Postharvest decay reduction of fig fruit (Ficus carica) by hot water sodium carbonate solutions dip.

Treatments as hot water dips or high temperature conditioning have been proven to be effective to control postharvest decay on various horticultural crops. These treatments reduce chilling injury and rot losses without causing detrimental effects on fruit firmness, flavour, taste or peel appearance. These technologies, aimed to control postharvest pathogens, can be easily matched with the use of "Generally Recognized as Safe" (G.R.A.S.) compounds and employed alternatively to pesticides, known to be harmful to health and environment. In this respect we studied the combined effect of sodium carbonate (SC) and hot water on the storability of black fig fruit cultivar 'Niedda Longa' of Sardinian germplasm. Second crop fig fruit, harvested in the middle of September, was dipped for one minute in water solutions containing 0, 0.05, 0.5, and 1% (w/v) of SC at 25 or 60 degrees C and then stored at 5 degrees C and 90% relative humidity (RH) for two weeks. After one and two weeks of storage decay, weight loss were monitored and visual assessment was scored. Treatments with hot solutions were more effective in controlling decay compared to cold ones and the best results were achieved with 0.5% of SC at 60 degrees C. This combination reduced the decay rate from 26% (control) to 0% after 1 week and from 50% to 14% after two weeks of storage, respectively. Lower or higher SC concentrations applied at 60 degrees C were less effective and, after two weeks of storage, decay percentages were 38 and 43.6%, respectively. Water dip at 60 degrees C did not affect the weight loss as compared to dips at 25 degrees C either after one or two weeks of storage. At the same time, a significant reduction was found only with 1% of SC at 25 degrees C. The fruit treated with 0.5% of SC at 60 degrees C also had the best visual assessment up to two weeks of storage.

Postharvest heat and cold treatment to control Ceratitis capitata on cactus pear fruit.

In order to work out a quarantine treatment for cactus pear fruit a factorial experimental plan was carried combining postharvest water dips at 20, 50, 54, 58 and 60 degrees C and storage at 1 degrees C for 3, 6 and 10 days. Cactus pear fruit cv 'Rossa' were artificially infested with Med. fly eggs (at least 20 eggs per fruit) then left in the lab at 25 degrees C for 4 days. Treatments took place by dipping the fruit at each water temperature for 2 mm. At each established time fruit was picked and checked for vital larvae and degree of chilling injury (CI). Probit 9 requirements were achieved in all cases when fruit was cold-stored for 10 days. When fruit was kept for 6 days the quarantine requirement was achieved only by dipping the fruit at 58 and 60 degrees C while none dip treatment was effective if fruit was stored for 3 days at 1 degrees C. All Fruit stored for 10 days at 1 degrees C showed severe CI symptoms and when kept for 6 days the same degree of CI was found on fruit dipped in water at 20, 58 and 60 degrees C. No CI was observed after 3 days at 1 degrees C. In conclusion only when fruit was dipped at 50-54 degrees C and stored for 10 days at 1 degrees C the probit 9 condition was attained with acceptable CI symptoms.

Carbonic acid salts at 25 or 45 degrees C to control loquat decay under shelf life conditions.

Generally recognised as save compounds (G.R.A.S) are attractive substitutes to synthetic chemicals in postharvest control diseases. They meet safety requirements, are cheap and able to be integrated with other disease control technologies. Among G.R.A.S compounds, carbonic acid salts have been investigated on carrots, bell pepper, melons, sweet cherries and their efficacy was also evaluated when combined with biological control agents. Moreover, the possibility to use sodium carbonate and sodium bicarbonate to prevent P. digitatum an P. italicum spread on Citrus fruit was studied since the begin of the 20th century. We explored the possibility to extend the use of carbonate-bicarbonate salts on loquat fruit in order to control the pathogens and to extend postharvest life. Loquat is a very perishable fruit, susceptible to decay, mechanical damage, moisture and nutritional losses during its postharvest life. We tested the combined effect of temperature and sodium or potassium carbonate-bicarbonate and ammonium carbonate. The fruit was dipped in the salt solutions at variable concentrations (0.5, 1 and 2% w/v) at 25 or 45 degrees C for two minutes and than stored under shelf life conditions (25 degrees C and 70% RH). Decay, weight loss, pH, titrable acidity and sugar content were detected after twelve days. Preliminary data show that the combined treatments were effective in decay control depending on salts. Best results were obtained with 2% potassium and sodium carbonate solution at 25 degrees C. Weight losses were related to treatment temperature and salts concentrations whereas, no differences were detected in the chemical parameters compared to the control.