Mango Sapburn: Components of Fruit Sap and Their Role in Causing Skin Damage.

Abstract

Damage caused to the skin of mango fruit by contact with sap exuded from the cut or broken pedicel reduces consumer acceptance and storage life of the fruit. Mangoes of the Kensington cultivar are particularly susceptible to sapburn injury. On centrifugation, the fruit sap separated into two phases. Skin damage was caused predominantly by the upper non-aqueous phase. A major component of this phase was terpinolene which gave symptoms indistinguishable from sapburn injury when applied to the fruit surface. The same type of damage could be induced by the application of synthetic terpinolene when applied undiluted, diluted in hexane or as an aqueous emulsion. Non-volatile sap components separated by distillation were not damaging to mango skin. Sap exuded from the mango leaf petioles also contained terpinolene, but its concentration was less than 1% of the concentration in pedicel sap and this sap was not damaging to the fruit skin.The Florida cultivar Irwin is less susceptible to sapburn injury and the predominant terpene in its sap was identified as car-3-ene. When applied to Kensington skin, car-3-ene caused significantly less damage than terpinolene. We conclude that the primary cause of mango sapburn is entry of volatile components of the sap such as terpinolene through the lenticels, resulting in tissue damage and subsequent enzymic browning.

Effect of arbuscular mycorrhizal fungi and water stress on ultrastructural change of glandular hairs and essential oil compositions in Ocimum gratissimum

“…The storage of terpenoid in these structures can be used to limit the toxicity risk to the plant itself, because it is proven that many terpenoids are potentially toxic to plant tissues when monoterpenes are released to the surrounding cells [20]. Injuries were also found when some sesquiterpenes were artificially deposited on sheets during tests on their ability to deter herbivores [23].…”

Development of Peltate Glandular Trichomes of Peppermint

“…However, in cryogenically fixed and microwave-fixed peppermint gland specimens, the fibrillar material appears clearly distinct from the walls. Since monoterpenes can be toxic to plant cells (Shomer and Erner, 1989;Loveys et al, 1992), the hydrophilic material could represent a protective mucilage-containing barrier between the secreted oil and the glandular cap cells. Histochemical staining has shown that, in addition to lipids which form the bulk of the stored secretion, the peltate glands of Salvia aurea (Serrato-Valenti et al, 1997), Salvia blepharophylla (Bisio et al, 1999), andO.…”

Lenticel damage on 'B74' mango fruit

“…Terpinolene was found to be the most abundant compound in the oil fraction at over 80% in KP mango, but it accounted for only 3.33% of the oil fraction in Irwin mango sap (Loveys et al 1992). …”

“…Sap can potentially leak out of resin ducts and enter lenticels due to high pressure. Laticifiers progressively become closer to the mango fruit surface and adjacent lenticels as the fruit develop (Loveys et al 1992).…”

“…Sap of mango fruit consists of two phases, these being an oil compound and a proteinpolysaccharide fraction that account for about 10% and 90% of total sap volume, respectively 13 (Loveys et al 1992). Mango fruit sap content, pH and composition depend on cultivar, year, growing location and fruit maturity (Hassan et al 2009).…”