Studies on the effect of fruit-coating polymers and organic acids on growth of Colletotrichum musae in vitro and on post harvest control of anthracnose of bananas.
Al-Zaemey, A. B.; Magan, N.; Thompson, A. K.;
Mycological Research Year: 1993 Vol: 97 Issue: 12 Pages: 1463-1468 Ref: 33 ref.
1993
บทคัดย่อ
Twelve coating materials and their components which can be applied to fruit, and 8 organic acids were incorporated into agar media to determine their ability to inhibit mycelial growth of C. musae. Of the coating materials tested, 2 formulations based on a mixture of sucrose esters + fatty acids, Semperfresh F (SFS) and Semperfresh acid-stable (SFAS) at 0.1-1% concn were most effective at inhibiting mycelial growth of C. musae. The components used in fruit-coating materials which significantly inhibited growth were oleic, palmitic and lauric acids. Coating materials like chitosan, carboxymethyl cellulose and carboxymethyl chitosan were ineffective at concn up to 1%. The effect of organic acids and their salts on the growth of C. musae varied with concn (1-3%). Malic, citric, oxalic and maleic acids all significantly (P<0.05) reduced growth of C. musae. Complete inhibition of growth was achieved with potassium sorbate and sodium benzoate at 0.125% and oxalic and maleic acids at 0.5% (w/v). Organic acids also increased the lag time prior to growth initiation. Coating materials, alone or in combination with organic acids or a fungicide (benomyl), were compared for their ability to inhibit postharvest lesion expansion of anthracnose symptoms on banana fruits at 25 deg C and 85-90 r.h. SFAS at 1.5 or 3% and SFAS + 2% potassium sorbate were the most effective treatments when intact skin of banana fruits was inoculated with spores of C. musae prior to application. When fruits were wound-inoculated with mycelium of C. musae, combinations of 3% SFAS with benomyl (250 or 500 micro g/litre) controlled lesion expansion more effectively than the fungicide alone. SFAS alone, or with potassium sorbate, or sodium benzoate significantly (P<0.05) delayed lesion expansion for up to 7 d, but after 11 d incubation differences between treatments and the untreated control were less marked.