Quality and volatile attributes of attached and detached ‘Pluk Mai Lie’ papaya during fruit ripening

The ‘Pluk Mai Lie’ papaya (Carica papaya L.) is a promising cultivated fruit for use in fresh and processed products due to its firm flesh, but the aroma it releases is flat. Changes in quality and volatile profiles were analyzed during on- and off-tree fruit ripening. Detached fruit ripened faster than attached fruit, accumulating high internal ethylene levels. Aside from peel color, which was redder in on-tree ripened fruit, most quality attributes changed similarly in the two ripening situations. A slight increase in total soluble solids (TSS) was measured from the onset of the preclimacteric stage, whereas titratable acidity (TA) remained stable throughout the development. Whereas 2-ethyl-1-hexanol was found specifically in green fruit, ethyl octanoate emerged only in fully-ripe fruit. Furthermore, benzyl isothiocyanate was the most abundant volatile and was present in fruit at every stage except full ripening. The production of total esters, highly correlated with a loss of firmness and an increase in cavity ethylene accumulation, was about 10-fold higher in off-tree ripened fruit. The levels of methanol and ethanol sources in fruit increased steadily throughout ripening, with esters formed from ethyl alcohol predominating from the half-ripe through the senescence phases. The alcohol dehydrogenase activity in the mesocarp increased dramatically during the early ripening stages, whereas alcohol acetyltransferase was active throughout ripening. No difference in volatile profiles was found in the papaya fruit during on-tree and postharvest ripening.     

Comparison of changes in sugars and ethylene production of cherimoya fruit grown at different seasons

Summary

Changes in fruit weight, total soluble solids (TSS), sugar content and postharvest ethylene production during fruit development were compared on fruit of cherimoya (Annona cherimola Mill., cv. Big Sister) pollinated at different times (early, at the beginning of April, 1995 and late, at the end of May, 1994). Fruit weight increased by growth, independently of pollination times. Changes in TSS and sugar content were strongly affected by pollination time. In late pollinated fruits, both TSS and sugar content increased during the growth period, 110–160 d after pollination, while neither increased with fruit growth in early pollinated fruit. Moreover, changes in TSS and sugar content after ripening depended not only on pollination time but also on the growth period. With late pollination, fruit harvested after 140 d became edible after ripening. The TSS and total sugar contents, (the sum of fructose, glucose and sucrose contents) increased to about 20° Brix and above 16%, respectively. But early pollinated fruits were not edible after ripening, since total sugar content increased only to about 7%, even though they kept growing for 160 d on the tree. The maximum rate of ethylene production declined and the number of days to the ethylene peak from harvest is also reduced with growth in both cases. These changes were closely correlated with days after pollination (r>0.9) regardless of pollination time. Comparisons of accumulated temperature suggest that temperature at pollination time and during the resting period of growth affected fruit development. These results indicate that neither fruit weight nor number of days after pollination is a suitable index for harvesting time.     

Involvement of 1-methylcyclopropene in ripening of harvested mei (Prunus mume) fruit

Summary

Harvested mei (Prunus mume) fruit were stored at 20°C after exposure to 500 nl l^–1 1-methylcyclopropene (1-MCP) for 8 h. Firmness, peel colour, chlorophyll content, chlorophyllase activity, soluble solids content (SSC), titratable acidity (TA), respiration and ethylene production, and cell wall hydrolysis enzyme activities were monitored to determine the efficacy of 1-MCP treatment in delaying mei fruit ripening compared to untreated control fruit. Results showed that control ‘daqinghe’ mei fruit displayed typical climacteric patterns of respiration and ethylene production. Peak CO₂ production and ethylene production were observed after 6 d. Fruit softening was accompanied by a progressive decrease in colour parameters expressed as hue angle (h°), chlorophyll content, SSC, TA and increases in chlorophyllase, pectin methylesterase (PME) and polygalacturonase (PG) activities. 1-MCP treatment prior to the climacteric increase significantly delayed the onset of the climacteric peaks of CO₂ and ethylene production. These delays were associated with reductions in fruit softening, consistent with delaying the activities of PME and PG. Fruit treated with 1-MCP exhibited less peel colour change from green-to-yellow because of their lower levels of chlorophyllase activity and less chlorophyll breakdown. Moreover, 1-MCP treatment also significantly retarded reductions in SSC and TA compared with control fruit. The shelf-life of mei fruit ripening was increased by 4 d following 1-MCP treatment. Thus, 1-MCP treatment can markedly extend the post-harvest life of ‘daqinghe’ mei fruit.     

Low leaf to fruit ratio delays fruit maturity of ‘Lapins’ sweet cherry on Gisela 5

Canopy leaf to fruit ratio (L:F) of 6-year-old ‘Lapins’ sweet cherry trees on Gisela 5 rootstock was manipulated at the end of stage II (38 DAFB) of fruit development. While control trees showed a L:F ratio of 0.7:1 without alteration, on other trees young fruit were manually removed to yield L:F ratios of 2:1 and 3:1, respectively. All leaves and young fruit on trees were counted 30 DAFB. The effect of altering the source–sink ratio of whole trees on sweet cherry fruit quality parameters (fruit increment, fruit mass, color, total soluble solids content, contents of individual sugars and organic acids) was evaluated in the study. High leaf area to fruit (LA:F) ratios influenced significantly darkest fruit color, higher fruit mass, higher total soluble solids content and higher ratio between sugars and acids, which corresponded to better ripening stage. Contents of glucose, fructose and sorbitol, but not sucrose, sum of individual sugars, and the content of malic acid differed significantly among fruit of the different treatments. Fruit of the most advanced maturity stage (treatment 3:1) had the highest quality. Each day of improved L:F ratio counts towards better sweet cherry fruit quality. The results show that low L:F ratio influenced prolonged ripening process and delayed fruit maturity of ‘Lapins’ sweet cherry.     

Improved fruit retention,yield and fruit quality in mango with exogenous application of polyamines

Aqueous solutions (0, 0.01, 0.1, 1 mM) of PAs (putrescine, spermine, spermidine) containing a surfactant ‘Tween 20’ were sprayed onto panicles of mango (Mangifera indica L. cv. Kensington Pride) at final fruit set (FFS) stage (when all flowers abscised but remain attached to the panicle) during 1999–2001 to investigate their effects on fruit retention, yield, size, and fruit quality. The optimum time of PA application for improving final fruit retention and fruit yield was determined by spraying different concentrations (0, 0.01, 0.1, 1 mM) of spermine (SPM) containing a surfactant ‘Tween 20’ at four phenological stages including flower bud differentiation (FBD), 5–8 cm long grown panicles (GP), full bloom (FB) and at initial fruit set (IFS) stage (when 2/3rd of the flowers were abscised but attached to the panicle) during 2000. Exogenous application of PAs at FFS stage did not significantly increase fruit retention. However, compared to control (0.79 and 2.3% fruit retention), PAs treatments resulted in comparatively higher mean fruit retention (1.53 and 2.92%) during 1999–2000 and 2000–2001, respectively. Among three PAs tested, SPM was more effective in increasing mean final fruit retention. Fruit size was not significantly affected by any PA treatment. Among the four application times, SPM (0.01 mM) spray at FB stage resulted in significantly (P ≤ 0.05) greater fruit retention (4.99%) compared with control (2.1%). However, fruit yield was comparatively higher with SPM (0.01 mM) application at IFS stage or 5–8 cm GP stage compared to the control. Overall FB application was found as the optimum time of application. Application of PAs at FFS stage retarded fruit skin colour development compared to the control. Sugars and total soluble solids (TSS) were generally reduced in PA-treated fruit. Fruit acidity was increased (16.7%) with SPM, whereas it was 11% with PUT treatment as compared to the control. Total carotenoids in pulp were generally improved (49%) with PA treatments, compared to the control. Ascorbic acid concentrations were significantly reduced with spermidine (SPD) (24%) and PUT (20%) treatments, whereas higher concentrations of SPM (1 mM) tended to increase it (12.7%) compared to the control. In conclusion, application of SPM (0.01 mM) at FB stage resulted in the highest fruit retention, whereas SPM (0.01) spray at GP or IFS stage resulted in higher fruit yield. PUT application at FFS stage significantly improved fruit quality by increasing total carotenoid, while reducing acid content of ripe fruit.     

Effect of overhead shading on yield and fruit quality of kiwifruit (Actinidia deliciosa)

Summary

Kiwifruit vines (cv. Hayward) were shaded from early spring until fruit harvest at levels of 100% (control), 70% or 45% full sun. Although shoot growth during the early part of the season was not significantly affected by the shading, the percentage bud burst was reduced and the time of full bloom appeared to be slightly delayed. The mean fresh weight of individual fruits was significantly reduced by shading, and fruit on shaded vines reached commercial harvest maturity of 6.2% soluble solids two to three days later than those on unshaded vines. During cool storage, fruit from vines grown under 45% full sun were slightly but consistently less firm and had lower soluble solids concentrations than unshaded fruit. No differences in the starch or total sugar contents were found between shaded or unshaded fruit, either at harvest or after cool storage. Shading vines did not affect either the colour (HunterLab values) or the chlorophyll concentration of fruit. Possible implications of these results for commercial orchards are discussed.     

调亏灌溉条件下鸭梨营养生长、产量和果实品质反应的研究

调亏灌溉条件下的研究结果表明,无论在1期(萌芽至盛花后25d)还是在2期(盛花后25～80d)进行调亏灌溉,树体营养生长受到显著抑制,新梢长度较对照下降15%～25%,夏季修剪量减少18%～33%,树体叶片的相对含水量显著下降,对成龄叶片叶面积和比叶重的影响差异不显著。各处理其花朵坐果率均大于85%,没有显著抑制果径和果实鲜重的增长。在水分胁迫处理结束时,2期胁迫和1+2胁迫处理果实的可溶性固形物含量、还原糖含量和全K含量显著高于对照,1+2胁迫处理的果径和果实鲜重也受到了显著抑制。在采收时各水分胁迫处理与对照相比,在产量、单果重和果实可溶性固形物含量方面无显著差异。     

Partial rootzone drying maintains fruit quality of ‘Golden Delicious’ apples at harvest and postharvest

Partial rootzone drying (PRD) has been evaluated at harvest, but its effects on apple fruit postharvest life is little known for apples grown in semi-arid regions. The objective of this study was to test the hypothesis that water savings via PRD may affect fruit quality at harvest and postharvest-life of ‘Golden Delicious’ apples grown in a semi-arid region. The experiment was conducted from 2005 to 2007. The irrigation treatments were commercial irrigation as control (CI) and PRD. After 3 years of evaluation, fruit quality at harvest, measured as fruit weight, flesh firmness, and total soluble solids concentration, was similar between CI fruit and PRD fruit. Dry matter concentration (DMC) was higher in PRD fruit than in CI fruit in 2005. The fruit quality after 18 days storage at room temperature (13–18 °C and 51–56% relative humidity) was similar between CI fruit and PRD fruit. The DMC was the highest in PRD fruit in the 2005 and 2007 growing seasons, and tended to be higher in PRD fruit than in CI fruit in 2006. Total soluble solids concentration was ≈8.7% higher in PRD fruit than in CI fruit in 2007. Fruit weight loss was similar between treatments. This study suggests that water deficit via PRD did not damage fruit quality at harvest or after storage at room temperature. Additionally, PRD irrigation saved about 3240 m³ of water per hectare. Therefore, PRD can be recommended for commercial use in semi-arid regions and to those growers interested in either long-term storage or distant markets.     

Grafting effects on postharvest ripening and quality of 1-methylcyclopropene-treated muskmelon fruit

In addition to managing soil-borne diseases in muskmelon (Cucumis melo L.) production, grafting with resistant rootstocks may impact fruit quality. The ethylene antagonist 1-methylcyclopropene (1-MCP) has been shown to extend shelf life of fresh muskmelon fruit. Postharvest characteristics of 1-MCP-treated melon fruit as affected by grafting, however, have not been well examined. This study was conducted to explore the influence of grafting with different rootstocks on ripening and quality attributes of 1-MCP-treated muskmelon fruit during postharvest storage. Grafted ‘Athena’ muskmelon with two commercial squash interspecific hybrid rootstocks including ‘Strong Tosa’ and ‘Tetsukabuto’ as well as non-grafted and self-grafted ‘Athena’ were grown in replicated field plots at the University of Florida Plant Science Research and Education Unit (Citra, FL, USA) during April–June 2010. Half-slip fruit from two harvests were treated with 1.0 μL L⁻¹ 1-MCP (18 h, 20 °C) and analyzed during storage at 13 °C. For fruit from the 27 May harvest, whole fruit and mesocarp firmness, titratable acidity, soluble solids, and ascorbic acid content were measured, while production of ethylene and CO₂ was determined on fruit from the 29 June harvest. Grafting did not show a significant impact on fruit yield but affected the fruit shelf life significantly. Fruit from non-grafted ‘Athena’ and ‘Athena’ grafted onto ‘Strong Tosa’ demonstrated a shelf life of 31 d for the first harvest and 22 d for the second harvest. Shelf life of fruit from self-grafted ‘Athena’ and ‘Athena’ grafted onto ‘Tetsukabuto’ declined by 6 d and 3 d for the first and second harvest, respectively. Whole fruit firmness decreased by approximately 15.5% on average from 13 to 31 d except day 19 as a result of grafting, but to a lesser extent with ‘Strong Tosa’ rootstock. Mesocarp firmness of grafted melon was reduced by about 30.2% at days 13 and 19 compared to non-grafted ‘Athena’ fruit. In contrast, titratable acidity, soluble solid content, and ascorbic acid concentration were less affected by grafting. All the measurements except for ethylene and CO₂ production declined during storage regardless of the grafting treatment. Compared with ‘Strong Tosa’ rootstock, ‘Tetsukabuto’ resulted in a more rapid ripening under 1-MCP application, as reflected by earlier increase in ethylene production and higher respiratory rate. The study demonstrates that grafting effects on postharvest ripening and quality of ‘Athena’ muskmelon can vary markedly with rootstocks used.     

硝酸钙和IAA对温州蜜柑果实钙含量及其品质的影响

在花期、花后1周、3周、采前2周对龟井蜜柑进行Ca(NO3)2、IAA和IAA+Ca(NO3)2喷布处理,同时测定了不同发育时期各处理果实钙含量及其采后果实的主要品质,并与采后浸钙处理和完熟采收果实品质进行了对比分析,结果表明:1)各处理的果皮钙含量在花后51d和112d均有所提高,但此期整个果实钙含量并无显著性差异,采收时各处理整个果实和果肉钙含量均显著高于对照;2)采收时各处理果实的可溶性固形物和可滴定酸均显著低于对照,可溶性糖、单果重、果皮色差值和相对电导率与对照无显著性差异,各处理糖酸比显著高于对照;3)采后30d时IAA+Ca(NO3)2喷布和采后浸钙处理果实的维生素C及完熟采收果实的可溶性固形物和可溶性糖均显著高于对照和其他处理。     

Fruit thinning in ‘Conference’ pear grown under deficit irrigation: Implications for fruit quality at harvest and after cold storage

Fruit thinning in pear is feasible for mitigation of water stress effects. However, it is not well known how fruit quality at harvest and after cold storage is affected by pre-harvest water stress. Even less is known about the effects of fruit thinning on quality under these circumstances. To elucidate these, we applied deficit irrigation (DI) and fruit thinning treatments to ‘Conference’ pear over the growing seasons of 2008 and 2009. At the onset of Stage II (80 and 67 days before harvest in 2008 and 2009, respectively), two irrigation treatments were applied: full irrigation (FI) and DI. FI trees received 100% of crop evapotranspiration (ETc). DI trees received no irrigation during the first three weeks of Stage II to induce water stress, but then received 20% of ETc to ensure tree survival. From bud-break until the onset of Stage II and during post-harvest, FI and DI trees received 100% of ETc. Each irrigation treatment received two thinning levels: no thinning leaving commercial crop load (∼180 fruits tree⁻¹), and hand-thinning at the onset of Stage II leaving a light crop load (∼85 fruits tree⁻¹). Under commercial crop loads, DI trees were moderately water-stressed and this had some positive effects on fruit quality. DI increased fruit firmness (FF), soluble solids concentrations (SSC) and acidity at harvest while no changes were observed in fruit maturity (based on ethylene production). Differences in FF and acidity at harvest between FI and DI fruit were maintained during cold storage. DI also reduced fruit weight loss during storage. But fruit size was reduced under DI. Fruit thinning under DI resulted in better fruit composition with no detrimental effect on fresh-market yield compared to un-thinned fruit. Fruit size at harvest and SSC values after five months of cold storage were higher in fruit from thinned trees than fruit from un-thinned trees. Fruit thinning increased fruit ethylene production, indicating advanced maturity. This may lead to earlier harvest which is desirable in years with impending drought. Fruit thinning is therefore a useful technique to enhance pear marketability under water shortage.     

不同药剂和包装处理对甜樱桃生理、品质及贮藏性的影响

研究了不同药剂和包装处理对贮藏期间甜樱桃果实生理和品质变化的影响。试验结果表明，包装和药剂处理组合对控制果实腐烂，保持果实硬度和颜色，减缓维生素Ｃ和可滴定酸含量的下降速率，抑制乙烯和乙醇生成都具有较明显的效果。但是药剂和包装处理并不影响贮藏期间果实可溶性固形物的含量。生物 １号药剂与 ０．０４ ｍｍ厚加有ＴＢＺ的聚乙烯塑料薄膜袋配合对减缓果实衰老，减少果实腐烂和保持果实品质的效果最好。     

Changes in physicochemical attributes of sweet pepper cv. Domino during fruit growth and development

The effect of harvesting sweet pepper ‘Domino’ fruit at different stages of growth and development on physicochemical attributes was studied. The suitability of fruit fresh weight, diameter and length, weeks from anthesis, total soluble solids (TSS), fruit colour change, firmness, internal CO₂ and C₂H₄ concentrations as well as fruit respiration and ethylene production as maturity indicators were evaluated. Fruits were harvested weekly until fully red ripe. Fruits took 8 weeks after anthesis (WAA) to reach harvest maturity and a further 2–3 weeks to reach full ripeness (11 WAA). Fruits exhibited a sigmoid growth pattern. Hue angle (change in colour from green to red) declined with time while chroma (colour intensity) values increased with fruit maturity, as did TSS. An increase in PⁱCO₂ and PⁱC₂H₄ accompanied the decrease in hue angle. The association between fruit ripening and the significant increase in PⁱC₂H₄ indicates that ethylene may be responsible for ripening of this cultivar of sweet pepper. Colour change and TSS were reasonable indicators of maturity of sweet pepper fruit complemented with fruit firmness.     

钙及钙调素拮抗剂CPZ对柿果实采后生理的影响

柿果在生长期喷施高于1%的CaCl_2可增加果实采收时的钙浓度,但造成叶面伤害,不能延迟柿衰老。喷施1%Ca(OH)_2显著地增加了果实钙含量,在贮藏过程中果实乙烯浓度显著高于对照。减压渗透CaCl_2可显著降低柿果呼吸强度、乙烯浓度、膜透性和PG酶活性,抑制果实软化,其中4%CaCl_2渗透最好。减压渗透CPZ促进呼吸增强、乙烯产生和果实软化。     

热水和1-MCP处理对杧果贮藏效果的影响

研究了常温下热处理、1-MCP处理及热处理结合1-MCP处理对杜果果实贮藏效果的影响。结果表明:热处理能有效控制杧果采后炭疽病的发生,改善果实外观,提高好果率,延长贮藏时间,但使呼吸增强,不能抑制果实后熟和减少果实失重率;1-MCP处理能降低果实在贮藏过程中的呼吸强度,抑制果实的后熟,减少果实失重率,但对炭疽病的防治无效;热处理结合1-MCP处理在一定程度上结合了2者的优点,该处理既有效的控制了炭疽病的发生,又延缓了杧果果实的后熟进程,延长了贮藏时间,且对杧果果实的品质无不良影响。所有处理对成熟时的可溶性固形物含量、可滴定酸含量及糖酸比无影响,且对蒂腐病的防治效果也均不理想。     

Regulated deficit irrigation in `Clementina de Nules' citrus trees. I. Yield and fruit quality effects

Summary

An experiment on Regulated Deficit Irrigation (RDI) was performed during 1995 and 1996 in a ten year old, drip-irrigated `Clementina de Nules' mandarin orchard in Moncada, Spain. Treatments consisted of a control, where irrigation was applied without restriction during the whole year at 125% ET_lys and RDI treatments where irrigation was reduced to 25% or to 50% of crop evapotranspiration measured by a weighing lysimeter (ET_lys) during one of the following periods: I) flowering and fruit set (spring, 20 March to 3 July in 1995, and 1 April to 1 July in 1996); II) initial fruit enlargement phase (summer, 4 July to 7 August in 1995, and 2 to 28 July in 1996), and III) final fruit growth and maturation phases (end of summer–autumn, 8 August in 1995, and 29 July in 1996 to harvest). An additional treatment, denominated 50%–Year, was irrigated at 50% ET_lys during the whole year. The effects of the treatments on yield and fruit quality in relation to tree water status (pre-dawn (c^a) and midday (c^md) leaf water potential, and their time integral) show large differences in sensitivity to water stress according to phenological stage. The critical periods were the flowering and fruit set phases. The main treatment effects during each period were: In spring, a decline in c^a and c^md with respect to the control of only 0.1 to 0.2 MPa reduced yield by 62% and 28%, respectively for the 25% and 50% levels, due to an increased ``June drop'' and consequent fewer fruit harvested per tree. Final fruit size and quality were similar to those of the control. In summer, RDI treatments allowed water savings between 7 and 14% without affecting yield or fruit quality, providing that a threshold value of c^a–1.3 MPa is not surpassed. In autumn, for the 25% and 50% levels there was a 25 to 11% reduction of fruit size, respectively, with some external peel disorders (creasing) which reduced fruit quality, even at the lower water stress levels reached in the 50% treatment during this period (c^a 20.64 MPa and 20.83 MPa in 1995 and 1996, respectively). In treatment 50%–Year, where water application was 44% of that in the control, minimum c^a values were around 20.6 MPa and 20.8 MPa in 1995 and 1996, respectively. Tree growth was reduced in both seasons and average yield decreased by 17%. Yield loss was due to smaller, not fewer fruit. This treatment increased TSS and acids in the juice, without affecting the maturity index or creasing. However, in the current market situation, this irrigation strategy could be recommended only as a long-term one in cases of very high water prices.     

Effects of deficit irrigation on fruit maturity and quality of ‘Braeburn’ apple

Effects of deficit irrigation (DI) on fruit maturity at harvest, ripening characteristics, and changes in fruit quality during and after storage of ‘Braeburn’ apple (Malus domestica Borkh.) were studied in two experiments. In Experiment 1, irrigation treatments were a commercially irrigated control (CI), an early deficit irrigation (EDI) applied from 63 to 118 days after full bloom (DAFB), and a late deficit irrigation (LDI) applied from 118 DAFB to final harvest on 201 DAFB. Irrigation treatments in Experiment 2 were a commercially irrigated control (CI) and a whole-season deficit irrigation (WDI). These DI treatments all reduced volumetric soil water content. The LDI and WDI advanced fruit ripening but EDI did not. All DI treatments increased fruit total soluble solids (TSS) and firmness regardless of maturity but had little or no effect on titratable acidity. The differences in TSS started during fruit growth much earlier than the onset of ripening and were maintained during and following storage at 0°C. The differences in firmness also started during fruit growth and were maintained for at least 10 weeks of storage at 0°C.     

Branch scoring encourages fruit development and climacteric in persimmon

Branch scoring of ‘Rojo Brillante’ persimmon (Diospyros kaki) increased fruit size at harvest and caused a significant shift in the distribution of fruit diameters to the larger sizes, the response magnitude depending on the date of scoring. Scoring at the 75–77 growth stage of the BBCH-scale encouraged the development of fruit which grew faster, reached commercial colour, ripening and flesh softness earlier, and therefore was harvested earlier. Although fruit weight was significantly increased by scoring, the number of fruit was not modified and there was not a significant increase in yield. Fruit from trees scored at the onset of cell enlargement stage initiate ethylene production before fruit from unscored trees. Scoring did not modify following yield.     

不同果袋对丰水梨果实发育微环境及采后冷藏品质的影响

选择10种不同类型的果袋对丰水梨果实进行套袋处理,研究了套袋对果实发育微环境及采后冷藏品质的影响。结果表明,套袋改变了果实生长发育的微环境,套袋果实在冷藏过程中品质发生了不同变化,如冷藏80d时大部分套袋处理果实的硬度、可溶性固形物、维生素C和可滴定酸含量均显著高于对照,表明套袋处理有效地维持冷藏过程中果实的内在品质。在10种果袋类型中,外黄内黑的双层袋(编号为D-6)套袋处理的果实在冷藏80d时品质最佳。