Activity and concentration of polyphenolic antioxidants in apple juice. 3. Stability during storage

Kinetic data are reported describing the stability of various classes of polyphenolic antioxidants in an apple juice enriched in these compounds as a function of storage temperature and oxygen concentration. The most thermally sensitive compounds were the various quercetin glycosides and epicatechin, whereas phloridzin and chlorogenic acid were more stable. The quercetin glycosides showed differences in their stability: quercetin galactoside approximately quercetin rhamnoside > quercetin glucoside/rutinoside > quercetin arabinoside. The effect of the presence of oxygen on the degradation rates was clear for only quercetin and to a lesser extent for epicatechin. Accelerated shelf-life testing of enriched apple juice during 4 days at 80 degrees C showed decreases in the antioxidant activity of 20-40%. The parameters obtained were used to predict the stability at different storage conditions. Calculations showed that polyphenolic antioxidants and antioxidant activity of enriched apple juice will be quite stable at ambient or refrigerated storage conditions up to half a year.     

Major phenolics in apple and their contribution to the total antioxidant capacity

The contribution of each phytochemical to the total antioxidant capacity of apples was determined. Major phenolic phytochemicals of six apple cultivars were identified and quantified, and their contributions to total antioxidant activity of apples were determined using a 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) radical scavenging assay and expressed as vitamin C equivalent antioxidant capacity (VCEAC). Average concentrations of major phenolics and vitamin C in six apple cultivars were as follows (mg/100 g of fresh weight of apples): quercetin glycosides, 13.20; procyanidin B(2), 9.35; chlorogenic acid, 9.02; epicatechin, 8.65; phloretin glycosides, 5.59; vitamin C, 12.80. A highly linear relationship (r (2) > 0.97) was attained between concentrations and total antioxidant capacity of phenolics and vitamin C. Relative VCEAC values of these compounds were in the order quercetin (3.06) > epicatechin (2.67) > procyanidin B(2) (2.36) > phloretin (1.63) > vitamin C (1.00) > chlorogenic acid (0.97). Therefore, the estimated contribution of major phenolics and vitamin C to the total antioxidant capacity of 100 g of fresh apples is as follows: quercetin (40.39 VCEAC) > epicatechin (23.10) > procyanidin B(2) (22.07) > vitamin C (12.80) > phloretin (9.11) > chlorogenic acid (8.75). These results indicate that flavonoids such as quercetin, epicatechin, and procyanidin B(2) rather than vitamin C contribute significantly to the total antioxidant activity of apples.     

Low temperature metabolism of apple phenolics and quiescence of Phlyctaena vagabunda.

The content of chlorogenic acid, (+)-catechin, (-)-epicatechin, phloretin glycosides, and quercetin glycosides in fresh and stored Golden Delicious apples (Malus domestica Borkh) was determined. The relative amount of phenolics in the peel, with the exception of chlorogenic acid and (-)-epicatechin, was higher than that in the flesh. In addition, quercetin glycosides were detected only in the skin. These compounds were tested for fungicidal activity against Phlyctaena vagabunda Desm., the causal agent of a postharvest rot. Chlorogenic acid only inhibited P. vagabunda spore germination and mycelial growth in vitro. Changes of apple phenolics and polyphenol oxidase activity during cold storage and the biological activity of these phenolics have also been analyzed with reference to the development of quiescent infections during cold storage plus shelf life at room temperature. The results obtained suggested that phloridzin and chlorogenic acid in combination with polyphenol oxidase activity could function to arrest P. vagabunda in quiescent infections associated with immature and ripening apple fruit.     

Polyphenolic profiles in eight apple cultivars using high-performance liquid chromatography (HPLC)

Polyphenolic compounds of apple may play an important role in physiologic functions related to human health. Different polyphenolics may have varied biological activities including antioxidant activity. The objective of this study was to investigate the profiles of polyphenolic compounds in different apple varieties and different parts of an apple. The total and individual polyphenolics differed significantly among the eight apple cultivars grown in Ontario, and the peels had higher concentrations than the flesh. Among the tested cultivars, Red Delicious and Northern Spy had the highest concentrations and Empire the lowest. Five major polyphenolic groups with a total of 16 identified individual compounds were found, among which the dihydroxycinnamic acid esters, phloretin glycosides, and flavan-3-ols were found in both flesh and peel, whereas quercetin glycosides were almost exclusively found in the peel. Cyanidin 3-galactoside was unique to and found only in red apple peels. In both apple peel and flesh, the predominant group of polyphenolics was the procyanidins, followed by quercetin glycosides in the peel and hydroxycinnamic acid esters in the flesh. 3-Hydroxyphloretin 2'-xyloglucoside was newly identified in apple. The results obtained in this study will further the understanding of the polyphenolic composition of apples and their roles in health-promoting physiological functions.     

Activity and concentration of polyphenolic antioxidants in apple juice. 2. Effect of novel production methods

There is a great interest in food components that possess possible health-protecting properties, as is the case with flavonoids. Previous research showed that conventional apple juice processing resulted in juices poor in flavonoids and with a low antioxidant activity. This paper shows that it is possible to improve flavonoid content in juice and its antioxidant activity by applying an alcoholic extraction either on the pulp or on the pomace. The levels of flavonoids and chlorogenic acid in enriched juice were between 1.4 (chlorogenic acid) and 9 (quercetin glycosides) times higher than in conventional apple juice. In enriched juice the antioxidant activity was 5 times higher than in conventional apple juice, with 52% of the antioxidant activity of the originating fruits present. The novel processing method had similar effects for three apple cultivars tested (Elstar, Golden Delicious, and Jonagold). The taste and color of enriched juice were different from those of conventional juice.     

Polyphenols are intensively metabolized in the human gastrointestinal tract after apple juice consumption

Polyphenols are secondary plant compounds showing anticarcinogenic effects both in vitro and in animal experiments and may thus reduce the risk of colorectal cancer in man. The identification of polyphenol metabolites formed via their passage through the small intestine of healthy ileostomy subjects after apple juice consumption is presented. Identification and quantification of polyphenols and their metabolites were performed using HPLC-DAD as well as HPLC-ESI-MS/MS. Total procyanidin content (TPA) was measured, and additionally the mean degree of polymerization (DPm) of the procyanidins was determined in the apple juice and ileostomy effluents. As products of polyphenol metabolism, D-(-)-quinic acid and methyl esters of caffeic acid and p-coumaric acid are liberated from the corresponding hydroxycinnamic acid esters. 1-Caffeoylquinic acid and 3-caffeoylquinic acid were determined as products of isomerization. Phloretin 2'-O-glucoside (phloridzin) and phloretin 2'-O-xyloglucoside were metabolized into the corresponding aglycons phloretin and phloretin 2'-O-glucuronide and all were found in the ileostomy effluent. Ninety percent of the consumed procyanidins were recovered in the ileostomy effluent and therefore would reach the colon under physiologic circumstances. The DP m was reduced (DP m of apple juice=5.7) and varied depending on the time point of excretion. The gastrointestinal passage seems to play an important role in the colonic availability of apple polyphenols.     

Quercetin and rutin reduced the bioavailability of cyclosporine from Neoral, an immunosuppressant, through activating P-glycoprotein and CYP 3A4

Quercetin and rutin are popular flavonoids in plant foods, herbs, and dietary supplements. Cyclosporine (CSP), an immunosuppressant with a narrow therapeutic window, is a substrate of P-glycoprotein (P-gp) and cytochrome P-450 3A4 (CYP3A4). This study investigated the effects of quercetin and rutin on CSP pharmacokinetics from Neoral and relevant mechanisms. Rats were orally administered Neoral with and without quercetin or rutin. The blood CSP concentration was assayed by a specific monoclonal fluorescence polarization immunoassay. The results showed that quercetin and rutin significantly decreased the C(max) of CSP by 67.8 and 63.2% and reduced the AUC(0-540) by 43.3 and 57.2%, respectively. The in vitro studies indicated that the quercetin and rutin induced the functions of P-gp and CYP3A4. In conclusion, quercetin and rutin decreased the bioavailability of CSP through activating P-gp and CYP3A. Transplant patients treated with Neoral should avoid concurrent consumption of quercetin or rutin to minimize the risk of allograft rejection.     

Effect of buckwheat extract on the antioxidant activity of lipid in mouse brain and its structural change during in vitro human digestion

This study was conducted to investigate the effects of buckwheat ( Fagopyrum esculentum Moench cv. Yangjul No. 2) extract on the antioxidant activity of lipids in mouse brain and the structural change during in vitro human digestion. Buckwheat was collected from a wild farm and extracted with water. The buckwheat extracts were then passed through an in vitro human digestion model that simulated the composition of the mouth, stomach, and small intestine juice. The results confirmed that the main phenolics of buckwheat extract were rutin, quercitrin, and quercetin. The rutin content increased with digestion of the buckwheat (from 48.82 to 96.34 μg/g) and rutin standard samples (from 92.76 to 556.56 μg/g). Antioxidant activity was more strongly influenced by in vitro human digestion of both buckwheat and rutin standard. After digestion by the small intestine, the antioxidant activity values were dramatically increased (from 5.06 to 87.82%), whereas the antioxidant activity was not influenced by digestion in the stomach for both buckwheat extract and rutin standard. Inhibition of lipid oxidation of buckwheat in mouse brain lipids increased after digestion in the stomach for both buckwheat extract and the rutin standard. The major finding of this study was that in vitro human digestion may be an important modulator of the antioxidant capacity of buckwheat and that this may be because in vitro human digestion increased the antioxidative activity via an increase in antioxidants such as rutin and quercetin.     

Antioxidant effectiveness of phenolic apple juice extracts and their gut fermentation products in the human colon carcinoma cell line caco-2

Apples represent a major dietary source of antioxidative polyphenols. Their metabolic conversion by the gut microflora might generate products that protect the intestine against oxidative damage. We studied the antioxidant effectiveness of supernatants of fermented apple juice extracts (F-AEs, 6 and 24 h fermentation) and of selected phenolic degradation products, identified by HPLC-DAD-ESI-MS. Cell free antioxidant capacity of unfermented apple juice extracts (AEs) was decreased after fermentation by 30-50%. In the human colon carcinoma cell line Caco-2, F-AEs (containing <0.5% of original AE-phenolics) decreased the reactive oxygen species (ROS) level more efficiently than the F-blank (fermented without AE) but were less effective than the respective AEs. Similarly, antioxidant effectiveness of individual degradation products was lower compared to respective AE constituents. Glutathione level was slightly increased and oxidative DNA damage slightly decreased by fermented AE03, rich in quercetin glycosides. In conclusion, F-AEs/degradation products exhibit antioxidant activity in colon cells but to a lesser extent than the respective unfermented AEs/constituents.     

Immunoglobulin E-reactive proteins in cashew (Anacardium occidentale) apple juice concentrate

Cashew apple juice has the potential to be a natural source of vitamin C and sugar in processed foods. The juice of the cashew apple is obtained by pressing the fleshy peduncle or receptacle, which forms a rounded apple that sits above the true fruit, the cashew nut. Cashew nut allergy is the second most commonly reported tree nut allergy in the United States. To determine if cashew apple juice contains cashew nut allergens, immunoblotting was performed using a cashew apple juice 6X concentrate that was extracted and further concentrated through dialysis, lyophilization, and resuspension. Serum IgE of individuals allergic to cashew nut bound proteins in the cashew apple juice concentrate extract. For some serum samples, IgE reactivity could be inhibited by preincubation of the serum with cashew nut extract, suggesting the presence of cashew nut-related allergens. Using monoclonal antibodies specific for cashew nut allergens, the concentrate was found to contain Ana o 1 (vicilin) and Ana o 2 (legumin). Neither IgE from cashew nut allergic sera nor the monoclonal antibodies bound any peptides in 5 kDa filtered cashew apple juice concentrate. The cashew apple juice concentrate used in these studies contains proteins with IgE-reactive epitopes, including cashew nut legumin and vicilin. No IgE-binding peptides remained after 5 kDa filtration of the concentrate.     

Grapefruit and oroblanco enhance hepatic detoxification enzymes in rats: possible role in protection against chemical carcinogenesis

Citrus fruits are considered to be functional foods that promote good health. This study was carried out to assess the effect of oroblanco and grapefruit consumption on hepatic detoxification enzymes. Male Sprague-Dawley rats were provided with either regular drinking water (control) or experimental treatments of oroblanco juice, grapefruit juice, or a sugar mix for 6 weeks. After 1 week of treatment, half the animals in each group were injected with the procarcinogen 1,2-dimethylhydrazine. Grapefruit juice significantly increased activity and expression of the hepatic phase I enzyme, cytochrome P450 CYP1A1, with a marked trend toward enhanced NAD(P)H:quinone reductase (QR) activity. Oroblanco juice significantly increased glutathione S-transferase phase II enzyme activity along with CYP1A1 expression and a notable trend toward increased activity of both CYP1A1 and QR. These results suggest that these citrus fruits are bifunctional inducers, modulating both phase I and phase II drug-metabolizing enzymes to enhance hepatic detoxification.     

微波预处理原料对苹果汁褐变的影响

为了防止苹果汁在贮藏过程中褐变,采用不同的微波功率和时间预处理原料苹果,研究微波预处理对苹果汁褐变的影响。结果表明,微波处理可以提高苹果汁的色值,降低多酚氧化酶的活性,引起氨基态氮含量的下降,并使苹果汁的酸度略微提高。在微波功率为720～900 W,处理时间75～125 s时,果汁色值较高。室温贮存45 d后,微波功率900 W,时间为100 s处理的果块,果汁色值为67.8,比未经微波处理的高91.5%。微波预处理是防止苹果汁褐变的一种简便安全、合理经济的加工方法。     

Effect of pectolytic enzyme preparations on the phenolic composition and antioxidant activity of asparagus juice

Commercial pectolytic enzymes were investigated for their influence on phenolics and antioxidant activities of asparagus juice. The antioxidant activity of asparagus juice was analyzed according to 2,2'-diphenyl-l-picrylhydrazyl and 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) methods. The enzymes, with the exception of pectinase from Rhizopus sp., contained rutinase, which hydrolyzed rutin to quercetin. Asparagus juice treated with Viscozyme had the highest quercetin content without exhibiting a significant increase in the antioxidant activity. For a pectinase from Aspergillus niger, the antioxidant activity of asparagus juice was markedly reduced. Caution should be paid in the selection of pectolytic enzyme preparations for production of antioxidant activity-rich juice.     

欧李种质叶片类黄酮含量及不同组分特征研究

为筛选出欧李叶片类黄酮和9种类黄酮物质中单一物质含量较高的品种,并分析确定具有抗氧化和抑制酪氨酸酶活性的物质,本研究以38份欧李种质基生枝成熟期叶片为试材,利用超高效液相色谱法(UHPLC)测定儿茶素、表儿茶素、甘草素、芦丁、槲皮素、槲皮素-7-O-葡萄糖苷、杨梅素、光甘草定、根皮素活性物质含量,对其抗氧化及抑制酪氨酸...     

Volatility of patulin in apple juice

Patulin is a mycotoxin produced by certain fungi, such as those found commonly on apples. The patulin content of apple juice is a regulatory concern because patulin is a suspected carcinogen and mutagen. A simple model of the apple juice concentration process was carried out to examine the possible contamination of patulin in apple aroma, a distillate produced commercially in the concentration of apple juice. The results show no evidence for patulin volatility, and document a reduction in patulin content by at least a factor of 250 in the apple distillate obtained from apple juice. Furthermore, a survey of several commercial apple aroma samples found no evidence of patulin content.     

Activity and concentration of polyphenolic antioxidants in apple juice. 1. Effect of existing production methods

Apples are an important source of flavonoids in the human diet. The effect of processing apples into juice on polyphenolic antioxidant content and activity is described. Raw juice obtained from Jonagold apples by pulping and straight pressing or after pulp enzyming had an antioxidant activity that was only 10 and 3%, respectively, of the activity of the fresh apples. The levels of flavonoids and chlorogenic acid in the juice were reduced to between 50% (chlorogenic acid) and 3% (catechins). Most of the antioxidants were retained in the pomace rather than being transferred into the juice. Apparently, most of the antioxidant compounds are absorbed to the solid matter of the pomace. In apple juice, 45% of the total measured antioxidant activity could be ascribed to the analyzed antioxidants. For three apple cultivars tested (Elstar, Golden Delicious, and Jonagold), the processing methods had similar effects. The results indicate that processing can have a major impact on the bioactivity of products.     

三种菌肥对苹果连作土壤环境及平邑甜茶幼苗生长的影响

【目的】以平邑甜茶 (Malus hupehensis Rehd.) 幼苗为试材,在连作土盆栽条件下探讨了圆弧青霉D12、哈茨木霉、草酸青霉A1三种不同菌肥对其生长和土壤环境的影响,为研究苹果连作障碍的缓解措施提供理论依据。【方法】试验共设置5个处理:载体基质对照 (CK1)、连作土壤 (CK2)、连作土施加圆弧青霉D12菌肥 (T1)、连作土施加哈茨木霉菌肥 (T2)、连作土施加草酸青霉A1菌肥 (T3)。菌肥加入量按照连作土壤质量比的1.6%,在幼苗移栽前与连作土壤混合。于2017年8月份测定平邑甜茶生物量、土壤酚酸含量和土壤微生物等相关指标。【结果】与对照相比,施加三种菌肥后对平邑甜茶幼苗的生物量均有不同程度的促进作用,其中施加哈茨木霉 (T2) 和草酸青霉A1菌肥 (T3) 效果相对较好,其株高、地径、鲜重、干重较CK2分别增加53.3%、56.0%、40.6%、106.3%,53.3%、56.0%、40.9%、99.8%,施加载体基质 (CK1) 较连作对照 (CK2) 在鲜重、干重方面差别较小;施加三种菌肥后,土壤酶活性有显著性提高;其中圆弧青霉D12(T1)、哈茨木霉 (T2)、草酸青霉A1 (T3) 的中性磷酸酶活性分别为对照的1.60倍、1.74倍、1.65倍,施加三种菌肥处理的效果明显,与对照处理差异显著;施加三种菌肥均增加了土壤中细菌、放线菌的数量,较连作对照 (CK2),施加三种菌肥后细菌数量分别增加1.79、1.88、2.07倍,降低了土壤中腐皮镰孢菌的基因拷贝数,与连作处理 (CK2) 相比分别降低了63.3%、70.7%、73.2%;与连作土对照相比,施加三种菌肥后降低了土壤中酚酸物质的含量,其中根皮苷、根皮素分别降低了62.6%、64.9%、69.8%,77.9%、78.9%、78.3%。【结论】施加三种菌肥均可提高连作平邑甜茶幼苗的生物量、根系呼吸速率以及土壤酶活性,降低土壤腐皮镰孢菌的基因拷贝数,但施加草酸青霉A1和哈茨木霉效果更为显著,可作为减缓苹果连作障碍的良好防控措施。     

The flavonoids of tomatoes

Tomatoes ( Lycopersicon esculentum Mill.) have been recognized as an important source of dietary flavonoids because of a high consumption worldwide. The qualitative and quantitative flavonoid compositions of assorted tomato cultivars including individual quantitative contributions of the five most significant flavonoids have been determined in this work. The dihydrochalcone phloretin 3',5'-di-C-beta-glucopyranoside and the flavonol quercetin 3-O-(2'-O-beta-apiofuranosyl-6'-O-alpha-rhamnopyranosyl-beta-glucopyranoside) were identified for the first time in Solanaceae spp. and found to be among the main flavonoids in all cultivars. Phloretin 3',5'-di-C-glc is the first C-glycoside identified in tomatoes and also the first dihydrochalcone from this species. In addition, chalconaringenin, kaempferol 3-rutinoside, and quercetin 3-rutinoside (rutin), though previously reported to occur in tomato, were fully characterized by extensive use of 2D NMR techniques and high-resolution LCMS. The total flavonoid content of different tomato types varied from 4 to 26 mg 100 (-1) g FW with chalconaringenin as the predominant compound comprising 35 to 71% of the total flavonoid content. The individual quantities of quercetin 3-O-(2'- O-beta-apiofuranosyl-6'- O-alpha-rhamnopyranosyl-beta-glucopyranoside) and phloretin 3',5'-di-C-beta-glucopyranoside was similar to that of rutin in several cultivars.