Malic Acid Promotes Cracking of Sweet Cherry Fruit

Abstract

<jats:p>When mature sweet cherries (<jats:italic>Prunus avium</jats:italic> L.) came into contact with sweet cherry juice, cracking dramatically increased. The objectives of our study were: 1) to quantify the cracking of fruit in cherry juice, 2) to determine which constituent(s) of the juice especially promote cracking and, 3) to establish its/their mode of action in promoting cracking. Artificial juice was made up as an aqueous solution of the same five pure chemicals and at the same relative concentrations as the five major osmolytes of real sweet cherry juice. Artificial and real juice was used at half-isotonic concentrations as the real juice from that batch of fruit. Cracking of sweet cherries placed in either artificial or real juice was more rapid and occurred for lower net water uptakes than of fruit placed in half-isotonic polyethylene glycol 6000. The crack-promoting component in sweet cherry juice was malic acid. Further tests with malic acid, and other organic acids, and with different concentrations of malic acid, with and without pH control, and with the enantiomers of malic acid, showed the effects were primarily related to the pH of the incubation solution. Leakage of anthocyanin from discs of flesh was increased in the presence of malic acid and greater in hypotonic than hypertonic solutions, suggesting that malic acid increases the permeability of the plasma membrane and tonoplast and weakens the cell walls. Malic acid may be an important link (amplifier) in a reaction chain that begins with the bursting of individual epidermal cells and ends with the formation of macroscopic skin cracks.</jats:p>

Factors Affecting Mechanical Properties of the Skin of Sweet Cherry Fruit

“…Flesh effects in vivo (before excision) will include exposure to juice resulting from compartmentation loss (particularly around the pit) or heterogeneity arising from localized cell death. Both these effects have been demonstrated for grape berries that have similar mechanical architecture to sweet cherry (Considine and Brown, 1981;Lang and D€ uring, 1991;Tilbrook and Tyerman, 2008) and malic acid, a major constituent of sweet cherry fruit juice, markedly increases sweet cherry cracking (Winkler et al, 2015). Also, in Table 1.…”

Effect of abscisic acid and methyl jasmonate preharvest applications on fruit quality and cracking tolerance of sweet cherry

“…Recently, it has been suggested that a primary cause of fruit cracking could be the increase in fruit surface area during fruit development in the absence of cuticle membrane (CM) deposition (Alkio et al, 2012). In this sense, cracking results from localized water uptake, the bursting of individual cells and the spreading of the damage to neighboring cells, the release of malic acid into the apoplast, the resulting swelling of cell walls and the weakening of the fruit skin until the crack becomes macroscopically visible (Winkler et al, 2015). Sweet cherry, like other Prunus species, presents a characteristic double-sigmoid pattern of fruit growth with three distinctive phases.…”

“Crispy” Blackberry Genotypes: A Breeding Innovation of the University of Arkansas Blackberry Breeding Program

“…Generally in fruits, firmness is related to modifications of the polysaccharide components of the primary cell wall and middle lamella during fruit ripening, resulting in a weaker fruit structure at the end of the ripening process (Brummell, 2006;Winkler et al, 2015). Alterations in the bonding between polymers along with degradation of polysaccharides can cause an increase in cell separation, softening, and swelling of the cell wall (Brummell, 2006).…”