Quality evaluation of peaches and nectarines by electrochemical and multivariate analyses: relationships between analytical measurements and sensory attributes

A propagation programme for peaches and nectarines has been targeted to select genotypes having taste attributes such as high sugar levels and well-balanced sugar/acid ratios. The analytical measurements of some soluble sugars and nonvolatile acids were carried out using innovative analytical procedures based on fast and selective devices which require very little or no sample pre-treatment whatsoever. These devices have found a unique application in detecting fructose, glucose and malic acid for the improvement of fruit genetics.

The present study examines relationships between the analytical measurements of sugars and non-volatile acids and the sensory attributes (sweetness and sourness) of 21 peach and nectarine cultivars. Certain chemical parameters were correlated with the organoleptic acceptance of common commercial cultivars and recently introduced high and low-acid genotypes. Multivariate statistical analyses were found to be useful in describing the variability of the chemical and sensory parameters which characterise peach quality, as they enabled the identification of sets of variables that could be used to classify peaches and nectarines into high and low-acid categories. Malic and citric acids, minor components of these fruits, were important taste attributes as they contributed to the sensory perception of sourness.     

Analysis of sugars,organic acids and vitamin C contents of blackberry genotypes from Turkey

The paper reports the composition of some quality characteristics of five blackberry varieties (“C. Thornless”, “Bursa 2”, “Navaho”, “Jumbo” and “Loch Ness”). Main soluble sugar and acid contents of experimental varieties were separated, identified and quantified using high-performance liquid chromatography with photo diode array spectrophotometric and refractive index detection, for organic acids, ascorbic acids and soluble sugars, respectively. According to the results, malic acid was detected as the main organic acid while citric acid was not detected in blackberry fruits. Ascorbic acid content was found very low quantity and also was not detected in all the cultivars. As for the sugars, fructose was found as the most abundant sugar and highly detected in “Navaho”. However, the highest total sugar/malic acid ratio was found in cv. C. Thornless.     

Composition of Sugars,Organic Acids,and Total Phenolics in 25 Wild or Cultivated Berry Species

Abstract: Sugars, organic acids, and total phenolic content in fruit of 25 wild and cultivated berry species were identified and quantified with high‐performance liquid chromatograph. The composition of sugars, organic acids, and total phenolic compounds in various species of Vaccinium, Rubus, Ribes, and Fragaria genus was evaluated. Additonally, total phenolics of less known berry species of the Morus, Amelanchier, Sorbus, Sambucus, Rosa, Lycium, Actinidia, and Aronia genus were determined in wild growing as well as in cultivated fruits. Significant differences in the concentration of sugars and organic acids were detected among the berry species. Glucose and fructose were the most abundant sugars in berry fruits and the major organic acids were malic and citric acid. However, in kiwi fruit, sucrose represented as much as 71.9% of total sugars. Sorbitol has been detected and quantified in chokeberry, rowanberry, and eastern shadbush fruit. The highest content of total analyzed sugars was determined in rowanberry fruit, followed by dog rose, eastern shadbush, hardy kiwifruit, American cranberry, chokeberry, and jostaberry fruit. Rowanberry stands out as the fruit with the highest content of total analyzed organic acids, followed by jostaberry, lingonberry, red gooseberry, hardy kiwifruit, and black currant. The berries of white gooseberry, black currant, red currant, and white currant had the lowest sugar/organic acid ratio and were thus perceptively the sourest species analyzed. On the other hand, the species with highest sugar/organic acid ratio were goji berry, eastern shadbush, black mulberry, and wild grown blackberry. The highest amounts of total phenols were quantified in chokeberry fruit. Wild strawberry, raspberry, and blackberry had 2‐ to 5‐fold more total phenolics compared to cultivated plants. Practical Application: The fruit of analyzed berry species contained different levels of sugars, organic acids, and total phenolics. Moreover, it has been demonstrated that wild grown species generally contain more phenolics than cultivated ones. This information is interesting for nutritionists as well as berry growers and breeders who can promote the cultivation of species and new cultivars with higher phenolic content.     

Sugar Composition and lnvertase Activity in Prickly Pear Fruit

Sucrose was the predominant sugar in peel samples and present in lesser amounts in pulp and juice samples of prickly pear fruit. The relative total content of glucose and fructose differed among species and within fruit tissues. Acid invertase activity was found in all fruits examined while neutral invertase activity was found in two of the three species. Red-skinned fruits had no neutral invertase activity and yellow-skinned fruits had relatively high neutral invertase activity. When both invertase activities were added, a pattern of distribution of invertase activity that corresponded with sucrose levels within fruits was observed. The overall total invertase activity levels in red-skinned fruits were about twofold that of the yellow-skinned fruits and fourfold that of purple-skinned fruits.     

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.     

黄土高原旱塬区不同品种苹果果实糖及有机酸含量比较分析

为明确黄土高原旱塬区不同品种苹果果实中糖与有机酸含量的特征,对主栽的30个品种果实中糖、酸类物质含量进行分析。采用高效液相色谱法（High-phase liquid chromatography,HPLC）对30个品种成熟期果实中可溶性糖与有机酸含量进行了测定,并对数据进行单因素方差分析与相关性分析。结果表明:不同品种苹果果实糖组分中果糖含量最高,均值为52.964 mg/g,占总糖含量的48.82%,且二者呈极显著性相关（r=0.787）,果糖含量最高的品种为‘嘎啦’（69.736 mg/g）,大部分品种果实中蔗糖含量高于葡萄糖含量,只有3个品种表现出葡萄糖含量高于蔗糖含量,分别为‘金冠’、‘八月富士’和‘无锈金矮生’;不同品种苹果果实酸组分中苹果酸含量最高,均值为3.857 mg/g,占总酸含量的57.44%,且二者呈极显著性相关（r=0.845）,奎宁酸含量次之,其他种类有机酸含量较低,苹果酸含量最高的品种为‘寒富’（8.109 mg/g）;甜度值/总酸含量大于30的品种有3个,分别为‘世界1号’、‘金冠’和‘嘎啦’,介于20～30之间的品种有13个,小于20的品种有14个。苹果果实中甜度值和总酸含量、以及甜度值与总酸含量的比值共同影响果实风味。     

Effect of maturation and cold storage on the organic acid composition of myrtle fruits

BACKGROUND: The effect of maturation and senescence on the chemical composition of two myrtle cultivars was studied in mature, overripe and cold‐stored fruits in order to find the most appropriate harvesting period and best storage technology for industrial purposes. RESULTS: After cold storage at 10 °C for 15 days, berry weight loss ranged from 12.5 to 18.4%, with the highest losses in less mature fruits. Titratable acidity decreased during maturation and cold storage in both cultivars. Reducing and total sugars increased during maturation. Anthocyanin concentration increased during maturation but decreased in overripe berries. The major organic acids in myrtle fruits were quinic, malic and gluconic acids. In fresh and cold‐stored fruits, malic acid rose to 3 g kg^?1 and decreased thereafter. Quinic acid peaked at 90 or 120 days after bloom and decreased thereafter to reach low concentrations in mature fruits. CONCLUSION: Cold storage for 15 days at 10 °C does not affect myrtle fruit quality for liqueur production. Anthocyanin concentration is the best indicator of harvest time for industrial purposes. Gluconic acid concentration is high in mature, overripe and cold‐stored berries. This parameter can be used as a marker of the onset of fruit senescence. Copyright © 2012 Society of Chemical Industry     

POSTHARVEST SENSORY AND PHYSIOCHEMICAL ATTRIBUTES OF PROCESSING AND NONPROCESSING TOMATO CULTIVARS

Fruits of processing and nonprocessing tomato cultivars harvested at the “breaker” stage of maturity were evaluated for changes in physical, chemical and sensory quality characteristics during storage at 20C and 30C after 7, 14 and 21 days. Percentage marketable fruits after 21 days at 20C and 30C were 61.9% and 56.6% for processing cultivars and 65.9% and 50.9% for nonprocessing cultivars. Fruits of the processing cultivars ripened earlier, remained firmer and were less prone to physical injuries than fruits of nonprocessing cultivars. Nonprocessing fruits had a higher mean fruit weight of 17.0 g, fruit diameter of 1.10 mm and locule number of 13 compared with fruits of the processing cultivars. Nonprocessing fruit cultivars had higher sugar/acid ratios and vitamin C contents as well as lower pH and total titratable acidity than processing fruit cultivars. Accordingly, nonprocessing cultivars on the whole, but specifically Walters, Floradel, Carnival, Calypso, Star Pak, Floradade and Early Set were most suitable as fresh-market fruits. Excellent processing quality attributes were obtained for Donore, Peto 94C, Rio Grande and Advantage. Among processing cultivars Caraibe, Cascade, Dorado and Neema 1401 gave good dual purpose fruits.     

Organic acids,antioxidant capacity,phenolic content and lipid characterisation of Georgia-grown underutilized fruit crops

Four underutilized Georgia-grown fruit crops, namely loquat (Eriobotrya japonica), mayhaw (Crataegus sp.), fig (Ficus carica), and pawpaw (Asimina triloba), and their leaves were analysed for total polyphenols by Folin–Ciocalteau method, and antioxidant capacity by ferric-reducing antioxidant power (FRAP) and Trolox-equivalent antioxidant capacity (TEAC) assays. Organic acids and phenolic compounds were identified by RP-HPLC. For lipid profile, fruits were separated into two fractions – seed and fruit (i.e., without seed); lipid was extracted using the Folch method and analysed for fatty acids, phytosterols, tocopherols, and phospholipids. The major organic acid identified in all samples was malic acid (177–1918 mg/100 g FW). The predominant phenolic acids in all the fruits were gallic (1.5–6.4 mg/100 g FW) and ellagic (0.2–33.8 mg/100 g FW), and the most abundant flavonoid was catechin (12.2–37.8 mg/100 g FW). Total lipid content varied from 0.1% in mayhaw fruit to 21.5% in pawpaw seed. Linoleic acid was the predominant fatty acid in all of the samples (28.2–55.7%).     

福建省4 个果梅主栽品种果实营养品质、香气成分分析与评价

以福建省4 个果梅主栽品种青竹梅、龙眼梅、杭梅和白粉梅为试材,分析测定果实的主要性状和营养成分,包括单果质量、果实大小、VC、总酚、类黄酮、可溶性糖、有机酸、香气组分以及矿质元素含量。结果表明,4 个果梅品种VC、总酚、类黄酮、可溶性糖、有机酸、香气组分以及矿质元素含量存在显著差异。果梅主要可溶性糖为蔗糖,其次为葡萄糖和果糖;主要有机酸为柠檬酸,其次为苹果酸、琥珀酸、乙酸和奎宁酸;4 个果梅品种果实共检测出110 种挥发性物质,包括30 种酯类、26 种醇类、17 种醛类、15 种酮类、7 种酸类以及15 种其他类,其中有26 种物质为4 个品种共有成分,2-己烯醛、己醛、己醇和反式-罗勒烯醇可能是果梅特征香气的重要物质;4 个果梅品种含有较高的K、Ca和Se含量。通过主成分分析提取,得出综合得分品种最高为青竹梅,青竹梅果实挥发性物质相对总含量高于其他3 个品种且综合品质最佳,适宜作为选育果梅良种的育种材料。本研究结果为明确果梅营养价值评价及其在良种选育、生产加工中的合理利用提供理论依据。     

Changes in Sucrose, Fructose and Glucose Content of Frozen Strawberries with Thawing

Free sugar composition of strawberries during thawing and up to 5-hr after-thaw storage was studied. Sucrose content of drained fruits and juice decreased by 70% whereas fructose and glucose content increased during thawing at 4 °C. Total free sugar content remained constant. Sucrose degradation caused by invertase activity in the strawberry fruit rather than by sucrose synthase activity or acid hydrolysis was demonstrated. The sucrose inversion was more pronounced in drained fruits than in juice. Sucrose inversion also occurred when fruit was thawed by a current of air, microwave heating, or 35 °C water, but to a lesser extent. The 5-hr holding period after thawing resulted in comparable sugar composition with all thawing procedures. For best preservation of the free sugar composition a fast thawing method should be chosen.     

基于原料与果汁品质的蓝莓果实加工性能评价

以‘蓝金’、‘瑞卡’、‘N5’等12个辽南露地栽培蓝莓品种果实为试材,通过果实外观、营养品质及加工性能指标的观测与分析,筛选加工适宜品种。结果表明,蓝莓果实以蓝色为主,呈不同程度扁球形,表面附着果粉,单果重0.95~2.63 g;含水量>80%,果越大,含水量越高,果型越扁,果实中均含有果糖、葡萄糖、草酸、奎尼酸、苹果酸、莽草酸和柠檬酸,果糖与葡萄糖含量相当,柠檬酸含量显著高于其它有机酸（P<0.05）,属于已糖积累型、柠檬酸优势型果品。供试品种果实中均含有钾、镁、钙、铁、锰、锌和铜元素,含量依次递减,钾含量最高（5786 mg?kg?1）,极显著高于其它元素（P<0.01）,‘达柔’果实中钾含量（7400 mg?kg?1）最高。不同品种果实不添加果胶酶处理出汁率差异极大（变异系数达60.42%）,添加果胶酶处理出汁率差异很小（变异系数仅3.88%）,添加果胶酶处理出汁率及果汁可溶性糖、可滴定酸含量明显提升,添加果胶酶处理能够提高果汁产率和质量。果实中果糖和葡萄糖含量越高,果汁中可溶性糖含量越高（相关系数为0.96和0.98）;果实中柠檬酸和奎尼酸含量越高,果汁中可滴定酸含量越高（相关系数为0.81和0.71）。‘日出’、‘蓝金’和‘北卫’3个品种可溶性糖（>90 mg?g?1）、有机酸含量（>10 mg?g?1）和出汁率（>74.6%）均较高,是较好的加工品种。综上,‘日出’、‘蓝金’和‘北卫’3个品种果实营养丰富、出汁率高,是加工的理想原料。     

Chemical compositional characterization of some apple cultivars

Eight commercially harvested apple cultivars were analysed by gas chromatography and high-performance liquid chromatography, in particular the composition and level of sugars, organic acids, amino acids, phenolic compounds and fatty acids. The results showed great quantitative differences in the composition of the apple cultivars, particularly in their phenolic contents. Fructose was the most dominant sugar in the different apple cultivars, followed by glucose and sucrose, while malic acid was the principal organic acid. The C16:0, C18:0, C18:1, C18:2 and C18:3 fatty acids were the most abundant fatty acids, and the C18 family accounted for more than 70% of the total fatty acids content. Asparagine and serine were the principal amino acids. Chlorogenic acid and protocatechuic acid were the dominating phenolic compounds. The results provide important information on how to make the best use of the apple cultivars investigated, for both technological research and processing practice.     

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     

高寒荒漠区延后栽培葡萄品质分析

为评价鲜食葡萄在高寒荒漠区延后栽培条件下的品质表现,以适应性较好的8个品种为研究对象,测定葡萄感官品质、内在品质、功效成分和糖酸品质,采用主成分分析法对果实品质进行综合分析和评价。结果表明,‘红地球’和‘紫地球’单果质量10 g以上,果粒大,能够保持原有的大果特征;无核品种较有核品种果粒小;8个品种果实果形指数均> 1,呈长椭圆形,除绿色品种外,果实着色较深;果皮颜色越深的品种,果皮花青素、类黄酮、总酚含量越高。2个无核品种(‘红宝石无核’和‘紫甜无核’)和‘红地球’可溶性固形物含量较高,在21%以上;糖酸组分及含量方面,果实中的糖分主要是果糖和葡萄糖,蔗糖未检出;酒石酸和苹果酸是主要有机酸,柠檬酸和草酸含量极微。酸甜风味方面,‘红宝石无核’口感最甜,其次为‘红地球’,‘瑞都香玉’和‘紫地球’口感较淡,‘摩尔多瓦’口感偏酸。通过主成分分析法提取了5个独立的主成分,累计贡献率87. 396%,以主成分为评价指标,对浆果品质进行综合评价,‘红宝石无核’、‘红地球’和‘玫瑰香’果实综合品质最好。     

桑葚果实不同发育期品质测定及其相关性分析

本研究对湛江地区7个桑葚品种青果期、转色期、成熟期三个时期桑葚果的单果重、可溶性固形物、可滴定酸含量及糖和有机酸组成和含量进行了测定,并进行了相关性分析。结果表明,在成熟过程中桑葚果实的可溶性固形物和糖含量呈增加的趋势,而酸则呈降低的趋势;在桑葚果实品种中检测出柠檬酸、苹果酸、奎宁酸、琥珀酸、酒石酸、酮戊二酸、抗坏血酸、草酸共8种有机酸,其中柠檬酸的含量最高,其在不同品种不同发育期含量为44.84%~80.86%,其次为奎宁酸和苹果酸;果糖和葡萄糖是桑葚重要的糖组成,其含量在成熟期的台湾长果桑的含量分别达到57.79 mg/g和66.72 mg/g,并且只有在台湾长果桑中检测到蔗糖;通过相关性分析,可滴定酸与可溶性固形物、果糖、葡萄糖、果重呈负相关,且可溶性固形物、果糖含量、葡萄糖含量三者之间呈极正相关。     

Changes of the composition in acerola (Malpighia emarginata DC.) fruit in relation to cultivar,growing region and maturity

BACKGROUND: Acerola (Malpighia emarginata DC.) has been known as a fruit rich in vitamin C. However, changes in composition of constituents in relation to cultivar, growing region and maturity have not been studied. We investigated the composition for five types of acerola fruits: three different cultivars (‘BOK’, ‘Flor Branca’ and ‘NRA309’) growing in Brazil, and one cultivar each in Vietnam (‘Vietnam’) and in Japan (‘Okinawa’). We also investigated the influence of fruit maturity on the compositional profiles. RESULTS: ‘BOK’ showed the highest vitamin C and malic acid contents whereas ‘Vietnam’ had the lowest vitamin C content. On the other hand, ‘NRA 309’ showed the highest level of total polyphenols. In the study of compositional changes during maturation, it was found that at immature stages proanthocyanidin was the major flavonoid, with high vitamin C content, but the levels of these constituents decreased as ripening progressed. At mature stages, anthocyanins appeared to be the major polyphenol in the ripe acerola fruit. CONCLUSION: This study showed that composition of acerola fruit differed significantly according to cultivar, growing region and maturity. The information provided in this study may help consumers to make an appropriate selection of functional food. Copyright © 2008 Society of Chemical Industry     

Chemical compositional characterization of eight pear cultivars grown in China

The sugar, organic acid, amino acid and fatty acid compounds of eight commercial pear cultivars were identified and quantified using high-performance liquid chromatography (HPLC) equipped with RI and UV detectors and gas-chromatography (GC) equipped with FID detector. The mineral composition was determined by inductively coupled plasma-mass spectrometry (ICP-MS). The results showed great quantitative differences in the composition of the pear cultivars. Fructose was the dominant sugar in the eight pear varieties, followed by glucose and sucrose, while malic acid was the principal organic acid. The C16:0, C18:0, C18:1, C18:2 and C18:3 fatty acids were clearly the most abundant fatty acids, and the C18 family comprised more than 70% of the total fatty acids content. Asparagine and serine were the principal amino acids. Potassium is the most abundant mineral, followed by magnesium and calcium. The results provide important information on how to make the best use of pear cultivars investigated for different uses, which is of significance for both technological research and processing practice.     

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。     

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.