Plant Pathology Research Institute, Agricultural Research Center, Giza, Egypt.
Apple fruits were heavily infected with
Bolrytis cinerea and
Penicillium
expansum during cold storage. causing serious economic: losses. Certain salts as
alternatives to fungicides, i.e. ammonium sulfate «(NH.hSO,), calcium chloride
(CaCI2), magnesium sulfate
(MgSO.) and potassium disulMe (K,;S20~) at 100,200
or
300 ppm and sodium hypochlorite (NaOel) at SO, 100 or 200 ppm were tested in
vitro
against both fungi. All tested salts inhibited mycelial fungal growth, particularty
K,S.Osand CaCI., While (NH.hS04 was the least effective one. Activity of PG, PME
and C. as cell degrading enzymes in treated
fruits was investigated. However, it
was
suggested that PG had a remar1<able role in infection of apples with
B. cinerea, while
C
x had an impact In infection 01 apples with
P. expansum. Sail treatments Ihat
inhibited PG, C. and PME activity concomitanUy conlrolled decay of apple fruits during
cold storage. K2S,OS and CaCI2 at 200 ppm proved to be the most effective
postharvest treatments to control apple fruit rots during cold storage at 0_1°C for 2
months. Patulin, a mycotoxin, was produced in Czapek's broth medium with
P.
expensum al concentration of 105.93 ~gI1itre, when incubated at 25
QC for 2 weeks,
while tested salts completely suppressed patulin production, except for NaOCI and
(NH.)2S0 •.
P. expansum produced patulin at 52.180
~g/kg in the control apple fruits.
No patulin was detected in apples treated with K2S20s, where low amount of patulln,
3.125 ~gllcg fruil, was
detected in apples
treated wilh either CaCI. or MgSO •.
Generally, it could be concluded that postharvest treatment of apple fruits
with sodium disulfite and calcium chloride at 200 ppm was very effective in controlling
fungal decay incited by
B. cinerea and
P. expansum and simultaneously in
suppression of patulin prooucnon. Salt treatmants maintained gOOd
fruit quality
including firmness, TSS, TA and TSSrrA ratio during the cold storage at 0·1°C for 2
months.
)
View on SCiNiTO