Peanut roasting process

By Spies ( ) classification, PN-IA is heat-stable whereas PN-IB is heat-sensitive and would be destroyed in the roasting process. PN-IA is present in extremely low amounts in the seed. We examined raw and roasted peanut allergen extracts using blood serum of two sensitive individuals as the source of antibody. The immunodiffusion reaction between the peanut allergen and antibodies in their blood produced a sharp precipitin arc, but the precipitin arc disappeared after saline deproteination of the gel on the glass plate. No precipitin arc occurred with blood from... 

The roasting process subjects peanuts to internal temperatures of 130 -150 C during which the typical roast peanut flavor is produced. The most important constituents of peanuts responsible for flavor formation are the amino acids, sugars, protein and lipids. There are close to 300 flavor compounds identified in roasted peanuts. Pyrazines contribute roasted nutty aroma and aldehydes are responsible for harsh green aroma. Recent development in the research include application of an absorption polymer Tenax GC to collect volatiles, quantitation of flavor components and computer aided correlation of instrmental and sensory data. 

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). 

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. 

Commercial products usually do not pose health threats to their consumers. However, botulism cases acquired after consumption of commercially prepared canned foods have been reported. In the U.S., 62 outbreaks occurred in the years 1899 to 1973 (Lynt et al., 1975). Only 7% of outbreaks reported between 1950 and 1996 were linked to commercially processed foods (Centers for Disease Control and Prevention, 1998). The implicated foodstuffs included chopped garlic in soy oil stored in glass bottles at room temperature (Louis et al., 1988), sliced roasted eggplant in oil, yogurt with hazelnuts, stuffed lotus rhizome, bottled caviar, and canned peanuts (Chou et al., 1988 D Argenio et al., 1995). 

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. 

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). 

Most of the flavor compounds in fats and oils are produced by the reaction of oxygen with unsaturated fatty acids in triacylglycerols or polar lipids. On the other hand, some flavor compounds such as those present in cocoa butter, roasted sesame oil, or roasted peanut oil are generated by the interaction of reducing sugars with amino compounds during thermal processing. 

Fried Nuts Peanuts, cashews, sunflower seeds, pumpkin seeds, and so on are sold in various forms, such as fried, dry roasted, coated, and glazed. The fried nuts absorb very little oil from the fryer. This makes the oil turnover time in a fryer very long. Oils used in this process must have good oxidative stability in order to have good product shelf life. 

Validated methods are just as important as the availability of reference materials for allergens [21], As peanut allergy is highly prevalent and peanut products may enter into the production of various food matrices, e.g. chocolate, ice cream, biscuits and breakfast cereals, it is essential to have a peanut reference material both for research and routine analysis. Peanuts available in the food sector are derived from various sources, such as peanut vari-eties/types from different geographical origins, and are treated by various technological processes, such as dry and oil roasting at various temperatures for various times. 

A qualitative PCR assay was developed for the detection of peanut in foods and validated further with the collaboration of six participant laboratories (Watanabe et al., 2007). Autoclaved, roasted, boiled, and nonprocessed doughs made out of Japanese yam spiked with different levels of defatted peanut flour (0, 0.001, 0.01, 0.1%) were used as food models. Results were compared with ELISA, which showed decreased protein levels in the processed food models, especially in the autoclaved dough. No protein was detected in aU of the nonspiked dough. PCR results from the six labs correctly identified dough samples (processed and nonprocessed), which correlated with results obtained from ELISA analysis. The assay was shown to be specific, reproducible, reliable, and applicable for the detection of peanut in the model processed food. 

As shown in Table IV, many pyrazine compounds were generated in IMP and deoxyalliin as well as in the IMP and alliin model systems. Pyrazines are widely distributed in thermally processed foods, such as roasted beef, roasted peanut, and roasted barley. The Maillard reaction, which involves the interactions of reducing carbonyl compounds and amino-containing compounds, has been shown to be the major mechanism for the formation of pyrazines (26). 

Roasting as a leading method of processing nuts and seed dates back to the earliest records. Roasting gives most nuts and oily seed their characteristic flavor, texture and aroma. About 70% of all edible peanuts are roasted. After roasting, they may be made into peanut butter (about 50%), used in confections, bakery goods, mixed nuts, ice cream desserts and a dozen other ways. 

When oily nuts and seed are roasted and ground to rupture a sufficient number of cell walls, a paste or butter is produced. When the nuts are of edible quality and the operation is sanitary, the paste becomes an important food item. Pulverizing nuts not only releases free oil, but flavors as well. Historically, grinding roasted nuts into paste was one of the first nut products to be made. It was adapted from grinding coffee with mortar and pestle, and crushing corn and wheat to make bread. While most oily nuts of the world - hazel nuts, almonds, macadamia, peanuts and pecans - have been made into paste commercially, the process is a part of the history of all edible nuts. 

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