Flavor automated analysis

Goals. The primary goal of this work was to adapt new instrumentation to the fully automated analysis of volatile flavor compounds in foods without compromising any other aspect of analytical capability. The goals of this work, in addition to automation, included ... 

WESTENDORF Automated Analysis of Volatile Flavor Compounds... 

A method for the automated analysis of volatile flavor compounds in foods is described. Volatile compounds are removed from the sample and concentrated via the dynamic headspace technique, with subsequent separation and detection by capillary column gas chromatography. With this method, detection limits of low ppb levels are obtainable with good reproducibility. This method has experienced rapid growth in recent years, and is now in routine use in a number of laboratories. 

Computers are pervading all areas of our life and, in this same way, they are pervading all areas of chemical research. In flavor analysis, computers with their information analysis capabilities are a natural ally with separation science which is an information generator. Our laboratory has extensive experience with the Hewlett-Packard 3357 Laboratory Automation System. The specific hardware which we have is given in Table I. 

New accessories are continually made available. This unit discusses the basics necessary to conduct SPME analysis for flavor analysis. An automated sampling and injection system is available from Varian. Supelco offers a manual sampling stand setup. Injection liners are available that reduce the injection port volume to presumably produce sharper peaks. Predrilled septa for the GC are available to reduce septum coring. 

The advantage of on-site and high-speed measurements are key motivations to apply IMS in traditional industrial interests, namely, analysis of feedstock purity and product composition, although these are, in this moment, somewhat limited in number and variety. An extension of this idea that has been explored in proof-of-concept applications is monitoring the processes or stages in production of food and beverages. In this application, the IMS measurement is considered objective in measures of odors or flavors, can be automated, and may be integrated into continuous, automated process control. 

The second analysis that is performed on most liquid ingredients and finished flavors is refractive index (RI). Refractive index is typically done using an Abbe refracto-meter in a smaller company or by automated systems in mid to large flavor companies. The Abbe refractometer is accurate to four decimal places, covers the RI range typically encountered in flavoring materials, and is rapid. The RI of a flavor is a function of all the components and their proportions. Therefore, this determination is very sensitive to mixture composition. RI and SG will detect many of the compounding errors made in the formulation area. 

Historically, GC was not routinely performed on finished flavorings. GC was slow, and the sample load did not permit this analysis on all outgoing products. However, the advent of automated operation and fast GC has resulted in GC being done on most finished flavorings. The purpose of running GC on a finished flavor may be more for insmance than to catch errors in formulation. Most compounding errors are caught by the simple RI, density, and sensory analyses. 

Headspace analysis involves chromatographing the vapors derived from a sample by warming it in a partially fQled vial sealed with a septum cap. After equilibration under controlled conditions, the proportions of volatile sample components in the headspace above the sample are representative of those in the bulk sample. The headspace vapors, which are under slight positive pressure, are sampled by a modified and automated injection system or gas s)uinge, and injected onto the column (Fig. 3(a)). The procedure is useful for mixtures of volatile and nonvolatile components, such as residual monomers in pol)uners, alcohol or solvents in blood samples (Fig. 3(b)), and flavors and perfumes in manufactured products, as it simplifies the chromatograms and protects the column from contamination by nonvolatile substances. 

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