Ascorbic acid and white wine production: a review of beneficial versus detrimental impacts

We review the use of ascorbic acid in winemaking and the benefits as well as the detrimental outcomes associated with its use. Initial discussion focuses on the antioxidant activity of ascorbic acid. The impact of the wine matrix and wine production practices, especially storage in bottle and oxygen ingress, on its antioxidant efficiency is discussed. The complementary roles of the antioxidant pair, ascorbic acid and sulfur dioxide, are presented. Thereafter, the ability of ascorbic acid to contribute to spoilage processes is covered. This includes both pro‐oxidant and non‐oxidative mechanisms induced by ascorbic acid that may lead to a reduced shelf life of white wine. Based on this review of scientific literature, the conditions most conducive to the beneficial impacts of ascorbic acid in wine are highlighted. Areas where lack of chemical knowledge still exists are identified for future research.     

Astaxanthin: a review of its chemistry and applications

Astaxanthin is a carotenoid widely used in salmonid and crustacean aquaculture to provide the pink color characteristic of that species. This application has been well documented for over two decades and is currently the major market driver for the pigment. Additionally, astaxanthin also plays a key role as an intermediary in reproductive processes. Synthetic astaxanthin dominates the world market but recent interest in natural sources of the pigment has increased substantially. Common sources of natural astaxanthin are the green algae Haematococcus pluvialis, the red yeast, Phaffia rhodozyma, as well as crustacean byproducts. Astaxanthin possesses an unusual antioxidant activity which has caused a surge in the nutraceutical market for the encapsulated product. Also, health benefits such as cardiovascular disease prevention, immune system boosting, bioactivity against Helycobacter pylori, and cataract prevention, have been associated with astaxanthin consumption. Research on the health benefits of astaxanthin is very recent and has mostly been performed in vitro or at the pre-clinical level with humans. This paper reviews the current available evidence regarding astaxanthin chemistry and its potential beneficial effects in humans.     

Biogenic amines in wine: a review

Biogenic amines are formed from precursor amino acids, mainly by the microbial decarboxylation. The presence of these compounds plays a vital role in oenology because high amounts of them can lead to health problems. Thus, the origin, detection, and quantity of biogenic amines in wine are extremely important for winemaking. This study, focusing on the articles of latest 5 years, not only reviews the analytical methods used for the determination of biogenic amines but also describes the source of biogenic amines from the perspective of microbiological and oenological factors and summarises the strategies for the degradation of amines. The information presented in this review is important to alert about the inadequate quality of wine products, and efforts from the entire productive chain and the government are required to attain consumer safety.     

Red wine astringency: a review

The chemical and physical basis for red wine astringency is reviewed. Models describing the physiological foundation of astringency are presented and compared. The phenolic and other red wine components that evoke astringency are described, together with their sensory properties and the factors that affect their perception. The paper also presents a detailed account of the chemical properties of saliva and the possible modes of interaction between these and red wine phenolics that lead to the necessary physical changes in saliva required to elicit astringency. Reasons for differences in astringency perception across oral sites and amongst individual tasters are also discussed. It is concluded that whilst great advances have been made in the field of red wine phenolic chemistry in recent years, a better understanding of the effect of wine polyphenol-salivary protein interaction on the rheological properties of saliva is required in order to gain a comprehensive understanding of red wine astringency.     

葡萄酒生产中的除酒石技术与实践

河北省涿鹿酿酒总厂是1949年建厂的国有中型企业，1958年开始生产葡萄酒，参加了我国名优葡萄酒的开发和研制，现已形成了年产5000吨葡萄酒的生产规模，通过几十年的研究和模索，生产技术达到了国际及国内领先水平，生产的“桑乾河牌干白、干红葡萄酒”和“华西村牌干红葡萄酒”受到了我国酿酒专家郭其昌、国际评酒师田雅丽等高级工程师的高度评价和认可，并荣获中国食品工业协会授予的“中国名优食品”称号。众所周知，葡萄酒产品的质量，除了符合GB/T15037-94的感观指标和理化指标外，就是要保证葡萄酒的稳定性，不致发生货架沉淀现象。…     

Acetic acid bacteria spoilage of bottled red wine -- a review

Acetic acid bacteria (AAB) are ubiquitous organisms that are well adapted to sugar and ethanol rich environments. This family of Gram-positive bacteria are well known for their ability to produce acetic acid, the main constituent in vinegar. The oxidation of ethanol through acetaldehyde to acetic acid is well understood and characterised. AAB form part of the complex natural microbial flora of grapes and wine, however their presence is less desirable than the lactic acid bacteria and yeast. Even though AAB were described by Pasteur in the 1850s, wine associated AAB are still difficult to cultivate on artificial laboratory media and until more recently, their taxonomy has not been well characterised. Wine is at most risk of spoilage during production and the presence of these strictly aerobic bacteria in grape must and during wine maturation can be controlled by eliminating, or at least limiting oxygen, an essential growth factor. However, a new risk, spoilage of wine by AAB after packaging, has only recently been reported. As wine is not always sterile filtered prior to bottling, especially red wine, it often has a small resident bacterial population (<10(3) cfu/mL), which under conducive conditions might proliferate. Bottled red wines, sealed with natural cork closures, and stored in a vertical upright position may develop spoilage by acetic acid bacteria. This spoilage is evident as a distinct deposit of bacterial biofilm in the neck of the bottle at the interface of the wine and the headspace of air, and is accompanied with vinegar, sherry, bruised apple, nutty, and solvent like off-aromas, depending on the degree of spoilage. This review focuses on the wine associated AAB species, the aroma and flavour changes in wine due to AAB metabolism, discusses the importance of oxygen ingress into the bottle and presents a hypothesis for the mechanism of spoilage of bottled red wine.     

Grain phytic acid content in japonica rice as affected by cultivar and environment and its relation to protein content

Phytic acid and protein contents in grains of japonica rice cultivars collected from different areas of China were assayed in this study. Meanwhile, a multi-location trial was conducted to determine phytic acid content of 24 cultivars grown at 4 locations with wide differences in ecological conditions. For 72 cultivars, phytic acid content ranged from 0.685% for Xiu217 to 1.03% for Huai9746, with a mean of 0.873%, and protein content ranged from 6.45% for Xiu52 to 11.1% for K45, with a mean of 8.26%. There was no significant correlation between grain phytic acid and protein content, suggesting the possibility of breeding japonica rice cultivars with low phytic acid and high protein contents. The effects of cultivars, environments (locations) and their interactions on phytic acid content were all highly significant, with the location having the largest effect. The highly significant interaction between cultivar and environment suggests that the correct evaluation of rice germplasm by phytic acid content should be conducted in multi-environments.     

Beef flavor: a review from chemistry to consumer

This paper briefly reviews research that describes the sensation, generation and consumer acceptance of beef flavor. Humans sense the five basic tastes in their taste buds, and receptors in the nasal and sinus cavities sense aromas. Additionally, trigeminal senses such as metallic and astringent are sensed in the oral and nasal cavities and can have an effect on the flavor of beef. Flavors are generated from a complex interaction of tastes, tactile senses and aromas taken collectively throughout the tongue, nasal, sinus and oral cavities. Cooking beef generates compounds that contribute to these senses and result in beef flavor, and the factors that are involved in the cookery process determine the amount and type of these compounds and therefore the flavor generated. A low‐heat, slow cooking method generates primarily lipid degradation products, while high‐heat, fast cookery generates more Maillard reaction products. The science of consumer acceptance, cluster analyses and drawing relationships among all flavor determinants is a relatively new discipline in beef flavor. Consumers rate beef that has lipid degradation products generated from a low degree of doneness and Maillard flavor products from fast, hot cookery the highest in overall liking, and current research has shown that strong relationships exist between beef flavor and consumer acceptability, even more so than juiciness or tenderness. © 2015 Society of Chemical Industry     

Chemistry of copper in white wine: a review

Copper is one element in wine that has considerable notoriety. While current winemaking practice tends to minimise the amount of copper that results from vineyard and winery sources, the addition of copper(II), either as its sulfate or citrate, to remove sulfidic off‐odours may result in an elevated concentration in the finished (bottled) wine. Residual copper in white wine has been linked to oxidative and reductive spoilage processes, although the mechanisms are at times speculative. The presence of copper has been implicated in haze formation (copper casse) and linked to protein instability. More recent concerns include the coexistence of residual copper and hydrogen sulfide in wine stored under low oxygen conditions. The chemistry of copper is important in both white and red wine. While there are some overlapping issues, especially with respect to sulfidic off‐odours, both white and red wine display their own unique chemistry. Thus, this review describes the state of knowledge of copper in white wine, differentiating between evidence‐based claims and speculation. It also identifies areas of research that will provide a much clearer understanding of the role of copper in wine spoilage.     

Ascorbic acid in food: Development of a rapid analysis technique and application to diffusivity determination

A rapid, easy to handle and low cost assay of ascorbic acid was developed, which consists in miniaturization on microplate of a redox reaction monitored spectrophotometrically, the signal being directly related to the concentration of ascorbic acid in the sample. This method was investigated in accordance with the prerogative of regulation covering food additives in terms of linear range/linearity, limits of detection and quantification, accuracy (including trueness and precision), robustness and selectivity. The application of the method was tested to determine ascorbic acid diffusivity in agar gel used as an aqueous food simulant. The diffusivity value obtained was 0.31 × 10^?9 m² s^?1, with a confidence interval of 20% at 95% level. Accuracy of the assay and of the point’s location on ascorbic acid profiles were examined by Monte-Carlo method to assess their influence on accuracy of diffusivity value obtained. Assay uncertainty was clearly demonstrated to be a critical parameter.     

乳酸菌的培养方法及在葡萄酒中的应用

采用109#培养基,使用不同方式对乳酸菌进行培养研究。结果表明:平板培养条件要求高,在目前条件下,几乎培养不出;斜面培养比较容易,但只能定性;液体培养能估测出最大活菌数;以上培养方式在葡萄酒中的乳酸菌检测方面都处于摸索阶段。     

氨基酸分析技术及其在皮革化学中的应用

论述了氨基酸分离分析技术的发展状况 ,分析检测原理以及在皮革工业中的应用     

Impact of exogenous tannin additions on wine chemistry and wine sensory character

Tannins are an important part of wine quality and are frequently added during winemaking. Tannin additives and their impact on wine are poorly documented. This work sought to characterize a range of enological tannins and their contribution to wine quality. Enological tannins were analysed for protein precipitable tannins and iron reactive phenolics. One tannin product was added to a Merlot wine during barrel ageing, at a range of concentrations from 60 to 300 mg/l. Condensed and hydrolysable tannins were added to Cabernet Sauvignon wine post-pressing at a recommended and excessive rate. Wines were analysed for anthocyanin, small and large polymeric pigment, precipitable tannin, iron reactive phenolics and sensory character. Enological tannins contained 12-48% tannin and recommended additions had little impact on wine tannin. High tannin additions were readily measured in the wines and were discriminated in sensory analysis with lower intensities of most parameters except brown colour, bitterness and earthy character. Recommended addition rates are too low to impact the measured tannin concentration of Merlot and Cabernet Sauvignon wines from Washington (USA). High enological tannin additions had a measureable impact on final wine had a negative impact on sensory character. Tannins are added to wines for a range of reasons and represent one of many input costs in an industry increasingly seeking efficiencies in response to global economic circumstances, over-supply and an ongoing price point squeeze. This research suggests many tannin additions may be unjustified and have limited or negative impacts on quality.     

Potential uses and applications of treated wine waste: a review

Recently, there has been an upsurge in the exploitation of the waste materials generated by the wine industry. Wine waste is characterised by the presence of natural antioxidants much safer than synthetic antioxidants. Wine waste‐derived antioxidants have been recently used in the food industry. Moreover, wine waste can be potentially used as soil conditioner, as adsorbent for heavy metals, for fertiliser and for pullulan production. This review aims at presenting the most important and economically viable applications of treated wine waste.     

The chemistry of coffee extraction in relation to polysaccharides

Technically produced extracts from roasted Arabica and Robusta coffees contain, just like the infusions prepared in the home, 20–36% carbohydrates, depending on the degree of extraction. They are composed predominantly of mannan and galactan in about the same proportions, the share of glucan and araban making up only 1–3% of the extracts. With dialysis a group of polysaccharides with a molecular weight of more than 10 000 can be separated. They make up about half of the carbohydrates of the extracts. Their composition corresponds to that of the latter. Finally, one can obtain yet another group of almost intact high polymeric carbohydrates as copper complexes. However, they consist only of mannan and galactan, mannan predominating significantly. Arabica and Robusta coffees showed differences in this respect. Whereas Arabica coffee was able to release only a certain amount of these very high-polymeric carbohydrates, Robusta coffee delivered ever greater amounts of these polysaccharides with increasing extract yields.     

Impact of closures on wine post-bottling development: a review

Closures have an important influence on wine quality during ageing in bottle. The increasing diversity of wine stoppers and their effect in wine development after bottling has been a subject of intense research. This review focuses on the impact of closures on wine quality during bottle storage. Studies dealing with the effectiveness of closures in protecting wine quality during storage and research conducted in order to determine the impact of closures on wine organoleptic properties are discussed. Several types of closures are described and, more particularly, differences in their permeability leading to variable levels of oxygen in the bottle, the role of closures on the removal and/or addition of undesirable compounds from/to wine are critically reviewed.     

黄酒中的γ-氨基丁酸及其功能

采用OPA-FMOC柱前衍生HPLC法对黄酒中的GABA进行了测定。结果显示：该方法回收率在95％以上，RSD为3．1％，古越龙山绍兴黄酒中GABA含量为167g/L～360g／L，说明古越龙山绍兴黄酒是一较理想的富含天然GABA的保健饮品。     

Products of ozone-initiated chemistry in a simulated aircraft environment

We used proton-transfer-reaction mass spectrometry (PTR-MS) to examine the products formed when ozone reacted with the materials in a simulated aircraft cabin, including a loaded high-efficiency particulate air (HEPA) filter in the return air system. Four conditions were examined: cabin (baseline), cabin plus ozone, cabin plus soiled T-shirts (surrogates for human occupants), and cabin plus soiled T-shirts plus ozone. The addition of ozone to the cabin without T-shirts, at concentrations typically encountered during commercial air travel, increased the mixing ratio (v:v concentration) of detected pollutants from 35 ppb to 80 ppb. Most of this increase was due to the production of saturated and unsaturated aldehydes and tentatively identified low-molecular-weight carboxylic acids. The addition of soiled T-shirts, with no ozone present, increased the mixing ratio of pollutants in the cabin air only slightly, whereas the combination of soiled T-shirts and ozone increased the mixing ratio of detected pollutants to 110 ppb, with more than 20 ppb originating from squalene oxidation products (acetone, 4-oxopentanal, and 6-methyl-5-hepten-2-one). For the two conditions with ozone present, the more-abundant oxidation products included acetone/propanal (8-20 ppb), formaldehyde (8-10 ppb), nonanal (approximately 6 ppb), 4-oxopentanal (3-7 ppb), acetic acid (approximately 7 ppb), formic acid (approximately 3 ppb), and 6-methyl-5-hepten-2-one (0.5-2.5 ppb), as well as compounds tentatively identified as acrolein (0.6-1 ppb) and crotonaldehyde (0.6-0.8 ppb). The odor thresholds of certain products were exceeded. With an outdoor air exchange of 3 h(-1) and a recirculation rate of 20 h(-1), the measured ozone surface removal rate constant was 6.3 h(-1) when T-shirts were not present, compared to 11.4 h(-1) when T-shirts were present.