Principal component analysis (PCA) of physicochemical compounds’ content in different cultivars of peach fruits, including qualification and quantification of sugars and organic acids by HPLC

High performance liquid chromatography (HPLC) based genetic diversity profiling of chilli germplasm for fruit pungency and phytochemical contents

Chilli peppers are widely consumed for their pungency, as used in flavoring the food and has many pharmaceutical and medicinal properties. Based on these properties an experiment was held using 83 varieties of chilli (Hot pepper and sweet pepper) were grown in suitable environment using Augment Block design and evaluated for fruit pungency and phytochemical contents using high proficiency liquid chromatography. Analysis of variance (ANOVA) of traits showed highly significant for all traits except for fruit length and capsaicin contents. The value of Least significant increase (LSI)was ranged 0.27-1289.9 for all traits showed high variation among varieties. Highly significant correlation was found among fruit diameter to fruit weight 0.98, while moderate to high correlation was present among all traits. The most pungent genotype 24,634 was 4.8 g in weight, while the least pungent genotypes i.e. PPE-311 (32.8 g), green wonder (40.67) had higher in weight. The genotypes 24,627, 32,344, 32,368 and 1108 marked as higher number of seeds in their placental region. It was observed that chilli genotype 24,621 had maximum length with considerable high amount of pungency act as novel cultivar. Principal component analysis (PCA) showed the high variability of 46.97 for two PCs with the eigen value 2.6 and 1.63 was recorded. Biplot analysis showed a considerable variability for fruit pungency, while huge variability was found for all traits among given varieties. PPE-311, T5 and T3 are found as highly divergent for all traits. The findings of this study are instrumental for selecting parents to improve desirable traits in future chilli pepper breeding programs. It will help plant/vegetable breeders for development of highly nutrient and pungent varieties and attractive for the consumer of food sector.

Evaluation of the Effect of Preharvest Melatonin Spraying on Fruit Quality of 'Yuluxiang' Pear Based on Principal Component Analysis

Melatonin (MT), an indoleamine compound, has a pleiotropic effect on plant growth and development and can regulate the quality of tree fruit. Systematic research on the effect of preharvest MT spraying on pear fruit quality and technical solutions for MT application to regulate pear fruit quality are still lacking. Thus, here we aimed to evaluate the effects of different spraying times, concentrations, and exogenous MT application times on 'Yuluxiang' pear fruit quality. Our results showed that the single fruit weight and vertical and horizontal diameters of pear fruit sprayed with MT twice at 30 and 90 d after full bloom were the largest, and the red and green values of the treatment were the highest. MT-treated pears had higher contents of total soluble solids, soluble sugar, sucrose, sorbitol, fructose, and glucose and lower contents of titratable acid, malic acid, and citric acid. Moreover, exogenous MT treatment increased the pear peel strength. Based on the principal component analysis of 10 fruit quality indices, the suitable periods for MT spraying on 'Yuluxiang' pears were 30 and 90 d after full bloom, the suitable concentration was 100 μmol/L, and the suitable number of times was two. This study provides a theoretical reference for optimizing MT application and improving pear fruit quality.

Investigation into Polyphenol Profile and Biological Activities of Enriched Persimmon/Apple Smoothies during Storage

Smoothies are becoming an increasingly popular product as a healthy alternative to snacks. The consumer expects from this product that, apart from its nutritional value, it will also be qualitatively stable during storage. Therefore, in this study, original smoothies obtained with persimmon fruit puree and apple juice (Dk/Md) enriched with Arbutus unedo fruits, Myrtus communis purple berry extract, Acca sellowiana, and Crocus sativus petal juice were evaluated for their polyphenol composition, antioxidant activity, and inhibition on targeted digestive enzymes, over six months of storage. The amount of polyphenols evaluated by UPLC-PDA analysis decreased in six months from 23.5% for both Dk/Md and enriched C. sativus smoothies to 42.5% for enriched A. sellowiana, with anthocyanins the most sensitive compounds (71.7-100% loss). Values of antioxidant assays generally strongly decreased during the first three months (up to ca. 60%) and to a lesser extent in the following three months (0.4-27%). In addition, inhibitory activity on α-amylase, α-glucosidase, and pancreatic lipase, especially on the last two enzymes, was negatively affected by time storage. The outcome of this study indicates that persimmon fruit is a good option for producing smoothies, and enrichment with other plant extracts can enhance the bioactive compound content and biological activities. It is recommended that appropriate storage strategies to preserve the properties of those smoothies should be developed.

The Optimization of Medium Conditions and Auxins in the Induction of Adventitious Roots of Pokeweed (Phytolacca americana L.) and Their Phytochemical Constituents

Pokeweed, Phytolacca americana L., is considered a widely spreading invasive plant, while saponin contents accumulated in the roots have pharmaceutical uses, such as rheumatism treatments and anti-inflammation. Adventitious root cultures are an important source of diverse secondary metabolites, which have significant applications in various fields. This study focused on the optimization of parameters for root induction using different medium states and treatments with auxins on a pokeweed leaf. Semisolid and liquid MS (Murashige and Skoog, 1962) media were supplemented with indole-3-butyric acid (IBA) and 1-naphthylacetic acid (NAA) at 0.5, 1, 2, and 4 mg/L. Root growth parameters, e.g., induction percentage, root numbers, length, and weight, were measured to determine the adventitious root induction efficiency. Total phenolic content, total flavonoid content, total saponin content, and antioxidant activity were recorded. Results showed that adventitious roots induced in semisolid MS medium supplemented with 0.5 mg/L NAA exhibited a high density of lateral roots. Appropriate medium state and auxin for adventitious root induction in pokeweed were determined as semisolid medium supplemented with 2 mg/L NAA. Considering phytochemicals, adventitious roots induced in liquid medium containing 0.5-1 mg/L NAA had the highest yield extract percentage. Additionally, adventitious roots cultivated in a liquid medium enriched with 1 mg/L NAA exhibited the highest phenolic and saponin contents. A principal component analysis (PCA) biplot and hierarchical cluster analysis (HCA) heatmap demonstrated different response patterns between semisolid and liquid media applied with NAA. The results of the semisolid media were grouped together due to high expression levels of the root induction parameters, while elevated phytochemical values were observed in the liquid media treatments. The results suggested two different media that provide the highest adventitious root induction efficiency and the greatest phytochemical contents: semisolid medium with 2 mg/L NAA and liquid medium with 1 mg/L NAA, respectively. These culture media can be applied to optimize adventitious root culture of pokeweed and in vitro phytochemical production.

Inhibition of α-Amylase, α-Glucosidase, Pancreatic Lipase, 15-Lipooxygenase and Acetylcholinesterase Modulated by Polyphenolic Compounds, Organic Acids, and Carbohydrates of Prunus domestica Fruit

This work aimed to establish the content of phenolic compounds, carbohydrates, and organic acids and to determine their potential to inactivate α-amylase, α-glucosidase, pancreatic lipase, 15-lipoxygenase (15-LOX), acetylcholinesterase (AChE), and butyrylcholinesterase (BuChE), and antioxidant activity (ABTS^o+ and FRAP) in 43 Prunus domestica cultivars. We identified 20 phenolic compounds, including, in the order of abundance, polymeric procyanidins, flavan-3-ols, phenolic acids, flavonols, and anthocyanins. The total content of phenolic compounds varied depending on the cultivar and ranged from 343.75 to 1419 mg/100 g d.w. The cultivars of Ś2, Ś11, and Ś16 accumulated the greatest amounts of polyphenols, while in cvs. Ś42, Ś35, and Ś20 polyphenols were the least abundant. The highest antioxidant potential of 7.71 (ABTS^o+) and 13.28 (FRAP) mmoL Trolox/100 g d.w. was confirmed for cv. Ś11. P. domestica fruits showed inhibitory activity toward α-amylase (2.63-61.53), α-glucosidase (0.19-24.07), pancreatic lipase (0.50-8.20), and lipoxygenase (15-LOX; 4.19-32.67), expressed as IC₅₀ (mg/mL). The anti-AChE effect was stronger than the anti-BuChE one. Cv. Ś3 did not inhibit AChE activity, while cv. Ś35 did not inhibit BuChE. Thanks to the abundance of biologically active compounds, P. domestica offers several health-promoting benefits and may prevent many diseases. For these reasons, they are worth introducing into a daily diet.

Flavor Characterization of Native Xinjiang Flat Peaches Based on Constructing Aroma Fingerprinting and Stoichiometry Analysis

The flat peach is a high economic value table fruit possessing excellent quality and a unique aroma. This article investigated the quality characteristics and aroma fingerprinting of flat peaches (Qingpan, QP; Ruipan 2, R2; Ruipan 4, R4; Wanpan, WP) from Xinjiang in terms of taste, antioxidant capacity, and volatile aroma compounds using high-performance liquid chromatography (HPLC) and HS-SPME-GC-MS. The results showed that the flat peaches had a good taste and high antioxidant capacity, mainly due to the high sugar-low acid property and high levels of phenolic compounds. This study found that sucrose (63.86~73.86%) was the main sugar, and malic acid (5.93~14.96%) and quinic acid (5.25~15.01%) were the main organic acids. Furthermore, chlorogenic acid (main phenolic compound), epicatechin, rutin, catechin, proanthocyanidin B1, and neochlorogenic acid were positively related to the antioxidant activity of flat peaches. All flat peaches had similar aroma characteristics and were rich in aromatic content. Aldehydes (especially benzaldehyde and 2-hexenal) and esters were the main volatile compounds. The aroma fingerprinting of flat peaches consisted of hexanal, 2-hexenal, nonanal, decanal, benzaldehyde, 2,4-decadienal, dihydro-β-ionone, 6-pentylpyran-2-one, 2-hexenyl acetate, ethyl caprylate, γ-decalactone, and theaspirane, with a "peach-like", "fruit", and "coconut-like" aroma. Among them, 2,4-decadienal, 2-hexenyl acetate, and theaspirane were the characteristic aroma compounds of flat peaches. The results provide a theoretical basis for the industrial application of the special aroma of flat peaches.

Evaluation of Preharvest Melatonin on Soft Rot and Quality of Kiwifruit Based on Principal Component Analysis

Botryosphaeria dothidea is the source of the deadly kiwifruit disease known as soft rot. In order to explore the role of melatonin in regulating the postharvest quality and disease resistance of kiwifruit at different growth and development stages, in this study, we applied melatonin at different concentrations to kiwifruit at the young fruit, expansion, and late expansion stages to assess its effect on fruit resistance to B. dothidea, minimize soft rot, and maintain postharvest fruit quality. The results showed that melatonin significantly suppressed the mycelial growth of B. dothidea, with 1.0 mmol/L melatonin inhibiting it by up to 50%. However, 0.1–0.3 mmol/L melatonin had the best control over soft rot. Furthermore, spraying MT during kiwifruit growth can successfully increase fruit weight; preserve postharvest fruit firmness; reduce respiration intensity in the early stages of storage; delay the rise in soluble solids, while maintaining a high titratable acid content to ensure suitable solid acid ratio; increase total phenol, flavonoid, chlorophyll, carotenoid, and ascorbic acid contents; and delay the rise in soluble sugar contents in the late stages of storage. These results have a positive effect on maintaining the nutritional composition of kiwifruit. However, the effects on weight loss, dry matter content, and soluble protein content were not significant. In addition, the results of the principal component analysis demonstrated that 0.3 mmol/L MT increased kiwifruit’s resistance to soft rot while preserving postharvest fruit quality.

Antioxidant Activity and Inhibition of Digestive Enzymes of New Strawberry Tree Fruit/Apple Smoothies

In this study, original smoothies obtained with strawberry tree fruit puree and apple juice enriched with Diospyros kaki fruits, Myrtus communis purple berry extract, Acca sellowiana, and Crocus sativus petal juice were evaluated for their antioxidant activity and inhibition of targeted digestive enzymes. Values of CUPRAC, FRAP, ORAC, DPPH•, and ABTS•+ assays generally increased with plant enrichment, particularly for A. sellowiana addition (ABTS•+ 2.51 ± 0.01 mmol Trolox/100 g fw). The same trend was observed regarding the ability to scavenge reactive oxygen species (ROS) tested in Caco-2 cell cultures. Inhibitory activity on α-amylase and α-glucosidase was increased by D. kaki, M. communis, and A. sellowiana. Total polyphenols evaluated by UPLC-PDA analysis ranged between 535.75 ± 3.11 and 635.96 ± 5.21 mg/100 g fw, and A. sellowiana provided the higher amount. Flavan-3-ols accounted for more than 70% of phenolic compounds, and only smoothies enriched with C. sativus showed a high amount of anthocyanins (25.12 ± 0.18 mg/100 g fw). The outcome of this study indicates these original smoothies as a possible ally in counteracting oxidative stress, as established by their favourable antioxidant compound profile, thus suggesting an interesting future application as nutraceuticals.

Comparative network analysis reveals the dynamics of organic acid diversity during fruit ripening in peach (Prunus persica L. Batsch)

BACKGROUND

Organic acids are important components that determine the fruit flavor of peach (Prunus persica L. Batsch). However, the dynamics of organic acid diversity during fruit ripening and the key genes that modulate the organic acids metabolism remain largely unknown in this kind of fruit tree which yield ranks sixth in the world.

RESULTS

In this study, we used 3D transcriptome data containing three dimensions of information, namely time, phenotype and gene expression, from 5 different varieties of peach to construct gene co-expression networks throughout fruit ripening of peach. With the network inferred, the time-ordered network comparative analysis was performed to select high-acid specific gene co-expression network and then clarify the regulatory factors controlling organic acid accumulation. As a result, network modules related to organic acid synthesis and metabolism under high-acid and low-acid comparison conditions were identified for our following research. In addition, we obtained 20 candidate genes as regulatory factors related to organic acid metabolism in peach.

CONCLUSIONS

The study provides new insights into the dynamics of organic acid accumulation during fruit ripening, complements the results of classical co-expression network analysis and establishes a foundation for key genes discovery from time-series multiple species transcriptome data.

Effect of Apple Juice Enrichment with Selected Plant Materials: Focus on Bioactive Compounds and Antioxidant Activity

Using a multi-analytical approach, this paper aimed to investigate the effect of apple juice enrichment with Arbutus unedo and Diospyros kaki fruits, Myrtus communis berry extract, Acca sellowiana, or Crocus sativus flower by-products on both bioactive compounds content and antioxidant activity. Physico-chemical parameters, vitamin C, sugars, organic acids, total polyphenol content, antioxidant activity, and sensory attributes were evaluated. An LC-PDA/MS QTof analysis allowed for the identification of 80 different phenolic compounds. The highest polyphenol content (179.84 and 194.06 mg of GAE/100 g fw) and antioxidant activity (CUPRAC, 6.01 and 7.04 mmol of Fe²⁺/100 g fw) were observed in products with added A. sellowiana and D. kaki, respectively. Furthermore, the study showed a positive correlation between polymeric procyanidins and antioxidant activity (0.7646-0.8539). The addition of A. unedo fruits had a positively significant influence on the increment of vitamin C (23.68 ± 0.23 mg/100 g fw). The obtained products were attractive to consumers, especially those with 0.1% C. sativus flower juice, M. communis berry extract, and persimmon D. kaki fruits. The synergy among the different analytical techniques allowed us to obtain a complete set of information, demonstrating that the new apple smoothies were enriched in both different beneficial molecules for human health and in antioxidant activity.

Improving berry quality and antioxidant ability in 'Ruidu Hongyu' grapevine through preharvest exogenous 2,4-epibrassinolide, jasmonic acid and their signaling inhibitors by regulating endogenous phytohormones

Grape berries contain a variety of metabolites, such as anthocyanins, sugars, fatty acids, and antioxidants. Endogenous phytohormones strongly influence these metabolites, which regulate berry quality improvement. In this study, we evaluated the effects of 2,4-epibrassinolide (EBR, brassinolide (BR)-like growth regulator), jasmonic acid (JA), and their signaling inhibitors brassinazole (Brz), and sodium diethyldithiocarbamate (DIECA) on berry quality and antioxidant ability. Overall, the pre-harvest application of 0.5 mg L^-1 EBR and 100 μmol L^-1 JA significantly influences the quality of the grape berry. Results showed that EBR was superior to other treatments at enhancing the content of different metabolites, including anthocyanins, fructose, glucose, and a variety of fatty acids, in grapes. EBR and JA also enhanced the synthesis of gibberellin₃ (GA₃), cytokinin (CTK), salicylic acid (SA), JA, methyl jasmonate (MeJA), BR, and abscisic acid (ABA), while inhibiting the synthesis of auxin (IAA). Most genes related to BR/JA and anthocyanins/sugars/fatty acids biosynthesis were up-regulated. The effects of Brz and DIECA on the grape berry quality were totally reversed throughout the study, as shown by EBR and JA. According to correlation analysis, EBR and JA have a beneficial positive interaction that promotes the formation of strong coherences in grape berries between ABA/IAA/ZT-fruit expansion, BR/JA/MeJA/GA₃/ZR-biochemical characteristics development, JA/MeJA/ABA/GA₃/SA/ZR-antioxidant capacity enhancement, and JA/MeJA/IAA/GA₃/ZT/ZR-fatty acids accumulation. In this regard, we concluded that preharvest exogenous 0.5 mg L^-1 EBR and 100 μmol L^-1 JA is a successful way to improve grape berry quality.

Enhancing the Antioxidant Ability of Momordica grosvenorii Saponin to Resist Gastrointestinal Stresses via Microcapsules of Sodium Alginate and Chitosan and Its Application in Beverage

Momordica grosvenorii saponin (MGS), as a promising dietary supplement with remarkable biological properties, has poor stability under acidic conditions and thus hinders its application in functional foods. In this study, capsules of chitosan and sodium alginate were successfully prepared to enhance the stability of MGS. The optimized parameters for preparing MGS capsules were established. Sodium alginate of 20.8 mg/mL and triplication of MGS powder were added to chitosan of 4 mg/mL and calcium chloride of 10 mg/mL at a volume ratio of 3:1, stirring at 1000 r/min for 30 min to form the capsules. In this case, the fresh particles averaged 1687 μm with an encapsulation efficiency (EE) of 80.25% MGS. The capsule tolerated acidic environments better, and in vitro MGS could be controlled to release in a stimulated gastrointestinal tract system. The antioxidant activity and delayed release of MGS could be achieved by microencapsulation of chitosan/sodium alginate. Moreover, one drink containing 19 mg/mL MGS was successfully developed for the fruit.

Carotenoid Profiling of Yellow-Flesh Peach Fruit

In this study, the carotenoid profiles and content in 132 cultivars of yellow-flesh peach having different fruit developmental periods (short, middle, and long), fruit surface indumenta (glabrous and pubescent skin), and flesh colors (yellow, golden, and orange) were investigated. We simultaneously analyzed and compared the levels of five carotenoids (lutein, zeaxanthin, β-cryptoxanthin, α-carotene, and β-carotene) through high-performance liquid chromatography. Large differences in carotenoid content among germplasms were observed, with coefficients of variation ranging from 21.24% to 67.78%. The carotenoid content, from high to low, was as follows: β-carotene > zeaxanthin > α-carotene > β-cryptoxanthin > lutein. We screened several varieties with high carotenoid content, including zeaxanthin in ‘Ruiguang2’, β-cryptoxanthin in ‘NJN76’ and ‘TX4F244C’, and β-carotene and total carotenoids in ‘Jintong7’, ‘77-26-7’, and ‘77-20-5’. A longer fruit developmental period was associated with greater β-carotene accumulation but lowered the zeaxanthin and β-cryptoxanthin accumulation. The zeaxanthin, β-carotene, and total carotenoid concentrations significantly increased as the flesh color deepened, but the lutein and α-carotene levels remained similar among the three flesh colors. The classification index of the indumenta significantly affected the β-carotene and total carotenoid content (p < 0.05) and was higher in pubescent than glabrous skin.

Quality Characteristics and Inhibitory Xanthine Oxidase Potential of 21 Sour Cherry (Prunus Cerasus L.) Varieties Cultivated in China

This study aims to analyze the physicochemical characteristics and activities of 21 sour cherry cultivars in China. The evaluated accessions differ in several quality traits including weight, moisture, color, total soluble solids, and total acids. Glucose and malic acid were the predominant individual sugar and organic acid in all accessions. The potassium (K) and iron (Fe) were of the highest contents in Érid jubileum (453.887 mg/100 g FW) and Meili (2.988 mg/100 g FW), respectively. The contents of total phenolics (TP) were from 9.309 to 24.118 mg GAE/g DW, and total flavonoids (TF) were 8.935–27.198 mg RE/g DW, which were highly positively correlated (r = 0.892, p < 0.001). M-15, Érdi fubileum, and Érid jubileum showed the highest inhibitory effects on xanthine oxidase, and the IC₅₀ inhibitory were 2.619, 3.117, and 3.940 mg/ml, respectively. This work evaluated the quality and nutritional characteristics of 21 sour cherry cultivars grown in China and explored their potential as an innovative food ingredient for hyperuricemia by evaluating the inhibitory effects of xanthine oxidase. And these results provide valuable data and new ideas for the future sour cherry breeding program as well as a processing guide.

Determination of Selected Beneficial Substances in Peach Fruits

Peaches (Prunus persica L.) are a popular and sought-after dessert fruit. This is mainly due to their flavour, aroma, attractive appearance, and high content of substances that play an important role in human nutrition. The present study was carried out to determine some important analytical properties (sugars/sucrose, glucose, fructose and sorbitol), total acid, total phenolics, flavonoids, antioxidant capacity, carotenoids and anthocyanins of 34 selected peach varieties. The analyses are also complemented by colorimetric measurements of peach skin colour using CIELAB and other chromatic parameters. The results show, for example, that all peach varieties are good sources of phenolic compounds (9.43–577 mg gallic acid equivalent (GAE).100 g−1), flavonoids (1.12–95.1 mg catechin equivalent (CAE).100 g−1), and antioxidant capacity (136–462 mg Trolox equivalent (TE).100 g−1).

The changes of physicochemical properties, antioxidants, organic, and key volatile compounds associated with the flavor of peach (Prunus cerasus L. Batsch) vinegar during the fermentation process

Peach is a delicious food preferred by consumers and widely used in the manufacture of peach juice, peach juice concentrate, peach jam, dried fruit, puree, etc. Alternatively, peach can be used in the production of vinegar. In this study, peach vinegar was produced as an alternative to other industrial products produced from peach. In this study, it was determined that the TPC content and ORAC value of peach vinegar were higher than those of peach juice and peach wine. In addition, the major contributor compounds to the aroma profiles of the samples were the γ-decalactone, linalool, and geraniol compounds for the peach juice; the ethanol, ɣ-decalactone, phenylacetic acid, acetic acid, 2-phenylethanol, ethyl decanoate, the linalool, and the decanoic-acid for the peach wine; and the ɣ-decalactone, phenylacetic acid, acetic-acid, phenethyl-acetate, and isovaleric acid for the peach vinegar. It is thought that the results of this study will pave the way for the widespread production of vinegar from peach, which has positive effects on health, is rich in volatile aroma components, and has a high potential to be preferred. Furthermore, this study is the first detailed study so far on peach vinegar. PRACTICAL APPLICATIONS: In this study, it was aimed to produce vinegar as a new and alternative foodstuff product from peach fruit which was normally processed as fresh or/ dried fruit, fruit juice, puree, and canned fruit by the industry. An alternative idea was created for the use of peach fruit, which has a short shelf life. In the study, the antioxidant capacity, organic compounds, and volatile compounds associated with aroma profile of peach vinegar during the fermentation process were determined. Moreover, the changes of these compounds were monitored during the fermentation process. The results of the study are a guide for the usability of peach fruit as a raw material in the production of peach vinegar, which has potentially positive effects on health, is rich in volatile aroma components, and has a high potential to be preferred. Furthermore, this study is the first detailed study on peach vinegar.

Evaluation indicators of Ruditapes philippinarum nutritional quality

To access the nutritional quality of the Ruditapes philippinarum, a comprehensive quality evaluation procedure is always important to be established. In this study, fifteen nutritional quality evaluation indicators of R. philippinarum from 7 months were analyzed, and the most important indicators were determined using a combination of multiple chemometric methods such as correlation analysis (CA), principal component analysis (PCA), and system cluster analysis (SCA). Significant differences in nutritional quality were observed across the 7 months, as per the ANOVA results (P < 0.05). The coefficient of variation values for the fifteen evaluation indicators for R. philippinarum across 7 months was 1.67-43.47%. The CA results revealed that some indicators were correlated to each other within a certain range. Four principal components with eigen-values > 1 were obtained with PCA, and a cumulative contribution of 92.11% was achieved. In addition, four essential quality indicators were extracted using SCA. Using these four indicators, a simple and efficient procedure can be applied for quality control in aquaculture.

Identifying sources of metabolomic diversity and reconfiguration in peach fruit: taking notes for quality fruit improvement

The metabolomic content determines many of the important features of a fruit, such as its taste, flavor, color, nutritional value, and abiotic or biotic resistance. Peach (Prunus persica (L.) Batsch) is one of the best genetically characterized species used as a model for Rosaceae, the drupes of which are a source of minerals, vitamins, fiber, and antioxidant compounds for healthy diets around the world. During the last few years, a great advance in the analysis of the metabolic diversity and reconfiguration in different peach varieties in response to developmental and environmental factors has occurred. These studies have shown that the great phenotypic diversity among different peach varieties is correlated with differential metabolomic content. Besides, the fruit metabolome of each peach variety is not static; on the contrary, it is drastically configured in response to both developmental and environmental signals, and moreover, it was found that these metabolic reconfigurations are also variety dependent. In the present review, the main sources of metabolic diversity and conditions that induce modifications in the peach fruit metabolome are summarized. It is postulated that comparison of the metabolic reconfigurations that take place among the fruits from different varieties may help us better understand peach fruit metabolism and their key drivers, which in turn may aid in the future design of high‐quality peach fruits.

Differentiation of peach cultivars by image analysis based on the skin, flesh, stone and seed textures

The peaches belonging to different cultivars can be characterized by differentiation in properties. The aim of this study was to evaluate the usefulness of individual parts of fruit (skin, flesh, stone and seed) for cultivar discrimination of peaches based on textures determined using image analysis. Discriminant analysis was performed using the classifiers of Bayes net, logistic, SMO, multi-class classifier and random forest based on a set of combined textures selected from all color channels R, G, B, L, a, b, X, Y, Z and for textures selected separately for RGB, Lab and XYZ color spaces. In the case of sets of textures selected from all color channels (R, G, B, L, a, b, X, Y, Z), the accuracy of 100% was observed for flesh, stones and seeds for selected classifiers. The sets of textures selected from RGB color space produced the correctness equal to 100% in the case of flesh and seeds of peaches. In the case of Lab and XYZ color spaces, slightly lower accuracies than for RGB color space were obtained and the accuracy reaching 100% was noted only for the discrimination of seeds of peaches. The research proved the usefulness of selected texture parameters of fruit flesh, stones and seeds for successful discrimination of peach cultivars with an accuracy of 100%. The distinguishing between cultivars may be important for breeders, consumers and the peach industry for ensuring adequate processing conditions and equipment parameters. The cultivar identification of fruit by human may be characterized by large errors. The molecular or chemical methods may require special equipment or be time-consuming. The image analysis may ensure objective, rapid and relatively inexpensive procedure and high accuracy for peach cultivar discrimination.

Physicochemical quality and metabolomics comparison of the green food apple and conventional apple in China

The Green Food apple production has increased rapidly in China recently, due to its sustainability and high-quality compared to the conventional apple. The aim of this study was evaluating and comparing physicochemical quality as well as metabolomics of the apples grown in green certified and conventional production systems. The results of physicochemical properties indicated that Green Food apples showed significant superiorities than conventional ones at soluble solids content, firmness and titratable acidity. While, in the vitamin C content comparison, there was no significant difference. Compounds, including several phenolic compounds and fatty acids, were revealed by the untargeted metabolomics as differential markers between apples grown in the two production systems, and could serve as the potential markers for differentiating these two types of apples. Overall, these results of this study could encourage the Green Food apples consumption, promote its production, and will benefit the development of Green Food production and the cleaner agricultural production in China.

Comparative Study of Early- and Mid-Ripening Peach (Prunus persica L.) Varieties: Biological Activity, Macro-, and Micro- Nutrient Profile

Exploring the chemical composition and biological activity of different fruit varieties is essential for the valorization of their health claims. The current study focuses on a detailed comparative analysis of three early- and two mid-ripening peach varieties: “Filina” (peach), “July Lady” (peach), “Laskava” (peach), “Gergana” (nectarine), and “Ufo 4” (flat peach). They were characterized in terms of essential nutrients such as carbohydrates (sugars and dietary fibers), amino acid content, and lipids as well as mineral content, fat-soluble vitamins, carotenoids, and chlorophyll. Polyphenolic compounds and the related antioxidant activity were also assessed. The methanolic extract of the peel seems to be richer in the studied biologically active substances compared to the fleshy part of the fruit. Anthocyanins were most abundant in “Gergana” and “July Lady” extracts (6624.8 ± 404.9 and 7133.6 ± 388.8 µg cyanidin-3-glucoside/100 g fw, resp.). The total phenol content of the samples varied from 34.11 ± 0.54 to 157.97 ± 0.67 mg gallic acid equivalents (GAE)/100 g fw. “Filina” and “July Lady” varieties possessed the highest antioxidant activity. Overall, the results of this study confirm that the studied peach varieties have satisfactory nutritional value and are potential sources of biologically active substances. Each variety represents an individual palette of nutrients that should be considered separately from the other.

Exogenous Abscisic Acid Mediates Berry Quality Improvement by Altered Endogenous Plant Hormones Level in "Ruiduhongyu" Grapevine

Abscisic acid (ABA) plays a key role in fruit development and ripening in non-climacteric fruit. A variety of metabolites such as sugars, anthocyanins, fatty acids, and several antioxidants, which are regulated by various phytohormones, are important components of fruit quality in grape. Here, grape cultivar "Ruiduhongyu" was used to investigate the relationship between endogenous phytohormones and metabolites associated to grape berry quality under exogenous ABA treatment. 500 mg/L ABA significantly improved the appearance parameters and the content of many metabolites including sugar, anthocyanin, and other compounds. Exogenous ABA also increased the contents of ABA, auxin (IAA), and cytokinins (CTKs), and transcription level of ABA biosynthesis and signaling related genes in fruit. Furthermore, a series of genes involved in biosynthesis and the metabolite pathway of sugars, anthocyanins, and fatty acids were shown to be significantly up-regulated under 500 mg/L ABA treatment. In addition, Pearson correlation analysis demonstrated that there existed relatively strong cooperativities in the ABA/kinetin (KT)-appearance parameters, ABA/IAA/KT-sugars, ABA/indolepopionic acid (IPA)/zeatin riboside (ZR)-anthocyanins, and gibberellin 3 (GA₃)/methyl jasmonate (MeJA)-fatty acids, indicating that 13 kinds of endogenous phytohormones induced by ABA had different contributions to the accumulation of quality-related metabolites, while all of them were involved in regulating the overall improvement of grape fruit quality. These results laid a primary foundation for better understanding that exogenous ABA improves fruit quality by mediating the endogenous phytohormones level in grape.

Anti-diabetic, anti-cholinesterase, and antioxidant potential, chemical composition and sensory evaluation of novel sea buckthorn-based smoothies

Sea buckthorn berries fit into the strategy of seeking natural factors in the non-communicable diseases prevention, but their sensory qualities are a challenge for consumers and food industry. The study aimed to evaluate anti-cholinesterase (anti-acetylcholinesterase and -butylcholinesterase), anti-diabetic (anti-α-amylase, -α-glucosidase, -pancreatic lipase) and antioxidant potential (FRAP, ORAC), phenolic compounds (UPLC-PDA-FL), basic chemical composition, and sensory quality of sea buckthorn-based smoothies. Eighteen novel products containing sea buckthorn (25-50%) with other fruits and vegetables were analyzed. Sea buckthorn enriched the smoothies in flavonols (25.46-95.13 mg/100 g), and fruits and vegetables provided phenolic acids and procyanidins. The anti-BuChE effect was higher than anti-AChE, while products with apricot, orange, grape and parsley root were strong inhibitors of carbohydrates digesting enzymes. Lipase inhibition by all smoothies was over 50%. Products with 75% fruits or 50% vegetables were the most sensory attractive. The results will be valuable in designing innovative food with rarely used berries.

Profiles of Sugar and Organic Acid of Fruit Juices: A Comparative Study and Implication for Authentication

A comparison of sugar and organic acid profiles among different fruit juices (including apple, pear, peach, grape, sweet cherry, strawberry, and blueberry with various varieties) was performed to assess the possibility for authentication coupled with chemometrics. It was found that the distribution of each sugar and organic acid in juices showed some specific characteristics related to fruit species, despite the fact that great differences in the content existed among different varieties. Sucrose was the most abundant sugar in peach juice, accounting for 58.26–77.11% of the total sugar content. However, in grape, blueberry, and sweet cherry juice, glucose and fructose were the predominant sugars. Pear juice contained the highest level of sorbitol, which contributed to 15.02–43.07% of the total sugar content. Tartaric acid was detected only in grape juice among the seven species of fruit juice, with a proportion of 57.95–89.68% in the total acid content. Malic acid was the predominant organic acid in apple and sweet cherry juice, accounting for 69.92–88.30% and 97.51–98.73% of the total acid content of each species. Citric acid was the predominant organic acid in strawberry and blueberry juice, which contributed to 62.39–83.73% and 73.36–89.56% of the total acid content of each species. With the aid of principal component analysis and linear discriminant analysis (LDA), the juice samples could be successfully classified according to fruit species by using the sugar and/or organic acid composition as analytical data. Combination of sugar and organic acid composition gave the best differentiation of these seven species of juices, with a 100% correct classification rate for both the original and the cross-validation method in LDA. Adding malic/citric into the dataset of the organic acid content may also improve the differentiation effect. Furthermore, the adulteration of sweet cherry juice, blueberry juice, raspberry juice, and grape juice with apple juice, pear juice, or peach juice could also be distinguished from their corresponding pure juices based on sugar and organic acid composition by LDA.

Assessment of organic acid accumulation and its related genes in peach

Fruit acidity is an important determinant of peach organoleptic quality, but its regulatory mechanism remains elusive. Measurement of organic acids in ripe fruits of seventy-five peach cultivars revealed the predominant components malate and citrate, accompanied by quinate. Organic acid accumulation increased at early stages of fruit growth, but exhibited a more dramatic reduction in low-acid cultivar during later stages of fruit development compared to high-acid cultivars. Low-acid cultivars showed citrate degradation and less transport of malate into the vacuole due to up- and down-regulation of a GABA pathway gene GAD and a malate transporter gene ALMT9, respectively. The NAD-MDH1 gene might control the rate-limiting step in malate synthesis, while three genes, PDK, PK, and ADH, could affect citrate synthesis through the pyruvate-to-acetyl-CoA-to-citrate pathway. Altogether, these results suggested that malate accumulation is controlled at the level of metabolism and vacuolar storage, while metabolism is crucial for citrate accumulation in peach.