Study on the spatial specificity of phenolics in fruit of different jujube varieties.

Phenol, an important bioactive substance in jujube fruit, is one of the most important indexes of fruit quality. In order to clarify the phenolic substance composition, content and distribution characteristics of different varieties of jujube fruits, this study measured and compared the content of total phenols, total flavonoids and phenolic substance composition in different parts of fruits of six jujube varieties, and combined with the principal component analysis, the results showed that: Fourteen phenolic substances were identified in the fruits of different jujube varieties, and proanthocyanidins, epicatechin, catechin and rutin were the main components, accounting for 58.60%, 16.08%, 13.56% and 5.57% of the total phenolic substances, respectively. The total phenolic and total flavonoid contents of jujube fruits of each variety were between 18.11 and 21.45 mg GAE/g DW and 10.56-20.25 mg RE/g DW, respectively, and the differences in the contents between the varieties were significant, and the contents of 'Junzao' and 'Jinlingyuanzao' were higher than those of other varieties.The phenolic content of different parts of jujube fruits showed spatial distribution differences, manifested as the total phenols, total flavonoids and their fractions of the peel were significantly higher than that of the pulp, while the content of the pulp near the kernel was significantly higher than that of other parts of the pulp, This study provides a theoretical basis for analysing the differences in phenolic substances in jujube fruits.

Drought stress in 'Shine Muscat' grapevine: Consequences and a novel mitigation strategy-5-aminolevulinic acid.

Drought is a common and serious abiotic stress in viticulture, and it is urgent to select effective measures to alleviate it. The new plant growth regulator 5-aminolevulinic acid (ALA) has been utilized to alleviate abiotic stresses in agriculture in recent years, which provided a novel idea to mitigate drought stress in viticulture. The leaves of 'Shine Muscat' grapevine (Vitis vinifera L.) seedlings were treated with drought (Dro), drought plus 5-aminolevulinic acid (ALA, 50 mg/L) (Dro_ALA) and normal watering (Control) to clarify the regulatory network used by ALA to alleviate drought stress in grapevine. Physiological indicators showed that ALA could effectively reduce the accumulation of malondialdehyde (MDA) and increase the activities of peroxidase (POD) and superoxide dismutase (SOD) in grapevine leaves under drought stress. At the end of treatment (day 16), the MDA content in Dro_ALA was reduced by 27.63% compared with that in Dro, while the activities of POD and SOD reached 2.97- and 5.09-fold of those in Dro, respectively. Furthermore, ALA reduces abscisic acid by upregulating CYP707A1, thus, relieving the closure of stomata under drought. The chlorophyll metabolic pathway and photosynthetic system are the major pathways affected by ALA to alleviate drought. Changes in the genes of chlorophyll synthesis, including CHLH, CHLD, POR, and DVR; genes related to degradation, such as CLH, SGR, PPH and PAO; the RCA gene that is related to Rubisco; and the genes AGT1 and GDCSP related to photorespiration form the basis of these pathways. In addition, the antioxidant system and osmotic regulation play important roles that enable ALA to maintain cell homeostasis under drought. The reduction of glutathione, ascorbic acid and betaine after the application of ALA confirmed the alleviation of drought. In summary, this study revealed the mechanism of effects of drought stress on grapevine, and the alleviating effect of ALA, which provides a new concept to alleviate drought stress in grapevine and other plants.

Effect of Winemaking on Phenolic Compounds and Antioxidant Activities of Msalais Wine.

Msalais wine (MW) is a popular traditional wine with the cultural characteristics of a specific Chinese ethnic group. In this study, phenolic profiles and antioxidant characteristics were identified using chromatographic analysis. A total of thirty-eight compounds, including eight furans, eleven phenolic acids, fourteen flavonoids, and five others, were identified via LC-MS/QTOF. It was found that catechin is the most abundant phenolic compound in MW, followed by epicatechin, gallic acid, caffeic acid, rutin, and p-coumaric acid. Winemaking had a significant influence on the levels of phenols and antioxidant activity. Condensed juice (CJ) displayed the highest phenol and antioxidant activity levels, while the levels were significantly decreased during the fermentation process and gradually stabilized thereafter during the aging process. A correlation analysis between the polyphenols in Msalais and their antioxidant capacity was performed to determine which molecules contributed more to the antioxidant capacity in a complex mixture of polyphenols. All of the phenolic compounds, except ferulic acid, showed good correlation with DPPH, ABTS, and CUPRAC. Among them, resveratrol had the strongest antioxidant capacity, although its concentration was very low. Catechin also had a strong antioxidant capacity, which was positively correlated with its concentration. This indicates that the antioxidant activity of Msalais is related to the number, type, and structure of polyphenols.

Antioxidative, cytoprotective and whitening activities of fragrant pear fruits at different growth stages.

Pear is one of the most popular fruits in the world. With the fruit ripening, a series of physiological changes have taken place in fragrant pear, but up to now, the research on the metabolism and biological activity of phenolic compounds in different growth stages of fragrant pear is still lacking. In this study, four kinds of Xinjiang pears were selected as research objects, and the changes of phenolic content, antioxidant capacity, cell protection and whitening activity during fruit development were analyzed. The results showed that the phenolic content and antioxidant capacity of four pear varieties presented a decreasing trend throughout the developmental stages. The phenolic content and antioxidant activity of the four pears in the young fruit stage were the highest, and the active ingredients of the Nanguo pear were higher than the other three pear fruits. Pear extract could protect cells by eliminating excessive ROS in cells, especially in young fruit stage. The western blot results showed that the extract of fragrant pear in the young fruit stage could inhibit the expression of TYR, TYR1 and MITF in B16 cells, and it was speculated that the extract of fragrant pear in the young fruit stage might have good whitening activity. Therefore, the findings suggest that young pear display a good antioxidant potential and could have a good application prospect in food preservation and health product industry.

Evolution of nonenzymatic browning during the simulated Msalais-production process in models of grape juice.

Msalais is a wine fermented from boiled grape juice. Nonenzymatic browning (NEB) greatly affects the quality of Msalais, but to date its mechanism has not been systematically analyzed. In the current study, the evolution of NEB during Msalais production was investigated using models of grape juice. 5-Hydroxymethylfurfural (5-HMF), browning index (BI), yellowness index (YI), sample absorbance at 420 (A420), and b* increased during heating, with a clear transition point at 110 min. The Maillard reaction (MR) was the major contributor to NEB. Vitamin C (VC) facilitated NEB in the late stage of heating. During heating that lasted over 130 min, glucose contributed to NEB more than fructose, while the reverse was true for heating lasting less than 130 min. Proline (Pro) was the most important amino acid in facilitating NEB. BI and A420 decreased during fermentation, while increasing slightly during wine storage. In conclusion, this study identified the evolution of NEB during the Msalais process, which will facilitate the control of traditional Msalais production for improved wine quality.

Conjugation of soy protein isolate (SPI) with pectin: effects of structural modification of the grafting polysaccharide.

Recently, there has been a great interest in enhancing the emulsifying properties of soy protein isolate (SPI) by Maillard reaction. As a commonly-used grafting polysaccharide, pectin has proved useful in modifying proteins. However, effects of its structural characteristics on conjugation are still not fully understood. To address this problem, we employed alkaline or/and enzymatic treatments to modify pectin and obtained three modified samples. Structural characteristics of pectin, including the molecular weight, degree of methoxylation and acetylation, and monosaccharide compositions were measured. When conjugated with SPI, pectin with lower molecular weight and less main chains induced higher conjugate yield. Fluorescence intensity and surface hydrophobicity of all conjugates markedly reduced compared to the original SPI, suggesting a more loosened protein structure after Maillard reaction. In this study, the enzymolysis pectin proved an optimum grafting polysaccharide considering the simple preparation procedures and the highest emulsifying properties of its resulting conjugates.

Physicochemical and antioxidant activity of fruit harvested from eight jujube (Ziziphus jujuba Mill.) cultivars at different development stages.

Jujube is a crop highly resistant to drought and salinity, making it one of the main fruit trees in Xinjiang. The present study evaluated the changes in the physicochemical and antioxidant activities of jujube fruit of eight different cultivars from Xinjiang, China. The developmental stages were selected according to the days after full bloom and fruit peel colour during ripening; these stages included young (S1), fruit core-hardening (S2), green ripening (S3), half-red maturity (S4) and complete red. In present study, different cultivars of jujube fruit showed similar chemical profiles, but their amounts showed great variation. HZ had the highest content of sugars, and JY had the highest content of cAMP and cGMP, while relatively higher levels of ascorbic acid, catechin, epicatechin, rutin, proanthocyanidin and antioxidant activity were found in 'FS' than in other cultivars, indicating that 'FS' could be used as a potential natural antioxidant. Regarding the development stages of jujube fruit, the moisture, ascorbic acid, total polyphenol, catechin, epicatechin, proanthocyanidin and rutin contents decreased during the development of all jujube cultivars, while the fructose, glucose, sucrose, cAMP, and cGMP contents greatly increased. The antioxidant activity determined by DPPH and ABTS radical scavenging decreased as the fruits matured. Therefore, the results suggest that green jujube (S1) could be used for natural antioxidants (catechin, epicatechin, proanthocyanidin) and that the advanced ripening stage(S5) is the proper picking period for fresh fruit and commercial processing.

High-intensity ultrasound processing of baobab fruit pulp: Effect on quality, bioactive compounds, and inhibitory potential on the activity of α-amylase and α-glucosidase.

Effect of high-intensity ultrasound (HIU) compared with thermal treatments on baobab fruit pulp (BFP) quality and bioactive properties were investigated. HIU treatments, particularly at intensities of 687.5 W/cm2 for 5 min, and 344 W/cm2 for 15 min significantly (p < 0.05) increased the cloudiness index, ascorbic acid (AA) retention, total phenolic and flavonoid contents, and antioxidant capacity besides a more potent α-amylase and α-glucosidase inhibition relative to thermally treated samples. Moreover, the physicochemical parameters, colour index, and browning index were maintained with HIU besides lower 5-hydroxymethylfurfural values than thermal processing. HPLC analysis revealed that the content of most phenolic compounds was the highest in HIU treatments besides a 235-256% increase in procyanidin C1 compared with control samples. The AA retention following HIU treatments was 87.62-102.86% compared to 30.47-61.90% in thermally treated samples. Our analyses portrayed ultrasound as a feasible alternative to conventional thermal processing of BFP.

Ultrasound-assisted adsorption/desorption for the enrichment and purification of flavonoids from baobab (Adansonia digitata) fruit pulp.

This work described the purification and enrichment of flavonoids from baobab (Adansonia digitata) fruit pulp (BFP) by ultrasound-assisted adsorption/desorption procedure using macroporous resins. Four resins were tested and HPD-500 polar resin exhibited the best adsorption/desorption properties. Based on preliminary experiments and literature reports, the effects of various ultrasonic conditions including high power short time (HPST, 540 W for 5 min), medium power medium time (MPMT, 270 W for 15 min) and low power long time (LPLT, 45 W for 30 min) as well as different temperatures (T = 25-45 °C) on the adsorption of Total Flavonoids Content (TFC) were investigated in comparison with orbital shaking/no sonication (NS). Also, the effect of ultrasound on the desorption capacity and recovery of TFC was determined at different concentrations of ethanol (30-100%). Remarkably, ultrasonic treatment significantly increased the adsorption/desorption capacity and recovery and shortened the equilibrium time. The pseudo-second-order kinetic and Freundlich isotherm models better delineated the adsorption process under ultrasound. Moreover, the adsorption process was both spontaneous and thermodynamically favourable with physical adsorption and multilinear intraparticle diffusion being the predominant mechanisms of the whole process. HPST treatment at 25 °C with 80% ethanol as the desorption solvent most noticeably enhanced the adsorption/desorption of flavonoids and contributed to the highest recovery of TFC, Total Phenolic Content (TPC), and antioxidant capacity in addition to a 5-8-fold reduction in total sugar and acid contents when compared with NS treatment. Moreover, HPLC analysis revealed that the content of nine out of thirteen phenolic compounds from the HPST treatment was the highest, and the individual flavonoids content increased by 2-3-fold compared with the other treatments. Our analyses suggested that ultrasound can be employed as a practical approach to intensify the adsorption and desorption of functional compounds in BFP.

Comparative study of DAM, Dof, and WRKY gene families in fourteen species and their expression in Vitis vinifera.

Bud dormancy is one of the most important defensive mechanisms through which plants resist cold stress during harsh winter weather. DAM, Dof, and WRKY have been reported to be involved in many biological processes, including bud dormancy. In the present study, grapevine (Vitis vinifera) and other thirteen plants (six woody plants and seven herbaceous plants) were analyzed for the quantity, sequence structure, and evolution patterns of their DAM, Dof, and WRKY gene family members. Moreover, the expression of VvDAM, VvDof, and VvWRKY genes was also investigated. Thus, 51 DAM, 1,205 WRKY, and 489 Dof genes were isolated from selected genomes, while 5 DAM, 114 WRKY, and 50 Dof duplicate gene pairs were identified in 10 genomes. Moreover, WGD and segmental duplication events were associated with the majority of the expansions of Dof and WRKY gene families. The VvDAM, VvDof, and VvWRKY genes significantly differentially expressed throughout bud dormancy outnumbered those significantly differentially expressed throughout fruit development or under abiotic stresses. Interestingly, multiple stress responsive genes were identified, such as VvDAM (VIT_00s0313g00070), two VvDof genes (VIT_18s0001g11310 and VIT_02s0025g02250), and two VvWRKY genes (VIT_07s0031g01710 and VIT_11s0052g00450). These data provide candidate genes for molecular biology research investigating bud dormancy and responses to abiotic stresses (namely salt, drought, copper, and waterlogging).

Characterizing the phenolic constituents of baobab (Adansonia digitata) fruit shell by LC-MS/QTOF and their in vitro biological activities.

Baobab (Adansonia digitata) fruit is a part of the baobab tree, a revered multi-purpose tree native to Africa with a myriad of potentials in providing shelter, food, medicine, clothing and as a valuable source of natural antioxidants. A massive quantity of baobab fruit shells (BFS) is generated as a waste from the baobab fruit processing representing significant economic and environmental challenges at the same time an opportunity for its valorization and commercial utilization. The present study explored the potentials of BFS as a source of phenolic compounds. For this purpose, the phenolic constituents of BFS were identified by LC-MS/QTOF analysis. Also, the Total Phenolic Chromatographic Index (TPCI), TPC, TFC, and antioxidant capacity were compared with the baobab seeds and pulp. The antidiabetic potential through α-amylase and α-glucosidase inhibitory activities was also compared with that of acarbose. The LC-MS/QTOF analysis led to the identification of 45 compounds, including quercetin, kaempferol, proanthocyanidins, phenolic acids and their derivatives, several of which had never been reported in baobab fruit. Moreover, the BFS showed higher TPC, TFC, and antioxidant capacity than the baobab seeds and pulp and inhibited α-amylase and α-glucosidase enzymes activities with much higher potency than acarbose. This research demonstrated the promising potentials of BFS as a good source of phenolic compounds that can further be utilized for food and pharmaceutical applications.

Ultrasound-assisted thawing of mango pulp: Effect on thawing rate, sensory, and nutritional properties.

Sensory and nutritional properties of mango pulp thawed by different ultrasound intensities and temperatures were studied. Compared to water immersion thawing, a thawing time reduction of 16-64% (p < 0.05) and more phenolic acids contents (gallic, hydroxybenzoic, and caffeic acid) were observed after ultrasonic thawing. The sensory evaluation revealed texture and aroma deterioration at higher ultrasonic intensities (4 °C:0.074 W/mL; 25 °C:0.123 W/mL) due to increase in viscosity and some volatile compounds in the mango pulp. Ultrasonic thawing treatment at 25 °C reduced thawing time by 51-73% compared to that at 4 °C. Mango pulp processed at 25 °C exhibited better sensory quality and retained 26.5-58.5% more total phenol and 8.7-11.0% more total carotenoid contents. In short, higher ultrasonic intensities (0.074-0.123 W/mL) at a temperature of 25 °C contributed to better thawing efficiency and nutritional quality. The results demonstrated that ultrasound processing at optimized conditions could serve as a potential alternative to conventional thawing processing of mango pulp.

Valorisation of baobab (Adansonia digitata) seeds by ultrasound assisted extraction of polyphenolics. Optimisation and comparison with conventional methods.

In this study, ultrasound-assisted extraction (UAE) of phenolic compounds in baobab (Adansonia digitata) seeds was optimised using RSM. Based on the single factor experiment results, the effect of four parameters, extraction time (10-20 min), temperature (40-60 °C), % amplitude (30-50) and solvent to solid ratio (20-30, mL/g) on Total Flavonoids Content (TFC) were investigated and optimised using a central composite design (CCD). The predicted optimal conditions with the highest desirably (0.874) were: 20 min, 30% amplitude, 60 °C temperature and 30 mL/g solvent to solid ratio. Under these conditions, the experimental TFC value (1633.84 ±â€¯10.75 mg RE/100 g DW) was highly correlated with the predicted value (1631.77 mg RE/100 g DW). Moreover, a comparative study confirmed that the recovery of TFC, TPC and antioxidant activity (DPPH and FRAP) was significantly higher in UAE than maceration and Heat Assisted Extraction (HAE) extraction methods in addition to a shorter extraction time. HPLC analysis of the UAE optimised sample extract revealed the presence of 10 phenolic compounds with the highest concentration of D-(+) catechin (87.18 ±â€¯14.57 µg/g). This study is the first attempt to optimise UAE parameters for the extraction of phenolic compounds in baobab seeds.

LC-MS/QTOF identification of phytochemicals and the effects of solvents on phenolic constituents and antioxidant activity of baobab (Adansonia digitata) fruit pulp.

Baobab fruit (Adansonia digitata) pulp has received a growing attention globally for its numerous nutritional and medicinal values. However, only limited information is available about its phytochemical composition. The purpose of this study was to identify the phytochemicals in baobab fruit pulp using LC-MS/QTOF and evaluate the effects of solvents on phenolic compounds content and antioxidant activity. The LC-MS analysis led to the identification of 46 compounds, based on standards and comparison with literature reports. Proanthocyanidins, phenolic acids, flavonols, and saponins were the most common compounds. The best solvent for Total Phenolic Compounds Content (TPCC), TPC, TFC and antioxidant activity was also defined: 80% acetone was the best for TPCC, TFC and FRAP, 30% acetone for TPC and 50% methanol for DPPH. Considering all the results, 80% acetone was determined as the best solvent for sample extraction. A high correlation was observed between phenolic compounds content and antioxidant activity.

Development of an analytical method for urocanic acid isomers in fish based on reactive extraction cleanup and chaotropic chromatography techniques.

Urocanic acid (UA), existing in trans- or cis-isoform, is of fairly recent interest to food researchers because of its potential public health hazards of scombrotoxicity and immunotoxicity, as well as associating with fish spoilage. This work is among the first efforts to study the analytical chemistry of UA in fish. With 0.6 M perchloric acid UA was extracted, and co-extracted fish matrix components were efficiently removed through a reactive extraction of UA. The optimum conditions for the reactive extraction, which allowed an 80% recovery of UA, were sample pH adjustment to 9, twice extractions with 32% (w/w) di (2-ethylhexyl) phosphate in hexanol, and a back-extraction with 0.1 M hydrochloric acid at 1:1 phase ratio. A chaotropic hexafluorophosphate salt was added to acidic water-acetonitrile mobile phases to improve the reversed-phase chromatography of UA, which otherwise was poorly retained. Optimum separation conditions were obtained for fish samples and enabled a fast (10 min), convenient-to-use chromatography that clearly outperforms cumbersome legacy ion-pair chromatography. Intended for routine use in our laboratory, the proposed method passed an in-house validation test for linearity, matrix effect (on reactive extraction), accuracy, precision, and detectability.

Systematic evaluation of bioactive components and antioxidant capacity of some new and common bayberry cultivars using an in vitro gastrointestinal digestion method.

This study was aimed to investigate the impact of in vitro gastrointestinal digestion on some common and new bayberry cultivars. The contents of total phenolics (246-669mg gallic acid equivalents/kg FW (fresh weight)), flavonoids (116-689mg quercetin-3-O-rutinoside equivalents/kg FW), procyanidins (28-133mg catechin equivalents/kg FW) and anthocyanins (1-7mg cyaniding-3-O-glucoside equivalents/kg FW) were detected in digested cultivars. HPLC-TOF-MS analysis identified 17 phenolic compounds in digested sample. Among all digested cultivars, the new cultivars Anhaizaomei (ABTS, IC50=2.95mg/mL; FRAP, 401.32mg vitamin C equivalents (VCE)/kg FW) and Yingsi (ABTS, IC50=3.28mg/mL; FRAP, 400.81mg VCE/kg FW) showed better in vitro antioxidant capacity. Further cellular assay indicated that the common cultivar Dongkui (2mg/mL) possessed the strongest ROS scavenging activity. The comprehensive evaluation of bioactive components and antioxidant properties using principal component analysis suggests that common cultivar Dongkui, new cultivars Yingsi and Anhaizaomei could be considered as dietary supplements.

Identification and Antioxidant Activity of Flavonoids Extracted from Xinjiang Jujube (Ziziphus jujube Mill.) Leaves with Ultra-High Pressure Extraction Technology.

In this study, the ultra-high pressure extraction (UHPE) conditions for obtaining the maximum flavonoid yield from Xinjiang jujube (Ziziphus jujuba Mill.) leaves (XJL) were optimized by response surface methodology (RSM). Box⁻Behnken design (BBD) was applied to evaluate the effects of four variables (extraction temperature, pressure, time and liquid-to-solid ratio) on flavonoid yield. The results showed that the optimal flavonoid yield (25.45 ± 0.21 mg/g) was derived at 50.0 °C, 342.39 MPa, 11.56 min, and a liquid-to-solid ratio of 43.95 mL/g. Eight compounds were tentatively identified and quantified as kaempferol and quercetin glycosides with UPLC-ESI-MS. Compared to ultrasound-assisted extraction (UAE), UHPE can obtain higher concentrations of total flavonoids and stronger DPPH and ABTS radical-scavenging activities in a much shorter time. Therefore, UHPE is an alternative to UAE for obtaining flavonoids from XJL, which may be an optional method for large-scale industrial flavonoid extraction from XJL.

Effect of harvest, drying and storage on the bitterness, moisture, sugars, free amino acids and phenolic compounds of jujube fruit (Zizyphus jujuba cv. Junzao).

BACKGROUND: The taste of dried jujube fruit when compared with fresh ones is less palatable, as it develops bitterness during drying and storage. Therefore, identifying the methods by which bitterness occurs is essential for developing strategies for processing and storage. RESULTS: Bitterness in fresh jujube fruit was negligible; however, it increased by 0.9-, 1.5- and 1.8-fold during drying and storage over 6 and 12 months. The moisture significantly decreased during harvesting and drying. Free amino acids, except proline and tyrosine, significantly decreased during drying and storage. Fructose, glucose and sucrose hardly changed during harvest, drying and storage. Titratable acidity, total phenolic and total flavonoids contents were stable during harvest and drying, but increased upon storage. Additionally, protocatechuic and ellagic acids were not detected in fresh jujube fruit, however, were found to increase during drying and storage. CONCLUSION: Bitterness in fresh jujube fruit tasted negligible because of meagre amount of phytochemicals, while the condensation effect of moisture reduction, the loss of free amino acids, and the formation of protocatechuic and ellagic acids could aggravate the bitterness of jujube fruit during drying and storage. © 2017 Society of Chemical Industry.