Juan Antonio Martínez

Controlled atmosphere storage of pomegranate

Pomegranates cv. “Mollar” were stored for up to 8 weeks at 5 °C and above 95% relative humidity (RH) in air and in controlled atmospheres of 10% O2 and 5% CO2, 5% O2 and 5% CO2, 5% O2 and 0% CO2 and 5% O2 and 0% CO2 ethylene-free. Storage was followed by a shelf-life period of 6 days at 20 °C in air. Respiratory activity slightly declined during storage at 20 °C, from 12 to 8 ml CO2 · kg−1 · h−1 and was around 4 ml CO2 · kg−1 · h−1 at 5 °C showing a non-climacteric pattern. When compared with color at harvest, an increase in thea* value in the juice from pomegranates stored in 10% O2 and 5% CO2 was observed. This supports that view that juice red colour can increase in intensity during storage. Controlled atmosphere storage reduced weight loss, the risk of decay and the severity of husk scald (except at 10% O2 and 5% CO2). The relatively low control of husk scald at 5% O2 disagrees with the level proposed previously for “Wonderful” cv.; “Mollar” cv. seems to be more sensitive to scald than other varieties. No symptoms of black spots or membranose and no off-flavours were detected at any time. However after a period of shelf-life storage, the controlled atmosphere caused a slight reduction (lower than in air-stored fruit) in titratable acidity, reducing sugars and vitamin C and an increase of the soluble solids content/titratable acidity (maturity index) without differences among the various gas compositions studied. The maturity index must be considered to be a good criterion of pomegranate maturity for sweet varieties.

Response to fire of a predominantly transient seed bank in a Mediterranean weedy pasture (eastern-central Spain)

Abstract The impact of fire on the viability of the entire soil seed bank in a Mediterranean pasture dominated by weeds originating from arable fields, and its recovery in the first post-fire year, were investigated. Soil samples were excavated separately in 0-2 cm and 2-5 cm deep layers, and their seed content was assessed using the seedling emergence method. Emergent seedling counts were carried out in the field during the spring following the fire. Analysis of samples from an unburnt stand revealed that annuals (83% species, 86% seeds), and weeds (50% species, 30% seeds) were a major component in the seed bank. Seed banks of most species (85%) were accumulated in the upper soil layer, denoting their transient nature. Fire severely reduced the density and species richness of the seed bank, as expected for a mainly transient soil seed bank in a community not exposed to a recurrent wildfire regime throughout its evolutionary history. One year after the fire, the seed bank increased in density and species richness, particularly in the upper soil layer. The recovery occurred in two ways: i) in-site seed production from seeds which survived the fire and germinated, and ii) wind-borne seed invasion from adjacent unburnt vegetation. The first type of recovery was mainly the result of relatively large-seeded species with short-distance seed dispersal mechanisms, whereas the second was observed for anemochorous and/or tiny-seeded species. We conclude that the ability of weedy communities to respond to fire is based on the colonizing and invasive nature of the species. Consequences for the use of fire in the management of such communities are discussed.

Efectos de la conservación frigorífica en la fisiología y calidad del melocotón Sudanell.

Firm-ripe (R) and firm-breaker (B) Sudanell and Sudanell-1 peach cultivars were stored at 0 °C and 90-95% relative humidity (RH) for 40 days plus a subsequent ripening period of 3 days at 20 °C. For one batch thermal pretreatment at 30 °C for 84 h was also applied. In Sudanell peaches after 2 weeks of cold storage plus subsequent ripening, radiating internal flesh browning (IB) was marked. In Sudanell-1 cv, a short delay in the appearance of IB was detected. The latency period of IB was 2 weeks for Sudanell R, and 3 weeks for Sudanell B and Sudanell-1. In Sudanell-1 R ethylene emis sion decreased to a minimum after 12 days of storage, probably related to the latency period of IB. Concomitantly with IB development, flesh firmness decreased, remaining relatively high after sub sequent ripening, when abnormal and astringent flavors appeared. When the latency period was surpassed ethylene emission and respiration increased slightly. After 48 h of thermal pretreatment, these emissions were reduced and remained constant until the end of treatment. This effect per sisted throughout cold storage and IB development was reduced. After 2 weeks of storage fungal attacks appeared and were widespread after 4 weeks (mainly Alternaria sp. alone or associated to IB). Sudanell-1 showed the highest weight losses due to fungal attacks and dehydration.

Influence of fungicide treatment and storage conditions on mould and yeast activity on “Satsuma” mandarin

The activity of mould and yeast population on the surface of ‘Satsuma’ mandarin was studied at four temperatures (2, 4, 10 and 20 °C) and two relative humidity (RH) levels (80 and 93%) on fruits washed and on fruits washed and treated with a fungicide mixture (1200 ppm thiabendazole + 800 guazatine + 400 ppm prochloraz), stored for 20 and 40 days. The lowest final microbial counts (CFU) were for the fruits treated and stored at 2 °C and 93% RH and the highest counts were for fruits stored at 20 °C and 93% RH regardless of fungicide treatment. Throughout the storage period, yeast and Cladosporium spp. were predominant in the microbial counts and generally showed reducing trends. The fungicide treatment was very efficient and persistent. The absence of antifungal treatment and the increase of RH levels caused a greater rise of CFU than the increase of the storage period or temperature. An increase in the CFU values with the increase of RH was observed in untreated fruits. The treatment of ‘Satsuma’ fruits with the fungicide mixture, followed by cold storage at 2 °C and 93% RH, extended the storage period at least 40 days.

Uncommon disorders and decay in near-isogenic lines of melon and reference cultivars

Postharvest disorders and rots can produce important economic losses in fruits stored for long time for exportation. The genetic and physiological basis of some disorders in melon (Cucumis melo L.) are unknown and particularly the possible relation with climacteric behavior. A collection of melon near-isogenic lines (NILs) (SC3-5 and seven more showing climacteric and two non-climacteric ripening pattern) were analyzed to study genetic and physiological aspects of fruit disorders and rots. Two non-climacteric (Nicolas; Inodorus Group; and Shongwan Charmi PI161375, Conomon Group) and two climacteric cultivars (Fado, Reticulatus Group; Vedrantais, Cantaloupensis Group) were used as reference. The field was divided in eight blocks containing one three-plant replication for each NIL, two for the parental cultivar Piel de Sapo and one or two for the reference cultivars. Replications evaluated were more than six in the cultivars studied. Plant problems included aphids, powdery mildew, and leaf wind injury. Preharvest fruit disorders included whole fruit cracking in cultivar Vedrantais and NIL 5M2, and stylar-end cracking in cultivar Fado. Climacteric NILs with yellow skin were particularly affected by over-ripening, stylar-end cracking, and sunburn during cultivation. At harvest, two NILs showed slight placental tissue necrosis which was inherited from SC and were also detected after storage. Other uncommon disorders seen at harvest or 30 days after storage at 8oC included warted skin (scarring), flesh discoloration (light brown or translucent areas), hollow flesh disorder, and deep furrow netting inherited from SC. Less common rots included grey mould, bacterial soft rot, Penicillium rot, cottony leak and internal Cladosporium rot. Stylar-end hardness below 20 N·mm-1 was associated with cracking and softening. The incidence of the disorders and rots was too low to confirm that the genetic component played a role in their development.