Investigation of different sample pre-treatment routes for liquid chromatography–tandem mass spectrometry detection of caseins and ovalbumin in fortified red wine

Different sample treatment protocols for the liquid chromatography–electrospray-tandem mass spectrometry (LC–ESI-MS/MS) analysis of potential residuals of ovalbumin and caseins added to red wines were developed. In particular, attention was paid to the simultaneous detection and quantitation of fining agent residues, i.e. ovalbumin, α- and β-casein, in wine samples. The different sample treatment methods were compared in terms of protein recovery. The use of denaturing agents combined with size exclusion concentration and purification allowed to obtain a reproducible (RDS < 20%) analytical protocol with good recoveries (73(±2) – 109(±4)% range) for digested proteins from 12.5 mL of wine sample. Matrix-matched calibration from LC–ESI-MS/MS analysis indicated that the devised method allowed detection of target peptides in the 0.01–0.8 μg/mL range. Finally, method applicability and selectivity was demonstrated by using fining agents commonly exploited in winery industry and by analyzing 20 commercial red wine samples.     

控轧控冷16Mn钢珠光体细化的研究

利用扫描电子显微镜和图像分析仪研究了控制冷却对控轧１６Ｍｎ钢珠光体细化程度的影响。实验结果表明，控轧控冷１６Ｍｎ钢中珠光体细化程度随轧后冷却速度增加而增加。     

Interactions between protein fining agents and proanthocyanidins in white wine

A comparative fining trial was conducted in a laboratory scale to study the influence of protein fining agents on proanthocyanidins, colour and browning potential of white wine. The monomeric flavanols were significantly depleted by casein, and gelatine with low molecular weight (MW) distribution, and isinglass obtained from fish swim bladder (MW > 94.0, containing some bands in the range 94.0–43.0 and at 20.1 kDa). However, the other gelatines and isinglass with a MW polydispersion below 20.1 kDa did not interact significantly (P < 0.05) with these compounds. In contrast, the oligomeric compounds were not decreased by swim bladder isinglass. It was also observed that neither of the isinglasses decreased the polymeric flavanols significantly (P < 0.05). Although casein and potassium caseinate had similar MW distributions and isoelectric points, potassium caseinate decreased the polymeric flavanols, whereas casein did decrease monomeric, oligomeric and polymeric flavanols significantly (P < 0.05). The degree of polymerisation of polymeric proanthocyanidins that remained in the fined wine decreased significantly (P < 0.05) after addition of protein fining agents except when potassium caseinate was used. Casein, potassium caseinate and swim bladder isinglass induced a significant (P < 0.05) decrease in wine colour (A_420nm), a decrease in browning potential and a decrease in turbidity.     

Changes in phenolic compounds and colour in pale Sherry wines subjected to fining treatments

 Changes in the concentrations of hydroxybenzoic acids, hydroxycinnamic acids and their esters, monomeric and dimeric derivatives of flavan-3-ol, and flavonols, as well as in the UV-visible absorbances of pale Sherry wines were studied. The wines were subjected to four different fining treatments: casein + bentonite, casein + bentonite + activated charcoal, casein + bentonite + polyvinylpyrrolidone (PVPP) and casein + bentonite + Riduxhigh. Based on the results, the treatments including activated charcoal and PVPP were the most effective at decreasing the overall concentration phenolic compounds, with no significant difference between them. Likewise, these treatments provided the best results in relation to wine colour in the visible spectral region, and particularly at 420 nm, at which wavelength browning compounds are usually measured. Received: 24 March 1997 / Revised version: 11 June 1997     

壳聚糖澄清果汁作用的研究

研究了壳聚糖对苹果汁的澄清作用,测定了苹果汁经壳聚糖澄清后其主要成分含量变化,并用高效液相层析对重要的酚类化合物进行了分离检测。结果表明:壳聚糖是一种有效的果汁澄清剂,能提高果汁的透光率,且不影响果汁中的营养成分和风味;经壳聚糖澄清后的苹果汁具有很好的贮藏稳定性,该方法优于目前工业上采用的果胶酶结合助凝剂的处理方法。     

Influence of some technological practices on the quantity of resveratrol in wine

 A study of the effects of some prefermentative and fining practices on the resveratrol concentration in wine was carried out. The trans- and cis-resveratrol contents in a red wine obtained using must hyperoxidation were reduced to about 50% compared with those of control wines; this decrease was greater than that observed for total phenols and catechins. In contrast, sparging the red grapes with SO₂ and ascorbic acid before crushing them resulted in the trans-resveratrol concentration being greater than that of the control wines. Moreover the amounts of trans- and cis-resveratrol in commercial and synthetic wines were determined before and after addition of charcol, polyvinylpolypyrrolidone (PVPP), bentonite, casein, gelatine, and two inert materials, cellulose and diatomaceous earth (kieselgur), used as a filter aid. The results showed that PVPP, charcoal and casein were more effective at removing trans- and cis-resveratrol both in synthetic wine and in commercial wines. In all the wines tested the other fining agents gave a limited decrease (2 – 5%) of trans- and cis-resveratrol. After charcoal and PVPP treatments, significant correlations were observed between the percentage of residual resveratrol and the total phenols in the wines. Received: 16 June 1997     

The evaluation of remedial treatments for wine affected by Harmonia axyridis

This study evaluated the efficacy of a range of commercially available fining agents and other interventions on reducing 2‐isopropyl‐3‐methoxypyrazine (IPMP) concentration and taint characteristics of white and red wine affected by Harmonia axyridis (HA). Wines fermented in the presence of HA beetles were treated with bentonite, activated charcoal, oak chips, deodorized oak chips and either ultraviolet (red wine) or visible (white wine) light. IPMP concentrations were lowered by activated charcoal in white wine and deodorized oak in red wine. Treatment with oak chips reduced the intensity of HA‐associated sensory attributes (‘ladybug taint’) in both white and red wines, while other applications generally had no effect on white wine and limited effect on red wines.     

Influence of wine-making protocol and fining agents on the evolution of the anthocyanin content,colour and general organoleptic quality of Vinhão wines

This paper reports the evolution, over two years, of the anthocyanin content, colour and organoleptic quality of red wines prepared from a single batch of Vinhão grapes by means of three different protocols (maceration/fermentation with conventional pumping-over or in rotary vats, and fermentation after initial carbonic maceration), with and without the use of four different fining agents (polyvinylpolypyrrolidine, gelatin, egg albumin, and casein). Carbonic maceration led to lower anthocyanin levels and less intense coloration than the other two methods immediately following vinification, but during storage the carbonic maceration wines underwent less colour degradation than the others, so that after two years the colour density differences among the three were negligible. Wines treated with fining agents tended to have somewhat lower anthocyanin levels and, especially in the case of PVPP, less intense colouration than untreated wines, and their colour was at best only marginally more stable during storage, but they nevertheless generally achieved higher panel ratings for organoleptic quality than untreated wines, especially as regards taste.     

正韵律砂层中渗透率级差对石油运移和聚集影响的模拟实验研究

正韵律砂层中渗透率级差对石油运移和聚集二维模型实验研究结果表明：①在同一注油速率下,小级差的正韵律砂层比大级差的正韵律砂层更易发生油的聚集,含油范围也更大;②当注油速率小于１．０ｍＬ／ｍｉｎ时,在同一注油速率下,油可以充注小级差的正韵律砂层内各个不同渗透率的砂层,并在其中运移,而大级差的正韵律砂层内,只有渗透率较大的砂层才能充注油;③级差较小的正韵律砂层内渗透率较小的砂层油充注所需的临界注油速率小于级差较大的同类砂层;④注油速率为０．１ｍＬ／ｍｉｎ时,小级差正韵律砂层内油的运移和分布达到稳定状态的注油时间和注油量均大于大级差的正韵律砂层,而注油速率大于０．５ｍＬ／ｍｉｎ时,则相反。     

BIM技术助力工程项目精细化管理——BIM技术在九洲花园2．1．2期项目建造阶段的应用

目前工程项目管理存在海量数据难以获取、管理条线协同效率低等问题，这些问题很大程度上提高了建造过程中资金、成本管控风险。本文主要介绍了九洲花园2．1．2期项目施工过程中应用BIM技术，进行项目BIM模型的创建与维护、材料过程管控、各专业碰撞检查、虚拟施工指导等内容，有效地提升项目精细化管理水平。