Effect of cultivar and processing method on the contents of polyphenols in table olives

Polyphenols were determined by HPLC in the juice and oil of packed table olives. The phenolic compositions of the two phases were very different, hydroxytyrosol and tyrosol being the main polyphenols in olive juice and tyrosol acetate, hydroxtyrosol acetate, hydroxytyrosol, tyrosol, and lignans (1-acetoxypinoresinol and pinoresinol) in oil. The type of processing had a marked influence on the concentration of polyphenols in olive juice and little on the content in oil. The analyses carried out on 48 samples showed that turning color olives in brine had the highest concentration in polyphenols ( approximately 1200 mg/kg), whereas oxidized olives had the lowest ( approximately 200 mg/kg). Among olive cultivars, Manzanilla had a higher concentration than Hojiblanca and Gordal. The type of olive presentation also influenced the concentration of polyphenols in olives, decreasing in the order plain > pitted > stuffed. The results obtained in this work indicate that table olives can be considered a good source of phenolic antioxidants, although their concentration depends on olive cultivar and processing method.     

Rapid method for proline determination in grape juice and wine

Proline is typically the most abundant amino acid present in grape juice and wine. The amount present is influenced by viticultural and winemaking factors and can be of diagnostic importance. A method for rapid routine quantitation of proline would therefore be of benefit for wine researchers and the industry in general. Colorimetric determination utilizing isatin as a derivatizing agent has previously been applied to plant extracts, biological fluids, and protein hydrolysates. In the current study, this method has been successfully adapted to grape juice and wine and proved to be sensitive to milligram per liter amounts of proline. At sugar concentrations above 60 g/L, interference from the isatin-proline reaction was observed, such that proline concentrations were considerably underestimated in grape juice and dessert wine. However, the method was robust for the analysis of fermentation samples and table wines. Results were within ±10% agreement with data generated from typical HPLC-based analyses. The isatin method is therefore considered suitable for the routine analysis required to support research into the utilization or release of proline by yeast during fermentation.     

An LC-MS method for analyzing total resveratrol in grape juice, cranberry juice, and in wine.

Resveratrol is an antioxidant found in grapes, grape products, and some other botanical sources with antiinflammatory and anticancer properties. In grapes and wine, it occurs both as free resveratrol and piceid, the 3beta-glucoside of resveratrol. Here we report a liquid chromatography-mass spectrometry method to analyze total resveratrol (including free resveratrol and resveratrol from piceid) in fruit products and wine. Samples were extracted using methanol, enzymatically hydrolyzed, and analyzed using reversed phase HPLC with positive ion atmospheric pressure chemical ionization (APCI) mass spectrometric detection. Following APCI, the abundance of protonated molecules was recorded using selected ion monitoring (SIM) of m/z 229. An external standard curve was used for quantitation, which showed a linear range of 0.52-2260 pmol of trans-resveratrol injected on-column with a correlation coefficient 0.9999. The coefficient of variance of the response factor over the same concentration range was determined to be 5.8%, and the intra-assay coefficient of variance was determined to be 4.2% (n = 7). The limit of quantitation, defined as signal-to-noise 10:1, was determined to be 0.31 pmol injected on-column. The extraction efficiency of the method was determined to be 92%. The stability of resveratrol under different conditions was also examined. For example, resveratrol was stable for up to 5 days at 4 degrees C in the dark but was not stable at room temperature without protection from light. Resveratrol was detected in grape, cranberry, and wine samples. Concentrations ranged from 1.56 to 1042 nmol/g in Concord grape products, and from 8.63 to 24.84 micromol/L in Italian red wine. The concentrations of resveratrol were silmilar in cranberry and grape juice at 1.07 and 1.56 nmol/g, respectively.     

Impact of different stages of juice processing on the anthocyanin, flavonol, and procyanidin contents of cranberries

Juice is the most common form in which cranberries are consumed; however there is limited information on the changes of polyphenolic content of the berries during juice processing. This study investigated the effects of three different pretreatments (grinding plus blanching; only grinding; only blanching) for cranberry juice processing on the concentrations of anthocyanins, flavonols, and procyanidins throughout processing. Flavonols and procyanidins were retained in the juice to a greater extent than anthocyanins, and pressing resulted in the most significant losses in polyphenolics due to removal of the seeds and skins. Flavonol aglycones were formed during processing as a result of heat treatment. Drying of cranberry pomace resulted in increased extraction of flavonols and procyanidin oligomers but lower extraction of polymeric procyanidins. The results indicate that cranberry polyphenolics are relatively stable during processing compared to other berries; however, more work is needed to determine their fate during storage of juices.     

橙汁加工过程对农药炔螨特残留的影响

为弄清橙汁加工过程中农药炔螨特残留的动态,通过田间喷施浓度为5倍于最高推荐剂量的农药溶液以强化炔螨特在甜橙上的残留,然后按照橙汁商业化加工过程进行加工,采用QuEChERS前处理技术结合气相色谱-串联质谱法检测炔螨特的含量,来考察橙汁商业化加工过程对炔螨特残留的影响。结果表明:炔螨特残留主要分布于甜橙果皮中,果肉中炔螨特的残留量不足全果的5%。清洗能除去全果中32.5%的炔螨特残留。初榨果汁、精滤果汁、非浓缩橙汁(NFC橙汁)和浓缩橙汁中的残留量分别为原料果的1.98%、1.95%、1.73%、1.37%,其中NFC橙汁和浓缩橙汁的加工因子分别为0.0173和0.0137,但炔螨特在果渣和精油中发生富集,加工因子分别为1.2822和18.4947。研究结果为橙汁加工工艺的优化和炔螨特残留的膳食暴露评估提供参考。     

氟对茶树生长、叶片营养元素含量、儿茶素类物质和香气成分的影响

本试验为水培试验,研究了不同氟浓度处理(0.1、 0.2、 0.3 mmol/L F)对茶苗(平阳特早)干物质量、 相对生长量、 叶片营养元素含量、 酚类物质和香气成分的影响。结果表明,随着氟浓度的增加,茶苗的干物质积累和相对生长率显著降低。氟处理显著增加了茶苗叶片总磷和氟的含量,显著降低了总氮与碳酸氢根的含量,但对叶片氯离子含量的影响不显著。随着氟浓度的增加,叶片钾、 镁、 铁、 锌的含量显著降低,而钙含量显著增加。对茶叶儿茶素类物质而言,氟处理显著降低了茶苗叶片四种儿茶素（EGC、 EC、 EGCG、 ECG）和茶氨酸、 咖啡碱的含量。此外, 0.1 mmol/L F处理降低了茶苗叶片中醛、 醇、 酯和芳香类物质含量,而0.2 mmol/L F和0.3 mmol/L F处理增加了茶苗叶片主要的香气成分。     

酸化软煮法制取胡萝卜汁的工艺

以新鲜胡萝卜为主要原料,研究了用酸化软煮法制取胡萝卜汁的加工工艺,并通过对比试验确定了最佳工艺参数。结果表明,用4％的NaOH,料液比1∶2,在95℃脱皮处理73 s,和添加0.5％柠檬酸,按料液比2∶1软煮45 min,可获得较好的脱皮和磨汁效果,并使其原料的利用率提高至80％以上。20%糖液和50%胡萝卜汁配成原浆含量15%的流态汁,在100℃杀菌处理20 min后,得到的胡萝卜汁色泽橙黄,口感细腻,流动性和稳定性较好;添加0.1％的琼脂和0.35％的羧甲基纤维素钠作为复合稳定剂,经高压均质杀菌处理,解决了产品沉淀问题。     

Resveratrol and a novel tyrosinase in Carignan grape juice

Polyphenol levels in wines are affected by the wine-making process. Resveratrol is one polyphenol which has been the subject of a commendable amount of recent research. In this work, we found that resveratrol is immediately degraded by tyrosinase. A novel tyrosinase was purified from Carignan grapes. The purification process included salting out and separation on a cation-exchange column, followed by gel filtration. Tyrosinase was purified in a homogeneous form by SDS-PAGE and was characterized: its specific activity toward 3-(3,4-dihydroxyphenyl)-L-alanine (DOPA) increased by a factor of 24 with an overall recovery of 3% of initial activity. The apparent molecular mass of the purified tyrosinase was 40 kDa as determined by SDS-PAGE, and 42 kDa as determined by gel filtration. Its activity was optimal at pH 6 and at 25 degrees C. The enzyme exhibited high activity toward phenylenediamine, epicatechin, pyrogallol, DOPA, and resveratrol. Tyrosinase activity was inhibited by KCN, thiourea, and SO(2). Resveratrol levels were stable following the removal of proteins from the juice, suggesting that early spraying of grapes with SO(2) is an important factor affecting the final amount of resveratrol in wine.     

超高压对鲜榨果蔬汁的杀菌效果

为防止鲜榨果蔬汁受微生物污染而腐败变质,通过超高压加工处理降低其污染的风险,延长产品货架期,提高产品的安全性。该文通过研究超高压处理鲜榨苹果汁和胡萝卜汁及其在贮藏期的菌落总数变化,确定超高压杀菌后的鲜榨苹果汁和胡萝卜汁的生物安全性。试验结果表明：超高压对低pH值的鲜榨苹果汁的杀菌效果优于pH值偏中性的鲜榨胡萝卜汁。随着处理压力的增大和处理时间的延长,鲜榨苹果汁和胡萝卜汁中的菌落总数显著降低（P＜0.05）。经过400 MPa、15 min处理的鲜榨苹果汁可在4℃下贮藏7 d仍保持食用安全性,而鲜榨胡萝卜汁经400 MPa、45 min处理,仅能在4℃下贮藏3d。     

Physico-chemical characteristics of nanovesicle-carbohydrate complexes in grape juice concentrate

It is generally assumed that polyphenols, such as anthocyanins in fruit juice, exist in a free soluble state and are readily available for absorption in the gastro-intestinal tract. In the present study, we have investigated the interaction of polyphenols with soluble carbohydrate polymers, such as pectin and lipid nanovesicles, that are generated during homogenization of the fruit tissue during juice extraction. A commercially available grape juice concentrate contained nearly 25% of polyphenol fraction bound to macromolecules that were nondialyzable. Treatment of dialyzed juice with cellulase, pectinase, and beta-galactosidase did not cause the release of bound polyphenols; however, treatment with triton X-100 caused an increased release of bound polyphenols. The dialyzate contained relatively more -3-O glucosides and -3-O-acetoyl glucosides in comparison to the bound fraction which was enriched in -3-O-coumaroyl glucosides, suggesting qualitative differences in the bound and the free anthocyanin composition. Electron microscopic analysis of the juice fractions revealed the presence of electron-dense nanovesicle-fiber complexes ranging from 10 to 200 nm in diameter. Such complexes were absent in the dialyzate fraction. Cellulase treatment did not change the morphology of the complexes; however, treatment with pectinase and beta-galactosidase disrupted the complexes, releasing vesicular structures, suggestive of the pectin nature of the fibrous matrix. The dialyzed and the dialyzate fractions also showed differences in their 1H NMR and fluorescence spectral characteristics. The dialyzed fraction containing polyphenol-pectin complexes showed no superoxide scavenging capacity, reduced hydroxyl radical scavenging activity, and high 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity, indicating potential changes in functionality because of the complex formation.     

Effects of tea catechins on the ERE-regulated estrogenic activity

Tea catechins exert many biological effects, including anticancer and antibacterial activities. Also, it is reported that some plant flavonoids exhibit estrogenic activity. In this study, we investigated estrogenic or antiestrogenic activities of catechins in HeLa cells transiently transfected with an estrogen response element (ERE)-regulated luciferase reporter and an estrogen receptor (ER) alpha or ERbeta expression vector. Catechins alone did not induce luciferase (luc) activity in either of the ERs. Addition of 17beta-estradiol (E2) plus epicatechin gallate (ECG) or epigallocatechin gallate (EGCG) at 5 x 10(-6) M resulted in significant decreases in the ERalpha-mediated luc activity compared with that of E2 alone. On the contrary, lower concentrations significantly increased the E2-induced luc activity. Similar effects were observed with tamoxifen. The ERbeta-mediated estrogenic activities were stimulated by catechins. In conclusion, some catechins, particularly EGCG, were antiestrogenic for ERalpha at higher doses, and co-estrogenic for ERalpha at lower doses and for ERbeta. The lower doses were found in human plasma after tea-drinking. In addition, some catechins may be antiendocrine disruptors because they suppressed bisphenol A-induced luc activities.     

Effects of domestic processing on steroidal saponins in Taiwanese yam cultivar (Dioscorea pseudojaponica Yamamoto)

The effects of domestic processing on steroidal saponins and furostanol and spirostanol glycosides in Taiwanese yam cultivar (Dioscorea pseudojaponica Yamamoto) were studied. The baking or frying of yam slices was conducted at 150, 180, and 200 degrees C for 3, 5, and 10 min. Yam slices were steamed or microwave cooked at 2450 MHz with an output power of 850 W for 3, 5, and 10 min. The various saponins were quantified by HPLC with an evaporative light scattering detector (ELSD). Results showed that the contents of saponins were decreased along with increasing cooking temperature and time except for the steaming treatment. None of the steamed yam slices significantly change their initial compositions or quantities of furostanol and spirostanol glycosides. Fried yam slices had the highest loss of saponins, especially at 200 degrees C for 10 min (93 and 97% reductions for total furostanol and spirostanol glycosides, respectively). After baking for 10 min at 200 degrees C, the total furostanol and spirostanol glycosides were reduced by 67 and 74%, respectively. There were 12, 44, and 84% decreases for total furostanol glycosides and 10, 35, and 75% reductions for total spirostanol glycosides in yam slices after microwave cooking for 3, 5, and 10 min, respectively. Diosgenin, the aglycone of these saponins, could be found in yams after microwave cooking and baking, but not in steamed and fried yams.     

单宁酶处理提高茶梗儿茶素含量及茶梗提取液生物活性

为综合利用茶叶加工副产物茶叶梗,试验设计利用固态发酵得到的单宁酶处理茶梗,比较不同处理条件下的茶梗提取液中儿茶素组成的差异及还原力、DPPH和OH自由基清除率、胰α-淀粉酶和胰脂肪酶抑制活性变化,探讨单宁酶处理提高茶梗提取物中儿茶素含量和生物活性可行性。研究发现：在50℃条件下,利用2 U/mL单宁酶溶液作用于茶梗粉末60 min,茶梗提取液中酯型儿茶素（EGCG、ECG、GCG）基本被水解生成非酯型儿茶素（EGC、EC、GC）和没食子酸（GA）,从而减少单宁-蛋白质聚合物和茶乳的形成量;此外,经单宁酶处理的茶梗提取液抗氧化活性与对照比较明显增强,表现为OH和DPPH自由基清除率IC50分别降低了74%和26%;酶解茶梗提取液质量浓度为5 000 mg/L时,胰α-淀粉酶和胰脂肪酶抑制率分别提高了89%和107%。研究结果表明单宁酶可高效水解茶梗提取液中酯型儿茶素,提高茶梗提取液的抗氧化活性以及体外抑制胰α-淀粉酶和胰脂肪酶活性。     

Enhancing the retention of phytochemicals and organoleptic attributes in muscadine grape juice through a combined approach between dense phase CO2 processing and copigmentation

This study evaluated the phytochemical stability and organoleptic attributes of an ascorbic acid-fortified muscadine grape juice as affected by dense phase CO2 processing (DP-CO2) and addition of thyme polyphenolic cofactors (Thymus vulgaris; 1:100 anthocyanin-to-cofactor molar ratio) in efforts to prevent phytochemical losses that occur during storage of anthocyanin-containing beverages, especially in the presence of carbonyl compounds commonly produced during thermal processing and storage. DP-CO2 processing insignificantly altered initial juice phytochemical and antioxidant content, whereas thermal pasteurization reduced anthocyanins (263 mg/L), ascorbic acid (42 mg/L), soluble phenolics (266 mg/L), and antioxidant capacity (6 microM Trolox equivalents/mL). Similar trends were observed during storage, and data showed that increasing the CO2 level from 8 to 16% during DP-CO2 was instrumental in reducing juice phytochemical and antioxidant degradation. Copigmentation was instrumental in retaining higher anthocyanin, soluble phenolics, and antioxidant capacity during storage without affecting initial juice aroma and flavor characteristics. Moreover, on the basis of overall likeability scores, panelists preferred copigmented juices, which had increased juice color intensity and masked the detrimental color fading that occurred during storage, especially when compared to thermally pasteurized juices. DP-CO2 and copigmentation were effective strategies to reduce phytochemical and color deterioration that occurred in muscadine juice during storage without affecting their organoleptic attributes.     

Effect of copigments and grape cultivar on the color of red wines fermented after the addition of copigments

The prefermentation addition of copigments led to significantly different red wines according to the copigment structure (flavonol or hydroxycinnamic acid) and the grape cultivar [Tempranillo (= Cencibel) or Cabernet Sauvignon]. The flavonol rutin enhanced copigmentation and anthocyanin extraction, improving the red color, but the hydroxycinnamic acids (especially caffeic acid) had converse results. The above effects were higher in Cabernet Sauvignon wines, particularly if rutin or p-coumaric acid was used. These wines showed the highest copigmentation as they contained more anthocyanins and flavonols, whereas the coumaroylated anthocyanins of Tempranillo wines could have prevented the action of the added copigments. After 21 months, the main pyranoanthocyanins found were the malvidin-3-glucoside 4-vinylphenol and the malvidin-3-glucoside 4-vinylcatechol (pinotin A) adducts. The results suggested that the former adduct was primarily generated following enzymatic decarboxylation of p-coumaric acid during fermentation, whereas pinotin A was formed through a pure chemical reaction, which depended on the concentration of free caffeic acid during aging.     

Influence of yield and maturation index on polysaccharides and other compounds of grape juice

Wine producers may attempt to increase vine productivity, which usually decreases the quality. The quality of Cava (Spanish sparkling wine; Certified Brand of Origin in Spain) mainly depends on the composition of its colloids, which also determine foam quality. The yield (kg of grape/ha) and maturation index (ratio between soluble solids and titratable acidity) are two external factors that may alter grape characteristics, especially its composition. Twenty white grapes of the same variety (Parellada), but different yields (between 6000 and 17,000 kg/ha) were studied. By PCA, two grape groups were separated according to yield (<10,500 and >10,500 kg/ha). Yield and maturation index were not significantly correlated. Grapes obtained with yield >10,500 kg/ha had significantly higher content of soluble proteins and lower content of total polysaccharides and some polysaccharides fractions (M(r) 62,000-48,000, M(r) 28,000-24,000, and M(r) 7000-5000) than the grapes of the low-yield group (<10 500 kg/ha). Thus, it may be interesting to monitor yield, below 10 500 kg/ha, in vines used to produce Cava.     

Effects of the environment, cultivar, maturity, and preservation method on red clover isoflavone concentration

Red clover (Trifolium pratense L.) contains isoflavones that are of interest because of their benefits for human health as well as their adverse effects on the fertility of farm animals. A series of field experiments was conducted in Sainte-Anne-de-Bellevue, QC, Canada, to determine the effects of the environment, cultivar, plant maturity, plant part, and preservation method on the concentration of the two predominant isoflavones in red clover, formononetin and biochanin A. In a multi-year, multisite trial, the total isoflavone concentration in 10 cultivars ranged between 8,923 and 12,753 microg g(-1) of DM averaged across sites, harvests, and years. Despite strong environmental effects, the cultivar "Start" consistently had the lowest isoflavone concentrations, with few differences observed among other cultivars. Across stages of maturity, leaves were found to have the highest isoflavone concentration followed by stems and inflorescences (11,970, 4,896, and 3,297 microg g(-1) of DM, respectively). Changes in isoflavone concentrations with increasing maturity varied depending on the plant part. Overall, highest isoflavone concentrations were found in leaves and stems during the vegetative stages, with the formononetin concentration declining until plants initiated flowering, especially in stems, with concentrations then stabilized in both parts. Upon initiation, inflorescences contained similar isoflavone concentrations than leaves, but concentrations decreased rapidly during flower development to fall even below those observed in stems. Inflorescences then had isoflavone concentrations that were as much as 11 times lower than leaves. Fresh herbage contained higher formononetin and total isoflavone concentrations than did silage and hay (14,464, 12,200, and 11,604 microg g(-1) of DM, respectively). The isoflavone concentration in field-grown red clover is thus high but can be affected by a range of agronomic factors.     

施氮量对不同品质类型小麦子粒蛋白质组分含量及加工品质的影响

选用强筋小麦济麦20、中筋小麦泰山23和弱筋小麦宁麦9号,利用反相高效液湘色谱（RP-HPLC）方法测定了施氮量对不同品质类型小麦子粒蛋白质组分含量和高分子量谷蛋白亚基（HMW-GS）、低分子量谷蛋白亚基（LMW-GS）含量的影响,并分析其与子粒加工品质的关系。结果表明,随施氮量增加,强筋小麦济麦20和中筋小麦泰山23的子粒蛋白质含量及各组分含量均呈先增加后降低的趋势,施氮量为N 240 kg/hm2时,蛋白质各组分含量较高,加工品质较好; 过量施氮抑制了HMW-GS合成,这是过量施氮导致强筋和中筋小麦子粒蛋白质品质变劣的原因之一。随施氮量增加,弱筋小麦宁麦9号子粒的蛋白质各组分含量显著增加,加工品质变劣。增施氮肥,3个品种的谷蛋白和醇溶蛋白含量的增加幅度显著高于清蛋白+球蛋白含量,这是施氮改善强筋和中筋小麦子粒加工品质的主要原因。济麦20和泰山23两品种的总蛋白质含量及醇溶蛋白含量无显著差异,但强筋小麦济麦20的谷蛋白含量、贮藏蛋白、HMW-GS、LMW-GS、谷蛋白大聚合体（GMP）含量及谷蛋白与醇溶蛋白含量的比值（Glu/Gli）和HMW-GS与LMW-GS含量的比值（HMW/LMW）高于中筋小麦泰山23,这是强筋小麦济麦20加工品质形成及其面团形成时间和稳定时间显著高于泰山23的重要原因。     

Liquid chromatography/mass spectrometry investigation of the impact of thermal processing and storage on peach procyanidins

Normal-phase liquid chromatography/mass spectrometry (LC/MS) was used to determine the levels and fate of procyanidins in frozen and canned Ross clingstone peaches as well as in the syrup used in the canning over a 3 month period. Procyanidin oligomers, monomers through undecamers, were identified in Ross clingstone peaches. Optimized methods allowed for the quantitation of oligomers through octamers. The profile of procyanidins in peaches is similar to profiles found in grapes, chocolate, and beverages linked to health benefits such as tea and wine. The monomer content in frozen peeled peaches was found to be 19.59 mg/kg. Dimers (39.59 mg/kg) and trimers (38.81 mg/kg) constituted the largest percent composition of oligomers in the peaches. Tetramers through octamers were present in levels of 17.81, 12.43, 10.62, 3.94 and 1.75 mg/kg, respectively. Thermal processing resulted in an 11% reduction in monomers, a 9% reduction in dimers, a 12% reduction in trimers, a 6% reduction in tetramers, and a 5% reduction in pentamers. Hexamers and heptamers demonstrated an approximate 30% loss, and octamers were no longer detected. Analysis of the syrup after thermal processing indicates that there is a migration of procyanidin monomers through hexamers into the syrup that can account for the losses observed during the canning process. Storage of canned peaches for 3 months demonstrated a time-related loss in higher oligomers and that by 3 months oligomers larger than tetramers are not observed. At 3 months postcanning, levels of monomers had decreased by 10%, dimers by 16%, trimers by 45%, and tetramers by 80%. A similar trend was observed in the canning syrup.     

Stability of copigmented anthocyanins and ascorbic acid in a grape juice model system

The stability of red grape anthocyanins (Vitis vinifera) was evaluated in a model juice system during normal (25 degrees C) and accelerated storage (35 degrees C) in the presence of ascorbic acid. Rosemary polyphenolic cofactors (0, 0.2, and 0.4% v/v) were evaluated as anthocyanin stabilizing agents. Cofactor addition resulted in concentration-dependent hyperchromic (up to 178%) and bathochromic (up to 23 nm) shifts, indicating a more intense red coloration of the models. Anthocyanin and ascorbic acid degradation followed first-order kinetics during storage. Results showed that copigmented treatments underwent a lower conversion of L-ascorbic acid into dehydroascorbic acid during storage when compared to the control, favorably impacting the vitamin retention of these models. Copigmentation did not affect anthocyanin degradation in the absence of ascorbic acid but in its presence aided to retain a higher anthocyanin content than the control. This study indicated that the addition of anthocyanin cofactors could be used to reduce the pigment and vitamin degradation while masking detrimental color changes in anthocyanin containing products.