Abstract
Treatment with calcium (0.1 M CaSO4, 0.1 M CaCl2) depressed respiration of avocado fruits during preclimacteric and climacteric phases. Na2SO4 was ineffective. Calcium not only inhibited respiration but delayed the onset of the climacteric and depressed the peak of ethylene production at the climacteric rise. Determinations of endogenous Ca confirmed that higher levels were positively correlated to delay in ripening and negatively correlated to peak of CO2 and ethylene production. It is inferred that this difference in Ca level is one of the factors causing lack of uniformity in ripening.
Synthesis of non-ethylene volatiles (NEV) undergoes significant alterations during the transition from vegetative growth to senescence in apple fruit. This change results in a substantial increase in the production of esters characteristic of ripe apples. The relationship between changes in NEV synthesis and other indicators of physiological and horticultural maturity were investigated using `Bisbee Delicious' apples. Analysis of NEV was conducted using headspace sampling and GC-MS. Aldehydes and alcohols were the largest NEV components from pre-climacteric fruit although several esters were detected. The concentration of all NEV components declined to a minimum prior to the onset of the climacteric rise in ethylene synthesis. Initial detection of 2-methyl butylacetate, the major ester in ripening `Bisbee Delicious' fruit, occurred several weeks prior to the onset of the climacteric. The increase in ester synthesis accelerated during the post-climacteric period and the amount of total aldehydes also increased.
irradiation stress was evident on day 3 for treated bananas. Respiration rates of fruit irradiated with 400 to 800 Gy remained higher than for control fruit through day 9. Similar studies have shown that irradiation decreased banana climacteric peaks but
Abstract
‘Fuerte’ avocado fruits at all development stages show a similar climacteric pattern; however, with development, the postharvest pre-climacteric becomes progressively shorter. The respiration rate of seeds is higher in young than in mature fruits when determined separately from that of the whole fruit. It is concluded that the contribution of seed respiration to whole fruit respiration decreases with development over the growth season.
concerned about its appearance and textual quality. As a typical climacteric fruit, kiwifruit postharvest ripening and senescence are very sensitive to ethylene, and even extremely low concentrations (0.1 μL·L −1 ) can stimulate fruit ripening and softening
climacteric fruit that experience a rise in respiration and ethylene during ripening. The rise in ethylene during climacteric ripening is due to ethylene biosynthesis transitioning from an autoinhibitory to an autocatalytic program, wherein ethylene increases
The objective of this work was to obtain information for designing modified-atmosphere packages for storing and transporting cherimoyas. Respiration rates of `Conchs Lisa' cherimoyas at 10C were monitored in a flow-through system using O2 consumption and CO2 production under atmospheres containing 5910, 10%, 15%, or 20% O2. Under normal atmosphere (20% O2), the respiration curve exhibited atypical climacteric rise 15 days after harvest, while 15% and 10 % O2 delayed this event. Fruit kept in 5% O2 did not show a detectable climacteric rise and did not produce ethylene. All fruit ripened normally after being transferred to air storage at 20C; however, the time needed to reach an edible condition differed with treatment and was inversely proportional to O2 content. Delay of the climacteric by 5 % O2, coupled with the continued ability to ripen, makes this procedure suitable for controlled- or modified-atmosphere cherimoya packaging.
Abstract
Starch hydrolysis, phosphorylase, phosphatase and α-amylase activity of ‘Marinelo’ banana (Musa acuminata Colla × Musa balbisiana Colla, ABB group) during ripening of whole fruit and thin slices infiltrated with water (controls), cycloheximide and actinomycin D were investigated. Phosphatase and α-amylase activity of whole fruit increased during the climacteric while phosphorylase decreased as starch degradation proceded. Starch degradation had a different temperature coefficient than that of α-amylase activity when the storage temperature was raised from 20 to 25°C and stopped when 25% of the starch was still present. Activity of α-amylase in slices infiltrated with water, increased before the onset of the climacteric as a result of injury and at the same time starch was being hydrolyzed. Cycloheximide inhibited this induced activity increase but not starch breakdown or the increase of activity which occurs during the climacteric. Actinomycin D did not inhibit the α-amylase increase and its effect was a general retardation of ripening.
Abstract
Changes in the level of 1-aminocyclopropane-1-carboxylic acid (ACC) were compared to ethylene production during fruit ripening of avocado (Persea americana Mill.) banana (Musa sapientum L.) and tomato (Lycopersicon esculentum Mill.). Preclimacteric tissues contained less than 0.1 nmol/g of ACC in all tissues. In avocado, the level of ACC increased to 45 nmol/g in the later stage of the climacteric rise, then decreased to 5 nmol/g, and later increased to over 100 nmol/g in overripe fruit. In banana ACC increased to 5 nmol/g during the climacteric, decreased to 2 nmol/g several days after the climacteric peak, and increased up to 5 nmol/g in overripe fruit. Levels of ACC in tomato ranged from 0.1 to 10 nmol/g and were significantly correlated with ethylene production rates in all but overripe fruits. The correlation between the ACC content and the production of ethylene is discussed.
1-Methylcyclopropene (1-MCP) maintained firmness of `Macoun' apple (Malus ×domestica Borkh.) above 50 N after 90 to 100 days regular air storage when harvested at a starch index of 2.7 to 3.5, and after 50 days when harvested at a starch index past 4.0. Softening of `Macoun' was slowed by 1-MCP in both preclimacteric and climacteric fruit, but for a shorter duration in climacteric fruit. 1-MCP reduced but did not eliminate the occurrence of senescent breakdown. The effect of 1-MCP on coreline browning was inconsistent, reducing its occurrence in 2002 and 2003, but increasing its occurrence in 2001 when fruit were harvested at an advanced maturity.