Overview of parameters

Resveratrol is a polyphenol that occurs as a cis and trans isomer in many plants to protect them as phytoalexin from parasites and fungal infections. Vines store resveratrol mainly in the leaves and berry pods in order to protect themselves, for example, from infestation by botrytis or downy mildew. Due to the distribution in the berries and the differences between red and white grape varieties, fresh white grape must contains up to 200 μg / l, while red grape must contains up to 1100 μg / l resveratrol. In red wine, the concentration is much higher with 2000 to 12000 μg / l. The contents of rosé and white wine are correspondingly lower. The 3-glucosides of resveratrol, which also occur naturally, are referred to be named as cis- or trans-piceid.

Dear customer,

Please take note, our laboratory is closed from December 23rd 2017 until January 1st 2018. The reception of your samples is assured on weekdays. We will start working on January 2nd 2018.

In urgent cases you can contact us by phone or by email (info [at] institut-heidger[.]de).

Thank you very much.
Your Institute Heidger

For the identification of turbidity’s and unknown particles in liquid products, the microscopy is a very important component. With a special microscope, the turbidity or the particle can be viewed in detail and even the size can be measured. Afterwards our trained staff is either able to identify the turbidity on base of experience value and literature Information or can do a suitable Analysis (e.g. analysis of cations and metals) for the identification and the final evaluation.

Sweeteners are used in some foods as a sugar substitute. Most of the producs have legal limits for the usage of sweeteners, so that this analysis is able to check the compliance with the limits. In other products like spirits the usage is forbidden, so that an illegal usage can be proved by this method.

The following sweeteners are checked routinely in our institute in different products:
Folgende Süßstoffe können routinemäßig in verschiedenen Produkten analysiert werden:

• Acesulfame K (E 950)
• Aspertame (E 951)
• Cyclamate (E 952)
• Neohesperidine DC (E 959)
• Neotame (E 961)
• Saccharine (E 954)
• Sucralose (E 955)
• Stevioglucosides (E 960)

Since December 2016 a nutrition table is obligatory for all products (with some exceptions like products with more than 1,2% vol. of alcohol). This table must suit with the legal requirements, so that normally the following values must appear:

• Calorific valuw
• Fat
• Saturated fatty acids
• Carbohydrates
• Sugar
• Salt
• Protein

For a correct nutrition table, it is important to know the content of different parameters like the sugar content of the product. On base of different analysis parameters we are able to calculate the correct values for the nutrition table for different beverages, so that you get a nutrition table which is suitable to the legal requirements.

In the isotope analysis different stable isotopes, which do not change during the product processing, are analysed in the product, so that an individual fingerprint of the product accures. Therefore, a statement of the authenticity of the product or the raw material can be made. Furthermore, the origin of the product can be evaluated and an addition of water and sugar (C3 or C4) can be determined.
According to the central issue the following isotop ratios can be analysed:

• D/H (I) in ethanol
• ¹³C/¹²C in ethanol
• ¹³C/¹²C in sugar
• ¹⁸O/¹⁶O in winewater
• ¹⁸O/¹⁶O in ethanol
• ¹⁴C Kohlendioxid
• ¹³C/¹²C in Carbon dioxide

Into almost all beverages, whether alcoholic or not, different amounts of different sugars occur, which are usually characteristic for the respective product. Depending on the nature of the drink, there exist legal limits for the sugar content, so that certain minimum or maximum concentrations have to be satisfied, so that control of sugar content is essential. Sugar content of a product is summarized as sugar before and after inversion, whereby every type of sugar can be detected individual analytically.

Sugar before inversion

Sugar before inversion is the total sugar content of a product as sum from glucose and fructose.

Sugar after inversion

If products like sparkling wines contain sucrose aside from glucose and fructose the total content of sugar is expressed as sugar after Inversion. Inversion is understood to be the cleavage of the disaccharide sucrose into the corresponding monosaccharides glucose and fructose. For the calculation of the sugar after inversion, the content of glucose and fructose, which could be produced by inversion of the sucrose, is added to the sum of the glucose and fructose present in the sample.

The total content of sugar in wines and sparkling wines results to the terms of indication of sweetness. FAus diesem Grund ist das Wissen des Zuckergehaltes für die Charakterisierung eines Weines unerlässlich. Neben der Zuordnung der Geschmacksangabe kann über das Verhältnis von Fructose und Glucose bzw. das Vorhandensein von Saccharose in einem Wein eine Anreicherung sowie eine unerlaubte Süßung mit Zucker nachgewiesen werden.

Ähnliche Regelungen zur Geschmacksangabe wie bei Wein existieren auch beispielsweise für Apfelweine, sodass auch hier zur Charakterisierung des Produktes der Gehalt des Zuckers bekannt sein sollte.

die verschiedenen Zuckerarten

Saccharose
Saccharose zählt zur Gruppe der Zucker und ist ein Disaccharid. Diese kommt in sehr hohen Konzentrationen im Mark des Zuckerrohrs sowie in der Zuckerrübe vor, weswegen diese Pflanzen in der Regel zur Zuckergewinnung verwendet werden.

In den Rohstoffen eines Weines, also den Trauben bzw. dem Most kommen nur sehr geringe Gehalte an Saccharose vor, da die Rebe den Zucker in den Trauben in Form von Glukose und Fruktose einlagert. Jedoch kann dennoch im Most dieser Zucker in größeren Mengen vorkommen, da die Zugabe zur Erhöhung des Alkoholgehaltes (Anreicherung bzw. Chaptalisation) bis zur Qualitätsstufe der Qualitätsweine in Weinbauzone A erlaubt ist. Diese invertiert im Most zu Glukose und Fruktose, welche anschließend zu Alkohol vergoren werden. Eine Zugabe von Saccharose zum Wein um diesen zu süßen ist in Europa nicht erlaubt, sodass keine größeren Gehalte im fertigen Wein vorkommen dürfen.

Eine etwas andere Gesetzgebung liegt im Hinblick auf Schaumweine vor, da hier sowohl in der Fülldosage (vor der zweiten Gärung) wie auch in der Versanddosage (zur Einstellung der Restsüße) Saccharose verwendet werden darf. Aus diesem Grund können in Schaumweinen durchaus größere Gehalte dieses Zuckers zu finden sein.

In anderen Produkten wie beispielsweise Fruchtschorlen, weinhaltige Getränke oder andere Mischgetränke wird Saccharose häufig zur Einstellung der Süße verwendet.

Glukose / Glucose
Glukose ist ein Einfachzucker und gehört zu den Kohlenhydraten. Im Traubenmost bildet diese Hexose gemeinsam mit der Hexose Fruktose den größten Anteil an Zuckern. Diese beiden Substanzen liegen im Traubenmost ungefähr im Verhältnis 1:1 vor. Bei der Gärung verschiebt sich dieses Verhältnis jedoch, da die Hefe (Saccharomyces cerevisiae) glucophil ist. Das heißt, dass diese vermehrt den Glukoseanteil verstoffwechselt. Daher liegt nach der Vergärung eines Mostes im verbleibenden Zuckerrest mehr Fruktose vor. Das Glukose/Fruktose-Verhältnis ist somit folglich kleiner 1. Ist ein Wein mit Süßreserve nach der Gärung gesüßt wurden, so verschiebt sich dieses Verhältnis, da Süßreserve wie auch der Most ein Glukose/Fruktose-Verhältnis von 1:1 hat. Neben der Verwendung von Süßreserve kann mittels des Glukose/Fruktose-Verhältnisses auch die unerlaubte Verwendung von Saccharose zur Süßung nachgewiesen werden, da aus einem Molekül Saccharose bei der Invertierung sowohl ein Glukosemolekül wie auch ein Fruktosemolekül entsteht.

Fruktose / Fructose
Fructose is just like glucose, a simple sugar and is one of the carbohydrates. In the grape must, these hexose together with the hexose glucose form the largest proportion of sugars. These two substances are in the grape must approximately in relation to 1:1. In fermentation, however, this ratio shifts as the yeast (Saccharomyces cerevisiae) is Glucophil. This means that the glucose is increasingly metabolized. Therefore, after the fermentation of a must in the remaining residual sugar, there is a higher Fruktoseanteil. The glucose/fructose ratio is therefore less than 1. If a wine has been sweetened with Süßreserve after fermentation, this ratio shifts, since Süßreserve as well as the must has a glucose/fructose ratio of 1:1. In addition to the use of Süßreserve, the glucose/fructose ratio can also be used to demonstrate the illicit use of sucrose for sweetening, since a molecule of sucrose in inverting both a glucose molecule and a Fruktosemolekül Is.

Arabinose
Arabinose is a naturally occurring monosaccharide consisting of five carbon atoms. This pentose occurs in small quantities in the grape must and also in the wine. Arabinose is as the other pentoses unfermentable by yeast. Lactic acid bacteria can metabolize arabinose, which results in lactic and acetic acid. The total quantity of pentoses is higher in red wines and press wines than in white wine, since pentoses are predominantly enriched in shells and stalk scaffolds. In wine the content of arabinose is less than 1 g/L. If the total content of arabinose is higher than 2 g/L, this is a reference for an addition of fruit wines.

Galactose
Galactose is a hexose whis a hexose which occurs in most as well as in wine only in small amounts (up to 200 mg/L).

Mannose
Mannose is a hexose which occurs in most only in small amounts (up to 50 mg/L).

Melibiose
Melibiose is a reducing disaccaride. This disaccharide is made and metabolized exclusively by bacteria and other microbes.

Raffinose
Raffinose is a plant-trisaccharid. The Raffinose is composed of the three simple sugars galactose, glucose and fructose.
In some plants the raffinose replaces the starch as a storage carbohydrate. The trisaccharid occurs in large quantities in legumes, as well as in sugar cane and sugar beet.

Rhamnose
Rhamnose is a methyl substituted pentose, which can be found in grape must and in the wine in a concentration up to 400 mg/L.
Like Arabinose and Xylose, the Rhamnose is also part of cell walls. According to this, it is released by the influence of fruit-specific enzymes and in the infestation of mould fungi (e.g. Bortrytis) by their hydrolytic effective enzymes from the polymer substances. Just like the Arabinose, the Rhamnose cannot be fermented by yeast.

Ribose
Ribose is a monosaccaride with five carbon atoms. It occurs in most naturally only in small amounts and as well as the other pentoses, it is not going to be metabolized from the yeast. Through the malolactic fermentation lactic acid and acetic acid is formed from the ribose. In wine, the Ribose itself plays practically no role.

Xylose

Xylose, which is found in the wood of beech and spruce, is a monosaccharide (simple sugar) with five carbon atoms (a pentose as well as arabinose, rhamnose and ribose), which is not metabolized in the human organism. Xylose is considered to be not or only barely fermentable. Xylose is present in wine only in very small quantities.

in wine and sparkling wine

Anthocyanins are red until slightly blue secondary plant pigment, these are built during grape ripeness into grape’s skin against sun. These pigments have to be isolated from grape’s skin in the course of the red wine winemaking. Colour of red wine also depends on its pH-value. Red wines with low acid contents and in consequence high pH-values shimmer slightly blue under dark red in consequence of anthocyanins absorption.
Determination of anthocyanins occur as percentage values of the anthocyanins listed below, so that from percentage distribution grape variety can be implied. As consequence blends of vine varieties and falsifications can be recognized through colour spectrum of a wine.

• Cyanidin-3-glucoside
• Petunidin-3-glucoside
• Paeonidin-3-glucoside
• Paeonidin-3-acetyl-glucoside
• Malvidin-3-acetyl-glucoside
• Paeonidin-3-cumaryl-glucoside
• Malvidin-3-cumaryl-glucoside

Negative-charged ions shift during an electrolysis to anode (positive terminal), therefore the name “anions” was chosen. Anions arise out through electron acceptance. Anions are as well as cations for plants minerals and trace elements, that’s why every product has a typical composition. From content of anions and cations the value of ash can be generated, furthermore it is possible to carry out assessments about the ingredients and therefore quality of product. Mineral composition changes through technical modifications of products or addition of water, such changes can be detected through the analysis of anions or cations.

Chloride

Chloride content of commercial wine is between 10 and 100 mg/l, whereby higher concentrations into wine from grapes grow up beside the ocean are possible. Wine from grapes grow up not beside the ocean, high chloride content derives from contaminations or illegal addition of table salt.
Fruit juices have also low chloride content, whereby location to ocean has influence to the content as in wine.
Chloride plays an important role for quality and taste of beer, it has influence to beer’s full-bodied character. In higher concentration, it leads to salty taste in beer.

Fluoride

German wine has in average 0,12 mg/l fluorine, whereby Germany has two legal limits for fluorine in wine. Legal limit for wine from wine-growing materials not treated with cryolite is 1 mg/l fluorine, while legal limit for wine from wine-growing materials treated with cryolite is 3 mg/l fluorine.

Nitrate

Nitrates are as nitrogen compound in the right amounts for growth of yeasts and fermentation necessary. Nitrates play an important role at plants growth, but it is also important not to use too much nitrate, because the vine can react with disease symptoms or “untypical aging off-flavors” develop later into wine together with other factors. Furthermore, certain amount of nitrate is important for fermentation as yeast assimiliable nitrogen.

Fruit juices have normally low nitrate contents, so that high contents are indications for external addition of drinking water for example.

During the brewing process of beer high nitrate concentration are able to react to nitrite. Nitrite has an inhibitory effect on yeasts, so that high nitrate contents into beer or brewing water have to be avoided.

Phosphate

Organic phosphate occurs as well as inorganic phosphate into wine. Concentration is between 100 to 1000 mg/l, according to quality, origin or vintage. High concentration of phosphate into wine are due to the allowing addition of diammoniumphosphate to fresh grapes, grape must or grape must in fermentation. This nutrient salt can be used to a limit of 1 g/l, this comply with a content of phosphate of 725 mg/l.

High concentrations of phosphate into fruit juices are due to dilution of juices with water or addition of phosphate based compounds. These products have also high ash contents.

Sulphate

Wine has strongly changing sulphate contents between 100 to 1500 mg/l expressed as potassium sulphate. In addition to the possibility of determination of sulphate with ion chromatography, it is also possible determine sulphate gravimetric.

Juices have low sulphate contents; whereby higher values can be detected into sulphured raw juices or into desulphurised grape juices.

Sulphate influences the taste of beer; whereby high concentrations highlight hoppy character of beer.

In wine and sparkling wine

For wine, sparkling wine and semi sparkling wine, there are different limits for contents of carbon dioxide (g/l) or overpressure (bar) depending on quality. Therefor the evaluation of carbon dioxide concentration or Overpressure is an important parameter for the marketability.
Furthermore, the concentration of carbon dioxide or overpressure is an important quality parameter, in that the freshness of the product is influenced through the content of carbon dioxide.
For wine exist a maximum value of 3 g/l (~ 1bar) carbon dioxide, whereas semi sparkling wine must have an overpressure of at least 1 bar and sparkling wine (Sekt) must have an overpressure of at least 3,5 bar. Depending on production of semi sparkling wine or sparkling wine, there is a difference between exogenous and endogenous carbon dioxide:

Exogenous carbon dioxide will be added to the product after the completed fermentation. This kind of carbon dioxide is normally technical produced.

Endogenous carbon dioxide is from first and second fermentation of the product. This carbon dioxide stays directly in product as for example during the traditional method of sparkling wine or it could be collected during the fermentation and added to the product later again.

In beer

The dissolved carbon dioxide content of beer is an important quality characteristic. The “Rezenz” (tingle) of beer depends essentially on appropriate concentrations of carbon dioxide (bottom-fermented beer 0,40-0,60 GG%, top-fermented beer 0,40-0,80 GG%), whereby beer with stale taste has low carbon dioxide concentrations. Furthermore, carbon dioxide plays an important role for foam formation. Besides the concentration of carbon dioxide has a bearing on thresholds of flavouring components and aromatic components, so that flavour profile is influenced.