Course Of Ripening Research Articles

Revisiting the role of ascorbate oxidase in plant systems.

Ascorbic acid (AsA) plays an indispensable role in plants, serving as both an antioxidant and a master regulator of the cellular redox balance. Ascorbate oxidase (AO) is a blue copper oxidase that is responsible for the oxidation of AsA with the concomitant production of water. For many decades, AO was erroneously postulated as an enzyme without any obvious advantage, as it decreases the AsA pool size and thus is expected to weaken plant stress resistance. It was only a decade ago that this perspective shifted towards the fundamental role of AO in orchestrating both AsA and oxygen levels by influencing the overall redox balance in the extracellular matrix. Consistent with its localization in the apoplast, AO is involved in cell expansion, division, resource allocation, and overall plant yield. An increasing number of transgenic studies has demonstrated that AO can also facilitate communication between the surrounding environment and the cell, as its gene expression is highly responsive to factors such as hormonal signaling, oxidative stress, and mechanical injury. This review aims to describe the multiple functions of AO in plant growth, development, and stress resilience, and explore any additional roles the enzyme might have in fruits during the course of ripening.

Spatial distribution of cereal aphids determines their abundance and population density in winter wheat stands

AbstractThe numbers per tiller (abundance) and per unit area of ground (population density) of the dominant cereal aphids in winter wheat crops, Sitobion avenae (Fabricius) and Metopolophium dirhodum (Walker) (Hemiptera: Aphididae) were recorded from 2000–2015. The results were used to test the hypothesis that at the population peak and 4 weeks previously, the population density of aphids in winter wheat crops (Triticum aestivum L., Poaceae) is uniformly distributed with respect to surface area and, as a result, their abundance is high in sparse stands (SPA) where the colonizing aphids are scattered among a small number of tillers (ca. 80 m−2), and low in dense stands (DEN) where they are scattered among a larger number of tillers (ca. 440 m−2). This prediction was verified for S. avenae, the population density of which did not significantly differ between SPA and DEN stands throughout this period. This species feeds mainly on the ears, whose nutritional quality for aphids varies little with crop density and during the course of ripening. In contrast and contrary to our prediction, the population density of M. dirhodum increased throughout this period more rapidly in SPA than in DEN stands. This species lives on leaves whose quality is better and remain present for longer during the course of ripening of the crop in SPA than DEN stands. The abundance of both species was higher in SPA than in DEN stands. Greater direct damage to cereal crops can be expected when using technologies and cultivars of winter wheat that need to be planted sparsely.

Changes in physicochemical properties and enzymes associated with ripening of snake tomato (Trichosanthes Cucumerina L.) fruit

Changes accompanied ripening of fruits as well as reduction in quality and/or nutritional qualities of fruits are caused by enzymes released during growth and development of the fruits. This study was intended at investigating physicochemical changes and enzymes associated with ripening of three varieties of snake tomato fruit. Firmness, ascorbic acid, moisture, non-reducing sugar, total chlorophyll and colour parameter L* value were decreased as ripening progressed while total soluble solid, carotenoids, total sugar, reducing sugar, and colour parameter a* and b* values increased as the fruits ripened. Activities of polyphenol oxidase, pectin methylesterase and α-mannosidase were maxima at half ripe stage in coat and pulp while cellulase and polygalacturonase activities were maxima at fully ripe stage in light green, light green with white stripe and dark green with white stripe varieties. Steady increased activities of pectin methylesterase, polygalacturonase and cellulase during fruit ripening correlate with decrease in firmness of the three snake tomato varieties. This establishes the roles the enzymes play on the loss of firmness (softening) of three varieties of snake tomato fruits in the course of ripening.

Structural and Compositional Characterization of Suppression of Uniform Ripening in Grapevine: A Paradoxical Ripening Disorder of Grape Berries with No Known Causative Clues

Grapes (Vitis vinifera) have been used as a model system for understanding ripening and ripening-related physiological disorders in fleshy fruit; hence, a comparative analysis was undertaken to explore the mechanistic basis of a paradoxical ripening phenomenon of grape berries known as suppression of uniform ripening (SOUR) shrivel. Fruit organoleptic attributes coupled with morphology and structure, and tissue organization in various organs of healthy and afflicted field-grown grapevines were examined using a range of microscopy techniques. As opposed to healthy berries, SOUR shrivel berries were flaccid and had the lowest pH and lowest levels of sugars, potassium (K), and malic acid that paralleled with a significant reduction in the synthesis of anthocyanin. On the other hand, titratable acidity, tartaric acids, and tannins were much higher than perfectly healthy berries. The SOUR shrivel cluster tinged its rachis red but held no relationship with flaccidity of the berries because healthy vines totally devoid of SOUR shrivel clusters also displayed same coloration. Furthermore, although the phloem sieve tubes in both cases were plugged with callose, a carbohydrate generally implicated in impeding translocation in phloem, the afflicted grapevines exhibited relatively more plugged sieve tubes. The study revealed that the spatiotemporal configuration of cell and tissue communities determining the structure–function relationship remained intact in afflicted vines throughout the growing season. However, the functionality, especially of flows in phloem sieve tubes, started to decelerate after veraison (initiation of ripening) most likely as a result of early activation of callose synthesis and subsequently plugging of sieve plates during the remaining course of ripening. Hence, in future studies, a broader analysis of phloem sieve tubes entailing its flows and ultrastructure in phloem-girdled grapevines simulating symptoms of SOUR shrivel is needed to characterize the mechanistic basis of SOUR shrivel.

Variations in the contents of vitamins A and E during the ripening of cheeses with different compositions

We investigated the composition in vitamins A and E of cheeses made from the milks of ewes, goats and cows. A total of 84 cheeses of known composition were prepared and controlled to determine the influence of different factors, e.g. the variable proportions of cow’s, ewe’s, and goat’s milks, seasonality (winter/summer), and evolution during the course of ripening. The variable proportions of milk from the different species did not vary in either the amount of vitamin A or that of vitamin E in the cheeses. Seasonality and ripening were seen to have a significant effect on the concentration of vitamin A.

Biochemical Characterization of Pectin Methylesterase from Musa acuminata Referring to Delayed Ripening

Several cell-wall degrading enzymes have been studied and their action involved in the softening concomitant with ripening of various fruits. However, studies pertaining to pectin methylesterase (PME) that catalyzes the demethylesterification of cell wall polygalacturonans have been very limited especially in fruit tissue. The present study covers the biochemical characterization of pectin methylesterase from Musa acuminata in context to delayed ripening phenomenon, principally dealing withidentification of a PME gene, namely, PME 1 from Grand Naineveriety of banana. The expression of this gene was well correlated with the ripening. After Ethylene treatment the expression of PME1 gene was peaked on day 3 while in control fruit, the progression of ripening was rather slow. The GA content was observed to augment significantly during the course of ripening of banana fruit. The overall data obtained provide new insights into correlation of the expression of PME1 with increased PME1 with increased PME activity as well as pectin content.

The Good, the Bad, and the Ugly: Tales of Mold-Ripened Cheese.

The history of cheese manufacture is a "natural history" in which animals, microorganisms, and the environment interact to yield human food. Part of the fascination with cheese, both scientifically and culturally, stems from its ability to assume amazingly diverse flavors as a result of seemingly small details in preparation. In this review, we trace the roots of cheesemaking and its development by a variety of human cultures over centuries. Traditional cheesemakers observed empirically that certain environments and processes produced the best cheeses, unwittingly selecting for microorganisms with the best biochemical properties for developing desirable aromas and textures. The focus of this review is on the role of fungi in cheese ripening, with a particular emphasis on the yeast-like fungus Geotrichum candidum. Conditions that encourage the growth of problematic fungi such as Mucor and Scopulariopsis as well as Arachnida (cheese mites), and how such contaminants might be avoided, are discussed. Bethlehem cheese, a pressed, uncooked, semihard, Saint-Nectaire-type cheese manufactured in the United Sates without commercial strains of bacteria or fungi, was used as a model for the study of stable microbial succession during ripening in a natural environment. The appearance of fungi during a 60-day ripening period was documented using light and scanning electron microscopy, and it was shown to be remarkably reproducible and parallel to the course of ripening of authentic Saint-Nectaire cheese in the Auvergne region of France. Geotrichum candidum, Mucor, and Trichothecium roseum predominate the microbiotas of both cheese types. Geotrichum in particular was shown to have high diversity in different traditional cheese ripening environments, suggesting that traditional manufacturing techniques selected for particular fungi. This and other studies suggest that strain diversity arises in relation to the lore and history of the regions from which these types of cheeses arose.

Changes in phenolic composition, ascorbic acid and antioxidant capacity in cashew apple (Anacardium occidentaleL.) during ripening

Introduction. Cashew apple is a rich source of sugars, vitamin C and polyphenols. In spite of its nutritional value, this pseudo-fruit has been left unexploited to a large extent in the crop-growing areas. Some reports of the chemical characteristics of cashew apple have been published. However, nothing is known about the changes in the composition of its bioactive compounds in the course of ripening. Materials and methods. Cashew apples at three different maturity stages were examined with respect to their ascorbic acid content, phenolic compounds and antioxidant capacity. Ascorbic acid was quantified by HPLC. Phenolic compounds were identified and quantified by using HPLC-ESI-MS/MS by comparison with authentic standard compounds. The antioxidant capacity was measured by TOSC assay against peroxyl radicals and peroxynitrite. Results. Amounts of identified phenolic compounds were the highest in unripe cashew apple and decreased in the course of ripening. Myricetin 3-O-rhamnoside, quercetin 3-O-galactoside and quercetin 3-O-rhamnoside turned out to be the main flavonoids in all maturity stages. The antioxidant capacity and the concentration of ascorbic acid increased in the course of ripening. The antioxidant activity was considerably influenced by ascorbic acid, more than by the content of phenolic compounds. Conclusion. This study provides, for the first time, information on changes in bioactive compounds and the antioxidant capacity in cashew apple during ripening. A dietary or technological exploitation of ascorbic acid is useful in the ripe condition. The unripe pseudo-fruits are a good source for the extraction of polyphenols with regard to possible food technological purposes or the preparation of food supplements.

Chemical characterization and evaluation of antioxidant properties of Açaí fruits (Euterpe oleraceae Mart.) during ripening

Consumption of açaí fruits has been linked to positive health effects due to its phenolic content and nutritive value. The objective of this study was to characterize açaí fruits chemically and to determine the antioxidant capacity at three different maturity stages. With the exception of fat, amounts of macronutrients, minerals and titratable acids decreased during the ripening process. The same trend was observed for most of the phenolic constituents identified by HPLC–ESI-MS/MS. A consistent decline was shown for flavones and hydroxycinnamic acids. The concentration of the anthocyanins increased in the course of ripening. In accordance with the total amount of the identified phenolic compounds, the antioxidant capacity, measured by TEAC and TOSC, also decreased. However, the contribution of the main phenolic compounds to the overall antioxidant capacity evaluated by TOSC was estimated to be low.

Analysis of chemical parameters determining the fruit quality of apricot cultivars during ripening

A HPLC instrument was used to analyse various acid (citric, malic, succinic acid) and sugar (sucrose, glucose, fructose, sorbitol) components in the fruit of three cultivars grown in Hungary (Gönci magyar kajszi, Mandulakajszi and Harcot), while the β-carotene content was analysed spectrophotometrically. Changes in the chemical content of apricot varieties have not previously been monitored in the course of ripening. The quality of various food products is greatly influenced by the chemical components of the raw materials.The cultivar Gönci magyar kajszi had exceptionally high β-carotene (3.79 mg/100 g in 90% maturity) and sugar content (sucrose: 11253.9 mg/100 g, fructose: 315.2 mg/100 g and glucose: 1434.8 mg/100 g). Mandulakajszi was the most acidic (citric acid: 1597.2 mg/100 g). The malic acid content was similar for all three varieties during ripening. In case of Harcot, the β-carotene content was high in 2008 (3.58 mg/100 g in 90% maturity), however in 2010 it was lower due to environmental influences (2.38 mg/100 g). The pH value was similar for all examined varieties in all ripening stages (3.16–3.50), the TSS/TA value was highest in the 100% mature fruit (18.41) of Gönci magyar kajszi.

Multiple forms of α-expansin genes are expressed during banana fruit ripening and development

Fruit ripening and softening involve depolymerization of complex cell wall components. The complexity of fruit softening through involvement of several cell wall modifying genes has been well documented. More than one class of enzymes and proteins are involved in the process of softening and these may either act sequentially or synergistically. In this paper we provide further evidence of the complexity of fruit softening by demonstrating the simultaneous expression of multiple genes of the same family during softening. We report the identification of four α-expansin genes, MaEXPA2, MaEXPA3, MaEXPA4 and MaEXPA5 from banana fruit which express differentially during fruit development and ripening. The ORFs range from 750 to 774 bp in size. All four genes also possess two introns with variable sizes ranging from 75 to 343 nucleotides that are conserved in position. All the four genes were expressed during the course of ripening. Of these, MaEXPA2 was fruit specific and showed a strong ripening related and ethylene dependent expression in banana fruit. MaEXPA4 expressed both during fruit growth as well as ripening and might be related to expansion. MaEXPA3 and MaEXPA5 were also expressed in tissues other than fruit. It is concluded that expression of multiple expansin genes might be required for softening not only in dicot fruit such as pear, apple and strawberry but also in monocot fruit such as banana.

Eh and pH gradients in Camembert cheese during ripening: Measurements using microelectrodes and correlations with texture

This study investigated the use of microelectrodes to continuously and simultaneously monitor pH and redox potential (Eh) gradients in Camembert cheeses from the rind to the core, as a function of ripening time (15 and 35 days). Cheeses were shown to be heterogeneous throughout their mass. An Eh gradient existed from the rind to the core. The surface was oxidizing (+330 to +360 mV) and the core was reducing and became more so in the course of ripening (−300 to −360 mV). A relationship between firmness and Eh was shown. pH gradients were in line with those previously described in the literature and related to ammonium and lactate gradients. Gradients evolved from the rind to the core (pH 7.7 to 5.2 at 15 d and 7.5 to 6.8 at 35 d). These findings showed that both the Eh and pH constituted control parameters for cheese ripening.

Regulation of the expression of a putative ethylene receptor, PeERS2, during the development of passion fruit (Passiflora edulis).

We isolated a full-length cDNA (PeERS2) that encoded the homologue in passion fruit of ERS1 of Arabidopsis and examined its expression during development of passion fruit. PeERS2 was 2357 bp long and included a single open reading frame that encoded a putative protein of 634 amino acids with a calculated molecular mass of 70.8 kDa. Expression of PeERS2 mRNA in arils of passion fruit was enhanced during ripening and after treatment with ethylene, but its level remained very low in seeds over the course of ripening. Accumulation of PeERS2 mRNA in arils was markedly reduced in fruits treated with 2,5-norbornadiene (NBD), but simultaneous application of ethylene abolished the inhibitory effects of NBD, suggesting that the continuous action of ethylene might promote ripening, with a concomitant increase in the abundance of PeERS2 mRNA. Levels of transcripts of the PeERS1 and PeERS2, which encode similar but not identical receptors for ethylene, increased during senescence of flowers and expression of PeERS2 mRNA was also enhanced during formation of the separation layer. The levels of transcripts of PeETR1 (the gene for yet another ethylene receptor) and PeERS1 were, respectively, higher than those of PeERS2 in sepals and ovaries. The transcripts of all three genes for ethylene receptors were barely detectable in anthers. These results suggest that the expression of the three genes for ethylene receptors is differentially regulated and that expression of the gene for PeERS2 is regulated not only by ethylene itself but also by developmental factors. Expression of each of the three individual genes for ethylene receptors might be controlled by different molecular mechanisms in the various tissues.

Changes in the pectic fraction of bush butter (Dacryodes edulis (G Don) HJ Lam) fruit pulp during ripening

AbstractCDTA‐soluble polysaccharides were extracted from cell wall material (prepared as alcohol‐insoluble solids) of bush butter fruit endocarp tissue at three stages of ripeness. The amount of soluble pectins remained constant but they underwent a gradual depolymerisation during ripening. The CDTA extracts were fractionated by anion exchange and the subfractions were analysed for their sugar composition and molecular weight distribution. For all degrees of ripeness the extracts were composed of three minor peaks and two major peaks. The minor peaks appeared to be composed of xyloglucan and mannan‐type polymers for the first peak and arabinogalactan‐type polymers for the other two peaks. The two main peaks were retained on the column. The first was exclusively composed of homogalacturonan polymers and the second contained principally highly branched rhamnogalacturonan polymers. During ripening, both homogalacturonan and rhamnogalacturonan populations were modified. Modifications in the rhamnogalacturonan fraction were principally marked by the accumulation of low‐molecular‐weight rhamnoglacturonan polymers in the course of ripening.© 2001 Society of Chemical Industry

Effect of Irrigation on Changes in Berry Composition of Tempranillo During Maturation. Sugars, Organic Acids, and Mineral Elements

The impact of water availability on the yield and must composition of <i>Vitis vinifera</i> L. cv. Tempranillo grapes was studied over a three-year period. Grape juice composition was compared during stages II and III of the berry growth. The object of this study was to ascertain the effect of irrigation regime on berry development and ripening, and hence on grape juice quality. Changes in berry weight, °Brix, glucose, fructose, titratable acidity, pH, tartaric acid, malic acid, citric acid, and mineral elements were monitored. The evolution of sugars and acids during berry growth followed patterns similar to those reported by previous investigators. Hence, water availability did not affect the accumulation patterns of the different sugars and acids. Glucose was the predominant sugar in the berries at veraison, while fructose predominated at the end of ripening, irrespective of the treatment applied. Organic acid concentration was highest when berries were pea-sized, and it began to decrease at veraison. The rate of decrease was greater for malic acid than for tartaric acid. The concentration of tartaric acid was higher than that of malic acid from veraison on, and differences between them increased as ripening progressed. The differences between malic acid and tartaric acid were greatest in the non-irrigated treatment. Total soluble solids, and the concentration of glucose and fructose were significantly higher in the irrigated vines than in the non-irrigated vines, mainly towards the end of ripening, except in 1992. In that year the values for the non-irrigated vines were slightly higher, though the differences were not significant on many sampling dates. The °Brix of the irrigated grapes at harvest were 2.8% to 14.9% higher than in the non-irrigated grapes. The largest increase in °Brix (67% - 124% in non-irrigated grapes and 58% -117% in the irrigated grapes) took place after veraison. Titratable acidity (TA) was significantly higher for the irrigated vines, primarily at the end of ripening. The TA of irrigated vines at harvest was 9.8% to 28.3% higher than the TA for non-irrigated vines. By expressing the data for glucose, fructose, tartaric acid, malic acid, and citric acid in grams per berry, we observed the largest number of sampling dates with significant differences between irrigation treatments in the years 1990 and 1992. The concentrations for the mineral elements followed differing trends over the course of ripening. Potassium increased until harvest time, and calcium and magnesium decreased, but sodium did not exhibit any clear trend, rising or falling on different sampling dates. Quantitatively, the values for all the parameters studied in the non-irrigated vines tended to be equal to or greater than those in the irrigated vines, even though per-berry quantities were higher in the irrigated vines. The results show that the effect of water deficits on the composition of the grape juice was more intense in the final year of the study, when the differences in soil water availability between treatments were greatest. The results further suggest that the higher yields in irrigated vines did not have any adverse effect on grape must composition and hence on grape juice quality, because on the whole synthesis and accumulation processes were able to offset any dilution effects.

ISOLATION OF LIPOFUSCIN‐LIKE FLUORESCENT PRODUCTS FROM RIPENING BANANA FRUIT

ABSTRACTRipening banana fruit contains water‐insoluble pigments which have a molecular weight in excess of 4000 and a fluorescence spectrum identical to lipofuscin or age pigments. The pigments were not decomposed by irradiation with ultraviolet light. The flourescent substances increased linearly in the peel and quadratically in the pulp during the course of ripening. It is suggested that the fluorescent substances are products of membrane lipo‐protein peroxidation like the lipofuscin pigments identified in animal tissues.

Ripening of tomato fruits at reduced atmospheric and partial oxygen pressures

STORAGE at reduced atmospheric pressure and low temperature is used to retard the post-harvest senescence of fruits, vegetables, cut flowers, and cuttings1–3. The effect of this low pressure storage (LPS) has mainly been ascribed to reduction of the internal concentration of the senescence-accelerating gas ethylene4, although occasionally effects of a lowered partial oxygen tension( ) have also been reported5–7, to determine the contribution of the reduction in to the total effect of LPS on the retardation of post-harvest senescence, we studied the course of ripening of tomato fruits at different atmospheric and partial oxygen pressures, with and without absorbing the ethylene produced. We report that both the onset and the rate of the ripening process are determined by the oxygen pressure, irrespective of the atmospheric pressure and the absorption of endogenously evolved ethylene.

園芸作物の硝酸塩蓄積に関する研究(第13報)

The study was carried out to investigate the variance of nitrate-nitrogen content in tomato fruit among the varieties and the physiological difference between low and high nitrate varieties.The variance of NO3-N content in ripe tomato fruit during the harvest season among sixteen varieties was investigated and these varieties were classified into three groups according to the content. The first group includes extremely early ripening varieties such as Fireball and Amature, and more than 5ppm of NO3-N was contained in the ripe fruit throughout the harvest season. The second group includes early or middle ripening varieties as Chico and Heinz 1370, and NO3-N contents were from 5 to 10ppm only at the early or middle period of the harvest season, then decreased to less than 3ppm at late period. Classified as the third group are Nozomi No.1, VF 36, and other middle or late ripening varieties, and NO3-N contents were less than 5ppm throughout the harvest season.Fluctuation of NO3-N content in the fruit was investigated in the course of ripening of some varieties. NO3-N content in the fruit of Fireball was high at the breaker stage and the level was maintained in the ripening course. While NO3-N contents in the fruits of Chico and Nozomi No.1 were lower at the breaker stage than Fireball and decreased further in the ripening course. When Taiho variety was grown on different culture conditions, the fruit grown on standard culture contained a high level of NO3-N at the breaker stage and a decline followed during the subsequent ripening period. The fruit grown under shading showed remarkable accumulation of NO3-N at the breaker stage followed by a slight decline, and the fruit on low level of NO3-N in culture solution showed a low level at the breaker stage followed by a further decline.The ripe fruit of Chico, low nitrate accumulating variety, as compared with Fireball, high nitrate accumulating variety, contained higher levels of total nitrogen, free amino acids, reducing sugar and calcium, and lower levels of organic acids and potassium.Nitrate reductase activity in the fruit of Heinz 1370, low nitrate accumulating variety, was higher level than Amature, high nitrate accumulating variety, in the ripening course.Remarkable amount of NO3-N was found in the fruit of Fireball grown on high level of NO3-N of culture solution or under shading with cheese cloth, but the content in the fruit of Chico grown on those conditions was further lower than Fireball.

The Constituents of Hops. VI Studies of the Volatile Composition of Humulus lupulus L. during Ripening

Abstract Evidence is presented for the volatile constituents of hops, not only in the resin glands, the so-called lupulin, but also in the stalk with leaves and in the three crops of cones during ripening. Lupulin shows a specific accumulation of myrcene, and the amount of the volatile constituents increases from fifty times to eight hundred times that in any other part of the plant in the course of ripening. While ripe cones contain neither any germacratrienes, the precursors of several sesquiterpenes, nor any aliphatic aldehydes, the stalk with leaves and the young cones have quite high concentrations of them respectively. Observation suggests that some of the volatile constituents are formed a t an early stage of growth, whilst others are formed later.

The Course of Ripening of Banana Fruits Stored in Sealed Polyethylene Bags1,2

Abstract Green, unripe banana fruits (Dwarf Cavendish) were stored in sealed polyethylene bags with and without potassium permanganate (KMnO4). Some fruits were triggered to ripen by ethylene before sealing the bags and in some of them ethylene was injected after sealing. The presence of ethylene stimulated pectin methyl esterase (PME) activity and starch hydrolysis and caused softening, but color change was inhibited by high concentrations of carbon dioxide. It is suggested that in the presence of high carbon dioxide and low oxygen concentrations, ethylene acts in different ways on the coloring and the softening processes of banana fruits.