Aroma volatiles emission in relation to chilling injury in ‘Kensington Pride’ mango fruit

Summary

Mature green mango fruit (Mangifera indica L. ‘Kensington Pride’) were stored at 0, 5, 10, 15 or 20°C for 1, 3, 7, 14, 21 or 28 d to induce different levels of chilling injury (CI) and to elucidate its relationship with aroma volatile production. The fruit were removed from storage and allowed to ripen at 22 ± 1°C and CI index was assessed on fully ripe fruit. Aroma volatile compounds were estimated from the pulp of fully ripe fruit. CI index significantly increased as the storage temperature was lowered and the storage period was extended, particularly in the fruit stored at 0, 5 or 10°C. CI symptoms did not develop on fruit stored at 15 or 20°C. Fifty-six aroma volatile compounds were identified from mango fruit pulp using headspace solid phase microextraction (SPME) technique with gas chromatography (GC-FID) and GC combined with mass spectrometry (GC-MS). Among the 56 aroma volatile compounds, 25 were quantified using GC, which included monoterpenes (±-pinene, ²-pinene, myrcene, 2-carene, ±-phellandrene, 3-carene, ±-terpinene, limonene, ocimine, ³-terpinene, ±-terpinolene, and a-terpineol), sesquiterpenes (±-copaene, ±-gurjunene, trans-carophyllene, aromadendrane, ±-humulene, alloaromadendrane, ³-gurjunene, and ledene), hydrocarbon (p-cymene), esters (methyl octanoate and ethyl caprylate), aldehyde (decanal), and norisoprenoid (²-ionone). A significant reduction in total aroma volatiles, monoterpenes, sesquiterpenes, hydrocarbon, esters, aldehyde, and norisoprenoid production were observed in fruit stored at 0, 5, 10 or 15°C compared with fruit stored at 20°C. The degree of reduction in aroma volatile compounds depended on the severity of CI, induced with different storage temperatures and storage periods. In conclusion lower temperature storage induced CI in mango fruit and adversely affected the aroma volatiles production.     

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.     

Changes in ripening behavior of ‘d'Anjou’ pears (Pyrus communis L.) after cold storage

‘d'Anjou’ pear fruit, harvested at optimum maturity with flesh firmness of 6.8 kg, were stored at ?1.1°C. Fruit were ripened at 20°C for 15 days following storage for 1–8 months. Dessert qualities were evaluated organoleptically on Day 10 of each ripening period. Changes in fruit firmness, extractable juice, titratable acids, solubl solids, respiration, ethylene production and internal ethylene were determined daily during each ripening period. Fruit firmness declined continually from 6.8 kg at harvest to 4.5 kg after 8 months of storage. Fruit stored for 2–8 months softened with a similar pattern during a 15-day ripening period at 20°C, while fruit stored for 1 month softened at a slower rate during ripening to 3.2 kg, with a coarse and dry texture after 15 days at 20°C. Fruit stored for 2–4 months ripened with the desirable buttery and juicy texture, while those stored for more than 5 months ripened with a coarse or mealy and dry texture. The buttery and juicy texture was highly correlated with a lower extractable juice, which could be used for quantitative determination of storage life based on ripened fruit quality. Changes in titratable acids and soluble solids during each ripening period were not associated with changes in dessert qualities of the ripened pears. Rates of respiration, ethylene production and internal ethylene during ripening at 20°C varied with duration of storage, but were not associated with changes in dessert qualities of the ripened fruit.     

有机胡萝卜风味品质分析

采用SPME结合GC-MS方法对有机种植的胡萝卜进行挥发性成分分析测定,研究有机胡萝卜风味化合物及其风味品质。结果表明:有机种植的胡萝卜京红五寸样品中鉴定出34种挥发性化学组分,主要以单萜和倍半萜为主,占总量的93.85%。这些组分分别对有机胡萝卜的口感风味品质具有重要作用。对照样品中共检测出25种风味组分,有16种组分与有机样品的化合物相同,但含量有差别。     

锦橙果实发育过程中香气成分的变化

为了研究锦橙果实发育过程中香气成分的组成及变化,使用气相色谱-质谱联用仪分析了10月、11月、12月、翌年1月的锦橙鲜果的挥发性成分,分别检测到47,50,57,46种成分,主要成分为烃类、醛类、醇类和酯类.挥发性物质的总峰面积以及烃类、酯类在12月的果实中达到最大,反式-2-己烯醛、反式-2-己烯-1-醇、顺式-3-...     

Season has a Major Effect on the Essential oil Yield response to Nutrient Supply in Origanum Majorana

Summary

The effect of different nutrients on growth and essential oil yield and composition in Origanum majorana L. were studied under two seasons differing mainly with respect to their temperature regimes. Oil composition was little affected by either season or nutrient regime. Growth rates and yield of essential oils were positively correlated with nutrient supply; less strongly so in the summer than in late spring. Speci®c oil yield (yield per unit plant weight) was generally positively correlated with nutrient level at the lower temperature, negatively at higher temperature. In both seasons, the oil yield per plant was closely correlated to the growth rate, regardless of the nutrient or dose, but the responses differed signi®cantly according to the season.     

猕猴桃果实采后香气成分的变化

 在‘魁蜜’猕猴桃采后的硬果期、食用期、过熟期, 及‘早鲜’采后的食用期,采用溶液萃取法提取果实中的香气成分。经气相色谱2质谱联机分析, 共分离出80 个峰值, 鉴定出77 种化合物, 占总峰面积的92. 10 %。硬果期至食用期, 香成分表现为高级饱和脂肪酸、C5～C7 醛、醇及烯类等减少, 而高级不饱和酯类、环酮类等增加; 食用期至过熟期, 高级饱和脂肪酸已降解为其他物质, 重要特征香气成分, 如法呢醇、香草醛等消失, 醇类化合物等明显增加, 表现出鲜食果实气味变劣的突出特点。     

Effect of temperature on anthocyanin accumulation in apple fruit as affected by cultivar,stage of fruit ripening and bagging

Non-bagged and bagged apples of cvs Jonathan, Fuji, Jonagold and Tsugaru were harvested at different stages of ripening and irradiated with light at 15, 20 and 25°C. The changes in anthocyanin accumulation during ripening varied with temperature, cultivar and bagging or otherwise. In ‘Jonathan’, the optimum temperature for anthocyanin accumulation increased clearly from 15°C to 25°C in non-bagged and from 20°C to 25°C in bagged fruit as it ripened. In ‘Fuji’ and ‘Jonagold’, 20 and 15°C, respectively, were always the optimum for anthocyanin synthesis in non-bagged and bagged apples. In non-bagged and bagged ‘Tsugaru’, the optimum temperaturfe increased from 15°C to 20°C with ripening.     

Polyphenoloxidase activity during ripening and chilling stress in ‘Manila’ mangoes

Summary

‘Manila’ mangoes were stored at 6 or 12°C, while a control lot was ripened at 258C. Polyphenoloxidase activity was measured in pulp and peel of mangoes during normal ripening and chilling-stress conditions. Compositional parameters (textural hardness, pH, acidity, and soluble solids) were monitored during ripening and chilling injury (CI) was assessed by visual inspection. PPO activity increased in refrigerated mangoes but fruit stored at 6°C displayed greater activity than those stored at 12°C. Both temperatures produced a peak in enzyme activity at day 16 of storage. Peel browning and acidity correlated with PPO activity (r.=.0.9073 and 0.9818) at 6°C. After the PPO peak was observed at day 16, refrigerated mangoes showed lower enzyme activities; however external browning became more pronounced.     

Characterization of monovarietal virgin olive oils from six crossing varieties

Volatile composition of virgin olive oil (VOO) from six Tunisian new cultivars was evaluated using headspace solid-phase microextraction method coupled to GC–MS and GC–FID. Various chemical classes were identified such as aldehydes, alcohols, esters, ketones, terpenes and carboxylic acids. The results showed that the most important contributors to olive oil aroma are C₆ aldehydes. These compounds are biogenerated from polyunsaturated fatty acids through the lipoxygenase pathway. Furthermore, they pointed out the predominance of the linolenic acid oxidation over linoleic acid one. The main volatile compounds present in the oil samples were C₆ derivatives such as (E)-hex-2-enal, (E)-hex-2-enol and hexanol. In addition to C₆ compounds, the aroma of the studied VOOs contains reasonable amounts of various classes of C₅ components. The tested oil samples showed different volatile profiles. Some components seem to occur exclusively in a specific oil samples and, consequently, their presence might be initially used to establish compositional differences. All results put in evidence that olive oil aroma compounds accumulate differently according to the cultivar.     

Effect of temperature manipulation during storage and ripening on firmness,extractable juice and woolliness in nectarines

‘Independence’ nectarines were stored at — 0.5°C for three or four weeks or at 3°C for four weeks or kept at room temperature for 18 h prior to storage for four weeks at -0.5°C. After cold storage, fruit from all treatments was ripened at 10°, 15°or20°C. In all treatments the percentage woolly fruit initially increased to high values and thereafter decreased with further ripening. The rate of increase and decrease in woolliness depended on the ripening temperature. A storage period of four weeks at — 0.5°C resulted more woolliness during subsequent ripening. Woolliness persisted longer after a four-week cold storage period than after a three-week one. When fruit was delayed at room temperature prior to cold storage, woolliness generally developed earlier and to a lesser extent during ripening. At all ripening temperatures initial storage at 3°C resulted in most woolliness extending over the longest period. In addition, browning of the meso- carp tissue occurred only in fruit cold stored at 3°C.-The delay period before cold storage decreased fruit firmness by 15.7 to 17.6 N. Except for fruit subjected to the delay period, the extractable juice in fruit of all treatments first decreased during ripening to low values then increased.     

Water stress induces in pear leaves the rise of betaine level that is associated with drought tolerance in pear

Summary

Mild water stress signi®cantly induced the accumulation of betaine in the leaves of young pear plants (Pyrus bretschneideri Rehd. `Suly'). The betaine induced by water stress in mature leaves was maintained for about two weeks of re-watering after water stress, and gradually declined two weeks after the relief of water stress, dropping to the normal level one month later. Exogenously foliar-applied betaine slightly improved the shoot growth and the ability of the leaves to resist dehydration, alleviated wilting of leaves under water stress, and promoted recovery of leaves from wilting after re-watering. These ®ndings indicate that the accumulated betaine induced by water stress was associated with drought tolerance in pear.     

Effect of different temperatures on the storage of papaya fruits and respirational activity during storage

Mature papaya fruits were stored at 10 and 15°C to study the effect of these temperatures on the storage and of respirational activity during storage. Percentage weight loss of fruits increased with prolonged storage period, and the increase was greater in fruits stored at 15 than at 10°C. The decay percentage was greater at the higher temperature than at the lower temperature. Total soluble solids showed a slight and gradual increase upto the end of the storage period. The high storage temperature accelerated colour development in the peel and total chlorophyll diminished. There was an increase in total carotenoids in both the peel and the pulp as the storage period increased, and the rate of increase was greater at the higher temperature.The respiration rate was relatively low at the beginning of ripening and tended to level off until the 11th and 12th day of storage, which were followed by a striking increase until it reached its maximum rate at the over ripe stage.     

‘小香水’梨果实后熟过程中挥发性组分分析

 采用顶空固相微萃取结合气相色谱质谱联用技术分析了秋子梨‘小香水’（Pyrus ussuriensis Maxim.‘Xiaoxiangshui’）果实后熟过程中果实挥发性组分的变化。结果表明,‘小香水’梨果实在20 ℃后熟过程中挥发性组分的种类及含量均表现为增多的趋势。共检测到酯类、醛类、醇类、酸类及萜类5大类共计38种挥发性物质,其中15种为整个后熟过程中的共有组分。5大类挥发性组分中酯类物质的种类最多,其含量在后熟过程中增幅最大,后熟9 d时达到最高。‘小香水’梨在后熟过程中共检测出包括醛类和酯类在内的10种特征香气组分,其中2–甲基丁酸乙酯、己酸乙酯及丁酸乙酯在9 d时香气值分别为668.09、279.58、190.60。20 ℃后熟6 ~ 9 d为食用最佳时期。     

Studies in the Development of the Strawberry: III. Flower-Bud Initiation and Development in Large-Fruited Perpetual (“Remontant”) Strawberries

Summary

Four N application rates generated a range of tree N status as indicated by leaf N concentrations in six year old trees of `Mission' almond (Prunus dulcis (Mill.) D. A. Webb). Leaf N concentrations were related positively with concentrations of amino acids - especially asparagine and glutamine - in phloem and xylem saps. A pulse of 1.25 kg N per tree was applied to trees previously receiving 0, 78, 157 or 313 g N per tree, annually. Apparent uptake of soil N into above-ground tree parts was determined over a 39 d period. N uptake was determined as the difference in the products of tree biomass and tissue N concentrations before and after the N pulse. Tissue N concentrations increased signi®cantly in trees previously receiving the two lowest N application rates, whereas trees previously receiving the high N treatments were unresponsive. Tree N contents (0 g N per year, and also 78 g N per year treatments) increased slightly in response to the N pulse, although statistical differences were not observed due possibly to high variability in biomass among trees. At the same time, the amino acid concentrations in phloem exudate and xylem sap were highest in trees grown under the highest N fertilization regime. We suggest that the high amino acid concentrations in the phloem and xylem saps are indicative of a larger pool of amino N cycling throughout the vasculature of high N-status trees. Our data indicate an inverse relationship between tree N status, amino acid concentrations in xylem and phloem saps and capacity for soil N uptake in ®eld-grown trees. These results represent the ®rst ®eld data to correlate the concentration of amino acids circulating in the plant vasculature with soil N uptake. A functional relationship between the amino acid concentrations cycling within the tree and the regulation of soil N uptake has, however, not yet been established.     

Storage conditions and ripening of papaya ‘Bentong’ and ‘Taiping’

The optimum storage and ripening temperature for the 2 cultivars was approximately 20°C. Both cultivars ripened earlier after exogenous application of C₂H₄ combined with the removal of CO₂. The storage life of the fruits could be extended by maintaining them in an atmosphere devoid of C₂H₄ but containing 5% (v/v) CO₂ and with a high relative humidity. Chilling-injuries occurred at temperatures below 15°C when the papayas were stored for more than 7 days. The nutritional value of ripe fruit decreased rapidly with prolonged storage. At the “eating-ripe” stage, the glucose, protein and ascorbic acid contents were 2.23 g, 209 mg and 33 mg per 100 g pulp in ‘Bentong’, and 2.15 g, 196 mg and 30 mg per 100 g pulp in ‘Taiping’, respectively.     

Comparative studies on the postharvest physiology of fruit from different species of Annona (custard apple)

Summary

Fruit of three Annona species, viz. cherimoya (A. cherimola Mill), sugar apple (A. squamosa L.) and custard apple (atemoya, Annona X) were ripened in ethylene-free air and under propylene. Differences were found in patterns of respiration, ethylene production and fruit firmness changes during ripening. Cherimoya and custard apple fruits showed two successive rises in respiration rate whereas sugar apple fruits showed only one. Ethylene production showed one main peak but the onset of rapid ethylene production occurred after the beginning of the respiration climacteric in all three species. Custard apple fruit had acceptable eating quality (as judged by sensory assessments and chemical analyses of pulp) for up to four days after first detectable softening, when ripened at 20°C in ethylene-free air or under propylene. Fruit ripened in ethylene-free air had better ripe fruit quality than fruit ripened under propylene.     

Physiological factors associated with overripeness,internal breakdown and gel breakdown in plums stored at low temperature

Plums (Prunus salicina cv. Songold) were stored at -0.5°C for up to 50 d. On the day of harvest and thereafter at ten-day intervals, sub-samples were stored at 15°C and allowed to ripen for eight days, with evaluations every two days. Low temperature storage prior to ripening at 15°C was a prerequisite for plums to ripen. Overripeness was inhibited by low- temperature storage but developed when fruit was ripened at, or before, 30 d of storage. Longer storage resulted in the development of gel and internal breakdown at both -0.5°C and during ripening. The transition from overripeness to gel and internal breakdown was associated with significant increases in electrolyte leakage and internal conductivity at a time that viscosities of water soluble pectins were high. The resulting decrease in extrac- table juice suggested that cell fluids which leaked through cell membranes had bound with pectic substances. This was associated with development of gel and internal breakdown.     

The post-harvest ripening of water stressed banana fruits

SUMMARY

Maintaining banana fruit in a low humidity environment accelerated fruit ripening. This was reflected in an earlier increase in respiration and ethylene production and more advanced peel colour and pulp sugars. At the end of the trial the fruit kept in low humidity were yellow with green tips (stage 5) whereas those kept at high humidity were still green (stage 1-2). Fruit kept at low humidity did not show a large increase in pulp ethylene production compared with the fruits stored at high humidity. This difference occurred despite a large increase in the 1-aminocyclopropane-l-carboxylic acid (ACC) content of both samples, with the low humidity fruit preceding the high by two days. The peel ethylene production of the low humidity stored fruit increased dramatically as the fruit ripened, coinciding with an increase in ACC. The ACC oxidase activity of the peel reflected the ethylene production with a large increase in the low humidity stored fruit and a later, smaller increase in the high humidity stored fruit. The ACC oxidase activity of the pulp of both low and high humidity stored fruit increased gradually during storage. The changes in ethylene production are discussed with reference to banana ripening being regarded as co-ordinated by pulp ethylene production while the peel is passive, depending on pulp ethylene production for degreening.