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In the beverage and food industries, sensory analysis is an essential part of a quality control program; for example, it serves as a valuable tool in determining the flavor stability of a beverage, in detecting any aberrations in quality, in promptly discovering fluctuations in a beverage or even in measuring the quality and intensity of certain flavor and aroma impressions. These aspects of sensory analysis represent points whereupon testing performed using laboratory equipment produces either inadequate results or fails to provide results at all. Sensory evaluation of products also affords a rapid, sensitive and specific means of assessing them. Many aroma compounds can be more readily detected with the human odor receptor cells, for the simple reason that these cells are more sensitive to such compounds than physico-chemical detectors. Results obtained from the chemical or biological analysis of finished products generally first become significant when they are consistent with results from sensory evaluation.

Therefore, before foods are introduced on the market, they should undergo sensory testing. As part of this testing, the internal and external features of the food are evaluated with the assistance of human sense organs regarding their character (e.g., sweetness) and expression (intensity as a function of time). Visual, olfactory (odor), gustatory (taste), tactile (e.g., tingling), trigeminal (e.g., burning, stabbing), kinesthetic (e.g., crispy, chewy), auditory (acoustic) impressions in addition to temperature (temperature sense) and nociception (pain perception, sensation) are differentiated.

In the case of beer, beer-based beverages, soft drinks and mineral water, the assessment is typically restricted to olfactory, gustatory, tactile and trigeminal characteristics, because other analysis methods, for example, for determining the foam stability of beer, are more accurate than a visual assessment.

Sensory analysis of food differs significantly from organoleptic evaluations for determining a person’s perceived sensitivity to certain odors and flavors. Organoleptic testing is considered a subjective sensory assessment, the results of which cannot be verified statistically. With sensory analysis, by contrast, precise procedures are employed in evaluating foods, and results are statistically assessed. The test methods in sensory analysis are standardized at an international level and include, for example, techniques for calibrating devices, which measure the physico-chemical attributes of foods, in order to obtain accurate results. Likewise, a sensory panel must be subject to certification, training and constant testing, with the ultimate goal of providing objective, accurate and reproducible results. These, in turn, allow conclusions to be made regarding the technology, raw materials and storage conditions. However, sensory analysis in the beverage industry is not only pertinent for the final product but also extends to the raw materials (e.g. brewing water, malt, hops, carbon dioxide), intermediate products (e.g. seasoning, natural lactic acid, green beer), processing aids and operating supplies (e.g., filter aids, stabilizing agents, air), auxiliary equipment and associated paraphernalia (e.g., closures, containers). Sensory analysis should comprise roughly one-third of the total analytical testing in a quality assurance program.

A distinction exists between simple sensory tests, which are part of the periodic monitoring in routine analysis of production processes, and up or down judgments, which must be reached in making ad hoc decisions. The latter are most often made by the person responsible for a particular production area, because a verdict is required quickly. Analysis of the finished product, however, must be performed by a sensory panel, because the opinion of one individual – regardless of their position – has little value. Due to ordinary inconsistencies in a person’s health, psychological condition and perception over the course of a day, a single individual is not capable of performing this function. For this reason, results from tastings by one person are always questionable and of no value for reliable quality control. The larger the number of participants on the sensory panel, the less influence the aforementioned sources of error have on the mean. Because differences also exist in the perceptive abilities of individuals, this requires that a sufficient number participate in the sensory analysis. Only an overall evaluation of the sensory panel’s results, especially if they can be expressed in a statistical form, can be considered reliable or plausible. Methods for conducting sensory analysis should therefore be selected only if they permit a statistical assessment of the results.
 

Food-grade lactic acid may be used to adjust the pH during mashing and wort production for products not subject to the regulations of the Reinheitsgebot or the German purity law concerning beer.

The VitaFast® microbiological assay for folic acid is carried out on microtiter plates and is suitable for the determination of total amount of folic acid in foods and beverages.

The beverage is sterile-filtered and diluted with sterile water for the determination of added folic acid.

The sample must be digested through enzymatic hydrolysis in order to measure the total content of folic acid (naturally occurring and added). 

The diluted sample and the folic acid assay medium are added to the wells of the microtiter plate, which are coated with Lactobacillus rhamnosus. Lactobacillus rhamnosus requires folic acid to grow. After an addition of folic acid, the microorganism exhibits growth until the vitamin is completely utilized. The plates are incubated at 37 °C for 44–48 h.

The growth of Lactobacillus rhamnosus is dependent upon the concentration of folic acid and is determined through measuring the turbidity. These results are compared with those obtained from a series of standard concentrations. The measurement is performed with a microtiter plate photometer at 610–630 nm (alternatively at 540–550 nm).

The VitaFast® microbiological assay for pantothenic acid is carried out on microtiter plates and is suitable for the determination of total amount of pantothenic acid in foods and beverages.

The beverage is sterile-filtered and diluted with sterile water for the determination of added pantothenic acid.

The sample must be digested through enzymatic hydrolysis in order to measure the total content of pantothenic acid (naturally occurring and added). 

The diluted sample and the pantothenic acid assay medium are added to the wells of the microtiter plate, which are coated with Lactobacillus plantarum. Lactobacillus plantarum requires pantothenic acid to grow. After an addition of pantothenic acid, the microorganism exhibits growth until the vitamin is completely utilized. The plates are incubated at 37 °C for 20–24 h.

The growth of Lactobacillus plantarum is dependent upon the concentration of pantothenic acid and is determined through measuring the turbidity. These results are compared with those obtained from a series of standard concentrations. The measurement is performed with a microtiter plate photometer at 610–630 nm (alternatively at 540–550 nm).

The VitaFast® microbiological assay for vitamin B₆ (pyridoxine) is carried out on microtiter plates and is suitable for the determination of total amount of vitamin B₆ in foods and beverages.

Vitamin B₆ is added as pyridoxine hydrochloride or as pyridoxine-5-phosphate. Since the phosphorylated vitamin B₆ form is not recognized by the microbes in the kit, the beverage is treated with acid phosphatase to determine the amount of supplemental vitamin B₆; if necessary, the beverage is diluted with sterile water from the test kit.

The sample must be digested through enzymatic hydrolysis in order to measure the total content of vitamin B₆ (naturally occurring and added). 

The diluted sample and the vitamin B₆ assay medium are added to the wells of the microtiter plate, which are coated with Saccharomyces cerevisiae. Saccharomyces cerevisiae requires vitamin B₆ to grow. After an addition of vitamin B₆, the microorganism exhibits growth until the vitamin is completely utilized. The plates are incubated at 30 °C for 44–48 h.

The growth of Saccharomyces cerevisiae is dependent upon the concentration of vitamin B₆ and is determined through measuring the turbidity. These results are compared with those obtained from a series of standard concentrations. The measurement is performed with a microtiter plate photometer at 610–630 nm (alternatively at 540–550 nm).

The VitaFast® microbiological assay for vitamin B₂ (riboflavin) is carried out on microtiter plates and is suitable for the determination of total amount of vitamin B₂ in foods and beverages.

The beverage is first treated enzymatically and subsequently extracted hot; if necessary, the beverage is diluted with sterile water from the test kit.

The sample must be digested through enzymatic hydrolysis in order to measure the total content of vitamin B₂ (naturally occurring and added). 

The diluted sample and the vitamin B₂ assay medium are added to the wells of the microtiter plate, which are coated with Lactobacillus rhamnosus. Lactobacillus rhamnosus requires vitamin B₂ to grow. After an addition of vitamin B₂, the microorganism exhibits growth until the vitamin is completely utilized. The plates are incubated at 37 °C for 44–48 h.

The growth of Lactobacillus rhamnosus is dependent upon the concentration of vitamin B₂ and is determined through measuring the turbidity. These results are compared with those obtained from a series of standard concentrations. The measurement is performed with a microtiter plate photometer at 610–630 nm (alternatively at 540–550 nm).