Flavor due to processing

Reineccius, M., Changes in food flavor due to processing, in Flavor Chemistry andTechnology, 2nd edn., CRC Press, Boca Raton, EL, p. 103, 2006. 

Modification of Flavor Due to Thermal Processing. Despite the similarity of the chromatographic profiles of headspace volatiles of canned and fresh truffles, a sensory analysis carried out by a panel of experts reported a marked difference between the two aromas. 

Off-flavor due to spontaneous oxidation of milk fat is a troublesome issue because the process and its prevention are not well understood and it tends to occur in otherwise well-managed, high-yielding dairy herds... 

A typical fruit juice evaporation system using the heat pump cycle is shown (PI, Cl), which uses low-temperature ammonia as the heating fluid. A frozen concentrated citrus juice process is described by Charm (Cl). The process uses a multistage falling-film evaporator. A major fault of concentrated orange juice is a flat flavor due to the loss of volatile constituents during evaporation. To overcome this, a portion of the fresh pulpy juice bypasses the evaporation cycle and is blended with the evaporated concentrate. 

Extrusion cooking has been shown to be an efficient method for the production of many types of food products. One disadvantage of this processing technique is the possible loss of flavor due to steam distillation of volatiles at the die, flavor binding to starch or protein, or the thermal degradation of flavors. In order to compensate for these losses, processors may add flavors during extrusion. In response to this, a number of researchers have studied how flavors are retained in an extruded material and what can be done to help retain these compounds. 

Cream lipolytic bacteria Cheesy off-flavor due to growth of lipolytic bacteria either in milk or during processing before pasteurization... 

Little will be said abont controlled release flavorings in this chapter simply because there is limited space. However, there is substantial interest in imparting controlled release properties to encapsulated flavorings. Ideally, the flavoring would be protected from the environment until the final product is ready for consumption. Unfortunately, there are limited opportunities for imparting controlled release to flavorings due to both materials limitations (FDA approved) and cost considerations — cost of both materials and processing. 

It has been found that the flavor of fmit can be increased by a process called precursor atmosphere (PA) (77). When apples were stored in a controlled atmosphere containing butyl alcohol [71-36-3] the butyl alcohol levels increase by a factor of two, and the polar products, butyl ester, and some sesquiterpene products increase significantly. The process offers the possibiUty of compensating for loss of flavor in fmit handling and processing due to improper transportation conditions or excessive heat. 

More and more raw spices are converted to finished products near the growing sites. This saves shipping costs of bulk vs concentrate. Rapid processing also assures less loss of flavor volatiles resulting from evaporation, reduction of colored components due to oxidation or isomeri2ation, and reduction of losses due to insect and rodent infestation. 

Freeze Drying. Commercial freeze drying of instant coffee has been a common practice in the United States since the mid-1960s. The freeze-drying process provides the opportunity to minimize flavor degradation due to heat (34). 

---