams by high hydrostatic pressure

Clam ( Venus gallina ) and shrimp ( Parapenaeus longirostris ) samples were high hydrostatic pressure (HHP) treated at 200, 220 and 250 MPa at 25, 30, 40 and 50 °C for 10 and 20 min. Based on the results of microbial reduction, the best combinations of HHP treatments were determined as 250 MPa, 50 °C, 10 min for shrimps and 220 MPa, 50 °C, 10 min for clams. HHP-treated samples stored at 25 °C (room tempertur) and 4 °C (refrigeration temperature) were analysed. According to the results evaluated, shelf-life of shrimps was found to be 12 and 16 days for storage at room and refrigeration temperatures, respectively, as compared with 4 days for non-HHP-treated samples at 4 °C. Similarly shelf-life for the clam samples was found to be 12 days for storage at room temperature and 18 days for storage at refrigeration temperature as compared with 4 days for non-HHP-treated samples at 4 °C.     

Effects of Electron Beam Irradiation on Physical, Textural, and Microstructural Properties of "Tommy Atkins" Mangoes (Mangifera indica L.)

This research focused on determining the dose levels suitable for electron beam irradiation of mangoes without detriment to the fruit's quality characteristics. Physicochemical, textural, respiration rates, microstructural, and sensory characteristics of “Tommy Atkins” mangoes irradiated at 1.0, 1.5, and 3.1 kGy using a 10 MeV (10 kW) linear accelerator with double‐beam fixture were determined. Fruits were stored at 12 °C and 62.7% RH for 21 d and evaluated at days 0, 5, 10, and 21. Nonirradiated mangoes served as controls. Irradiation did affect the textural characteristics of mangoes at doses higher than 1.0 kGy. Mangoes exposed to 1.5 and 3.1 kGy were softer and less stiff throughout storage. The radiation‐induced softening of the fruits may be associated with changes in the structural cell such as cracks and depressions on the surface and the breakdown of the cells and its components. Irradiation at 3.1 kGy affected the color of mangoes by the end of storage. Doses up to 1.5 kGy kept respiration rates at a normal level. Irradiation did not affect the specific gravity of mangoes, a parameter associated with fruit maturity levels. No effect of irradiation on pH, water activity, moisture content, acidity, and juiciness of mangoes was detected at the dose levels used in this study. Only fruits irradiated at 3.1 kGy were unacceptable to the sensory panelists in terms of overall quality, texture, and aroma. Electron beam irradiation of “Tommy Atkins” mangoes at 1.0 kGy is the recommended treatment to maintain the overall fruit quality attributes.     

Sugars and organic acids in Japanese plums (Prunus salicinaLindell) as influenced by maturation, harvest date, storage temperature and period

The effects of fruit maturation, harvest date, storage temperature, storage period and shelf life, on the concentrations of individual sugars and organic acids in Japanese plums were investigated. During fruit maturation in 'Amber Jewel' plums, sucrose concentration increased significantly from 101 days after full bloom (DAFB) to 1 week after commercial maturity (136 DAFB) with a non-significant change in the concentration of total organic acids and malic acid, the major organic acid. The changes in concentrations of sugars and organic acids during cold storage of 'Amber Jewel' plums harvested on 129 and 136 DAFB appeared to be independent of harvest date. Storage of 'Amber Jewel' plums at 5 °C accelerated the loss of sucrose and increased the concentrations of fructose and glucose from the 4^th week of storage compared with those stored at 0 °C. 'Blackamber' plums did not undergo any significant increase in the total and individual sugars during 5 weeks storage and subsequent shelf-life of 8 days at 20 °C. Malic acid concentrations declined during storage from 3 weeks onwards with a further substantial loss during ripening at 20 °C. Maturation, harvest date, storage temperature, storage period and shelf-life affect the concentrations of sugars and organic acids in Japanese plums.     

Methyl jasmonate reduces chilling injury symptoms and enhances colour development of ‘Kent’ mangoes

Treatment of mango (Mangifera indica cv ‘Kent’) fruits with methyl jasmonate (MJ) vapour for 20 h at 20 °C reduced chilling injury (CI) symptoms and enhanced skin colour development. MJ at 10^?4 M was the most effective concentration for reducing CI and decay in fruits stored at 5 °C followed by 7 days at 20 °C (shelf‐life period). The use of 10^?5 M MJ enhanced yellow and red colour development of mangoes stored at 20 °C. These fruits possessed higher L*, a* and b* values than untreated fruits and those treated with 10^?4 M MJ. Ripening processes were inhibited by cold storage (5 °C) in control fruits. After cold storage and shelf‐life period, fruits treated with 10^?5 M MJ ripened normally and contained the highest total soluble solids (TSS). These fruits also maintained higher sugar and organic acid levels than fruits subjected to other treatments. We concluded that MJ treatment could be used to reduce decay and CI symptoms and also to improve colour development of mango fruits without adversely affecting quality. © 2001 Society of Chemical Industry     

Effect of Processing Under Ultraviolet Light on the Shelf Life of Fresh-Cut Cantaloupe Melon

ABSTRACT: The effect of processing cantaloupe melon under ultraviolet-C (UV-C) radiation on storage properties of the cut fruit at 10 °C was compared with post-cut UV-C fruit treatment and the untreated control. Cutting fruit under UV-C light induced a hypersensitive defense response that resulted in increased accumulation of ascorbate peroxidase relative to the other 2 treatments. Fruit processed under UV-C radiation had the lowest esterase activity throughout the storage period. Lipase activity was higher in post-cut treated fruit than fruit processed under UV-C light and the control fruit. Lipase activity, however, decreased rapidly in fruit processed under UV-C and was undetectable after 7 d of storage. Human sensory aroma evaluation indicates reduced rancidity, and instrumental texture measurements suggested improved firmness retention in fruit cut under UV-C radiation. The treatment also reduced respiration during cut fruit storage. UV-C was effective in reducing yeast, mold, and Pseudomonas spp populations in both treatments. Fresh-cut pieces from whole melon cut under UV light had lower populations of aerobic mesophilic and lactic acid bacteria relative to the control and post-cut treated pieces. Results indicate that while post-cut application of UV improved shelf life of cut cantaloupe melon, cutting fruit under UV-C radiation further improves product quality.     

Reduction of chilling injury in ripe Alphonso mango fruit in cold storage by temperature conditioning

The influence of ripening temperature and cold conditioning of pre-climacteric fruits on the incidence of chilling injury (CI) in ripe mango fruits cv. Alphonso during refrigerated storage was investigated. Fruits previously held and ripened at tropical ambient temperature (AT, 27–34°C) developed CI (skin staining or browning) when ripe fruits were subsequently stored at 5, 10, or 15°C for shelf-life extension. Fruits held and ripened at 20°C1°C, RH 85–90% showed little evidence of CI when subsequently stored at 5 or 10°C up to 14 days. Chilling injury in ripe mangoes was also avoided by holding pre-climacteric fruits for a minimum period of 30 days at 10°C and then ripening them at 27–34°C. The quality of the ripe mangoes remained good during cold storage for 7 days and were acceptable until 10–14 days with minimal changes in texture, flesh colour, carotenoids, total soluble solids, titratable acids and ascorbic acid. Shelf-life of ripe mangoes can thus be extended under refrigeration by pre-storage conditioning.     

UV‐C irradiation reduces breakdown and chilling injury of peaches during cold storage

Pre‐storage exposure of peaches (Prunus persica cv Jefferson) with UV‐C irradiation for 3, 5 or 10 min significantly reduced chilling injury after 14 and 21 days of storage at 5 °C plus 7 days of shelf‐life at 20 °C. Similar reduction in fungal decay was also found by these treatments. Skin browning and UV damage were found to be moderate to severe in peaches after the 15 or 20 min of UV‐C treatments. The 20 min of exposure accelerated deterioration. Fruit treated with UV‐C for 3, 5 or 10 min remained firmer and softened more slowly than the control and those treated with longer durations of exposure. No differences were found in weight loss or respiration rates among the treatments. However, ethylene production was stimulated by all of the UV‐C treatments compared with the control. Putrescine levels increased initially after 3 or 5 min of exposure to UV‐C. A tendency toward higher accumulation of spermidine and spermine was found in peaches after UV exposure. These higher levels of polyamines apparently are a response to the UV‐C irradiation and might be beneficial in increasing the resistance of fruit tissue to deterioration and chilling injury. Copyright © 2004 Society of Chemical Industry     

Irradiation Effects on the Ripening of Kent Mangoes

SUMMARY— Kent mango fruit irradiated with 0, 100, 200, and 300 Krad were ripened at 20°C for 0, 4, and 8 days.
Irradiated mangoes were less firm than control fruit immediately after irradiation, but fruit softening due to ripeness was more pronounced than softening induced by irradiation. Irradiated fruit contained higher water-soluble and lower Versene-vinsoluble pectic fractions as compared to unirradiated fruit. NO differences were observed in the content of the Versene-soluble fraction among all irradiation dosages. Higher PE activities were exhibited by the irradiated fruit throughout the ripening period. Irradiated fruit contained higher AIS and lower soluble solids than control fruit. No differences in sucrose content due to irradiation were observed, but there were less reducing and total sugars at the 300 Krad dose as compared to other dosages.
Changes in pectic fractions and PE activity were more pronounced immediately following irradiation in comparison to those occurring during ripening. The increase in soluble solids as well as sucrose, and the decrease in AIS, titratable acidity, reducing sugars and firmness during ripening proceeded at faster rates in control fruit than in the irradiated fruit. These variable rates of change were reflected by the significant irradiation dose and storage duration interactions.
Results suggest that irradiation induces a delay in ripening of Kent mangoes.     

UV-C处理对杨梅采后品质及苯丙烷类代谢的影响

以“东魁”杨梅果实为材料,研究不同剂量的短波紫外线（UV-C）照射处理对杨梅果实采后品质、抗氧化活性、苯丙烷类代谢产物含量和相关酶活性的影响。杨梅果实先用0、1.5、3.0、4.5、6.0 kJ/m2剂量的UV-C照射处理,然后转入5 ℃贮藏12 d。结果表明,3.0 kJ/m2 UV-C处理显著地抑制了杨梅果实贮藏期间腐烂的发生,延缓了果实硬度和VC含量的下降,保持了果实品质;UV-C处理还显著提高了果实中苯丙氨酸解氨酶、4-香豆酰辅酶A连接酶、查尔酮异构酶和肉桂醛羟化酶等苯丙烷类代谢相关酶的活性,增加了总酚、花色苷、胡萝卜素和类黄酮的积累,保持了果实较高的抗氧化活性。     

Control of Postharvest Quality in Blueberry Fruit by Combined 1-Methylcyclopropene (1-MCP) and UV-C Irradiation

The objective of this study was to investigate the effects of 1-methylcyclopropene (1-MCP) combined with UV-C irradiation on postharvest quality of blueberry fruit (Vaccinium spp. Berkeley) stored at 4 ± 1 °C for 8 days. Respiration rate, ethylene production, decay incidence, softness, color, total anthocyanin content, malondialdehyde (MDA) content, titratable acid content, soluble solid content, peroxidase (POD), phenylalanine ammonia lyase (PAL), and catalase (CAT) of treated blueberry fruit were examined. The results indicated that treatment with 1-MCP plus UV-C irradiation inhibited respiration rate, ethylene production, decay incidence, and MDA content. The combined treatment also delayed softness, color, titratable acid, and soluble solid content and improved total anthocyanin content of blueberries throughout the storage period at 4 ± 1 °C compared to the untreated samples. The efficiency of the combined treatment (1-MCP + UV-C irradiation) was better than that of 1-MCP or UV-C irradiation alone. Furthermore, combination of 1-MCP and UV-C irradiation effectively enhanced PAL and CAT activities and inhibited the increasing of POD activity in blueberries. Therefore, our results shows that 1-MCP plus UV-C irradiation treatments may be a useful method in maintaining commercial quality and extending shelf life of blueberries.     

Effect of temperature and fruit-moisture content on discolouration of dried, sulphured Bon Chretien pears during storage

Summary Discolouration of Bon Chretien pears which had been treated with sulphur dioxide and which had moisture contents of either 16, 18 or 20%, was monitored during storage at 4, 7, 10 and 20 °C. Colour was quantified in terms of CIE L*, a*, b*, hue and chroma. L* was used to predict quality retention. Discolouration was categorized as a decrease in all colour parameters, except a* which increased with storage. Measurement of L* showed that only fruit at 16% moisture content and stored at T ≤ 10 °C retained their original colour. The rate of change in overall colour was observed in the following order at 20 °C, 20% > 18 > 16% moisture content. Fruit with 18 and 20% moisture content could be stored at 10 °C for at least 140 weeks without changing their quality grading. Storage at 20 °C shortened this period to 60 and 27 weeks for fruit at 18 and 20% moisture content, respectively.     

Efficacy of Pressure-Assisted Thermal Processing, in Combination with Organic Acids, against Bacillus amyloliquefaciens Spores Suspended in Deionized Water and Carrot Puree

ABSTRACT:  Effect of organic acids (acetic, citric, and lactic; 100 mM, pH 5) on spore inactivation by pressure-assisted thermal processing (PATP; 700 MPa and 105 °C), high pressure processing (HPP; 700 MPa, 35 °C), and thermal processing (TP; 105 °C, 0.1 MPa) was investigated.  Bacillus amyloliquefaciens  spores were inoculated into sterile organic acid solutions to obtain a final concentration of approximately 1.3 × 10⁸ CFU/mL.  B. amyloliquefaciens  spores were inactivated to undetectable levels with or without organic acids after 3 min PATP holding time. At a shorter PATP treatment time (approximately 2 min), the inactivation was greater when spores were suspended in citric and acetic acids than in lactic acid or deionized water. Presence of organic acids during PATP resulted in 33% to 80% germination in the population of spores that survived the treatment. In contrast to PATP, neither HPP nor TP, for up to 5 min holding time with or without addition of organic acids, was sporicidal. In a separate set of experiments, carrot puree was tested, as a low-acid food matrix, to study spore recovery during extended storage following PATP. Results showed that organic acids were effective in inhibiting spore recovery in treated carrot puree during extended storage (up to 28 d) at 32 °C. In conclusion, addition of some organic acids provided significant lethality enhancement ( P  < 0.05) during PATP treatments and suppressed spore recovery in the treated carrot puree.     

Effect of hot water surface pasteurization of whole fruit on shelf life and quality of fresh-cut cantaloupe

ABSTRACT:  Cantaloupes are associated with recent outbreaks of foodborne illnesses and recalls. Therefore, new approaches are needed for sanitization of whole and cut fruit. In the present study, whole cantaloupes were submerged into water in the following 3 conditions: 10 °C water for 20 min (control), 20 ppm chlorine at 10 °C for 20 min, and 76 °C water for 3 min. Populations of microflora were measured on the rinds of the whole cantaloupes. Quality and microbial populations of fresh-cut cantaloupes prepared from whole fruit were analyzed after 1, 6, 8, 10, 13, 16, and 20 d of storage at 4 °C. The hot water significantly reduced both total plate count (TPC) and yeast and mold count on rind of whole fruits while chlorine or cold water wash did not result in a significant reduction of microbial population. Fresh-cut pieces prepared from hot water-treated cantaloupes had lower TPC than the other 2 treatments in the later storage periods (days 13 to 20) in 2 of 3 trials. The hot water treatment of whole fruits was inconsistent in reducing yeast and mold count of fresh-cut pieces. Soluble solids content, ascorbic acid content, fluid loss, and aroma and appearance scores were not consistently affected by either hot water or chlorine treatment. Our results suggested that hot water pasteurization of whole cantaloupes frequently resulted in lower TPCs of fresh-cut fruit during storage and did not negatively affect quality of fresh-cut cantaloupes.     

采后UV-C照射对芦柑抗病性和品质的影响

研究不同剂量UV-C照射处理对采后芦柑在15℃贮藏期间腐烂率及主要品质指标的影响。结果表明,1.5kJ/m2或3kJ/m2UV-C照射能有效减轻果实贮藏期间腐烂,推迟腐烂6d或12d,显著降低腐烂率。贮藏后期,1.5kJ/m2或3kJ/m2处理降低了失重率,提高了果实的可溶性固形物含量、糖酸比和VC含量,且促进了果肉中类黄酮和总酚的次生代谢合成,从而较好地保持了果实的感官品质和营养品质。1.5kJ/m2或3kJ/m2处理也有助于提高果皮中类黄酮和总酚含量。UV-C照射处理作为采后芦柑的非化学贮藏保鲜手段,具有潜在的应用前景。     

Microbial growth and colour of minimally processed shiitake mushroom stored at different temperatures

The effect of storage temperature on the microbiological and sensory characteristics of minimally processed shiitake was investigated. Shiitake mushrooms were washed, sanitised, packed in polystyrene trays, overwrapped with plastic film and stored at 7, 10 or 15 °C. Microbial counts, polyphenoloxidase activity, external lightness ( L* ) and acceptance tests were conducted. Mesophilic, aerobic psychrotrophic bacteria, yeasts and moulds predominated during storage. Pseudomonas was detected after 10 days' storage showing an increase of, approximately, 7 log cycles at 15 °C. Mushroom rejection occurred when the microbial population was lower than 10⁶ CFU g⁻¹, suggesting that, other factors, such as browning, affect mushroom spoilage more than microbial activity. Mushrooms treated with citric or ascorbic acids maintained high L * value during 10 days. The shelf life of minimally processed shiitake mushrooms was 10 days at 7 °C, but less than 5 days at 10 °C, and approximately 3 days at 15 °C.     

短波紫外线对草莓采后腐烂、苯丙烷类代谢和抗氧化活性的影响

以‘红艳’草莓为材料,研究短波紫外线(ultraviolet-C,UV-C)处理对草莓果实在5℃、12 d贮藏期间腐烂、苯丙烷类代谢和抗氧化活性的影响。结果表明,2.0 k J/m2 UV-C处理能显著抑制草莓果实贮藏期间腐烂指数的上升。同时,UV-C处理能有效诱导果实贮藏期间苯丙氨酸解氨酶、肉桂酸羧化酶、对香豆酰-Co A连接酶、查尔酮异构酶和二氢黄酮醇还原酶活性的增加,维持较高的总酚、总花色苷、总黄酮以及主要酚类和花色苷类单体的含量,促进果实1,1-二苯基-2-三硝基苯肼自由基清除率和总还原力的上升,抑制羟自由基清除率的下降,从而保持了果实较高的抗氧化活性。     

Storage technology of onion bulbs c.v. Rouge Amposta: effects of irradiation, maleic hydrazide and carbamate isopropyl, N-phenyl (CIP) on respiration rate and carbohydrates

The effects of γ-irradiation, maleic hydrazide (MH) and carbamate isopropyl, N-phenyl (CIP) on the carbohydrate content, respiration rate (RR) sprouting and rotting of red onion bulbs ( Allium cepa L.) c.v. Rouge Amposta stored at 4, 10 and 20 °C were investigated. Between 6 and 8 weeks soluble sugars increased in concentration and varied between 6.0 and 6.5% fresh weight both at 10 and 20 °C. However, this peak did not exceed 6.0% fresh weight at 4 °C. The basal amount of soluble sugars was about 3% fresh weight. The content appeared to be influenced by temperature, with greater accumulation at 10 and 20 °C than at 4 °C. The RR increased when the bulbs sprouted, whereas it was reduced by the following treatments: irradiation, MH and CIP, the respiration of irradiated bulbs decreased during the final stage of storage because of the death of the sprouts. The chemical treatment used were effective in controlling sprouting of the bulbs during storage, although not as effective as irradiation and chilling.