Thursday, November 10, 2011


Peanuts are nutritionally a much acclaimed food with high levels of protein, fat, fiber and some micro nutrients. The "war of nuts" between peanut and soybean for market supremacy has given prominence to both these oil seeds though the protein in peanut is always looked down because of low levels of the essential amino acid Lysine present in this oil seed. In contrast peanut oil has much better stability as a cooking oil while soybean oil is more nutritious because of higher content of unsaturated fats. As a food peanut is a main stream component of diets in India and a few other countries. Soybean is invariably called the "cow of the orient" because of the popularity of soy milk among people in South East Asia. With relatively low consumption of animal milk in many Asian countries, soybean milk presents itself as a highly acceptable alternative. Industrially peanut lags behind soybean which is used extensively to manufacture hundreds of products with high consumer acceptability. Meat substitutes made from soybean are relatively cheap and are considered poor man's meat with almost same texture.

Peanut is consumed at the consumer level as snack items and products like roasted, coated and fried peanut snacks are popular in many countries. Confectionery products made from peanuts, called "Chikkis" using Jaggery or sugar are produced in India by thousands of cottage scale units working in the informal sector. Soybean takes a beating on this score as its major use is confined to extraction of oil and using the residue in animal feed formulations. Soybean curd or Toffu is a favored item liked by Asians and is becoming popular like cheese in other countries also. The processing methods are distinctively different with these two crops. While peanut seeds are processed in Expeller presses followed by solvent extraction, soybean, due to its low oil content goes straight for solvent extraction and refining. 

Peanuts hit the headlines recently because of the claims made by some scientific groups that it is rich in a rare phytochemical Resveratrol with supposed credentials for achieving longevity. It was a news because a major source of Resveratrol was red wine about which lot has been written. While Red wine contains this chemical in the range of 0.2 to 12.59 mg per liter, raw Peanut has less than 2 mg per kg. What caught the attention of the world was that the same peanut when boiled increased its Resveratrol level to about 9 mg per kg. However such arithmatic jugglery cannot conceal the fact that while wine can be easily consumed one or two glasses a day, it is unimaginable that one can eat 300 gm of peanut a day to deliver the same quantity. Also not understandable is the loud claims being made about the capability of Resveratrol to prolong life without any human trials so far. At best this phytochemical has been proved to be helpful in keeping at bay diseases like cancers, diabetes etc only in animal experiments. Probably sensationalism and vested commercial interests seem to be floating such claims with practically no scientific basis.

It is true that nature has equipped many plants with toxic chemicals for fighting against pathogens and  other marauders and Resveratrol present mostly in the skin of fruits like Red grapes is a proven fighter against bacteria and fungi. Interestingly, during wine production the pomace, rich in Resveratrol is discarded and only a small portion of this chemical is passed on to the juice. Therefore it makes more sense to eat fresh grapes or drink crushed grape juice than the wine to get full benefit of the fruit's Resveratrol content. Is it not a commercial ploy by the wine industry to tout about the ability of wine to prolong life? Same appears to be true in the case of peanuts also as consumption of this oil seed directly as food is limited and a major portion goes for recovery of edible oil leaving the residue for feeding cattle. Whether Resveratrol is more concentrated in the pressed residue or in the oil fraction is some what not clear but refined peanut oil
definitely cannot be a source because of the severe refining process the raw oil has to go through under which Resveratrol cannot be expected to be stable.

Another side of Resveratrol story is still more fascinating. It concerns about its solubility, biological absorption and metabolism. Being practically insoluble in water delivery of Resveratrol to the cells is fraught with many uncertainties. Buccal delivery (by chewing in the mouth) is supposed to be some what better and based on this finding by some scientists, chewing gum formulations containing Resveratrol are already in some markets. Oral ingestion is supposed to be very inefficient with not even 5% of the administered quantity ending up in the blood stream. Both small intestine and liver are known to conjugate Resveratrol into glucuronate and sulfonate, both inactive in any way. Synthetic versions and bio-technologically made products are available but due to uncertainty about the real effect of Resveratrol in human body, no approved drug formulations have been marketed though some major drug companies are reported to be investing in this area with the hope of coming out with a successful product eventually. If they succeed humanity may have an effective drug that can counteract many diseases including cancers, severe inflammation, diabetes and cardiovascular aberrations. 


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