Adulteration sources

Applications. The most ubiquitous use of infrared spectrometry is chemical identification. It has long been an important tool for studying newly synthesi2ed compounds in the research lab, but industrial identification uses cover an even wider range. In many industries ir spectrometry is used to assay feedstocks (qv). In the flavors (see Flavors and spices), fragrances (see Perfumes), and cosmetics (qv) industries, it can be used not only for gross identification of feedstocks, but for determining specific sources. The spectra of essential oils (see Oils, essential), essences, and other natural products vary with the season and source. Adulteration and dilution can also be identified. 

But by applying the process of fractional distillation to a sample, and determining the characters of numerous fractions, the actual number of available determinations may be, and frequently is, so largely increased that there is practically no chance of the adulterator being able to standardise his oils to meet all these figures. This proposition, of course, fails where it is possible to use a substance obtained from a cheaper source which is identical with one contained naturally in the oil, and which is added in such amount as not to materially exceed, in the total, the amount naturally occurring in the essential oil in question. 

The authors discounted the existence of two chemotypes of L. dulcis on the grounds that no evidence appears to exist as to this level of plasticity in this species. Rather, they suggested that the problem likely arose in the source of the Mexican specimen, which consisted of plants collected in the vicinity of Tlayacapan (Morelos) and mixed with hierba dulce purchased in a market in Mexico City. Adulteration of the commercial product, not an uncommon practice, likely accounts for the striking chemical differences between the two specimens. 

Quantitative and qualitative anthocyanin composition must be known in order to determine the feasibility of application of new plant materials as anthocyanin-based colorant sources and to understand the relationships of structures and functions of anthocyanins. In addition, anthocyanin compositions of fruits and vegetables have also been used to detect adulteration of anthocyanin-based products - and as indicators of product quality. - ... 

Highly diluted honey is unlikely a realistic adulteration practice. Honey water content can naturally be lower than 13.6% or higher than 23% based on the source of the honey, climate conditions, and other factors. Fermentation does not usually become a problem in honeys if water content is less than 18%. 

So-called street drugs for identification of principal components, impurities, adulterants, and cutting agents in order to establish the method of synthesis, to compare the samples seized from users with those from dealers, as well as for comparative analysis or so-called profiling to find out the source of the material. 

Natural products such as wine, fruit juices, flavors, oils, and honey are prime targets for fraudulent adulteration because of their high prices. Sophisticated analytical methods (perhaps including isotope abundance measurements) are required to detect whether natural ingredients have been mixed with ones from cheaper synthetic sources. Isotope abundance is markedly different for natural vs. synthetic molecules and these differences can be exploited to detect adulteration. Several examples follow. 

Honey and maple syrup are complex products of high market price (813C — 23%o). The main source of adulteration is cheap high fructose corn syrup (813C — 13%o) or cane sugar (813C —ll%o) and the adulterated product is easily detected at levels as low as 10% or so of added sugar. 

Surveillance is biased sampling directed at particular carcasses or products. Surveillance comes into play when the Program receives information from monitoring or other sources, e.g., from slaughter inspection, indicating that adulterating residues may be present. Product may be held until laboratory tests determine the appropriate regulatory action. 

The use of enantiomers as additional markers for taxonomic characterization of aromatic plants may be very helpful. The differences in the enantiomeric distribution of trans- and cis- sabinene hydrates in two Origanum species enable the species to be distinguished in spite of their similar essential oil compositions. A further study on the natural variation of the enantiomeric composition within a wild population may be carried out in order to examine the stability in a taxon (including the possible presence of chemotypes). The enantiomeric ratio of essential oil components is a reliable parameter for assessing quality because it may be indicative of adulteration, contamination, aging, shelf life, technological process and the botanical source of a specific chiral compound. ... 

Methanol or methyl alcohol can become an alcoholic s main source of alcohol because it is cheaper. Methanol is frequently used as an additive for industrial ethanol to circumvent taxes. Methanol may be purposely adulterated to make it less palatable, but it is used nevertheless Methanol ingestion can be fatal due to its CNS depressant effects. In addition it is toxic because it is a substrate for alcohol dehydrogenase forming formic acid and formaldehyde which... 

The purple coneflower Echinacea purpura, and its close relatives, E. angustifolia and E. pallida, are the source of the herb Echinacea, which is widely popular as a nonspecific immune stimulant. These perennials are native to the prairies of North America and are now widely grown garden ornamentals. The root and aerial parts of the plant are the portions used, and the preparation s potency can be verified by the transient tingling sensation produced when it is tasted. Echinacea contains alkamides, caffeic acid esters (echinacoside, cichoric acid, caftaric acid), polysaccharides (heteroxylan), and an essential oil. Some echinacea products are standardized for their echinacoside content. In the past, adulteration with American feverfew (Parthenium integri-folium) was common. Echinacea is now sold either by itself or in combination with golden seal or zinc for the treatment of colds and influenza. 

Research in Chinese medicinal herbs has been conducted for decades in China, Japan, and Korea and recently in the West. Unfortunately, language barriers and the unreliability of sources and herbal material have hampered progress. A basic scientific understanding of the Chinese herbal preparations is the first step toward building consumer confidence in herbal medications. Proper procedures to eliminate adulteration, contamination, and toxic side effects are also urgently needed to regulate the use of Chinese herbs. 

The protocols presented here allow one to analyze the anthocyanins in fruit juices, natural colorants, and extracts from various anthocyanin sources. These profiles are useful for the identification of species, varieties, and for quality assessment of commercial products. They are also used to detect misbranding or adulteration of fruit products with other anthocyanin containing fruits, juices, or colorants. 

More recently, enantiomer ratios have been used as evidence of adulteration in natural foods and essential oils. If the enantiomer distribution of achiral component of a natural food does not agree with that of a questionable sample, then adulteration can be suspected. Chiral GC analysis alone may not provide adequate evidence of adulteration, so it is often used in conjunction with other instrumental methods to completely authenticate the source of a natural food. These methods include isotope ratio mass spectrometry (IRMS), which determines an overall 13C/12C ratio (Mosandl, 1995), and site-specific natural isotope fractionation measured by nuclear magnetic resonance spectroscopy (SNIF-NMR), which determines a 2H/ H ratio at different sites in a molecule (Martin et al 1993), which have largely replaced more traditional analytical methods using GC, GC-MS, and HPLC. 

The second category of adulteration is by far the most common. For example, apple juice will normally contain around 11% by weight of solids. At least 90% of these solids are carbohydrates - sucrose, dextrose and fructose predominating. Considerably cheaper sources of carbohydrates can be found, and the simple addition of a mixture of carbohydrates in roughly the same proportion as those found naturally in apple juice can be used to stretch apple juice by a considerable proportion. In more sophisticated forms of adulteration the added components can be made to cany a similar signature to the juice. 

Fructose syrup. In addition to the glucose/fructose syrups mentioned above, a fructose syrup has been produced using inulin as a source. Inulin is the fructose analogue of starch, and the chicory root is the standard source for commercial hydrolysis. Fructose syrups are usually too expensive for routine use in beverage production but they have been employed where a particular claim is to be made for fructose. They have also been used for the adulteration of fruit juices as they are chemically difficult to detect. Detection is possible at the sub-molecular level by techniques such as stable isotope ratio measurement. Fructose is also manufactured using sucrose as a starting material. 

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