Kucuker et al., J. Anim. Plant Sci. 25(3):2015 763 EFFECT OF PRE-HARVEST AMINOETHOXYVINYLGLYCINE (AVG) APPLICATION ON BIOACTIVE COMPOUNDS AND FRUIT QUALITY OF PLUM (PRUNUS SALICINA LINDELL CV. BLACK BEAUTY) AT THE TIME OF HARVEST AND DURING COLD STORAGE E. Kucuker 1* , B.Ozturk 2 , H. Aksit 3 and N. Genc 3 1 Department of Horticulture, Faculty of Agriculture, University of Gaziosmanpasa, 60240, Tasliciftlik, Tokat-Turkey 2 Department of Horticulture, Faculty of Agriculture, University of Ordu, 52200, Altınordu, Ordu-Turkey 3 Department of Chemistry, Faculty of Science and Arts, Gaziosmanpasa University, 60240, Tasliciftlik, Tokat-Turkey * Corresponding author E-mail address: emine2346@gmail.com (Emine Kucuker) ABSTRACT This study aimed at determining the effects of preharvest aminoethoxyvinylglycine (AVG) applications in different doses on the fruit quality of Black Beauty plum during cold storage. Plum trees were applied AVG doses (100 and 200 mgL -1 ) two weeks before the estimated harvest date. Change in physical, mechanical, chemical and bioactive compounds in fruit samples were determined at weekly intervals. Applications of AVG delayed the parameters related with maturation such as weight loss, color and firmness during storage. At the end of 28 days, the least weight loss was with 200 mgL -1 AVG application, while the highest weight loss (%) was in control treatment. While, the lowest fruit firmness (11.31 N) was recorded in control fruits, the highest (26.78 N) was obtained with 200 mgL -1 AVG application. At the end of the storage duration, all applications were statistically similar in terms of TSSC value. The applications of AVG had a significant effect on the bioactive compounds of the fruits. Overall, both total phenolics and total antioxidant acitivity exhibited a linear decrease with increasing the storage duration regardless of AVG treatments. A similar decrease with storage was also observed in chlorogenic acid, epicatechin, catechin, caffeic acid, p-coumaric acid, quercetin. Naringenin displayed a significant decrease due to AVG applications during the cold storage. Keywords: Antioxidant, cold storage, chlorogenic acid, firmness, phenolic, plum. INTRODUCTION Plum, a fruit exhibits a typical climacteric ripening behavior. Its quality characteristics vary considerably depending on the stage of harvest. As with other climacteric types, the softening in fruit flesh and the increase in TSSC (total soluble solids content) are the basic parametres indicating the start of maturation (Valero et al., 2003; Jan and Rab, 2012). Excessive softening in plum fruit following harvest limits its market life (Skog et al., 2003; Singh and Khan, 2010). Therefore, plums are kept in cold storage for 2 – 6 weeks to extend postharvest market life (Crisosto et al., 1999; Skog et al., 2003; Demir, 2010). Producing quality fruits and extending the postharvest shelf life of fruits are among the basic goals of modern fruit growing. Postharvest softening in plums is an important factor limiting the storage span (Skog et al., 2003). Presenting a quality product to market in line with consumer demand calls for the use of plant growth regulators in plum, a perishable fruit kind, so as to extend cold storage duration (Jobling et al., 2003; Khan et al., 2007). Cold storage of fruits and vegetables delays the changes associated with maturation such as softening in fruit flesh, pigment changes, increase in TSSC and decrease in acidity (Zhou et al., 2001; Guerra and Casquero, 2008). The applications of plant growth regulators such as AVG (1-methylcyclopropene), polyamines, methyl jasmonate, and salicylic acid have come into prominence to maintain the fruit quality under low temperatures for longer periods (Valero et al., 2003; Khan and Singh, 2007; Diaz-Mula et al., 2009; Luo et al., 2009). Plant growth regulators are natural or synthetic compounds affecting one or more physiological events in a plant. AVG is an inhibitor of ethylene. A considerable amount of research has been carried out on ReTain, which is the commercial formulation of AVG, and it has be come a product whose use in apple, pear, peach, plum and nectarines in many countries throughout the world was registered (Greene, 2005). AVG extends storage span of fruits by maintaining postharvest fruit firmness (Jobling et al., 2003; Schupp and Greene, 2004). Although there are many studies on quality parameters in plum, the change in bioactive compounds during harvest and storage has not been studied enough. Therefore, this study aimed at determining the effects of different doses of preharvest applied AVG in ‘Black Beauty’ plum variety on weight loss and color change, fruit firmness, total soluble solids content, total phenolics, total antioxidant activitiy and individual phenolics compounds. The Journal of Animal & Plant Sciences, 25(3): 2015, Page: 763-770 ISSN: 1018-7081