Cell wall composition and enzyme-related activities in eggplant as affected by hot water, 1-MCP and calcium chloride treatments.

The effects of postharvest applications of hot water (HWT) (45, 50, and 55 °C), 1-MCP (1, 5, and 10 µL/L), and CaCl2 (1, 2, and 3%) on polygalacturonase (PG), pectin methylesterase (PME), α-galactosidase (α-Gal), ß-galactosidase (ß-Gal) and ß-1,4-glucanase (ß-1,4-Glu) activities, and the fruit firmness and cell wall composition of eggplant fruit were investigated. The results showed that the decrease in the eggplants firmness was delayed by HWT, 1-MCP, and CaCl2 treatments during storage compared with the control. However, HWTs were less effective than the 1-MCP and CaCl2 treatments. The results show that 1-MCP and CaCl2 treatments inhibited the depolymerization of water (WSP), CDTA (CSP), and sodium carbonate (SSP) soluble polyuronides. The results suggest that 1-MCP (5 and 10 µL/L) and CaCl2 (1, 2, and 3%) could prevent eggplant softening by inhibiting hydrolase enzymes and reducing the disintegration of the polysaccharides. In addition, 1-MCP and CaCl2 were more effective than hot water treatment in extending postharvest storage life. There is a significantly high correlation between firmness, polyuronide content and cell wall enzyme activity.

Early Harvest Effects on Hydrophilic Phenolic Components of Extra Virgin Olive Oils Cvs. 'Ayvalik', 'Memecik' and 'Topakasi'.

The study was conducted to determine the effects of cultivar, harvest period and their interaction on the hydrophilic phenolic components extra virgin olive oils of the cultivars 'Ayvalik', 'Memecik' and 'Topakasi'. Olives were collected at three different harvesting periods; (1) early harvest period-1 (Beginning of spotting), (2) early harvest period-2 (End of spotting), and (3) optimum harvest period. Oils were extracted using an abencor system. HPLC (High-performance liquid chromatograph) technique was used to quantify The phenolic compounds including: tyrosol (p-HPEA), hydroxytyrosol (3,4-DHPEA), luteolin, rutin, quercetin, catechin, sinapinic acid, p-coumaric acid, cinnamic acid, vanillin, vanillic acid, ferulic acid and gallic acid were quantified using HPLC. The results indicated that the effects of harvest period on the phenolic components were variety dependent. At the early harvest period-1, 'Memecik' and 'Topakasi' had the highest efficiency in luteolin, cinnamic acid, vanillic acid, and ferulic acid contents, while 'Ayvalik' had the highest efficiency in hydroxytyrosol, sinapinic acid, p-coumaric, vanillin and ferulic acid contents. At the optimum harvest period, 'Ayvalik' had the highest efficiency in luteolin, tyrosol and gallic acid contents, while 'Topakasi' had the highest efficiency in tyrosol, hydroxytyrosol and rutin content. The highest phenolic content was detected in the early harvest period-1. The content of tyrosol linearly increased with the progress of maturity harvest period, whereas the contents of the sinapinic acid, vanillin, vanilic acid and ferulic acid decreased. The oils of 'Memecik' variety had significantly higher phenolic content than those of 'Ayvalik' and 'Topakasi' varieties.

Ethylene-induced gene expression, enzyme activities, and water soaking in immature and ripe watermelon (Citrullus lanatus) fruit.

Watermelon fruit exhibit acute softening and placental-tissue water soaking following short exposure to exogenous ethylene. Experiments were performed to address transcript abundance and activities of cell wall and membrane hydrolases in placental tissue in response to treatment of watermelon fruit with ethylene. Watermelon fruit were harvested at immature and full-ripe stages and exposed to 50 microL L(-1) ethylene for 6 days at 20 degrees C. Ethylene affected the abundance of transcripts for PME (EC 3.2.1.11), and alpha-(EC 3.2.1.22) and beta-GAL (EC 3.2.1.23) but these effects were dependent on fruit maturity and appeared not to be associated with the water-soaking syndrome. PG (EC 3.2.1.15) and EXP mRNAs accumulated significantly in response to ethylene exposure. Additionally, the levels of mRNA and activities of LOX (EC 1.13.11.12), PLC (EC 3.1.4.3) and PLD (EC 3.1.4.4) were elevated in fruit of both maturity classes exposed to ethylene and were temporally associated with the visible symptoms of water soaking. The activity trends and transcript abundance in ethylene- compared with air-treated fruit indicate that PG, EXP, LOX, PLC and PLD levels increase with the onset and development of the water-soaking disorder and support the view that catabolic reactions targeting the membranes and cell-walls contribute to the disorder.