Respiratory metabolism during cold storage of apple fruit. I. Sucrose metabolism and glycolysis

Abstract

This study provides the first report on the occurrence of the respiratory climacteric during cold storage of apple fruit (Malus domestica Borkh. cv. Reinette du Canada). The respiratory pattern at 4°C was very similar to that observed during postharvest ripening at room temperature, except that shelf life was considerably extended and the onset of the climacteric delayed. Increasing the calcium content of the apple fruit significantly reduced loss of firmness during cold storage, but showed no effect on respiration or on the other parameters determined. A gradual accumulation of soluble sugars occurred during the first 60 days after harvest and was effectively completed before the climacteric peak was reached. This increase in sugars correlated with an increase in the activity of sucrose‐phosphate synthase (EC 2.4.1.14), and a marked change in the kinetic properties of the enzyme was observed after sucrose accumulation ceased. Changes in the hexose‐phosphate pool and in glycolytic and gluconeogenic activities indicated an initial increase in the gluconeogenic flow at early stages of the climacteric, followed by activation of glycolysis, with the carbon flow being most likely regulated at the reversible phosphorylation of fructose‐6‐phosphate to fructose‐1,6‐bisphosphate (mostly via pyrophosphate:fructose‐6‐phosphate phosphotransferase, EC 2.7.1.90) and at the pyruvate kinase (EC 2.7.1.40) steps. The results presented indicate that the respiratory climacteric does not occur to accommodate extra ATP requirements during sucrose synthesis nor can it be a consequence of an increased supply of respiratory substrate.

Influence of harvest time and storage duration on “Cripps Pink” apple cultivar (Malus×domesticaBorkh) quality parameters Influencia del tiempo de cosecha y duración en almacenamiento en los parámetros de calidad de la variedad de manzana Cripps Pink (Malus×domesticaBorkh)

“…On the other side, comparing average total acids content by storage durations, significant differences between storage durations was measured; as expected, total acids content decreased with the duration of fruits storage ( Table 1). The fact that the total acids decreased during the storage life has been confirmed by other authors (Aaby et al, 2001;Duquea, Barreiro, & Arrabac, 1999;Lo´pez et al, 2006).…”

Storage behaviour of ‘Reinette du Canada’ apple cultivars

“…Significant differences were also found between treated and untreated fruit from 60 days until the end of storage, treated fruit having a higher value of firmness. It has been previously reported that calcium treatments immediately after harvest assure a slower fruit softening during storage (Duque et al, 1999;Valero et al, 2002). As far as TSS is concerned, 'RC' always had higher values than 'RG' (Tables 1 and 2).…”

“…Although a previous study with apple cv. Reinette du Canada concluded that increasing the calcium content of the fruit showed no effect on TSS (Duque et al, 1999), treated 'RC' fruit had higher TSS than untreated fruit (Table 1) and treated 'RG' fruit had lower TSS than untreated fruit, especially in CS (Table 2). Therefore, the absence of postharvest treatments in 'RG' would allow the fruit to reach higher TSS values during storage.…”

“…In general, no significant differences between treated and untreated fruit were observed in TA during storage (Tables 1 and 2). Duque et al (1999) assured that postharvest calcium treatment did not significantly affect TA of apple cv. 'Reinette du Canada'.…”

Physico-chemical quality parameters and overall quality index of apple during storage

“…The decrease was probably due to conversion of sugar into starch (Wills et al 1980), which shows that apple may become less sweet with the passage of time. Later on, it again increased due to re-conversion of starch into monosaccharide (Duque et al 1999). Therefore, the TSS in apple underwent cyclic changes under the storage condition.…”