Biosynthesis and metabolism of ascorbic acid in plants

Loewus, Frank A.; Loewus, Mary W.; Seib, Paul A.

doi:10.1080/07352688709382235

Cited by 98 publications

(68 citation statements)

References 143 publications

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“…Tissue damage and bruising leads to a decrease in the ascorbic acid content on account of increased water loss and exposure of ascorbic acid to oxidation (Klein 1987;Loewus and Loewus 1987). During this study, although the ascorbic acid content decreased under all the packaging treatments (Table 1), it was largely undetectable in control samples after 23rd days because of tissue rupture.…”

Section: Resultsmentioning

confidence: 69%

Biochemical, microbiological and physiological changes in Jamun (Syzyium cumini L.) kept for long term storage under modified atmosphere packaging

Raj

Chadha²,

Kaur³

et al. 2011

J Food Sci Technol

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Jamun or Indian blackberry (Syzygium cumini L.) is a minor and highly perishable fruit enriched with flavonoids, essential oils, anthocyanins phenolic compounds and other antioxidants. The quantitative and qualitative losses in this seasonal fruit are tremendous and can be reduced by appropriate packaging and storage techniques which have not been applied hitherto. This study was undertaken to extend the shelf-life as well as to assess the biochemical, microbiological and physiological changes in jamun fruit under perforated and non-perforated modified atmosphere (MA) conditions. Fruits were stored under differential MA in macro-perforated (1 and 2 perforations, 0.3 mm dia. each) and non-perforated polypropylene (PP) film packages (Thickness: 35 μm, bag area: 0.036 m 2 ) at 5°C and 75% relative humidity (RH) for 23 days. Sachets containing white silica gel beads were placed inside all the packages to check water accumulation, if any. Different physiological, biochemical and microbiological characteristics which generally affect the postharvest life of the produce were monitored during the storage period. Results of the study suggested most of the subjectively and objectively determined qualitative parameters to be retained satisfactorily under macro-perforated packaging treatments. Further, the microbiological analysis, surmised that the fruits could be stored for long term using packages with 1 macro-perforation.Keywords Antioxidants . Jamun . Modified atmosphere packaging . Headspace . Pigments . Microbial load Indian blackberry (Syzygium cumini L.), commonly known as jamun is a minor and under-utilised tree-fruit of Indian subcontinent. The plant belongs to Myrtaceae family and grows naturally in clayey loamy soil in tropical as well as in sub-tropical zones of Indo-gangetic plains. These species are reported to be very rich in tannins, flavonoids, essential oils, anthocyanins and other phenolic constituents (Sharma et al. 2003;Reynertson et al. 2008). The purple coloured fruits are available abundantly during summer season for a short span of time, causing a seasonal glut. Jamun contains 19.7% carbohydrates, 0.7% proteins, 0.02% calcium, 0.1% fat, 0.01% phosphorous, 0.4% mineral matter, 0.1% iron and 0.9% fiber (Singh et al. 1967;Benherlal and Arumughan 2007). Besides, they contain anthocyanins which are the most important and widespread groups of colouring matters in plants. These intensely coloured water soluble pigments are responsible for nearly all colours in leaves, petals and fruits of higher plants. Jamun fruits and seeds are sweet, acrid and sour and they are used for treatment and control of diabetes, diarrhoea and ringworm. It is also reported to be a blood pressure regulator (Bhargava et al. 1968). Jamun trees are available around parks, on roadsides, on avenues and are good windbreakers. On account of its unorganised farming, consolidated information regarding its area and production in India is apparently not available. The fruits are highly perishable and are sold by the roadside vend...

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Section: Resultsmentioning

confidence: 69%

Biochemical, microbiological and physiological changes in Jamun (Syzyium cumini L.) kept for long term storage under modified atmosphere packaging

Raj

Chadha²,

Kaur³

et al. 2011

J Food Sci Technol

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“…These oxygen species might be responsible for the chlorosis observed in mature leaves. Because the content of ascorbic acid in the chloroplast depends on a constant supply from the cytosol (Foyer, 1993), where ascorbic acid is synthesized (Loewus and Loewus, 1987), events happening outside of the chloroplast leave this organelle with lower concentrations of antioxidant, a situation that promotes chlorosis when the tissue is exposed to higher irradiance. This chain of events would not require excess Mn in chloroplasts of mature leaves.…”

Section: Discussionmentioning

confidence: 99%

Light and Excess Manganese

1998

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The effect of light intensity on antioxidants, antioxidant enzymes, and chlorophyll content was studied in common bean (Phaseolus vulgaris L.) exposed to excess Mn. Leaves of bean genotypes contrasting in Mn tolerance were exposed to two different light intensities and to excess Mn; light was controlled by shading a leaflet with filter paper. After 5 d of Mn treatment ascorbate was depleted by 45% in leaves of the Mn-sensitive genotype ZPV-292 and by 20% in the Mn-tolerant genotype CALIMA. Nonprotein sulfhydryl groups and glutathione reductase were not affected by Mn or light treatment. Ten days of Mn-toxicity stress increased leaf ascorbate peroxidase activity of cv ZPV-292 by 78% in low light and by 235% in high light, and superoxide dismutase activity followed a similar trend. Increases of ascorbate peroxidase and superoxide dismutase activity observed in cv CALIMA were lower than those observed in the susceptible cv ZPV-292. The cv CALIMA had less ascorbate oxidation under excess Mn-toxicity stress. Depletion of ascorbate occurred before the onset of chlorosis in Mn-stressed plants, especially in cv ZPV-292. Lipid peroxidation was not detected in floating leaf discs of mature leaves exposed to excess Mn. Our results suggest that Mn toxicity may be mediated by oxidative stress, and that the tolerant genotype may maintain higher ascorbate levels under stress than the sensitive genotype.

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“…Ascorbic acid (ASC) is a universal metabolite in photosynthetic eukaryotes (Loewus & Loewus, 1987 ;Smirnoff, 1996). Although various metabolic functions have been proposed for ASC, its chief role is generally regarded as that of an antioxidant.…”

Section: mentioning

confidence: 99%

Effects of exogenous application and stem infusion of ascorbate on soybean (Glycine max) root nodules

Bashor

Dalton

1999

New Phytologist

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Numerous biochemical and physiological studies have demonstrated the importance of ascorbate (ASC) as a reducing agent and antioxidant in higher plant metabolism. Of special note is the capacity of ASC to eliminate damaging activated oxygen species (AOS) including O # d and H # O # . N # -fixing legume nodules are especially vulnerable to oxidative damage because they contain large amounts of leghaemoglobin which produces AOS through spontaneous autoxidation ; thus, ASC and other components of the ascorbate-reduced glutathione (ASC-GSH) pathway are critical antioxidants in nodules. In order to establish a meaningful correlation between concentrations of ASC and capacity for N # fixation in legume root nodules, soybean (Glycine max) plants were treated with excess ASC via exogenous irrigation or continuous intravascular infusion through needles inserted directly into plant stems. Treatment with ASC led to striking increases in nitrogenase activity (acetylene reduction), nodule leghaemoglobin content, and activity of ASC peroxidase, a key antioxidant enzyme. The concentration of lipid peroxides, which are indicators of oxidative damage and onset of senescence, was decreased in ASC-treated nodules. These results support the conclusion that ASC is critical for N # fixation and that elevated ASC allows nodules to maintain a greater capacity to fix N # over longer periods.

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Biosynthesis and metabolism of ascorbic acid in plants

Cited by 98 publications

References 143 publications

Biochemical, microbiological and physiological changes in Jamun (Syzyium cumini L.) kept for long term storage under modified atmosphere packaging

Biochemical, microbiological and physiological changes in Jamun (Syzyium cumini L.) kept for long term storage under modified atmosphere packaging

Light and Excess Manganese

Effects of exogenous application and stem infusion of ascorbate on soybean (Glycine max) root nodules

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