Proteins adulteration

Milk consists of 85—89% water and 11—15% total soflds (Table 1) the latter comprises soflds-not-fat (SNF) and fat. Milk having a higher fat content also has higher SNF, with an increase of 0.4% SNF for each 1% fat increase. The principal components of SNF are protein, lactose, and minerals (ash). The fat content and other constituents of the milk vary with the animal species, and the composition of milk varies with feed, stage of lactation, health of the animal, location of withdrawal from the udder, and seasonal and environmental conditions. The nonfat soflds, fat soflds, and moisture relationships are well estabhshed and can be used as a basis for detecting adulteration with water (qv). Physical properties of milk are given in Table 2. 

White, J. W. and Winters, K. (1989). Honey protein as internal standard for stable carbon isotope ratio detection of adulteration of honey. J. Assoc. Ojfic. Anal. Chem. 72,907-911. 

Fanton, C. Delogu, G. Maccioni, E. Podda, G. Seraglia, R. Traldi, P. MALDI-MS in die Dairy Industry 2. The Protein Fingerprint of Ewe Cheese and Its Application to Detection of Adulteration by Bovine Milk. Rapid Commun. Mass Spectrom. 1998,12, 1569-1573. 

Meat proteins comprise a water-soluble fraction (containing the muscle pigment myoglobin and enzymes), a salt-soluble fraction composed mainly of contractile proteins, and an insoluble fraction comprising connective tissue proteins and membrane proteins. As reviewed by Dierckx and Huyghebaert [107], HPLC analysis of meat proteins has been successfully applied to evaluate heat-induced changes in the protein prohle, to detect adulterations (addition of protein of lower value, the replacement of meat from high-value species with meat from lower-value species, etc.), and for specie identification in noncooked products (also for fish sample). 

Most of the applications of HPLC for protein analysis deal with the storage proteins in cereals (wheat, corn, rice, oat, barley) and beans (pea, soybeans). HPLC has proved useful for cultivar identihcation, protein separation, and characterization to detect adulterations (illegal addition of common wheat flour to durum wheat flour) [107]. Recently Losso et al. [146] have reported a rapid method for rice prolamin separation by perfusion chromatography on a RP POROS RH/2 column (UV detection at 230nm), sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis (PAGE), and molecular size determination by MALDl-MS. DuPont et al. [147] used a combination of RP-HPLC and SDS-PAGE to determine the composition of wheat flour proteins previously fractionated by sequential extraction. 

Saz and Marina [148] published a comprehensive review on HPLC methods and their developments to characterize soybean proteins and to analyze soybean proteins in meals. In the case of soybean derived products, a number of papers dealing with cultivar identification [149,150], quantification of soybean proteins [151-154], detection of adulteration with bovine milk proteins [151,155-158], and characterization of commercial soybean products on the basis of their chromatographic protein profile [159,160] have been published in the last years. Other studies deal with the analysis of soybean proteins added to meat [161-165], dairy [151,165-167], and bakery products [156,163,168,169]. The same research group developed perfusion RP-HPLC methods for very rapid separation of maize proteins (3.4 min) and characterization of commercial maize products using multivariate analysis [170], and for the characterization of European and North American inbred and hybrid maize lines [171]. 

The nature of plants having secondary metabolites as defensive agents greatly increases the expectation that there will be interactions with other botanical products and drugs. If well-established traditional botanical products are used according to directions, they are likely a low risk. Risk increases when botanical products are combined with conventional drug therapies and lies in the possibility of unknown natural product-drug interactions. Other risks include product deviation due to misidentification of species, the lack of standardization, or adulteration. Most of the interactions have been reported with cytochrome P-450 (CYP) 3A4, but there are interactions with other metabolism enzymes and transport proteins. 

Adulterants are any material deliberately added to the food material usually to reduce cost. Typical examples are incorporation of cheaper meats into more expensive ones or substituting non-meat proteins for meat. Additives, on the other hand, are added to impart improved flavor and/or texture characteristics to foods. However, either case creates problems for some of the consumers on health, economic and/or religious grounds. Therefore, it became imperative to... 

Fishmeal is an important, and sometimes the only, source of animal protein available for poultry feeding in most Asian countries (Ravindran and Blair, 1993). It is either imported or is produced locally. The local fishmeals contain between 400 and 500 g/kg CP, but are generally of low quality due to lack of control over raw fish quality, processing and storage conditions. Also, they are often adulterated with cheap diluents such as sand. Samples containing as much as 150 g/kg salt are not uncommon. This situation underlines the need for strict enforcement of quality control measures in several Asian countries. 

Faster and finer approaches for the analysis of food proteins are necessary for the assurance of food quality and safety (106). Generally, the most recent applications of microchip electrophoresis for the analysis of proteins or peptide biomarkers in foods include the characterization of protein extracts (107), the detection of high-quality value products adulterated with products of inferior quality (108), and the evaluation of the quality due to food storage or different technological process (109). 

Other applications involve detection of adulteration of dairy products with soy, pea, and wheat proteins (Haasnoot et al., 2001), presence of asrcasein in milk (the detection threshold for this protein was 0.87pg/mL) (Muller-Renaud et al., 2005), [3-casein in milk and cheese (Muller-Renard et al., 2004), and detection of peanut allergenic proteins (the detection threshold for this protein was 0.7 pg/mL) (Mohammed et al., 2001). 

It is claimed that commercially-available ultrasound equipment can measure the following quality parameters of dairy products levels of solids, solids non-fat (SNF), protein, water and fat solid fat content (SFC), colloidal stability, gelation point, adulteration with oil, particle size, particle size distribution, oil composition, protein denaturation and fat oxidation. This incomplete list represents an impressive contribution towards the solution of food quality measurement although the present authors are slightly skeptical regarding some of these claims. In this review only those applications will be addressed which are regarded as robust. 

Serum is classically added to cell cultures to provide hormones, growth factors, binding and transport proteins and other supplemental nutrients. Not all lots of serum have the same potential to support cell growth because they may have lower amounts of these components. Conversely, some lots may be toxic or inhibitory due to adulteration or contamination with microbes or viruses. Such sera may inhibit or kill cells at low serum concentrations due to high endotoxin levels or other inhibitory factors. This effect has nothing to do with the ability of the cells to adapt to serum-free conditions. The first step in serum-free adaptation is, therefore, to select a serum lot that can support growth of the cell line at low serum concentrations. 

Antimicrobial agents are known to be protein inhibitors therefore, it is important to titrate the amount of the agent to act as a preservative. This preservative must be able to kill or inhibit microbial agents that could contaminate the product and adulterate it. The other issue is that the concentration of the preservative or antimicrobial agent may inhibit the protein drug. A significant amount of laboratory time must be devoted to this project—much more than a unit dose will require. 

There are and have been available for some time a number of well-known texts which consider the chemistry of foods—their chemical character as carbohydrates, proteins, lipides, vitamins, vitagens, mineral matters, coloring matters, and related categories. In some of these the stress is on the nutritional aspects, as in Sherman s Chemistry of Food and Nutrition and Food Products Bailey s Food Products from Afar and Olsen s Pure Foods Their Adulteration, Nutritive Value, and Costs. One of the earliest of such texts was that of Richards and Woodman, Air, Water, and Food (1900), which stressed sanitary aspects. Possibly the first book to tie chemistry directly to food industries was Chemistry and Technology of Food and Food Products edited by Jacobs in 1944. 

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