Article

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

Journal of Horticultural Science and Biotechnology (Impact Factor: 0.51). 03/2013; 80:611-617.
Source: OAI

ABSTRACT 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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    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
    Scientia Horticulturae 12/2014; 180:1-5. · 1.50 Impact Factor

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