María Serrano

Postharvest biology and technology for preserving fruit quality.

Introduction and Overview Fruit Ripening Introduction Fruit Growth Fruit Ripening and Related Parameters Changes in Fruit Quality Attributes During Handling, Processing, and Storage Introduction What is Quality? Weight Loss Appearance Texture Flavor, Taste, and Aroma Bioactive Compounds Decay Mechanical Damage versus Fruit Quality Cold Storage and Fruit Quality Introduction Effect of Low Temperature Storage on Fruit Metabolism Cooling Rates Precooling Techniques Chilling Injury Heat Treatments Introduction Means of Heat Application Heat Treatments and Fruit Quality Storability Limitations: Heat Damage Calcium Treatments Introduction Calcium Sources and Pre- and Postharvest Methods for Application Pre- and Postharvest Calcium Treatments and Calcium Fruit Content Effect of Preharvest Treatment on Fruit Size Calcium Treatments and Fruit Firmness Calcium Treatments and Color, Soluble Solids, and Total Acidity Calcium Treatment and Bioactive Compounds Calcium Treatment, Cell Membrane Stability, and CI Reduction Effects of Calcium Treatment on Postharvest Decay Calcium Treatment and Ethylene Production and Respiration Rate Undesirable Effects of Calcium Treatments Polyamine Treatments Introduction Polyamine Biosynthesis and Regulation in Plant Tissues Polyamine and Human Diet Polyamine and Fruit Development Preharvest Polyamine Application and Fruit Ripening Postharvest Polyamine Application and Fruit Quality Polyamines and Chilling Injury Polyamines and Mechanical Damage Future Trends 1-Methylcyclopropene Treatments Introduction 1-MCP as Blocking Ethylene Receptors Postharvest 1-MCP Application 1-MCP in Nonclimacteric Fruits Preharvest 1-MCP Application 1-MCP on Physiological and Pathological Disorders Storage in Modified Atmosphere Packaging Introduction Films used in MA Packaging Generation of the Steady-State or Equilibrium Atmosphere Optimal CO2 and O2 Concentration Importance of Temperature Stability MAP and Fruit Quality Maintenance MAP Benefits for Storage of Fresh-Cut Fruits and Vegetables Future Research Needs Active Packaging Introduction Active Packaging Technologies Ethylene Adsorbers Antimicrobial Fruit Packaging Edible Coatings Future Trends Emerging Technologies Introduction Atmospheres with High O2 Biological Control UV-Irradiation References

Tools to Maintain Postharvest Fruit and Vegetable Quality through the Inhibition of Ethylene Action: A Review

Ethylene is a plant hormone controlling a wide range of physiological processes in plants. During postharvest storage of fruit and vegetables ethylene can induce negative effects including senescence, over-ripening, accelerated quality loss, increased fruit pathogen susceptibility, and physiological disorders, among others. Apart from the endogenous ethylene production by plant tissues, external sources of ethylene (e.g. engine exhausts, pollutants, plant, and fungi metabolism) occur along the food chain, in packages, storage chambers, during transportation, and in domestic refrigerators. Thus, it is a great goal in postharvest to avoid ethylene action. This review focuses on tools which may be used to inhibit ethylene biosynthesis/action or to remove ethylene surrounding commodities in order to avoid its detrimental effects on fruit and vegetable quality. As inhibitors of ethylene biosynthesis and action, good results have been found with polyamines and 1-methylcyclopropene (1-MCP) in terms of maintenance of fruit and vegetable quality and extension of postharvest shelf-life. As ethylene scavengers, the best results can be achieved by adsorbers combined with catalysts, either chemical or biological (biofilters).

Maturity stage at harvest determines the fruit quality and antioxidant potential after storage of sweet cherry cultivars.

Eleven sweet cherry cultivars were harvested at three maturity stages (S1 to S3) based on skin color and stored at 2 degrees C for 16 days and a further period of 2 days at 20 degrees C (shelf life, SL) to analyze quality (color, total soluble solids, and total acidity) and bioactive compounds (total phenolics and anthocyanins) and their relationship to total antioxidant activity (TAA), determined in hydrophilic (H-TAA) or lipophilic (L-TAA) fraction. For all cultivars and maturity stages, the ripening process advanced during postharvest storage with increases in color intensity and decreases in acidity, as well as enhancements in phenolics, anthocyanins, and TAA in both H-TAA and L-TAA, although important differences existed among cultivars. The results showed that sweet cherry should be harvested at stage S3 (4 days later than the commercial harvest date) since after 16 days of cold storage + SL, the highest antioxidant capacity was achieved for both H-TAA and L-TAA.

Spectroscopy and Lasing of Yb-Doped

Tetragonal (space group f4 macr) single crystals of NaY(WO4)2 doped with Yb to a density of 4.52 times 1020 cm-3 have been employed as laser active materials for the 1-mum spectral range, operating at room temperature. Using Ti:sapphire laser pumping, slope efficiencies as high as 74.6% were achieved without special cooling for the pi-polarization. The Yb-laser was continuously tunable from 1003.7 to 1073.0 nm with a birefringent filter. Pulses as short as 53 fs were obtained at 1035 nm by SESAM passive mode-locking with intracavity dispersion compensation and additional extracavity pulse compression using analogous prism pairs. Experimental data on the spectroscopic properties of Yb3+ in the 5-300 K temperature range and the room temperature optical properties of this novel Yb-host is also presented.

{\hbox {NaY}}{({\hbox {WO}}_{4})}_{2}

Abstract Lettuce seeds from nine cultivars were germinated under control and saline (150 mM NaCl) conditions. The effect of salt stress on germination, growth, ethylene production, respiration rate and polyamine levels was investigated. Salinity delayed germination and reduced the growth of all studied cultivars, but only significantly reduced final germination percentage in Inverna and Baby Star cultivars, while the other seven cultivars reached 100% germination under saline conditions. Respiration rate and ethylene production increased with salinity in all the nine lettuce cultivars. Moreover, cultivars that had a higher increase in ethylene production under salt stress showed the lowest reduction in fresh weight. The presence of salt reduced putrescine (Put) level, while spermidine (Spd) and spermine (Spm) increased. The effects of salinity on ethylene production and polyamine metabolism are discussed in relation to salinity tolerance of lettuce seedlings. The possible role of ethylene and polyamines as physiological markers for salinity tolerance in lettuce seedlings is also discussed.

: Tunable and Femtosecond Mode-Locked Laser Operation

In this work the antifungal efficacy of thymol, carvacrol and the mixture of both pure essential oils has been proved against Penicillium digitatum and Penicillium italicum, by using in vitro (liquid media, PDA plates and disk growth) and in vivo (lemon) tests. Results indicated that both essential oils were effective in inhibiting fungal growth in all in vitro tests, with the highest efficacy displayed by thymol. In addition, the application of wax with thymol and carvacrol to lemons inoculated with P. digitatum demonstrated the reduction of decay (expressed as percentage of infected fruit surface) in a concentration dependent manner, as well as reduced respiration rate, ethylene production and total acidity losses. Thus, the application of these essential oils together with wax in the citrus packing lines could be considered as good alternatives to reduce the use of synthetic fungicides.

Changes in ethylene evolution and polyamine profiles of seedlings of nine cultivars of Lactuca sativa L. in response to salt stress during germination

Abstract The role of putrescine was investigated, exogenously applied during postharvest storage of mechanically damaged (50 N force) plums, (Prunus salicina Lindl., cv. BlackStar) at 10 °C, in relation to fruit firmness (force–deformation ratio and fruit flesh deformation) and ethylene and CO2 production rates. The metabolism of endogenous polyamines (free, conjugated-soluble, and cell wall-bound was also studied. Infiltration of putrescine led to a reduction in mechanical damage, and an increase in firmness of both force–deformation ratio and fruit flesh firmness parameters. Exogenous putrescine inhibited and delayed ethylene and CO2 production rates. The analysis of polyamine metabolism revealed an activation of the polyamine biosynthesis pathway, showing an accumulation of cell wall putrescine and spermidine, which are possibly responsible for the greater firmness of putrescine-treated plums compared with controls. In these treated fruit, the increase in free spermidine levels could be acting as a physiological marker of mechanical damage.

THE EFFECTS OF ESSENTIAL OILS CARVACROL AND THYMOL ON GROWTH OF PENICILLIUM DIGITATUM AND P. ITALICUM INVOLVED IN LEMON DECAY

In this article 11 commercial sweet cherry cultivars were selected to evaluate sensory, nutritive and functional properties over the maturation process on tree. Fruit quality was significantly different among cultivars and maturity stages at harvest, with the highest quality scores being found in the harvest which was 4 days beyond current commercial harvest maturity for all the cultivars tested. Taking into account all of the measured parameters (weight, firmness, color, acidity and total soluble solids), ‘NY-6479’, ‘Prime Giant’ and ‘Sunburst’ could be classified as having the highest quality in terms of sensory attributes. However, ‘Cristalina’ and ‘Sonata’ had the highest functional quality, as determined by the measurement of bioactive compound content and antioxidant capacity. We conclude that a delay of a few days in harvesting of sweet cherries would lead to achieve maximal nutritional (highest sugar and organic acid contents), sensory (greatest firmness and color development) and functional (greatest phenolics content, anthocyanins and antioxidant capacity) quality to provide both eating enjoyment and health benefits to the consumer.

Role of polyamines in extending shelf life and the reduction of mechanical damage during plum (Prunus salicina Lindl.) storage

Oxalic acid at three concentrations (2, 4, and 6 mM) was applied by dipping to pomegranate fruits of cv. Mollar de Elche, which were then stored for 84 days at 2 degrees C. Pomegranate is a chilling-sensitive fruit and, thus, control fruits exhibited chilling injury (CI) symptoms after long-term storage at 2 degrees C that were accompanied by increased respiration rate, weight loss, and electrolyte leakage (EL). The CI symptoms were significantly reduced by oxalic acid treatment, especially for the 6 mM concentration. In addition, control pomegranates showed significant reduction in the content of total phenolics and ascorbic acid as well as in total antioxidant activity (TAA), in both hydrophilic (H-TAA) and lipophilic (L-TAA) fractions. The application of oxalic acid led to lower losses of total phenolics and significant increase in both ascorbic acid content and H-TAA, whereas L-TAA remained unaffected. Thus, oxalic acid could be a promising postharvest treatment to alleviate CI and increase antioxidant potential.

Sensory, Nutritive and Functional Properties of Sweet Cherry as Affected by Cultivar and Ripening Stage

Output powers as high as 300mW were obtained at 1925nm in the cw regime with a Tm laser operating at room temperature, either with Ti-sapphire or diode laser pumping, using a new single crystal of NaGd(WO4)2 grown by the Czochralski method and doped with 5mol.% of Tm3+ in the melt. This crystal belongs to the I4¯ tetragonal space group and exhibits a locally disordered structure due to the random occupancy of the same lattice sites by Na and Gd (or Tm) ions. The local disorder results in large bandwidths of the Tm3+ optical transitions (e.g., FWHM≈60cm−1 at 5K for the H63-->F43 transition involved in the laser emission), which allows one to obtain one of the broadest laser tunability ranges, from 1813 to 2025nm(≈17THz), achieved with a Tm3+-doped crystalline material. A detailed characterization of the Tm3+ optical spectroscopy in this novel host was performed at 5 and 300K.