Effect of postharvest calcium treatments on physicochemical aspects of cell wall pectin in nectarine fruits during their ripening after harvest or cold storage

Department of Plant Production, University of Milan, Milano, Lombardy, Italy
Journal of Horticultural Science and Biotechnology (Impact Factor: 0.54). 03/2013; 80:611-617.
Source: OAI


The effects of post-harvest dips with calcium salts on the quality attributes of nectarine fruits (Prunus persica var. nectarina Ait. Maxim, cv. ‘Caldesi 2000’) were determined after harvest or in cold storage for up to 6 weeks. Nectarine fruits were harvested at the firm-ripe stage (flesh firmness 70 ± 2 N; soluble solids content 10.5 ± 0.2%) and dipped in deionised water (control) or calcium salts (chloride, lactate or propionate) at two calcium concentrations (62.5 or 187.5 mM). The calcium content of nectarine fruits increased up to 240% in the peel, and up to 31% in the flesh, 1 d after immersion. The increase in calcium content in the flesh was accompanied by increased cell wall calcium, corresponding to a significant increase in the “insoluble” pectin fraction. The highest calcium accumulation in the “insoluble” pectin fraction was attained with 62.5 mM calcium which positively affected fruit firmness. The higher calcium concentration (187.5 mM) resulted in increased calcium in the “water-soluble” pectin fraction which did not appear to contribute to retention of tissue firmness. Additionally, still higher concentrations of calcium lactate and calcium propionate resulted in surface damage, leading to undesirable characteristics during fruit ripening.

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    • "r content of covalent and ionic bonded pectins decreased during their shelf life . Reduced PG activity was also noted , while PE activity increased ( Cao et al . , 2008 ) . However , calcium propionate and calcium lactate are not recommended as calcium treatments for nectarines , because their too high concen - trations can damage the fruit skin ( Manganaris et al . , 2005b ) . Nitrogen monoxide treatment can alleviate symptoms of chil - ling injuries , and especially woolliness . Nitric monoxide changes the relationship between PE and PG , which stops the increase in the content of soluble pectins and the reduction in the ionic pectins ."
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    ABSTRACT: One of the main problems during peach and nectarine cold storage is the associated chilling injuries, which can include woolliness, mealiness, leatheriness, flesh browning, internal reddening, and flesh or pit cavities. Woolliness is one form of chilling injury. It manifests as a lack of juiciness and a dry ‘woolly’ texture of the fruit flesh. Its occurrence is correlated with pectin metabolism and is controlled directly or indirectly by the pectolytic enzymes (i.e., polygalacturonase, pectin esterase, cellulase, lipoxygenase). Chilling injury to these fruit also results in changes in the fruit physiology and cell anatomy. A reduction in woolliness is possible with post-harvest treatments, such as with heat (which must be carried out carefully), calcium, ethylene (blocking or producing), nitrogen monoxide, or a controlled atmosphere. This paper focuses only on woolliness and factors affecting its occurrence. In this paper the role of pectin metabolism, temperature and postharvest treatments on occurrence of woolliness is discussed. The role of some enzymes, such as pectin esterase, and postharvest treatment with 1-MCP still remain unclear and further research is needed to elucidate physiological mechanisms that lead to development of woolliness
    Full-text · Article · Dec 2014 · Scientia Horticulturae
    • "An effective prediction of bitter pit would allow for measures to be taken to reduce its incidence by either increasing the application of Ca sprays or by reducing the application of fertilizers involving nitrogen and potassium (Retamales and Lepe, 2000). If predictions could be made close to harvest time, it would be helpful to packing houses that have to make management decisions: whether to use Ca salt dips, design appropriate storage strategies, etc. (Manganaris et al., 2005; Torres and Alegre, 2012). "
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    ABSTRACT: An effective method for predicting bitter pit incidence implemented before harvest could be a useful instrument for both the fruit industry and growers. Between 2009 and 2011, various methods for the prediction of bitter pit were evaluated at 60, 40, and 20 days before harvest (dbh) and at a commercial harvest in ‘Golden Smoothee’ apples. Four methodologies, two new ones (the development of natural bitter pit before harvest through the ‘passive method’ and bagging detached fruit before commercial ripening), and two of known efficacy under other conditions (infiltration with magnesium salts and maturity enhancement with ethephon dips) were assessed. To estimate the predictive accuracy of each method, bitter pit-like symptoms were related to the postharvest presence of bitter pit. The ‘passive method’ assesses bitter pit-like symptoms that appear naturally in fruit once they are picked from the tree, and left at room temperature during its evaluation. The ‘passive method’, as well as the infiltration with magnesium salts and ethephon dips, recognized bitter pit-like symptoms approximately 5–7 days after sampling (at 40 dbh) and showed significant correlation with the incidence of bitter pit after three months of cold storage. The ‘passive’ and ‘ethephon’ methods were also validated over two additional seasons in 30 and 16 different orchards, respectively. The results of these validations supported the efficacy of using the ‘passive method’ as the main method for predicting bitter pit, without having to use either reactive products or specialized equipment.
    No preview · Article · Nov 2014 · Postharvest Biology and Technology