Influence of the cultivar on the organic acid and sugar composition of potatoes

BACKGROUND: Citric, malic, tartaric, oxalic, ascorbic, aconitic and fumaric acids, and sucrose, fructose and glucose, were determined in ten potato cultivars (Azucena negra, Bonita, Bonita negra, Borralla, Colorada de baga, Mora, Negra, Palmera lagarteada, Peluca blanca and Terrenta) from the Canary Islands in order to differentiate them. The influence of the production zone was also considered. RESULTS: Citric acid and sucrose were the most abundant organic acid and sugar, respectively. There were significant differences in all the analysed sugars and organic acids between the potato cultivars, except for oxalic and malic acids. Differences associated with the production zone were found in the contents of organic acids for some cultivars. Linear discriminant analysis is a useful tool to differentiate the potato samples according to the cultivar and the zone of production. CONCLUSIONS: Seven organic acids (citric, oxalic, malic, tartaric, aconitic, fumaric, and ascorbic acids) were identified and quantified in potatoes. The main sugars (sucrose, glucose and fructose) were also determined. The genetic information of the cultivars determines marked differences in sugars and organic acid contents among the analysed potato cultivars. The soil and climatic conditions affect the organic acid and sugar contents of some potato cultivars. Copyright © 2010 Society of Chemical Industry     

Identification and quantitative analysis of sugars and non-volatile organic acids in Chinese gooseberry fruit (Actinidia chinensis Planch.).

The free sugars and non-volatile organic acids in Chinese gooseberry fruit were extracted and separated by lead salt and ion-exchange procedures. Sugars and acids were identified and quantitatively determined by gas-liquid chromatography (g.l.c.) of their trimethylsilyl (TMS) derivatives. Glucose, fructose, sucrose and trace amounts of sorbitol accounted for the total sugars. Citric, quinic and malic are the major acids, the outstanding feature being the high content of quinic acid in mature fruit. Small amounts of phosphoric, ascorbic, glucuronic, galacturonic, oxalic, succinic, fumaric, oxalacetic and p-coumaric acids are also present. Qualitative and quantitative analysis of acids prepared as lead salts agreed closely with the determination of acids isolated by the ion-exchange procedure. Identifications of sugars and acids were confirmed by paper and thin-layer chromatography. Reducing sugars, total sugars and titratable acidity were determined by AOAC methods and the results compared with those from g.l.c.     

Sugars and organic acids in Japanese plums (Prunus salicinaLindell) as influenced by maturation, harvest date, storage temperature and period

The effects of fruit maturation, harvest date, storage temperature, storage period and shelf life, on the concentrations of individual sugars and organic acids in Japanese plums were investigated. During fruit maturation in 'Amber Jewel' plums, sucrose concentration increased significantly from 101 days after full bloom (DAFB) to 1 week after commercial maturity (136 DAFB) with a non-significant change in the concentration of total organic acids and malic acid, the major organic acid. The changes in concentrations of sugars and organic acids during cold storage of 'Amber Jewel' plums harvested on 129 and 136 DAFB appeared to be independent of harvest date. Storage of 'Amber Jewel' plums at 5 °C accelerated the loss of sucrose and increased the concentrations of fructose and glucose from the 4^th week of storage compared with those stored at 0 °C. 'Blackamber' plums did not undergo any significant increase in the total and individual sugars during 5 weeks storage and subsequent shelf-life of 8 days at 20 °C. Malic acid concentrations declined during storage from 3 weeks onwards with a further substantial loss during ripening at 20 °C. Maturation, harvest date, storage temperature, storage period and shelf-life affect the concentrations of sugars and organic acids in Japanese plums.     

Sugar and acid concentrations in 98 grape cultivars analyzed by principal component analysis

A total of 98 grape cultivars were studied for content and composition of organic acids and sugars in grape juice during two consecutive years. Glucose and fructose were the predominant sugars in grape berries and ranged from 45.86 to 122.89 mg mL^?1, and 47.64 to 131.04 mg mL^?1, respectively, in two years. Sucrose was present at trace amounts in most cultivars, but two cultivars of hybrids between Vitis labrusca and V. vinifera contained large amounts of sucrose. Tartaric acid content in berries, varying from 1.57 to 9.09 and 1.54 to 9.05 mg mL^?1, respectively, in two years, was significantly higher than malic acid, which ranged from 0.38 to 6.05 and 0.36 to 7.06 mg mL^?1, respectively, in two years. Moreover, significantly higher total soluble sugars and fructose and lower total acids and malic acid were found in cultivars from hybrids between V. labrusca and V. vinifera than those in V. vinifera cultivars, and wine grapes had higher total sugars and acids than table grapes from V. vinifera. Principal component analysis (PCA) indicated that genotypic correlations among sugar and acid contents were stable and the first three PCs accounted for about 82% of total variance in both years. PC1 was highly connected with glucose and fructose contents, and sucrose was an important contributor to the variance for PC2, as well as for PC3. PC2 and PC3 were highly connected also with organic acids, but the contributor to variance differed from one year to the next. Tartaric acid was the main contributor to variance in 2003, and malic acid was important in 2004 for PC2 and PC3. In a scatter plot of the score values of all genotypes projected to the PC1 and PC2 plane, three groups of cultivars tend to cluster based on their genetic background or purpose of use. The cultivars of hybrid V. labrusca and V. vinifera were represented by high sugars, especially sucrose, and low acids. Among the cultivars of V. vinifera, wine grapes were found in general to have more sugars and acids than table grapes. The composition of sugars was stable in grape berries between the two years, while acids were sensitive to climate changes. Finally, the different responses of malic and tartaric acids to climate change is discussed. Copyright © 2006 Society of Chemical Industry     

HPLC双检测器法同时测定饮料中的有机酸与糖

本文提出了用高效液相色谱法同时测定饮料及果汁中的酸味物质与甜味物质。用交联度为8％的氢型阳离子交换树脂Aminex HPX-87H色谱柱,对各种有机酸及糖分的保留性质进行了研究。以0.01NH_2SO_4为移动相,糖分及有机酸分别得到了较好分离。利用糖分及有机酸对紫外光吸收强弱的差异,采用双检测器系统,使有机酸及糖分均能在对其具有较高灵敏度的检测器中得到检测。因而一次直接进样可同时定性及定量分析待测样品中的柠檬酸、酒石酸、苹果酸 (或维生素C) 琥珀酸、蔗糖、葡萄糖及果糖。每一样品的分析过程不超过十五分钟,这是其它方法很难达到的,特别对样品数量较多的日常分析,本方法的优越性更为明显。     

Evaluation of chemical constituents and antioxidant activity of sweet cherry (Prunus avium L.) cultivars

This research was undertaken to evaluate the sugars, organic acids, phenolic compositions and antioxidant capacities of sweet cherry cultivars (Van, Noir de Guben, Larian and 0‐900 Ziraat) grown in Turkey. High‐performance liquid chromatographic methods were used to identify and quantify four sugars (sucrose, glucose, fructose and sorbitol) and four organic acids (malic, citric, shikimic, and fumaric acid). The major organic acid was found as malic acid (8.54–10.02 g kg^?1 of FW). With regard to sugars, glucose was present in the largest amounts (44.71–48.31 g kg^?1 of FW) for sweet cherry cultivars. The sum of sugars ranged from 103.87 (Larian) to 113.13 g kg^?1 of FW (0‐900 Ziraat) and that of organic acids from 12.01 (0‐900 Ziraat) to 14.17 g kg^?1 of FW (Noir de Guben). A total of eleven phenolic compounds were identified and quantified in sweet cherry cultivars, including hydroxycinnamic acids (3), anthocyanins (5), flavan‐3‐ols (2) and flavonol (1) compounds. Total phenolic contents ranged from 88.72 (Van) to 239.54 (Noir de Guben) mg/100 g of FW, while antioxidant activities ranged from 2.02 to 7.75 μm Trolox equivalents g^?1 of FW.     

草莓汁中糖酸组成分析及其在掺假鉴别中的应用

为了解草莓汁的糖酸组成特点并探索其在掺假鉴别中的应用,采用高效液相色谱法对10个品种草莓果汁中可溶性糖、有机酸组成与含量进行分析,结合化学计量学方法探索其在草莓汁掺假鉴别中的应用。结果表明,草莓汁中可溶性糖主要由蔗糖、葡萄糖和果糖组成,有机酸主要是柠檬酸和苹果酸。不同品种草莓果汁中各种可溶性糖和有机酸的含量存在较大差异,但葡萄糖与果糖的比值受品种影响较小,柠檬酸占检测到总有机酸含量的62.39%~82.73%。通过分析草莓原汁及其掺假样品中可溶性糖和有机酸组成,结合主成分分析和线性辨别分析等模式识别方法,可以实现对草莓果汁与掺加梨汁、苹果汁、杏汁和桃汁等掺假样品的区分,而且掺假量越大,区分效果越好。草莓果汁可溶性糖和有机酸组成特征结合化学计量学分析能够对掺假草莓果汁进行较好地区分,可用于草莓果汁掺假鉴定和质量控制。     

Developmental changes of carbohydrates,organic acids,amino acids,and phenolic compounds in ‘Honeycrisp’ apple flesh

The developmental changes of carbohydrates, organic acids, amino acids and phenolic compounds in ‘Honeycrisp’ apple flesh were investigated using GC–MS and HPLC. A total of 12 carbohydrates, 8 organic acids, 20 amino acids, and 18 phenolic compounds were identified and quantified. Each metabolite showed characteristic changes during fruit development, but in general, concentrations of most sugars and sugar alcohols either increased or remained unchanged whereas concentrations of most organic acids, amino acids and phenolic compounds decreased with fruit development, indicating that most sugars and sugar alcohols are synthesised and/or accumulate at a faster or similar rate relative to fruit growth whereas organic acids, amino acids and phenolics are synthesised and/or accumulate at a slower rate relative to fruit growth. On a whole fruit basis, the content of most metabolites increased with fruit development. In the flesh of mature ‘Honeycrisp’ apple, fructose and sucrose and sorbitol are the major sugars and sugar alcohol; malic acid is the major organic acid; aspartic acid, asparagine, glutamic acid, proline, threonine and γ-aminobutyric acid are the major amino acids; and procyanidin B1, procyanidin B2, chlorogenic acid, catechin and epicatechin are the major phenolic compounds, respectively.     

苹果酵素天然发酵过程中代谢产物的变化规律

为研究苹果酵素天然发酵过程中物质代谢变化,对天然发酵过程中pH值、总酸、有机酸(乳酸、醋酸、苹果酸)、糖类(蔗糖、葡萄糖、果糖)、乙醇、总酚含量、1,1-二苯基-2-三硝基苯肼(1,1-diphenyl-2-picrylhydrazyl,DPPH)自由基清除率的变化进行分析。结果表明,发酵过程中pH值从5.05降至3.88,总酸、乳酸含量呈不断上升趋势,乙酸质量分数由0.018%升至0.23%,苹果酸质量浓度在发酵前14?d由初值0.67?g/L上升至2.45?g/L后略微下降;葡萄糖、果糖质量浓度呈先升后降趋势,且二者均在发酵第21天达到最大值130.6、177.2?g/L,蔗糖质量浓度不断下降趋于0?g/L;乙醇在发酵14~21?d过程中产生,发酵4周后乙醇体积分数可达6.6%;总酚质量浓度与DPPH自由基清除率呈先升后降趋势,均在发酵第21天达到最大值为259.4?mg/L、90.9%。     

Sugar and Nonvolatile Acid Composition of Persimmons During Maturation

Sugars and nonvolatile acids of Japanese persimmons were identified and quantitated by GLC as oxime-TMS derivatives. Sugars quantitated were arabinose, galactose, glucose, fructose and sucrose. Fructose, glucose and sucrose were predominant and present in all cultivars from mature green to fully ripe. Quantities of all sugars varied significantly by cultivar and maturity. Nonvolatile acids quantitated were succinic, malic, citric, and quinic. Malic was the predominant acid in all cultivars followed by citric. Quantities of malic increased with maturity; citric decreased. Sorbitol and inositol were present in minor quantities and varied significantly by cultivar and maturity stage.     

Factors influencing quantities of sugars and organic acids in blackcurrant concentrates

 Use of endogenous non-volatile flavour components, i. e. sugars and organic acids, in fruit juice products is desirable. A study of 133 blackcurrant concentrates from three seasons examined variation in sugars and acids arising from storage of fruit at freezing or sub-ambient temperature, seasonal differences, geographical origin and choice of conventional thermal-evaporative or freeze concentration technology. Compared with freeze concentrates, conventional concentrates had significantly higher contents of total sugars and acids, notably malic acid, and higher fructose/glucose, lower malic/citric acid and similar sugar/acid ratios. Concentrates from frozen fruit generally had smaller amounts of fructose, total sugars and fructose/glucose ratios than those from fresh fruit, as well as less citric, ascorbic and total acids and lower sugar/acid ratios. Principal component analysis of 40 randomly chosen concentrates showed that variance is dominated by differences in fructose, total sugars and ascorbic acid contents and sugar/acid ratios. Geographical origin and concentration technology were major sources of variance but changes in post-production sub-ambient storage could not be excluded. Received: 4 July 1997 /  Revised version: 14 October 1997     

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.     

Effect of cold storage and ozone treatment on physicochemical parameters,soluble sugars and organic acids in Actinidia deliciosa

The production of kiwi fruits is a dynamic agricultural activity in Corsica (France). The fruits are either consumed directly or used to produce kiwi wine. They are often stored for 4–6 months in industrial freezer chambers at 0 °C or industrial ozone chambers. The aim of this study was to measure physical, chemical and fungicidal parameters, soluble sugars and non-volatile organic acids during storage in each of these types of chamber. Various standard and instrumental methods (physicochemical techniques, HPLC) in conjunction with statistical analysis were used. During storage, the kiwi mass, firmness and acidity decreased, whereas reducing sugar, °Brix and pH increased. There were statistical differences between the two chambers regarding reducing sugar and acidity. The ozone gas treatment had a fungicidal effect on Botrytis cinerea. The major soluble sugar present in the kiwi fruit was fructose, followed by glucose and sucrose. The concentrations of these sugars increased during storage in both air at 0 °C and ozone-enriched air. Organic acids are one of the important factors influencing fruit flavour. Citric and quinic acids predominated over malic, tartaric and ascorbic acids. During storage in the ozone chamber, concentrations of non-volatile organic acids decreased sharply after 25 weeks. Storage at 0 °C enabled better retention of organic acids.     

Sugars and Acid Analysis and Effect of Heating on Color Stability of Northwest Concord Grape Juice

Changes during storage in color of Concord grape juice extracted after heating to different temperatures and the carbohydrate and nonvolatile acid composition of Concord grapes were studied. Heating crushed Concord grapes under pilot plant conditions to 88° and 99°C inactivated nearly all of the polyphenoloxidase, increased the extraction of anthocyanins (ACN) and reduced polymeric color in the grape juice. During storage of the juice for 8 months, the rate of ACN degradation and color density decrease was the same in all samples. Glucose, fructose and sucrose were the only sugars found in Northwest Concord grapes, while malic and tartaric acids were the major nonvolatile acids. Lesser amounts of phosphoric, citric and coumaric acids were present.     

BIOCHEMISTRY OF UNEVEN RIPENING IN GULABI GRAPE1

Physico-chemical changes, organic acids content and activities of enzymes related to softening, glycolytic, gluconeogenic and organic acids metabolism were studied from 70 to 100 days after anthesis in ripening of berries of Gulabi grape. Uneven ripening was observed in 70 day old clusters. The disorder affected 22.76 and 32.38% of berries in bunches harvested at 90 and 100 days, respectively. Unripe berries had less dry matter, sugars, skin anthocyanins and more seed, fresh weight and acidity compared to ripe berries. Green berries had more malic and less tartaric acid, while brown berries had less malic acid and black berries contained more tartaric acid. Green berries contained more polygalacturonase, cellulase, hexokinase, glucose 6-phosphatase, phosphoenol pyruvate carboxylase, pyruvate decarboxylase and polyphenol oxidase activities than ripe fruit. Brown berries contained the highest phosphofractokinase, malate and glutamate dehydrogenase activities, and black berries had the highest activities of pectinesterase, fructose 1,6-bisphosphatase and malic enzyme. The role of dry matter, malic acid, pectinesterase and certain enzymes of gluconeogenic and organic acids metabolism in uneven ripening is discussed.     

Sugars and acids of strawberry varieties

The sugar and acid compositions of six strawberry (Fragaria×ananassa Duch.) varieties from 1997 and 1998, grown in different conditions, 26 samples in all, were investigated by GC as trimethylsilyl derivatives. The major sugars were glucose (1.89–4.52?g/100?ml), fructose (2.14–4.14?g/100?ml) and sucrose (0.90–3.87?g/100?ml), the major acids being citric (0.73–1.58?g/100?ml) and malic (0.22–0.69?g/100?ml). Total sugar content (glucose+fructose+sucrose) varied from 5.35?g/100?ml to 10.96?g/100?ml in accordance with soluble solids (°Brix). The correlation between them showed a linear regression y=0.873x-0.420, the percentage of determination of the regression model being 82.1%. Among one variety only, ‘Senga Sengana’, the percentage of the model was 86.9%. No significant differences were found between the strawberries from conventional versus those from organic farms. Contents of sugars and soluble solids were lower in varieties ‘Jonsok’ and ‘Honeoye’ than in ‘Korona’, ‘Bounty’ and ‘Polka’. The concentrations of malic acid were significantly higher in Senga Sengana, Jonsok and Bounty than in other varieties.     

Effect of postharvest period on sugars,organic acids and fatty acids composition in commercially sold medlar (<Emphasis Type="Italic">Mespilus germanica</Emphasis> 'Dutch') fruit

Fructose, glucose, and sucrose as the major soluble sugars, and citric, malic, and ascorbic acids as the major organic acids were determined by HPLC, and palmitic acid (16:0) and stearic acid (18:0), oleic acid (18:1), linoleic acid (18:2n-6) and linolenic acid (18:3n-3) as the major fatty acids were determined by GC in medlar (Mespilus germanica 'Dutch') fruit. The compositional changes of these constituents were monitored during the post harvest period of commercially sold Dutch form throughout its rapid ripening (fruit softening-darkening). Sucrose was highest at 1 WAH (228.4 mg/100 g fresh wt) and then decreased, remaining very low at 4 WAH (1.4 mg/100 g fresh wt). As for the levels of fructose and glucose, their levels shifted up to 2230.8 and 845.2 mg/100 g fresh wt at 2 and 3 WAHs, then the levels lessened to their lowest concentration. The levels of the three acids were high at the beginning, except malic acid level at 2 WAH, all acids leveled off through the latter weeks of post harvest period. In the fruit studied, the levels of saturated palmitic acid (16:0) and stearic acid (18:0), and unsaturated oleic acid (18:1), linoleic acid (18:2n-6) and linolenic acid (18:3n-3) were most abundant fatty acids detected throughout medlar ripening (pulp softening and darkening). The level of palmitic and stearic acids as well as the level of linoleic and linolenic acids were the highest at 1 WAH and then suddenly decreased as the medlar soften and the pulp becomes slightly (2 WAH) and fully (3 WAH) brown through 2 and 4 WAHs. In addition to these prominent fatty acids, a remarkable decrease was also obtained in the content of some other fatty acids (C_10-15, C_16:1, C_20-24).     

果啤与啤酒组分差异比较研究

采用气相色谱和高效液相色谱的分析方法,分析了市售同一品牌菠萝果啤、啤酒的风味成分、有机酸、糖的组成及含量,结果表明,果啤中酯含量类物质的种类相对普通啤酒丰富,组成协调,高级醇含量低。有机酸含量果啤高于啤酒,柠檬酸积累较多。果啤中蔗糖消耗大,而果糖和葡萄糖含量有所升高。     

金丝小枣在生长成熟过程中理化特性的变化规律

本文研究了6个不同生长成熟期(S1~S6)金丝小枣果实的色泽、叶绿素、可溶性糖及其代谢酶活性、有机酸及氨基酸的动态变化,以明确其代谢规律。研究结果表明:枣果生长成熟过程中,叶绿素含量降低,枣果由绿变红;葡萄糖、果糖均逐步积累,而山梨醇含量逐渐降低,蔗糖则在生长发育初期未被检出,其积累主要发生在枣果成熟后期,且其含量最高,金丝小枣为蔗糖积累型果实,蔗糖磷酸合成酶是蔗糖积累的关键酶;金丝小枣为苹果酸型果实,苹果酸随枣果的成熟而积累,而柠檬酸含量先上升后降低;Pro和Asp在枣果成熟过程中被大量合成,是成熟枣果中最主要的两种氨基酸。全红枣的可溶性总糖、糖酸比以及游离氨基酸总量最高,可作为金丝小枣鲜食的最佳采收时期。     

不同产区的妃子笑及怀枝荔枝的甜酸滋味物质比较及电子舌分析

以妃子笑和怀枝荔枝为研究对象,分析产区和品种对荔枝滋味物质的影响。通过对深圳、惠东、惠来和钦州4大产区妃子笑和怀枝荔枝甜酸滋味物质和电子舌的测定,可知荔枝中含有葡萄糖、果糖和蔗糖3种糖,有机酸主要有草酸、酒石酸、苹果酸、抗坏血酸等8种;在同一产区内,妃子笑的总甜度均大于怀枝;对于妃子笑荔枝来说,深圳和钦州荔枝的糖酸比最大;对于怀枝来说,深圳荔枝的糖酸比最大。蔗糖对深圳妃子笑甜味贡献最大,对于所测荔枝样品,果糖的贡献值大于蔗糖和葡萄糖。电子舌图谱与理化指标图谱之间具有相似性,可以明显区分不同产区的荔枝样品。