Flavoring Materials Made by Processing

The term processed flavor is used in different contexts to describe (a) products where the natural raw materials lack a characteristic flavor profile and the desired aromatic profile is achieved only by deliberate processing (e.g., coffee) (b) flavorings created as a result of Maillard and other related reactions between amino acids and sugars (e.g., meat-like flavors) (c) flavorings resulting from controlled enzymatic reactions (e.g., enzyme-modified dairy products) (d) products made by fermentation (e.g., wines, vinegar) and (e) products of thermal reactions of lipids (e.g. French fry flavor). 

2 NATURAL PRODUCTS MADE BY ROASTING COCOA/CHOCOLATE 

The production of cocoa and chocolate from cocoa beans involves three prime processes (a) fermentation, (b) drying, and (c) roasting, each of which has a significant effect upon the final flavor profile. The chemistry involved is complex [1-3] and the quantitative mix of aromatic constituents resnlting from processing is determined by the precise conditions employed. Processing may be summarized as follows  

Fermentation facilitates separation of beans from the surronnding pulp and shell, inactivates the seeds, initiates the aromatic precursors and color development, and significantly reduces bitterness. During this stage the sucrose and proteinaceous constituents are partially hydrolyzed, any polyphenolic compounds are oxidized and glucose is converted into alcohol and then oxidized to acetic and lactic acids. Beans that have not been fermented do not develop a chocolate flavor when roasted [4], 

Roasting develops the desired flavor profile and completes the color changes, further reduces the moisture content to about 5%, conditions the 

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However, the lower fatty acid esters (particularly the acetates) of the acyclic terpene alcohols geraniol, linalool, and citronellol are extremely important both as fragrance and as flavor substances. The acetates occur in many essential oils, sometimes in rather high amounts. Formates, propionates, and butyrates occur less frequently. As a result of the development of large-scale production processes for terpenes, the esters of acyclic terpene alcohols are nearly always made synthetically. All acyclic terpene esters that are used as fragrance and flavor materials can be prepared by direct esterification of the appropriate alcohols. However, special precautions are required for the esterification of linalool. 

A question that should be addressed at this point is the origin of the essential oils and the processing methods. First, the method of extraction, wiA a few exceptions, is steam distillation, but just how different the proportionalities of the compounds are from batch to batch is not elaborated. Neither are the possible changes from season to season taken into account. No consideration has been made as to the possible synergism between the components, if any. And last, it is common knowledge that flavor profiles obtained on extracts made by supercritical fluid extraction show many more products than are obtained by steam distillation. That is, certain compounds are not captured by steam distillation. While these finer points may not be of interest to the flavor market because the public has been conditioned to accept those materials presently available, the implications that these non-captured volatiles may have other uses should not be ignored. 

Traditionally, soy sauce is made by fermentation as described above however, soy sauce can also be made by acid hydrolysis. The resulting product is known as chemical soy sauce, or protein chemical hydrolysate. In this process, defatted soy products or other proteinous materials are first hydrolyzed by heating with 18% HCl for 8—12 h. After hydrolysis, the hydrolysate is neutralized with sodium carbonate and filtered to remove the insoluble materials. The resulting product (chemical soy sauce) is a clear dark-brown liquid. However, chemical soy sauce does not possess the flavor and odor of fermented shoyu. Therefore, to improve its quality, chemical soy sauce is often blended with fermented shoyu to become a semi-chemical product before being sold. 

One of the earliest and most commercially successful examples of producing flavoring materials by fermentation is the production of 4-decalactone from castor oil (Figure 9.11, [83]). Castor oil is unique in that it is made up of nearly 80% ricinoleic acid (12-hydroxy-9-octadecenoic acid). Yarrowia lipolytica initially hydrolyses the ricinoleic acid from the triglyceride and then through P-oxidation, converts this acid to 4-hydroxydecanoic acid. This acid forms a lactone at low pHs to yield the y-decalactone. The yield on this process is generally considered to be ca. 6 g/L which is very attractive. 

Unstabilized bran and polish have been used almost exclusively for animal feed, due to the bitter flavor that develops from the lipolytic action of enzymes on the oil found in them. However, development of a thermal process that inactivates the lipases has resulted in a stabilized rice bran product that is suitable for the food industry. The impressive nutritional qualities of the oil, fiber, carbohydrate and proteins of rice bran have made it a valuable food material. Removal of fiber from the bran by physical K,J7or enzymic1819 processes produces a milk-like product having desirable nutritional and functional properties. The nutritional composition of the rice bran milk product described by California Natural Products has been shown to match the nutritional requirements of an infant formula. Originally, the anti-nutritional factor of the residual phytates was of concern. However, as of 2005, phytase enzymes are suitable for use to break down these phytates. 

Flavor and fragrance compounds can exist in nature their free forms, such as the terpenes of orange oil which are synthesized by the planfs metabolic processes. The terpenes can be released in a fine spray by merely squeezing the peel. Other F F materials are only made available when enzymes, microbial reactions, or heat transform odorless substrates into aromatic materials. The grinding of mustard permits the mixing and reaction of odorless enzymes and... 

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