Syrah grape skin valorisation using ultrasound-assisted extraction: Phenolic compounds recovery,antioxidant capacity and phenolic profile

The influence of ultrasound power (1000–3000 W/L), citric acid concentration (0–3%) and solid:liquid ratio (1:5–1:15) on the phenolic compounds recovery and antioxidant capacity of Syrah grape skin extracts were evaluated. Total phenolic compounds varied from 6485 to 11732 mg gallic acid/100 g and monomeric anthocyanin content from 453 to 685 mg malvidin-3-glucoside/100 g. The antioxidant capacity measured by ORAC and ABTS methods ranged from 230 to 516 μmol Trolox/g and from 442 to 939 μmol Trolox/g, respectively. The most suitable conditions chosen for extraction, within the studied ranges, were 3000 W/L of power, 2.5% citric acid and solid:liquid ratio of 1:15. The extraction yield was satisfactory, with a recovery of 59% of the quantified phenolic compounds, with only 3 min of processing. Ultrasound was considered a suitable method as compared to the conventional extraction, improving the extraction of phenolic acids and facilitating their release.     

Autochthonous white grape pomaces as bioactive source for functional jams

Seeds and skins from grape pomaces of Pecorello and Mantonico cv underwent extraction (ultrasound–assisted or maceration), in order to obtain added-value ingredients for the production of a functional pear jam. The antioxidant features of the extracts were tested by in vitro colorimetric assays. Among seeds, Mantonico by maceration (MSC) showed the best results, as well as Mantonico by ultrasound-assisted extraction (MBs) among skin extracts. The selected extracts were fully characterised by NMR and MS techniques, confirming the presence of many polyphenols, flavonoids and tannins among others. Pectin was then derivatised by the grafting procedure with the active molecules of MBs and MSC. The latter produced the best antioxidant polymer also without toxicity evaluated using Caco-2 cells and was used for the jam preparation. The functional pear jam showed improved antioxidant performances in comparison with its non-functional counterparts as well as its maintenance over time (15 days).     

葡萄籽提取物原花青素对肉兔抗氧化功能、脂质含量及血清代谢产物浓度的影响

研究葡萄籽提取物原花青素(grape seed proanthocyanidin extracts,GSPE)对肉兔抗氧化功能、脂质含量及血清代谢产物浓度的影响。采用单因子随机区组试验设计,选择128只60日龄、体重相近的健康新西兰兔,随机分为4组(1个对照组和3个试验组),每组32个重复,每个重复1只。对照组饲喂基础饲粮,3个试验组分别饲喂在基础饲粮中添加100、200及400 mg/kg GSPE的试验饲粮。试验期为39 d,其中预试期为6 d,正试期为33 d。结果表明:随饲粮中GSPE添加量升高,试验兔背最长肌、肝脏及血清总抗氧化能力、总超氧化物歧化酶与谷胱甘肽过氧化物酶活性均显著(P0.05)或极显著(P0.01)升高,而丙二醛浓度极显著(P0.01)降低;对照组试验兔背最长肌粗脂肪含量极显著(P0.01)高于200 mg/kg组和400 mg/kg组,而肝脏粗脂肪含量、血清三酰甘油与总胆固醇浓度均显著(P0.05)或极显著(P0.01)高于其余3组;对照组试验兔血清葡萄糖与尿素氮浓度均显著(P0.05)或极显著(P0.01)高于其余3组,而尿酸浓度显著(P0.05)或极显著(P0.01)低于200 mg/kg组和400 mg/kg组。研究结果提示:饲粮添加GSPE,可增强肉兔机体抗氧化功能,改善脂质、糖和氮代谢,且作用效果随添加量升高而增强。     

葡萄籽原花青素提取物对砷诱导人肝细胞HL-7702损伤的保护作用及其机制

目的：研究葡萄籽原花青素提取物（grape seed proanthocyanidin extract,GSPE）对砷诱导的人肝细胞 HL-7702损伤的保护作用及其机制,为砷中毒的防治和GSPE的抗氧化研究提供理论依据。方法：将人肝细胞HL-7702 分为对照组、砷染毒组（25 μmol/L）、GSPE干预组（5、10、25、50 mg/L）以及GSPE单独干预组（50 mg/L）, 分别处理24 h和48 h后,分别测定天门冬氨酸氨基转移酶（aspartate transaminase,AST）、丙氨酸氨基转移酶 （alanine aminotransferase,ALT）、谷胱甘肽（glutathione,GSH）、超氧化物歧化酶（superoxide dismutase, SOD）和丙二醛（malondialdehyde,MDA）水平以及总抗氧化能力（total antioxidant capacity,T-AOC）变化。噻 唑蓝（3-(4,5)-dimethylthiahiazo(-z-yl)-3,5-di-phenytetrazoliumromide,MTT）法分析细胞生存率,利用实时定量聚 合酶链式反应以及Western blot法检测HL-7702细胞中核因子E2相关因子（nuclear factor erythroid-2 related factor 2, Nrf2）、血红素氧合酶1（heme oxygenase 1,HO-1）、醌氧化还原酶1（quinone oxidoreductase 1,NQO1）和谷 胱甘肽巯基转移酶（glutathione S-transferase,GST）的mRNA以及蛋白表达。结果：MTT实验发现,与对照组比 较,高浓度砷（≥25 μmol/L）染毒组细胞存活率显著降低（P＜0.05）。GSPE干预组（＞10 mg/L）细胞中的ALT 和AST活力、MDA水平显著低于砷染毒组（P＜0.05）,SOD活力、GSH含量以及T-AOC水平显著高于砷染毒组 （P＜0.05）,GSPE干预组HL-7702细胞中Nrf2、HO-1、NQO1、GST的mRNA及蛋白表达增高（P＜0.05）。结 论：GSPE对砷诱导的人肝细胞HL-7702氧化损伤具有拮抗作用,且具有一定的剂量效应关系,其机制可能是通过 激活Nrf2介导的抗氧化信号通路,提高细胞抗氧化能力,从而改善砷引起的肝损伤。     

代谢组学技术在葡萄生理研究中的应用

葡萄是多种与人体健康密切相关的代谢产物的重要来源。代谢组学在葡萄研究中的应用对于揭示葡萄代谢生理机制具有十分重要的意义。本文综述了近年来代谢组学手段在葡萄品种区分、生长发育特性研究、对外界环境条件应答及未知代谢物筛查方面的应用和研究进展,并分析了现有研究内容的局限,展望了后续研究重点,以期为葡萄发育生理、代谢生理及逆境生理研究提供参考依据。     

Utilization of Whey and Grape Must for Citric Acid Production by Two Yarrowia lipolytica Strains

In this study, utilization of whey and grape must were investigated for citric acid production using Yarrowia lipolytica NBRC 1658 and a domestic strain Y. lipolytica 57. In addition to its use as a sole nutrient source, whey was also fortified with glucose or fructose as well as other nutrients. The best results for citric acid production were obtained in the medium containing whey supplemented with fructose. Maximum citric acid concentrations in this medium were 49.23 and 32.65 g/L for the domestic and NBRC 1658 strains, respectively. In grape must, maximum citric acid concentrations obtained using domestic and NBRC 1658 strains were 32.09 and 10.39 g/L, respectively. Both of the natural nutrient sources were found to be promising for utilization in citric acid production process. A domestic Turkish yeast strain was confirmed to be superior for citric acid production for the first time. This can be targeted for enhancing citric acid production efficiencies from locally available substrates such as whey or grape must.     

连续式变温对鲜食葡萄货架品质调控规律

鲜食葡萄易腐烂、难贮藏,特别是经过长期冷链贮运,货架品质及营养成分大幅下降。以市场上常见的"红地球"鲜食葡萄为试材,在0℃和20℃之间变温总时间相同条件下,试验设计0次(对照组), 1次和2次连续变温处理,置于20℃常温货架贮藏,研究其物理、感官品质和营养成分变化。结果表明,连续变温处理对于果实的综合指标影响较大,贮藏期间货架品质和营养成分成倍下降。变温2次处理,品质下降和营养流失最为严重(p<0.05)。试验阐明连续变温对鲜食葡萄货架品质影响机理和作用规律,为鲜食果品冷链配送提供依据。     

Pre-bottling use of dehydrated waste grape skins to improve colour,phenolic and aroma composition of red wines

Different dehydrated waste grape skins from the juice industry were added into aged and young red wines as an innovative way of compensating for colour loss before bottling. After addition of grape skins, colour intensity of wines increased a mean 11% and a maximum of 31% with predominance of the red component. Total polyphenols mean increase was 10% with a maximum value of 20%. Analysis of low molecular weight phenolic compounds by HPLC–DAD showed a significant (p < 0.05) content increase of the bioactive compounds gallic acid, (+)-catechin, (−)-epicatechin, and (E)-resveratrol. Anthocyanins content also increased at an average of 50 mg/l. The volatile profile of wines analysed by SBSE–GC–MS was only moderately influenced by the treatments. Mixtures of dehydrated waste grape skins were useful to improve the colour and polyphenol profile of red wines, considering them a useful tool for correcting colour loss before bottling.