枇杷果实成熟和贮藏过程中有机酸的代谢

以高效液相色谱法测定解放钟和早钟六号枇杷成熟过程中及其在8-10℃低温保鲜与MAP保鲜过程中有机酸成分的变化。结果表明:枇杷鲜果中有机酸有苹果酸、乳酸、草酸、酒石酸、富马酸、柠檬酸、丙酮酸等,其中主要有机酸为苹果酸(约占85%),其次为乳酸(约占10%),草酸、酒石酸的含量较低,富马酸微量,不含乙酸和琥珀酸。随着采收成熟度的提高与贮藏时间的延长,有机酸的种类增加,总酸含量下降,有机酸代谢消耗主要是苹果酸的代谢消耗。MAP保鲜主要是通过抑制苹果酸的代谢来减少有机酸在贮藏过程中的消耗。     

Combinations of GA3 and AVG delay fruit maturation,increase fruit size and improve storage life of `Feicheng' peaches

Summary

Different concentrations of aminoethoxyvinylglycine (AVG) and gibberellic acid (GA₃) and their combinations, applied at two stages of fruit growth, were evaluated for prolonging the marketing season of `Feicheng' peaches. GA<sub>3</sub> applied at the end of pit hardening, or AVG applied two weeks before commercial harvest, inhibited fruit maturation on the tree, delayed harvest and reduced flesh browning after cold storage in a concentration-dependent manner. A synergistic effect was found when both GA<sub>3</sub> and AVG were used, with the combination of 100 or 150.mg l<sup>±1</sup> GA<sub>3</sub>, applied at the end of pit hardening, and 100 mg l<sup>±1</sup> AVG, applied two weeks before harvest giving the best results. These combinations retarded the change in ground colour, loss of firmness, and reduction in acidity by 2±3 weeks. Since harvest was prolonged by 2±3 weeks, soluble solids content (SSC) in fruit increased compared with the control (harvested earlier). Fruit size was significantly greater on treated trees compared with the controls when fruit set was controlled to the same level by hand thinning. After four weeks of storage and 4.d at 208C, 83% of control fruit developed tissue browning, but only 5% of AVG + GA<sub>3</sub>-treated fruit developed browning after six weeks of storage and 4 d at 208C. Thus, the marketing season of `Feicheng' peaches was prolonged by at least four weeks by 100 or 150 mg l^±1 of GA₃ and 100 mg l^±1 of AVG. Fruit treated with 150 mg l^±1 GA₃ plus 100 to 150 mg l^±1 AVG showed similar results but failed to ripen properly after cold storage.     

Relationship between watercore and maturity or sorbitol in apples affected by preharvest fruit temperature

The effect of preharvest fruit temperature on the relationships between development of watercore and ethylene evolution, flesh firmness, membrane permeability and sorbitol level in two watercore-susceptible apple (Malus domestica Borkh.) cultivars, ‘Himekami' and ‘Fuji', was investigated at ambient or modified temperatures of 10, 15 or 25°C. Watercore occurrence was completely inhibited at 25°C in both cultivars whereas fruit subjected to 10 or 15°C exhibited significantly higher watercore ratings after two or three weeks of the treatment than those at 25°C and ambient temperatures. Ethylene production of ‘Himekami' apples increased at 25°C and ambient temperature but not at 15°C. Ethylene production was not affected by treatment in ‘Fuji' apples. Flesh firmness of ‘Himekami' tended to maintain a higher level at 15°C than at 25°C, while there was no clear difference among the treatments in ‘Fuji'. The rate of potassium (K) ion elution from the flesh tissues of either cultivar was not affected by fruit temperature treatment. Sorbitol content at 15°C maintained significantly higher level than that at 25°C during the treatment in ‘Himekami' apples although no sorbitol difference was observed among the temperature treatments in ‘Fuji' apples.     

A comparison of the response of different citrus fruit cultivars to storage temperature

A comparison was made of the response to storage temperatures (0–17°C) of grapefruit ‘Shamouti’ and ‘Valencia’ oranges, and lemon fruit. There was no chilling injury (CI) and the incidence of rot was relatively low at 12°C or higher for all cultivars. At low storage temperatures, however, pitting and subsequent rot development in grapefruit and in ‘Shamouti’ and ‘Valencia’ oranges were highest at 6°C, while in lemon the incidence of these disorders rose with the decrease in storage temperature, and was highest at 2°C. Grapefruit and ‘Shamouti’ oranges exhibited the highest susceptibility to CI, lemon showed an intermediate susceptibility, and ‘Valencia’ orange a very low one. In grapefruit, severe peel pittings that developed in cold storage were covered by mold rots during cold storage and shelf-life, but in ‘Valencia’ and particularly in ‘Shamouti’ oranges the incidence of decay during cold storage was low. During shelf-life, a pronounced CI-induced increase in the incidence of mold rots was evident. This breakdown during shelf-life may be associated with microscopic peel injuries which are formed during cold storage and covered by mold rots during shelf-life. Increased susceptibility of the cultivar to CI could be correlated with an increase in ethanol content at low temperatures.     

Yield,chemical composition,growth and maturity of ‘Williams’ banana fruit in relation to supply of potassium,magnesium and manganese

In New South Wales, banana plantations are subject to shortages of K, Mg and possibly high Mn. We investigated the effects of a low supply of K and Mg and high Mn on ‘Williams’ banana grown in drainage lysimeters over 3 crop cycles. Low K supply reduced yield by 73%, low Mg reduced it by 17% and high Mn had no effect. The bunch-weight component, mean finger weight, was reduced most (57 and 13% by low K and Mg, respectively) and the fruit number per hand was reduced least (16 and 8%, respectively). Fruit growth was exponential, and the relative fruit growth rate was influenced by K supply and seasonal conditions.High Mn supply decreased fruit maturity (greenlife) by 23%. Low K supply increased greenlife 79%, but only in relation to its effect on fruit size. The concentrations of K and Mg in the fruit dry matter were largely independent of the concentration in the solution around the roots. Mn concentration in fruit dry matter was directly proportional to Mn supply. The concentration of Ca in fruit dry matter showed a significant (P = 0.01) positive association with greenlife over all treatments.     

Cellular wall metabolism in citrus fruit pericarp and its relation to creasing fruit rate

Citrus creasing results in serious economic loss in many citrus orchards. Based on the different incidence of creasing, two sweet orange cultivars ‘Hong Jiang’ (grafting chimaera of which flesh is mostly from Citrus reticulata Blanco and peel is from Citrus sinensis Osbeck in) and ‘An Liu’ (Citrus sinensis Osbeck) were used to investigate the creasing rate. The ultrastructure in cellular wall, cellular wall component, cellular wall degradation-related enzymes and expansin (Ct-Exp1) of sweet orange during fruit ripening in field were comparatively analyzed. ‘Hong Jiang’ sweet orange had a higher creasing rate than ‘An Liu’ during ripening. The activities of polygalacturonase, cellulase and pectinesterase in cellular wall of ‘Hong Jiang’ increased more markedly compared with ‘An Liu’. The increases in the content of soluble pectin, ionically associated pectin, covalently bound pectin, hemicellulose and cellulose of ‘Hong Jiang’ were higher than those of ‘An Liu’. Furthermore, the enhanced degradation of the ultrastructure in the albedo cellular walls was observed in ‘Hong Jiang’. Moreover, the northern blot analysis indicated that the Ct-Exp1 gene expressed more strongly in peel of ‘Hong Jiang’ than ‘An Liu’ during fruit ripening. These data suggest that enhanced loss of pectin and cellulose in the cellular walls of peel tissue of sweet orange could result in fruit creasing.     

叶面喷施金雀异黄素对套袋蟠桃果实着色及品质的影响

以转色始期早硕蜜蟠桃为试材,探讨了叶面喷施金雀异黄素(GNT)对套袋果实花青素积累与其他品质的影响。结果表明,纸袋提高果实花青素含量,增幅约为70%,塑膜袋降低花青素含量,约为6%;GNT能提高套袋和未套袋果实花青素含量,增幅为16%～73%。套袋使果实可溶性糖降低约8%,可滴定酸含量增加20%;GNT提高果实可溶性糖4%～26%,并降低可滴定酸10%～28%,明显提高果实糖酸比。叶片组织相对电导率和丙二醛含量分析表明,GNT对叶片细胞膜透性和脂质过氧化没有明显影响。因而,即使在套袋条件下用适宜质量浓度GNT也能提高蟠桃果实内外品质,并且不会对叶片造成伤害。     

不同地区酿酒葡萄成熟度与葡萄酒质量的研究

含糖量、糖／酸是酿酒葡萄的成熟度指标，决定着葡萄酒的质量，适期采收能达到葡萄酒质与量的统一，成熟期昼夜温差、降水量的不同是造成陕西丹凤、陕西杨陵、甘肃武威三地区葡萄成熟度差异的主要原因，并导致葡萄酒质量的差异。在武威生态条件下，雷司令最佳成熟度的含糖量和糖／酸分别为１９９．２ｇ／Ｌ和２６．４９，法国兰分别为１９４ｇ／Ｌ和２７．２。     

Defense response of tomato fruit at different maturity stages to salicylic acid and ethephon

In order to elucidate whether fruit maturity stage influence the induced resistance of exogenous elicitors in tomato and the involved mechanisms, we investigated the defense responses of tomato fruits against Botrytis cinerea, ethylene production and internal quality following treatments of fruit with salicylic acid (SA) or ethephon (ET) at mature green (MG) and breaker (BR). SA significantly suppressed decay and disease incidence in tomato fruits at both MG and BR stages, along with higher expression level of PR1 gene after 2 days of treatment. All fruits treated by SA had lower contents of ethylene and lycopene. The ET-treated fruit at both maturity stages showed lower disease incidence and higher level of PR2 and PR3 expression compared with the control fruit. ET treatment significantly enhanced ethylene and lycopene contents, and accelerated fruit ripening. Our results suggest that SA and ET induced disease resistance in fruits by mediating the expression of different pathogenesis-related genes and have different effects on fruit ripening, which in turn influences the disease resistance of tomato fruits.     

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.     

Growth rates of glasshouse tomato fruit in relation to final size

The individual growth rates of the first five tomato fruits on 25 trusses of similar age within a crop grown in commercial glasshouse conditions were assessed from anthesis to ripening during April and May. Final size of fruit at ripening was proportional to the maximum rate of increase in fresh weight, about 40 d after anthesis, and related to the maximum rate of increase in diameter, between 15 and 20 d after anthesis, even though ripe fruit fresh weight varied from 20 g to over 100 g. On any one truss these fruit ripened within the same week, regardless of fruit size and prevailing growth rate. These findings suggest that final size was related to the peak fruit growth rate rather than the duration of development. A high growth rate late in development did not delay fruit ripening. The implications for recent continuous measurements of the diameter growth rate in young fruit are discussed.     

采摘成熟度对'新白8号'枇杷常温贮藏效果的影响

【目的】探讨白肉枇杷新品种'新白8号'不同成熟度果实的常温贮藏效果的变化,为指导科学采摘与合理贮藏提供参考依据。【方法】比较了室温贮藏条件下,七成熟至十成熟的'新白8号'鲜果,果皮色差、果实失水率、坏果率、皱果率、果肉硬度、糖组分、酸组分等指标的动态变化。【结果】各成熟度的H0值缓慢下降,a*值上升,L*值略降,b*、c*值呈"升—降—升"的趋势;失水率呈抛物线式上升,七成熟最高;贮藏4 d后,十成熟皱果率快速增大,至13 d达34.71%,八、九成熟增加较缓慢,七成熟无皱果;坏果率呈增大趋势,十成熟最高,至13 d达44.29%,其次是七成熟;果肉硬度均缓慢增大,成熟度越高增加幅度越大;TSS、总糖含量0～4 d小幅上升,之后均缓慢下降;果糖含量呈上升趋势,七成熟的增幅最大;0～7 d葡萄糖含量上升,7 d后九、十成熟的下降;蔗糖含量变幅最大,除十成熟外,0～1 d提高12.03%～16.08%,而后下降,七成熟降幅最大;山梨醇先增大后降低,十成熟增幅最大;总酸、苹果酸含量总体下降且趋势一致,成熟度越低下降幅度越大;奎尼酸、富马酸含量有波动,贮藏后差异不显著;乳酸含量在贮藏4～10 d时上升后下降;糖酸比、固酸比呈"升—降—升"波动上升,低成熟度果接近贮藏前十成熟果。【结论】采摘成熟度对'新白8号'枇杷常温贮藏效果的影响较大,八、九成熟果更适合常温贮藏,有效贮藏期宜小于10 d;十成熟果常温贮藏宜小于4 d。     

Deposition of calcium compounds in tomato fruit in relation to calcium transport

The deposition of calcium in tomato fruit grown at a range of salinities (electrical conductivities between 3 and 17 mS cm“1), with or without IAA-transport inhibitor treatment, was investigated. Calcium (Ca) in the flesh and pulp of tomato fruit was sequentially separated into four fractions: FI soluble in water, FII soluble in 2.5 mol dm“3 NaCl, Fill soluble in 2% acetic acid and FIV soluble in 5% HC1. In mature fruit, grown at 3 mS cm“1, more than half the Ca was in FI, and the Ca concentration was higher in the pulp than in the flesh. FII and Fill each contained less than 20% of the Ca, and the Ca concentration was higher in the flesh than in the pulp. In general, salinity reduced the concentration of Ca in all fractions and slightly altered the proportional distribution of Ca in fractions. The deposition of calcium in young fruit, grown at 3 and 8 mS cm“1, was highest in FII in the flesh or in FI in the pulp. When 45Ca was supplied to detached fruit, the patterns of45 Ca distribution in the fractions were similar to that of total Ca. Treatment with an IAA-transport inhibitor, CME, reduced both the uptake and transport of 45Ca. While the amount of 45Ca in all fractions was significantly reduced by CME, the proportional distribution of 45Ca among fractions was not affected substantially. Although the proportional deposition of Ca in different fractions was not significantly affected by either salinity or CME, further reduction of the intrinsically low deposition of Ca in FII of distal pulp caused by these factors may be the cause of blossom-end rot in tomato fruit.     

Light distribution in apple orchard systems in relation to production and fruit quality

Summary

The effect of tree density (2000, 2667, and 4000 trees per ha) and the ratio of between to within-row distance (1:1, 2:1, and 3:1) on light interception, fruit production, colour and individual fruit weight was evaluated in a ten-year comparative field study with apple at two sites in The Netherlands (51° 30′ and 52°0′ N) and one site in Denmark (55°30′). For each combination of tree density and rectangularity, trees were pruned at three heights (1.50, 1.88, or 2.25 m). Fruit production over nine years and seasonal incoming radiation between bloom and harvest were 20 and 15% greater in The Netherlands. Climate-based estimates of potential production as provided by a crop-growth model, predicted 18% higher fruit production in The Netherlands. Production was proportional to light interception and increased with tree density, but the amount of well-coloured fruit per ha in later years did not increase with planting density. With more than 70% light interception in later years, a large proportion of shade within the canopy was found. Fruits were smaller and less coloured at the Danish site. Fruits were more coloured in the taller and more open trees, even at the highest tree densities. Plantings with 1:1 and 2:1 between-to within-row distances intercepted more light and had a more uniform light distribution than 3:1 designs. This led to higher fruit production and better fruit colour. Fruit weight was not influenced by tree density, rectangularity, or tree height.     

Maintenance of fresh boysenberry fruit quality with UV-C light and heat treatments combined with low storage temperature

Summary

Mature boysenberries (Rubus hybrid) were harvested, heat-treated (45°C for 1 or 3 h or 47°C for 1 h) or exposed to UV-C light (2.3, 4.6 or 9.2 kJ m^–2), and stored at 20°C for 2 d. Fruit treated with 9.2 kJ m^–2 or 45°C for 1 h showed less damaged drupelets per fruit and/or remained firmer than untreated fruit after 2 d. Those treatments were selected for further analyses. In another experiment, boysenberries were either UV-C (9.2 kJ m^–2) or heat-treated (45°C for 1 h) and stored either at 20°C for 1 d or at 0°C for 4 d before transfer to 20°C for 1 d. Both UV-C and heat treatments reduced softening and/or fruit damage. Treated fruit had lower respiration rates and anthocyanin leakage than control fruit suggesting greater tissue integrity. Titratable acidity, pH, total sugar content and antioxidant activity in treated fruit showed fewer changes than in control fruit when stored at 20°C for 1 d. Results suggest that heat or UV-C treatment, alone or in combination with refrigerated storage, may be a useful non-chemical mean of maintaining boysenberry fruit quality and extending postharvest life.     

果蔬产品保鲜贮藏的效益

保鲜贮藏是保持果蔬产品鲜活品质和营养价值的主要手段。从事果蔬产品保鲜贮藏者 ,最终目标是获取经济效益。从技术角度探讨 ,影响果蔬产品保鲜贮藏效益的因素主要有 4方面 ,即保鲜设施的整体水平 ;果蔬产品的属性 ;保鲜技术和保鲜效果 ;经营管理水平等     

MAP贮藏对甜樱桃品质的影响

对甜樱桃的贮藏保鲜试验表明,MAP与专用保鲜剂结合可有效地保持果实的鲜食品质,减少果实的腐烂和褐变,降低果实的呼吸强度,延长果实的贮藏期.‘红灯‘甜樱桃贮藏保鲜80 d果实的腐烂率为3.62%;对照果实只贮藏了40 d.‘雷尼‘甜樱桃贮藏保鲜110 d果实的腐烂率为2.1%,褐变率为0,果柄抽干率为0.32%;对照果实只贮藏了50 d.     

Watercore in Japanese pear (Pyrus serotina Rehder var. ‘Culta’ Rehder). I. Description of the disorder and its relation to fruit maturity

Out of 119 Japanese pear cultivars and selections and 12 Chinese ones and their 9 hybrids, 30 cultivars and selections showed a physiological disorder in the flesh of the fruit while still on the tree. The affected tissues were generally watery and translucent, and tasted sweet, but in some cultivars the area was slightly brown and tasted bitter. Cavities and/or pithiness developed in these areas both on the tree and during storage. Distribution of affected tissues on a transversely cut surface at the equator of the fruits showed 5 different types of appearance. In most cases the affected tissues were observed near or around the vascular bundles.In the most susceptible selection ‘93-3’, a higher percentage of affected fruits and severer symptoms were observed in the later-picked fruits. Greater severity of disorder was also found in the softer and more yellowed fruits with the more soluble solids. Because of several properties common to both the watercore of apples and this disorder, the term ‘Watercore in Japanese pear’ was chosen to describe it.     

Phytochemical accumulation and antioxidant capacity at four maturity stages of cranberry fruit

Specific components of cranberry fruit are being associated with human health attributes, such as maintenance of urinary tract health and antioxidant status. Some of the chemical properties and antioxidant capacity of cranberry (Vaccinium macrocarpon Ait. cv. Pilgrim) fruits were investigated at light green, blush, light red and dark red maturation stages. Fruit total phenolics, total monomeric anthocyanins, soluble solids, titratable acidity and individual organic acids were examined. Antioxidant capacity of fruits were determined by both the ferric reducing antioxidant power (FRAP) and trolox equivalent antioxidant capacity (TEAC) assays. The fruit color was measured using a portable chromameter. A converse relationship was found between total phenolics and anthocyanin as fruits mature. Total phenolic concentration was declined from 7990 to 4745 mg GAE/kg fw, while total monomeric anthocyanin content was increased from 0.8 to 111.0 mg/kg fw from green to dark red stage. Brix was increased from 6 to 9.3% as well. The main organic acid was citric acid determined by the HPLC method. The antioxidant capacity of cranberries decreased to light red stage; when a fruit accumulates more anthocyanin the activity increased again in both FRAP and TEAC methods. Averaged antioxidant capacity measured was 12.61 and 17.48 mmol TE/kg fw by FRAP and TEAC methods.     

Site and fruit maturity influence on the quality of European plum in organic production

Information available on the role of site and fruit maturity in the quality of European plums in organic production has not been studied to date. European plum cv. ‘Green Gage’ grown in organic production was harvested in order to study the effect of site and fruit maturity on fruit quality. At harvest, significant differences were found in fruit weight, colour, firmness and TSS between harvest dates, whereas significant differences were found in fruit weight, colour, firmness and fruit Ca content between sites. Differences remained during storage. Fruit weight loss during storage was affected by site. Fruit with high Ca content showed higher firmness both at harvest and during storage. Harvest moment should not be chosen according to date, since differences between sites at the same date have been found. Firmness and colour parameters a* and h° would be useful to distinguish maturity at harvest between different sites and harvest dates. Linear regression between h° and firmness at harvest would allow the use of the h° colour parameter as a non-destructive measurement to distinguish maturity. Organic orchards should keep a minimum level of Ca in order to assure a slower fruit softening during storage.