Changes in the individual sugars of tomato fruit during ripening

Changes in the concentrations of the individual sugars of the walls and locular contents of tomato fruit during ripening have been studied. The major sugars were glucose and fructose together with much smaller amounts of sucrose and myoinositol. During the initial stages of development the fruit contained approximately twice as much glucose as fructose, but with approaching maturity and the onset of ripening the glucose/fructose ratio declined to less than unity. On a per fruit basis the distribution of the major sugars between the walls and locular contents was about 3 : 1 at the green stage, falling to 2 : 1 as the fruit ripened. Total reducing sugars (% fresh weight or per fruit) increased markedly between the mature green and green-yellow stages with a tendency to decrease with subsequent ripening. These changes were predominantly influenced by changes in fructose content, with glucose changing little. The concentrations of sucrose and myoinositol, both less than 0.05% fresh weight, declined with ripening. The green areas of the outer walls of “blotchy” fruit contained much less glucose and fructose than did the walls of normal mature green fruit, while the red areas contained amounts similar to those encountered in normally ripened red fruit.     

Changes in the non-volatile organic acids of tomato fruit during ripening

A study has been made of the individual non-volatile organic acids in ethanolic extracts of tomato fruit during ripening. Whole fruit of three varieties and the outer walls and locular contents of one variety each at five stages of ripeness from mature green to full red were analysed. No trace of many of the K rebs-cycle acids could be detected. Maximum citric acid concentrations were found at either the green-yellow or yellow-orange stage of ripeness according to variety. Malic acid concentrations and the malic/citric acid ratio decreased progressively as the fruit ripened. Glutamic acid increased approximately ten-fold and aspartic acid more than doubled from the mature green to red stage of ripeness, but changes in pyrrolidonecarboxylic acid (PCA) during ripening were not statistically significant. In general, similar trends were observed in whole fruit and in the outer walls and locular contents, but malic, citric, glutamic and aspartic acid concentrations were higher in the locular contents than in the outer walls at all stages of ripeness. Alcohol-insoluble solids (AIS) decreased markedly between the green and green-yellow stages and then more slowly with further ripening.     

Metabolism of citric and malic acids during ripening of tomato fruit

Tomato fruit at various stages of ripeness were injected with ¹⁴C-labelled citric and malic acids. The ¹⁴CO₂ evolved by individual fruit was determined over a 72 h period and the fruit then analysed for the incorporation of ¹⁴C into sugars, amino acids and individual non-volatile organic acids. In mature green tomato fruit citric and malic acids were found to be metabolised to a comparable extent. Appreciable interconversion occurred together with oxidation to CO₂ and some labelling of glutamic acid and glutamine. In red fruit, citric acid was not as readily oxidised to CO₂ and little conversion to malic acid was observed. On the other hand, malic acid was oxidised to CO₂ and converted to citric acid as rapidly as in green fruit with, in addition, appreciable conversion to glutamic acid. These results are discussed in relation to the changes in concentration of the endogenous acids which take place during the ripening of tomato fruit.     

Organic Acid Changes During Ripening of Processing Peaches

Organic acids and their changes during peach (Prunus persica L. Batsch) fruit ripening were quantified by HPLC for clingstone culti-vars,‘Babygold 5’and‘Babygold 7′, and a freestone cultivar,‘Cresthaven’. At full maturity,‘Babygold 5’and‘Babygold 7’had about 60% malic, 20% citric and 19% quinic acid; whereas‘Cresthaven’had similar amounts of all three organic acids (37, 3.5 and 28%, respectively). During fruit ripening,‘Babygold 5’and‘Babygold 7’increased in malic acid and decreased in citric and quinic acids, whereas,‘Cresthaven’showed little change in these organic acids.     

Protein and enzyme changes in tomato fruit in relation to blotchy ripening and potassium nutrition.

The effects of potasium deficiency and blotchy ripening in tomato fruit on some nitrogenous constituents, especially the proteins, have been investigated. The distribution of nitrogen in normal and potassium-deficient fruit of the cherry tomato Lycopersicon pimpinellifolium was examined and compared with that from potassiumdeficient and blotchy ripened fruit of a cultivated variety (L. esculentum, cv. Moneymaker). The protein fraction from cv. Amberley Cross was analysed in detail using disc gel electrophoresis. Changes induced by potassium deficiency in the general protein pattern and on a wide range of enzymes active in ripening were compared with the effects brought about by blotchy ripening. The distribution of protein components and isoenzymes in low potassium fruit was to a large extent similar to that of normal tissue at an earlier stage of development, whereas the alterations in blotchy tissue appeared to be of a random nature.     

Phenolase activity in tomato fruit in relation to growth and to various ripening disorders

An efficient method for the extraction of phenolase from tomato fruit is described. It has indicated that phenolase activity increases towards maturity and then decreases somewhat during normal ripening. The red area of fruit which showed a physiological ripening disorder known as ‘blotch’ contained an abnormally high activity while the green areas contained an even higher activity. Tomatoes exhibiting ‘blossom-end’ rot also contained enhanced activity, especially in the affected region. Levels of phenolase in tomato species other than Lycopersicon esculentum have also been examined. The browning symptoms associated with specific physiological ripening disorders are discussed in relation to phenolase activity and the availability of phenolic substrates.     

Physicochemical changes during strawberry development in the field compared with those that occur in harvested fruit during storage

‘Chandler’, ‘Oso Grande’ and ‘Sweet Charlie’ strawberry cultivars were harvested at four stages of color development ranging from color break to full red and stored in the dark for 8 days at 1 °C. Changes in the physical and chemical characteristics of fruit during storage were compared with those occurring during development in the field. Strawberry fruit harvested at the three‐quarters colored and full red stages continued their development and ripening during storage. However, fruit harvested at the color break and half‐colored stages did not develop like those ripened in the field. Strawberries harvested at the three‐quarters colored stage developed the same pH, acidity, soluble solids, ascorbic acid and total phenolics content during storage as the at‐harvest levels present in strawberries harvested at the full red stage. In addition, three‐quarters colored strawberries were as firm and red after storage as the full red stage fruit were at the time of harvest. Thus, strawberries harvested at the three‐quarters colored stage can be stored for a longer period than strawberries harvested full red while retaining better color and firmness. Copyright © 2005 Society of Chemical Industry     

EFFECT OF COLD STORAGE ON THE QUALITY CHARACTERISTICS OF ‘AU-RUBRUM’ PLUMS1

The effect of cold storage (0°C) and maturity on the physical, chemical and sensory characteristics of plums (cv. ‘AU-Rubrum’) was determined. The size, weight, soluble solids and total sugar contents of the more mature fruit were significantly higher (P<0.05) and the “L” and hue angle were significantly lower (P<0.05) than plums in the less mature class. ‘AU-Rubrum’ fruit contained glucose, fructose and sorbitol but had no sucrose. Artificially ripening fruit at 20°C had a significant effect (P<0.01) on all color values for both maturity 1 and 2 fruit. The titratable acidity and sugar contents of the fruit ripened at 20°C were lower for ripened than for unripened fruit. Storage of the plums at 0°C for 5 weeks followed by subsequent ripening at 20°C had no significant effect on physical, chemical or sensory characteristics. Data indicate that ‘A U-Rubrum’ plums which have one-half red ground color (maturity 1) will develop full color and complete the normal ripening process. Data also indicate that the plums can be stored for at least 5 weeks at O°C without loss of quality and that the cultivar has potential for shipping to distant markets.     

Effect of Fruit Ripening Stage on Physico-Chemical Properties, Nutritional Composition and Antioxidant Components of Tomato (Lycopersicum esculentum) Cultivars

In this study, we investigated the effects of fruit ripening stage on the physico-chemical properties and nutritional contents of three greenhouse grown tomato cultivars (‘Monika’, ‘Isabella’ and ‘Cherry’). Significant changes (p?≤?0.05) occurred in fruit colour, total soluble solids, protein, fibre, ascorbic acid (vitamin C) and lycopene content at different stages of ripening. ‘Cherry’ tomato contained significantly (p?≤?0.05) higher total soluble sugar and several nutrients including fibre. However, the plum-type tomato cultivars (‘Monika’ and ‘Isabella’) contained higher vitamin C and lycopene than ‘Cherry’ tomato. In all tomato cultivars, it was found that up to 50% of final lycopene content occurred during the final phase (from red to deep red colour) of fruit ripening.     

Influence of the ripening environment on the development of finger drop in bananas

‘Finger drop’, which is the dislodgement of individual banana ‘fingers’ from the bunch during ripening and marketing, was shown to be related to the conditions during fruit ripening. At high ripening temperatures fruit are generally softer than those ripened at temperatures of 20°C or lower when they reach eating ripeness. This is reflected in the strength of the fruit pedicel and can result in their having a strength sufficiently low that the fruit can easily be dislodged in handling and transport during marketing. However, ripening at very high temperatures (40°C) did not result in development of finger drop, but fruit ripened at this temperature were unmarketable. No consistent effects of ripening humidity were shown on the development of finger drop. Prolonged exposure of fruit to ethylene gas during ripening could increase finger drop in certain circumstances. Possible reasons as to how finger drop might be related to the ripening physiology of the fruit are discussed, and recommendations are made for further studies.     

不同解冻方式对软儿梨果实品质与抗氧化物质含量的影响

冷冻和解冻是产区消费者传统上消费软儿梨的两个必要步骤,外源乙烯可以加速呼吸跃变型果实的后熟进 程。本实验以自然后熟和乙烯利催熟的软儿梨为材料,研究了传统的空气解冻和水浴解冻对解冻后果实品质和酚类 物质含量的影响。结果表明：对于自然后熟的软儿梨,空气解冻组果实的可滴定酸含量、可溶性固形物含量、固酸 比均显著高于水浴解冻组;同时使自然后熟组果实保留了更多的VC,降低了石细胞含量。空气解冻较水浴解冻降 低了乙烯利处理组果实的可滴定酸和可溶性固形物含量,但对其固酸比、VC和石细胞含量无显著影响。空气解冻 和水浴解冻均对自然后熟组果实的总酚含量无显著影响,但乙烯利处理组果实的总酚含量上升;两种解冻方式对几 种主要酚类物质的影响表现各异,但相似的是解冻后果实均不能测出绿原酸和阿魏酸。不同解冻方式对果实不同的 抗氧化指标影响各异,但从抗氧化能力综合指数来评价,不同工艺点的果实抗氧化能力依次为：水浴解冻＞空气解 冻＞后熟,在后熟和解冻中均为：乙烯利处理组果实＞自然后熟组果实。     

EFFECTS OF THE RATE OF HEATING ON APPLE AND PEAR FRUIT QUALITY

There is evidence that the rate of heating to meet quarantine security impacts fruit quality as well as insect mortality. Linear heating rates, of 4, 6, 8, 10, and 12C/h to treatment temperatures of 44 and 46C were used to treat 8 cultivars of apples (‘Delicious’, ‘Golden Delicious’, ‘Granny Smith’, ‘Fuji’, ‘Gala’, ‘Jonagold’, ‘Braeburn’, and ‘Cameo’) and two cultivars of winter pear (‘d'Anjou’ and ‘Bosc’). Fruit were stored, ripened, and tested for various quality parameters. Scald was controlled, firmness was higher in heat treated fruit, ripening was delayed but uniform in pears, decay organisms were suppressed, red fruit became redder and green fruit remained green, the Brix‐acid ratio (SS/TA) was either unchanged (‘Granny Smith’) or increased. Physiological disorders such as bitter pit were exacerbated by the heat treatment, requiring culling after treatment to avoid storage of fruit so affected.     

ETHYLENE CAPSULE PROMOTES EARLY RIPENING OF 'd'ANJOU' PEARS PACKED IN MODIFIED ATMOSPHERE BAGS

‘d'Anjou’ pears (Pyrus communis, L.) harvested commercially with flesh firmness of 64.5 N were incapable of ripening normally at 20C within 60 days of air storage at ‐1C (denoted as “under‐chilled” fruits). When under‐chilled ‘d'Anjou’ fruits (8 fruits, total fruit weight of 1.8 kg) were packed in a 3.8‐liter perforated bag inserted with an ethylene capsule, fruit would ripen normally at 20C. The ethylene concentration in the packed bag maintained no less than 100 ppm after 4 days at 20C, and declined to about 25 ppm on day 7. Regardless of the storage length, ripened fruit induced by the ethylene capsule developed high buttery and juicy texture. If ‘d’ Anjou’ fruit had been stored at ‐1C for less than 30 days, ripened fruit lacked high flavor quality. Flavor quality of ripened fruit improved rapidly when the fruit had been stored for longer than 30 days.     

Changes in pH, acids, sugars and other quality parameters during extended vine holding of ripe processing tomatoes

BACKGROUND: Two important quality attributes of processing tomatoes are pH and titratable acidity. These and other quality attributes can be affected by tomato fruit maturity and over‐maturity. We have determined the magnitude of these maturity effects in four processing tomato cultivars commonly grown in California. RESULTS: Allowing tomatoes to remain on the vine for up to 4 weeks after ripening resulted in an increase in fruit pH of between 0.01 and 0.02 unit per day for the four cultivars examined. The increase in pH was paralleled by a decrease in titratable acidity, due to a loss of citric acid. Glucose and fructose concentrations also declined with increasing maturity after ripening. Other quality parameters (color, lycopene, total pectin, pectin solubility, and Bostwick consistency) all showed little change. CONCLUSION: Vine holding of ripe fruit adversely affects quality, especially pH and titratable acidity. Recent problems with high tomato juice pH encountered by tomato processors in California could be the result of increased average fruit maturity at harvest. Copyright © 2011 Society of Chemical Industry     

Preharvest application of methyl jasmonate increases fruit quality and antioxidant capacity in raspberries

The effects of preharvest methyl jasmonate (MJ) application on fruit quality, flavonoid content and antioxidant capacity in black raspberry cv. Jewel (Rubus occidentalis L) and red raspberry cv. Autumn Bliss (Rubus idaeus subsp.) were studied under field condition. Raspberries treated with MJ had higher soluble solids content, total sugars, fructose, glucose, sucrose and lower titratable acids (TAs), malic acid and citric acid than untreated fruit. MJ also significantly enhanced the content of flavonoids and the antioxidant capacities in the fruit. The cv. Jewel had higher soluble solids and lower TAs compared with the cv. Autumn Bliss. On the basis of fresh weight of fruit, ‘Jewel’ also had significantly higher anthocyanin, total phenolic content and antioxidant activity than ‘Autumn Bliss’.     

Investigation of UV-A light irradiation on tomato fruit injury during storage

We investigated the effect of UV-A light (wavelength 315 to 400 nm) irradiation during storage on tomato fruit injury. Mature green tomato fruit (cv. House Momotaro) were exposed to UV-A at doses of 0.02, 0.5, and 2 mW x cm(-2) throughout storage at 25 degrees C. The physiological disorders, fruit ripening, superoxide dismutase (SOD) activity, and increases in fruit temperature were evaluated. All UV-A-irradiated and nonirradiated tomatoes developed a full red color at the same time (2 weeks). Irradiated fruit ripened normally, and exposure of tomato fruits to UV-A did not lead to the discoloration of ripe tomato fruit at any dosage. The fruit temperature did not increase in response to various UV-A light doses and exposure times, and none of the UV-irradiated fruits showed physiological disorders (dull skin blemish, pitting). The SOD activity of UV-A-irradiated fruit exposed to the various UV-A doses did not significantly (P = 0.05) differ from that of fruit stored in dark conditions. The SOD results imply that UV-A light might not induce reactive oxygen species in UV-A-irradiated fruit.     

CHARACTERIZATION OF TOMATO RIPENING PROCESS AS INFLUENCED BY INDIVIDUAL SEAL-PACKAGING AND TEMPERATURE

Tomatoes were individually seal-packaged and ripened at two temperatures, 12 and 21° C. Both the temperature and seal-packaging delayed the tomato ripening process. The delay in ripening due to seal-packaging occurred prior to the ‘turning’ and ‘pink’ USDA color maturity stage when stored at 21° C and 12° C, respectively. Lower concentrations of lycopene were associated with lower chroma values in seal-packaged fruits. Both temperature and seal-packaging prolonged the ripening period but did not affect the firmness values at various color stages of tomatoes.     

Compositional changes in normal and mutant tomato fruit during ripening and storage

Mutations that drastically slow down fruit ripening known as ‘ripening inhibitor’ (rin) and ‘non-ripening’ (nor) have been incorporated by backcrossing into isogenic lines of the tomato cultivar, Ailsa Craig. F₁ hybrids (rin/+ and nor/+) were then produced by crossing with the recurrent parent. The rates of deterioration of fruit from the hybrid plants were compared with those from the recurrent parent and a typical glasshouse cultivar, Sonatine. Levels of acids and sugars, and also the colour, firmness and dry matter content of the fruit, were measured at two selected stages of ripeness and after storage of the ripe fruit for 10 and 20 days at 20°C. Shelf-life of the ripe fruit was also assessed. Although the acidity fell continuously from a high value early in ripening for all four lines, during storage that in the rin/+ was better and Sonatine was worse than average. Sugar levels generally peaked close to the red stage and fell thereafter, but much variability in this component was encountered. Both cv. Sonatine and Ailsa Craig overcoloured and lost firmness during storage, but the mutant lines survived well. The results suggest that the disadvantage of a high-quality line such as Ailsa Craig in deteriorating quickly once the fruit are fully ripe can be partially overcome through the introduction of one of the ‘non-ripening’ alleles.     

Perception of flavour in standardised fruit pulps with additions of acids or sugars

We hypothesised that adding sugars or acids to pulps derived from fruit of different genetic background, or of lower or higher carbohydrate status should give similar results until a threshold for sweetness or acidity perception in the pulp background was reached. Pulps made from fruit of Actinidia deliciosa ‘Hayward’—a fresh sweet-acid kiwifruit—and A. chinensis ‘Hort16A’—a sweet tropical flavoured kiwifruit, were compared. Flavour volatiles and background sugar and acid composition differed between the two fruit. Using high (14.1–14.5%) or low (11.5–11.9%) soluble solids (SS) pulps, trained tasters perceived added sugar as sweeter, confirming earlier research with consumers. Added acids (7 mmoles H⁺ 100 g⁻¹) reduced perceptions of sweetness and tasters perceived quinic acid to have a strong impact on the pulps tasted, resulting in a greater perception of acidity than addition of citric, ascorbic or malic acids. However perceptions of acidity also depended on background pulp composition. Addition of sugar or acid to pulps affected measured headspace volatiles. Volatile compounds affected included mid-chain length aldehydes, alcohols and esters, but only a few showed significant alteration. For example, hexanal, (E)-3-hexen-1-ol and (Z)-3-hexenol increased significantly when malic acid was added to ‘Hayward’ pulps. We suggest that the release of alcohols was associated with change in acidity and pulp metabolism rather than a ‘salting out’ effect. Perceived changes to banana and lemon flavours with both sugar and acid addition appear to be due to interactions in taster mouths or associated memories rather than release of specific volatiles.     

Organic acids of various kinds of vegetables. IV. Changes in the acids and sugar in tomatoes, sweet peppers and cucumbers during development and ripening

Concentrations of organic acids and sugars in tomatoes and sweet peppers change notably during ripening. The concentration of malic acid decreases while that of citric acid increases considerably and in redripe fruits clearly exceeds the content of malic acid. Several maxima and minima in acid concentrations occur during development. Both species show constant proportions of citric and isocitric acid (200:1 and 30:1 respectively). In sweet pepper, quinic and ascorbic acid can be found in noticeably higher amounts than in tomatoes. Additionally, succinic acid was detected in tomatoes and fumaric and shikimic acid in sweet pepper. Glucose and fructose, in approximately equal amounts, are the main sugar components; their concentrations are increased during ripening, especially in sweet peppers. The leaves of tomatoes and sweet pepper contain more malic acid and less citric acid than redripe fruits, though here as well citric acid predominates. There is considerably less glucose and fructose present in the leaves of sweet pepper than in the fruits while sucrose is increased. Sucrose is the main sugar component in the leaves. Compared to tomatoes and sweet peppers, egg-plants contain more amounts. - Potatoes contain citric, malic, quinic, succinic, fumaric, and soluble oxalic acid (in order of decreasing amounts). - In cucumbers malic acid notably exceeds citric acid. Both acids hardly change in concentration during ripening. Sugar content decreases during ripening.