K. J. Scott

The control of rotting and browning of litchi fruit by hot benomyl and plastic film

Abstract Browning, weight loss and rotting of litchis (Litchi chinensis Sonn) were studied in 3 seasons with fruit from several growing-areas in Australia. Post-harvest wastage was reduced when the fruit were dipped in hot benomyl and packed in plastic film. A benomyl dip (0.05% at 52°C for 2 min) followed by packing the fruit in punnets and over-wrapping with a “cling” pvc film (0.01 mm thickness) is suggested for controlling rotting, browning and loss in weight at temperatures of 20–30°C.

Ethanol vapour—a new anti-scald treatment for apples

Abstract Superficial scald was controlled on highly susceptible Granny Smith apples, grown in New South Wales, by exposing the fruit to evaporating ethanol at 0 or 20 °C. To avoid cross contamination of ethanol, the fruit were stored in sealed polyethylene bags (0.05 mm thickness). The ethanol was added at the rate of 0, 0.25, 0.5 or 1.0 g fruit−1 to five small cups each containing 10 g vermiculite. The bags were then sealed and the fruit held at 0 or at 20 °C for four days before storage at 0 °C. The addition of 0.5 or 1.0 g ethanol fruit−1 completely controlled scald in four of the five experiments carried out during three seasons. These levels of ethanol substantially reduced scald in the fifth experiment. Scald was also greatly reduced when 0.25 g ethanol fruit−1 was used. 90–100% of untreated fruit in all five experiments were affected with scald. There was no fruit injury or apparent off-flavour after several months storage. Superficial scald was also significantly reduced when fruit was injected, twice, early in storage with 0.3 ml ethanol. In a second experiment scald was reduced with a single injection of 0.25 ml ethanol.

Prediction of bitter pit with calcium content of apple fruit

Abstract Calcium concentrations in apples were found to be correlated with bitter pit susceptibility, a low calcium concentration being synonymous with high pit susceptibility. The concentration of calcium in the fruit 3 weeks before harvest was as reliable a guide for predicting pit as the concentration in the fruit at harvest. However, between districts and varieties, and in different seasons, there were marked differences in the amount of calcium above which fruit were unlikely to develop pit. Although calcium concentration was most closely correlated with pit, potassium and, to a less extent, magnesium concentration were also positively correlated with the disorder. The ratio of K/Ca was very highly correlated with pit.

Reduction of superficial scald of apples with vegetable oils

Abstract Five vegetables oils were applied by hand to Granny Smith apples that were highly susceptible to superficial scald and stored at 0 °C for several months. A petroleum-derived ‘baby oil’ was included for comparison. Sunflower oil was applied in two seasons. Canola, castor, palm, peanut and the purified petroleum oil were used in a single season. All oils considerably reduced scald without causing injury. Two drops of oil (approximately 25 mg) had marked effects on the severity of superficial scald. The severity of the disorder was related logarithmically to the number of drops of oil applied. The regression equation was: Scald score = 2.24−0.73 log e (no. of drops). However, oils were not significantly different in their effects on scald. Thus scald control by the different oils does not appear to be related to chain length of fatty acids or degree of unsaturation. A physical effect may be responsible for the control of superficial scald by the six oils. Apples treated with castor or palm oil remained greasy even after storage for several months. The other oils were far less greasy and when applied in low doses there were little observable differences in greasiness compared to the controls. Canola, peanut and sunflower oils appear to have possibilities as commercial scald control agents. Baby oil would probably be unacceptable due to its petroleum origin. The testing of a greater range of vegetable oils on other apple cultivars is worth further investigation.

Chemical induction of low temperature breakdown in apples

Abstract Jonathan apples injected with acetate, mevalonate, malonate, formate, butyrate, benzoate, caffeine, amytal, adenosine triphosphate and octanol showed an increase in low temperature breakdown after storage at −1°. Injection of calcium resulted in a decrease in the incidence of breakdown. It is suggested that isoprenoid metabolism may be involved in the metabolic events leading to breakdown.

Hexanol and hexyl acetate and soft scald of apples

Abstract Jonathan apples which had been injected with hexanol or hexyl acetate during cool storage had a higher level of soft scald than control fruit. Twenty other compounds had no effect on the level of the disorder.

The action of phorone and other compounds in controlling superficial scald of apples

Abstract A new inhibitor of superficial scald, phorone (2,6-dimethylhepta-2,5-dien-4-one) is reported. Phorone reduced scald on ‘Granny Smith’ apples when applied by injection or as a vapour. Phorone was found to limit the accumulation of α-farnesene during storage and the amounts of conjugated triene oxidation products derived from α-farnesene. Monoterpenes also reduced α-farnesene, oxidation products and scald, but these compounds were less effective than phorone. In contrast, diphenylamine had little effect on the amount of α-farnesene in the fruit but it prevented the autoxidation of α-farnesene and controlled scald.

Evaluation of the use of butylated hydroxytoluene to reduce superficial scald of apples

Abstract Butylated hydroxytoluene (BHT) was found to be effective in reducing the incidence of superficial scald in ‘Granny Smith’ apples grown in Australia and New Zealand, when it was applied to the fruit as a post-harvest dip or when the fruit were stored in wraps impregnated with BHT. However, much higher concentrations of BHT were required to produce an equivalent reduction in scald compared with diphenylamine or ethoxyquin.

Evaluation of the use of gibberellic acid in dip solutions to reduce storage breakdown in apples

Abstract The. reduction of storage breakdown by gibberellic acid (GA3) was studied over several seasons m New .Zealand and Australia. GA3 was applied by dipping the fruit in aqueous solutIOns contammg a water-soluble formulation (‘GroceI’, ‘Berelex’) at concentrations from 12 ppm to 2000 ppm. It was foun? that GA3 did not always give consistent reductions in breakdown. The lowest concentratIOn of GA3 that produced a reduction in disorder was 25 ppm.

Effect of Geraniol on Levels of Volatile Terpenoid Compounds Produced by Apples During Cool Storage

SummaryThe addition of geraniol to the core of Jonathan apples susceptible to storage breakdown, caused a reduction in the level of volatile terpenoid compounds, and induced breakdown in the fruit. No free geraniol was detected in the flesh tissue, and it is suggested that geraniol is rapidly converted to a non-volatile compound which affected the production of the volatile compounds. a-Farnesene was tentatively indentified as the major component, and its level in the fruit was greatly reduced by geraniol. No other terpenoid compound was found to be as effective as geraniol in inducing breakdown.