Peanut flavor

Nearly half of the U.S. domestic food consumption of peanuts in 1993 was as peanut butter salted peanuts, at 27.3%, and peanut candy, at 23.9% made up the other half (137). Although the per capita domestic peanut consumption in the United States has increased steadily, the consumption in recent years has not kept pace with production. Domestic food use of peanuts has been confined almost entirely to roasted peanuts. A number of investigations and developmental efforts are being made to extend the use of nonroasted peanut products such as flour and meal flakes. As of the mid-1990s, market outlets for these latter products are neither sizable nor firmly established. The food-use patterns emphasize the uniqueness and demand for products having a distinct roasted-peanut flavor. The development of the desired flavor as well as the storage stability of such flavor in peanut-food products are therefore important. 

Partially Defatted Nuts. There is considerable demand for nuts and nut products of reduced fat content. Almond meal and peanut meal are examples of products having low fat content achieved by pressing oil from the nuts and by grinding the cake. Much of the flavor is in the oil defatted nuts are thus less tasty. 

A process has been developed (139) whereby up to 80% of the oil can be removed from whole, raw peanuts without the use of solvent. In this process, the blanched peanuts are brought to a proper moisture content, pressed mechanically, and then reshaped or reconstituted by dipping in hot water subsequently they can be roasted and salted, or used in confections or other formulations. Defatted peanuts may also be ground into meal and added to cookies, cakes, and many other products, where they impart a distinctly nutty flavor and cmnchy texture. On the other hand, the resulting high grade oil is refined and employed in cooking and industrial products. This process can also be used for pecans, walnuts, almonds, Brazil nuts, cashews, and other nuts (140-142). 

Defatted peanuts are high in protein, low in moisture, contain only 20% of the naturally occurring fat, and have better stability than whole peanuts. Monosodium glutamate (MSG) has been used as a flavor enhancer for defatted nuts, but the result has not been entirely satisfactory as the addition of MSG produces a meaty rather than nutty flavor. This meaty flavor is more compatible with salted butter and nuts than with candy. 

Initial work to establish chip preparation conditions showed that end product characteristics were influenced by meal particle size, by the amount of water added to form the dough, and by the length of time the dough was mixed (1). A very acceptable product was achieved with these process conditions a blend of particle sizes most of which were in the 14-30 mesh range, an 18% added water level, and a mixing time of 5 min. The final product had a crisp texture, a typical roasted peanut flavor, and was quite similar in composition to full-fat roasted peanuts. Chips contained about 49% oil, 27% protein, and 1% moisture. 

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... 

The importance of direct gas chromatography and combined direct GC/MS to the food industry is demonstrated by the analysis of volatile flavor components and contaminants in experimental samples of rice, food blends, and raw and roasted peanuts. By examining these samples, we are able to investigate flavor systems that are probably associated with lipid oxidation, thermal degradation of protein, or protein interactions with other compounds. 

Ranid instrumental techniques were used to elucidate off-flavor problems in raw and processed rice products, raw and roasted peanuts, and corn-soy food blends. Less than a gram of the solid material was secured in a standard or special injection port liner of the gas chromatograph. Then, the volatiles from the sample were steam distilled in situ and identified by combined gas chromatography/mass spectrometry. 

Chemical modification of simple sugars during drying, baking, or roasting operations can either have a desirable or undesirable effect upon the organoleptic quality of the final product. We have become accustomed to the characteristic roasted or baked flavors of coffee, peanuts, popcorn, and freshly-baked bread. The color and flavor and aroma of caramel make it a useful additive for the food industry. On the other hand, the burnt flavor of overheated dry beans or soy milk reduces marketability of these products. 

Tastes are also acquired over a period of time. For example. When many North Americans first taste cola drinks or coffee as children or youlhs, the tastes may be repugnant, but over a period of lime these tastes become personal favorites, or they may be shunned fora lifetime. Similarly, many Europeans upon their first exposure to the taste of popular American cola beverages, peanut butter, root beer, and so on. react negatively and may never acquire a real taste for such products. Likewise, flavors such as cassis-or black-curreni-flavorcd drinks, which are popular in many European countries, have nut enjoyed acceptance in North America. 

Roasted nuts were one of the first foods in which large amounts and numbers of pyrazines were isolated and identified. The pioneering work on roasted peanuts by Mason (68) in the middle 1968 s contributed a great deal to the understanding of the relations of pyrazines, roasting and the development of nut—like flavor. In more recent time some unique pyrazines have been isolated in a number of different roasted nuts(61.62). 

Sample b c roasted (bread, coffee, peanut, walnut, malt), burnt, popcorn, slightly rancid, heated cooking oil Sample ds heated cooking oil, deep-frying fat, solvent, old paint Since the panel found no difference between samples b and c in the triangle test, it was not possible to ask for two distinct "profiles" in the descriptive test. However, it was evident that samples b and c were the most attractive oils from a flavor point of view. There were similarities with sesame oil and Swedish crispbread. 

Besides their general flavor forming potential peptides are also reported to be unique precursors of composite food aromas. Peptides formed in the fermentative stage of cacao processing have been linked to roast generated chocolate aroma (5). Also, a methionine rich polypeptide has been associated vith roasted peanut volatiles (15). 

Com syrup (polysaccharide) and sucrose are cooked together producing larger polysaccharides and eventually forming a plastic mass. Peanuts are added, as is baking soda (sodium bicarbonate) to provide small bubbles of CO that decrease the density. A little butter is added, partly for flavor partly for texture, and partly to reduce sticking. The hot, molten composite is spread out in thin sheets and cooled. In some recipes, the still hot, taffy-like material is stretched to produce a thinner transparent final product. 

Peanut Oil (Unhydrogenated) is a pale-yellow oil obtained from the kernel of the peanut plant Arachis hypogaea L. (Fam. Fabaceae) by mechanical expression or solvent extraction. It is refined, bleached, and deodorized to substantially remove free fatty acids, phospholipids, color, odor and flavor components, and miscellaneous other non-oil materials. It is a liquid at 21° to 27°, but solidifies to a gel-like consistency at 2° to 4°. It is free from visible foreign matter at 21° to 27°, but sometimes clouds at temperatures above 21°. 

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