Maturity, peanut

Peanut oil is composed of mixed acylglycerol of approximately 80% unsaturated and 20% samrated fatty acids (37). In mature peanuts, the oil is 96% triacylglycerol... 

Peanut phytoalexins appear to be involved in resistance to drought-induced preharvest aflatoxin contamination of immature peanuts. Mature peanuts are considerably more resistant to environmentally-induced preharvest aflatoxin contamination of peanuts than are immature peanuts. The mechanism of this latter resistance is unknown. The identification of this resistance mechanism and other resistance may provide one approach to subsequent use of biotechnology to incorporate field resistance traits into commercially acceptable varieties. Biotechnology may also be a valuable approach to exploiting genetic resistance to preharvest aflatoxin found in wild species that have evolved in an arid environment. 

Therefore, it can be seen that when aw falls below 0.95 where phytoalexin-producing capacity is lost, immature peanuts are more likely to become contaminated than mature peanuts, particularly in high temperature soil (Table I). However, in mature peanuts, low aw and the loss of the capacity to produce phytoalexins does not result in the same degree of contamination (both in numbers and levels) as... 

Phytoalexins appear to be at least partly involved in resistance to drought-induced preharvest aflatoxin contamination of peanuts. Phytoalexin-based resistance appears to be more important in immature peanuts than in mature peanuts. Therefore, mature peanuts are more resistant to preharvest aflatoxin contamination than are immature peanuts. The exact mechanism of this resistance is not known. 

The onset of aflatoxin contamination did not occur until peanut kernels had lost the capacity to produce phytoalexins as an apparent result of drought-induced moisture loss. However, mature peanuts retained a higher degree of resistance to aflatoxin contamination than immature peanuts even after the loss of phytoalexin-producing capability. This indicated that immature kernels rely more heavily on a phytoalexin-based resistance than mature kernels, which apparently have some additional resistance not based on stilbene phytoalexins. 

Williams, E.J. Drexler, J.S. A non-destructive method for determining peanut pod maturity. Peanut Sci. 1981, 8, 134. 

Figure 4. Precision of rapid test for ADH. ADH was prepared from uncured mature peanuts.

Glucose-0 or fructose-C (both uniformly labeled) Acetate-l-C Maturing peanut cotyledon slices Rats Fatty acids Saturated fatty acids of liver 6% of added hexoses converted to fatty acids (223o) (212) ... 

The cellulosic shell comprises about 20-30% of the weight of the mature peanut. The proximate composition of peanut shells has been reported on a moisture-free basis, as follows protein, 5-7.3% ether extract, 1.2-2.1% crude fiber, 66-80% nitrogen-free extract, 10.6-21.2% ash, 3-4.6%. The presence of reducing sugars, 0.6%, disaccharide sugars, 1.7%, starch, 0.7%, and pentosans, 18%, has also been reported (26-27, 84,92,100,187). 

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