Mango (Mangifera indica L.) cv. Jinhwang, is a commercial variety in Taiwan which has a high value as export [1]. This cultivar is an average weight of 1,200 grams, is elongated and oval shape, small stone. In addition, this cultivar has highly resistant to diseases and insects, and also tolerates adverse weather conditions. All of these advantages value to the plant improvement [2]. It is necessary to measure the physical, bio-chemical and physiological variables that have been examined to define the optimal stage of maturity for harvest [3]. The measurement of maturity is important to harvest fruit to have good postharvest quality. There have been numerous studies investigating the physical, bio-chemical and physiological changes of several fruits during growth and development. Several mango fruit is harvested before the onset of the climacteric but, when physiologically mature stage at 105-112 days after fruit set, to get optimum fruit quality, whereas immature fruit do not ripen normally [4]. The suitable maturity for harvesting Jinhwang cultivar at 120 to 130 days after anthesis (DAA) [5]. TSS increases slightly at the mature-green stage. The firmness of the fruit remains almost constant throughout the growth period and fruit become less firm after maturity [4]. Starch accumulation is a major chemical change in mango fruit during growth and maturation [6].
Total sugars (sucrose, fructose, glucose) are one of the bio-chemical components of fruit quality [7] which is related to sink strength and is important in fruit development [8]. Increase in total sugar content during fruit maturity is dependent sucrose accumulation [9]. Several enzymes are involved in sucrose metabolism [10]; Sucrose phosphate synthase (SPS; EC 2.4.1.14) is a soluble enzyme located in the cytoplasm and plays a major role in control of sucrose biosynthesis because the hydrolysis of sucrose phosphate by an accompanying specific phosphatase renders the synthetic irreversible reaction in favour of sucrose accumulation [11]. Sucrose synthase (SS; EC 2.4.1.13) and invertases (AI, NI; EC 3.2.1.26) are sucrose-cleaving enzymes important for determining sink strength [10]. The major role of SS during the active growth phase is cleaved the sucrose moiety and also linked to cell wall biosynthesis by providing UDP-glucose for the cellulose synthase complex and substrates for starch synthesis during fruit growth and development. Fruit invertases are involved in the degradation of sucrose which catalyze the irreversible hydrolysis of sucrose to glucose and fructose [12]. Acid invertase (NI; EC 3.2.1.26) is compartmentalized in the vacuole, the site of sucrose accumulation, and neutral invertase (NI; EC 3.2.1.26) is located in the cytosol, the site of sucrose synthesis [13].