Food products, experimental procedures

The methods I- 4 of sample preparation are classics. As a mle they give a high value of blank and some of them take a lot of time. Microwave sample preparation is perspective, more convenient and much more faster procedure than classical mineralization. There are some problems with the combination Cendall-Kolthoff s kinetic method and microwave sample preparation which discussed. The experimental data of different complex organic matrix are demonstrated (food products on fat, peptides, hydrocarbone matrix, urine etc). 

Dupuy and coworkers have reported a direct gas chromatographic procedure for the examination of volatiles in vegetable oils (11). peanuts and peanut butters (12, 13), and rice and com products (14). When the procedure was appTTed to the analysis of flavor-scored samples, the instrumental data correlated well with sensory data (15, 16, 17), showing that food flavor can be measured by instrvmental means. Our present report provides additional evidence that the direct gas chromatographic method, when coupled with mass spectrometry for the identification of the compounds, can supply valid information about the flavor quality of certain food products. Such information can then be used to understand the mechanisms that affect flavor quality. Experimental Procedures... 

Since the last symposium there have been several changes in attitudes or directions. One of these has been the recognition that alkali treatment of proteins is a chemical procedure, and in particular, a chemical modification. Another has been the recognition that, although there are still difficult problems in assessing the safety aspects of chemical modifications of foods, both chemical and enzymatic treatments can be useful in laboratory experimentation and, perhaps, in eventual application to food production. Increase in nutritional value through modifications is now recognized. 

A few of the many manuals on chemical analysis which include instructions on sample collection may be mentioned. For over 100 years, AOAC INTERNATIONAL, has published detailed experimental procedures for sampling, subsampling and pretreatment of natural materials with the latest volume (Horwitz 2000) containing procedures for materials such as agricultural liming materials, fertilizers, plants, animal feed and dairy products in various chapters. A chapter on sampling dairy and related products is in the book edited by Marshall (1993) on Standard Methods for the Examination of Dairy Products. Specific sampling procedures for various food commodities are summarized by Ihnat (1982), based mostly on the AOAC manual. 

Two similar experimental procedures have been used to quantify the skin contact effects of soluble silicates both are based on the Draize method(27). The first is the protocol adopted by the U.S. Food and Drug Administration and Consumer Product Safety Commission for determining the contact hazard of substances under the Federal Hazardous Substances Act, and is specified in 16 C.F.R. i1300.41 et seq. The second, is the protocol adopted by the U.S. Department of Transportation for determining the contact hazard of substances under the Federal Hazardous Materials Transporation Act, and is specified in 49 C.F.R. A173.240. 

Experimental Procedure Sensing of the DNA plays an important role in medicine as well as in food production or quality control. It is necessary in all these fields to target specific DNA sequence in the sample to detect the presence of diseases or pathogens. One of the most common ways for sensing of the DNA is by using fluorescence microscopy with fluorescently labeled DNA samples. For a successful biosensing, the DNA probe needs to be immobilized on the surface. It is designed to match the sequence of interest in the tested sample and is fully complementary to that sequence. 

Hazard identification, step one, means identification of new chemicals or other factors that may cause harmful health effects. Previously, novel hazards were usually observed in case studies or after accidents or other excessive exposures, usually in occupational environments. Today, thorough toxicity studies are required on all pesticides, food additives, and drugs. New chemicals also have to be studied for their potential toxic effects. Thus, earlier hazards were in most cases identified after they had caused harmful effects in humans. Today, most chemical products have been evaluated for their toxicity with experimental animals. Therefore, hazard identification has become a preventive procedure based on safety studies conducted before a chemical compound or product reaches the market, and before individuals are exposed to it. ... 

In more recent times chemically defined basal media have been elaborated, on which the growth of various lactic acid bacteria is luxuriant and acid production is near-optimal. The proportions of the nutrients in the basal media have been determined which induce maximum sensitivity of the organisms for the test substance and minimize the stimulatory or inhibitory action of other nutrilites introduced with the test sample. Assay conditions have been provided which permit the attainment of satisfactory precision and accuracy in the determination of amino acids. Experimental techniques have been provided which facilitate the microbiological determination of amino acids. On the whole, microbiological procedures now available for the determination of all the amino acids except hydroxy-proline are convenient, reasonably accurate, and applicable to the assay of purified proteins, food, blood, urine, plant products, and other types of biological materials. On the other hand, it is improbable that any microbiological procedure approaches perfection and it is to be expected that old methods will be improved and new ones proposed by the many investigators interested in this problem. 

Harmonization of standards and evaluation procedures in the area of consumer safety will strengthen public confidence in the safety of food stuffs of animal origin, decrease trade barriers for food commodities and veterinary medicinal products, and help to reduce the amount of animal experimentation. In any... 

It was mentioned earlier that the standard procedure in the snack food industry is to discard oil when the free fatty acid in the fryer oil reaches or exceeds 0.5%. The experimental oil contained 2% free fatty acids, and yet the product flavor was unaffected until the oil began to oxidize. 

It is necessary to correlate the composition of the volatile fraction of a product with sensory properties. In fact, less abundant components can be relevant to the aroma of a food. This problem can be solved by performing an adequate statistical treatment to correlate the GC-MS data to experimental sensory evaluations. The success of this approach strongly depends on the reliability of the sampling procedure used. In this context, a combined analytical-sensory technique, such as GC-olfactometry, can help to solve these problems. 

---