1,720,984 research outputs found
The effect of heat conditioning treatments on the postharvest quality of horticultural crops
No full textPurpose of the review: While postharvest heat treatments (heat therapy) were first applied to horticultural crops during the first dec-ades of the past century to control fungal diseases and insect infestation, they were later abandoned with the advent of synthetic fungi-cides. This is because heat treatments are more expensive and more difficult to apply than chemical treatments, as the conditions that are lethal to fungal decay or the fruit fly may be close to the treatment threshold tolerance of fruit. In recent years, the use of synthetic chemicals on harvested fresh produce has become more difficult to justify due to consumer requirements, environmental concern and regulatory issues. Thus, current studies are focused on alternative strategies and there has been renewed interest in heat therapy. This article provides a brief overview of studies published over the last five years on postharvest heat treatments, with emphasis on the ef-fects on the quality of horticultural crops. Recent findings: Postharvest heat treatment may be applied to horticultural crops in several ways: vapour or hot dry air, hot water dips, or by hot water rinsing and brushing. The range of temperatures may vary depending on treatment type and application time. Ef-fects on the quality of horticultural commodities originate from the following factors: limited effectiveness in the control of moulds, insects or physiological disorders and the need to integrate heat therapy with other treatments; direct internal or external damage; ef-fects on ripening and senescence processes; and modification of physiological patterns with loss/retention of nutritional, technological and external quality of commodities. Limitations/implications. Heat treatments are difficult to apply on a commercial scale as the conditions for decay control or those that are lethal to the fruit fly, for example, may be close to the treatment threshold tolerance of fruit. Thus, heat therapy may have beneficial effects on certain cultivars and detrimental effects on others. Furthermore, its efficacy may be influenced by preharvest factors. Directions for future research: Goals for future investigations include prevention of direct damage and the understanding of risk mar-gins for safe application of postharvest heat. The potential application of many practices to a wide range of commodities is also the direction for selecting the most quality-saving processes. Additionally, future studies should be addressed to enhance both the nutri-tional and functional properties of horticultural crops
Compositional changes in developing almond kernels in relation to rootstock and water supply
Full text linkThe investigations conducted on almond trees (Prunus amygdalus, cv Texas), showed differences
due to rootstocks in the rate of oil accumulation but not on oil content at maturity; water
supply resulted in an increase of kernel moisture and free fatty acids in the oil. Neither the
rootstock nor water supply significantly affected fatty acid composition or the oil spectrophotometric
indices
Studi sulla suscettibilità alle fisiopatie da raffreddamento dell'arancio "Washington navel" in relazione all'ambiente di produzione
No full textThe Authors refer to "Washington navel" orange susceptibility to chilling injury (C l) as related to environmental
factors and storage temperatures.
The fruits were harvested from three different areas in Sardinia and stored far eleven weeks at 4° - 7°C
and 90% R.H..
The results show a close relation between C l and environmental factors. The fruits, produced in the hot
areas with sandy soil, ripened early and total acidity was low. During starage they were more resistant to
C l as compared to oranges produced in cooler areas and with clay soi!.
Storage temperatures also influenced susceptibility to C l test and at 4°C showed a greater amount of chilling
injured fruits.
Weight loss during storage was al so influenced by C l
Frigoconservazione degli agrumi: prime esperienze in Sardegna sulla conservazione delle cultivar di arancio «Washington navel», «Tarocco» e «Valencia late»
No full textA two-year research on cold storage of «Washington navel» «Tarocco », «Valencia late». oranges conducted
in Sardinia showed considerable differences among cultivars tested.
Changes in the main morpho-qualitative fruit characteristics during a two-month storage at 6° C and 85%
relative humidity were studied.
Among the cultivars compared, «Valencia late» orange was found the most resistant to storage conditions.
Fungicide treatment with Imazalil, in wax at 1500 ppm, proved to be the bes t for controlling rot development,
while TBZ (3000 ppm) was not very eftective; but the combination of OPP and TBZ in wax provided
adeguate control.
Weight losses during storage was also evaluated and related to wax treatment
Determination of free radical scavenging activity of plant extracts through DPPH assay: an EPR and UV-VIS study
No full textSeveral methods have been developed to assess the radical scavenging activity. Among them, the 2,2-diphenyl-1-picrylhydrazyl (DPPH) spectrophotometric method is one of the most widely applied and is appreciated for its reliability. In this study, a comparison of two spectroscopic methods (electron paramagnetic resonance (EPR) and ultraviolet-visible (UV-Vis) spectroscopy) was performed analysing the spectroscopic features of DPPH in mixed ethanol/water solution and the free radical scavenging properties of myrtle leaves extracts and citrus juices. When DPPH was dissolved in mixed solvents, EPR enabled to identify the aggregation phenomena that occur when high amounts of water were employed. On the contrary, UV-Vis revealed only small differences in the absorption maximum among solutions with increasing water contents, without detecting aggregation. EC 50 values of myrtle leaf extracts and citrus juices calculated from UV-Vis data were lower than those calculated with EPR. In myrtle extracts, the DPPH depletion measured by UV-Vis was not concentration dependent, revealing the interference in the analysis of the decomposition products of the antioxidants, which absorb at 517 nm. EPR spectroscopy was proven to be most reliable with all types of matrix since it is not dependent on the chemical composition of the extract
Test morfoqualitativi e chimici applicabili ai frutti di agrumi frigoconservati
No full textA preliminary bibliographical research provided the methods to be followed for a morpho-qualitative control
of refrigerated citrus fruit.
The different methods were then checked in order to determine the procedures through which the qualitative
aspects and their changes in refrigerated citrus fruit are best shown.
The methods which can be suggested to those in charge for this type of control are then described
Sulla valutazione di cultivar di olivo da mensa: nota II: «Manna» e «Majorca»
No full textThe results of this work have shown that olive varieties «Manna» and «Majorca» have characteristics wich
recommend them for processing as table-olive.
The olives processed by both Sevillan system (lactic fermentation) and traditional one (storage in brine),
have been panel tested with favourable response for both mentioned varietles, but better results were obtalned
with «Manna» which can also yield enough production for a possible industrial processing
Storage life and quality attributes of cactus pears cultivar "Gialla" as affected by packaging
No full textFruits of "Gialla" first-crop cactus pear (Opuntia ficus-indicaL. Mill.) were either wrapped with a heat-shrinkable film or kept unwrapped and stored at 6°C for 3 or 6 weeks, with each period followed by 1 week at 20°C to simulate market conditions. Film wrapping notably reduced weight-loss during storage and shelf-life. Packaging also resulted in a significant reduction of chilling injury (CI) following 3 weeks of storage and throughout the merchandising periods, while after 6 weeks of cold storage, film wrapping led to no beneficial effects on CI incidence, but the percentage of saleable fruit was higher for those that were wrapped compared to the control. The packaged fruit also maintained a better external appearance than did unwrapped fruit. Rots occurred only during the shelf-life period and were not affected by film wrapping. Physiological behaviour and chemical attributes were not influenced by packaging with respect to control
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
- …
