Under the shell of peanut #1. Loss of vitamins during processing

Many people do love peanuts and some are highly “addicted” to it. No doubts, roasted and salted they make me feel “positively” obsessed, while peanut butter is very welcome in a variety of dessert recipes.

Do you like peanuts?

Plenty of health benefits are described for the use of peanuts and its products. Peanuts are launched with vitamins, minerals, phytochemicals – natural antioxidants – like flavonoids, isoflavons, resveratrol, etc.

This article is not about it. In this article I would like to touch the “peanut topics” which lay under its shell (in other words, sensitive topics) and define the subtopics for future posts.

“Sensitive” topics regarding PEANUTS:

  • Loss of vitamins, minerals, other constituents during peanut processing
  • Contamination of peanuts with aflatoxins (1) Aflatoxins are a family of toxins produced by certain fungi Aspergillus flavus and Aspergillus parasiticus. These fungi may increase the risk of cancer (have cancerogenic effect), acute poisoning (in large doses) and acute liver failure (lethargy, nausea, even death)
  • Peanut allergies (may trigger severe, even fatal allergenic reactions)

Today we will cover the first clause – peanut processing and its effect on nutritional value

Effects of processing on vitamins in peanuts (2)

Generally, peanuts are processed into two main products: roasted peanuts and peanut butter. Commercial peanut processing involves blanching, roasting and peanut butter making.

Peanut are blanched after shelling to simply remove the reddish skin covering the kernels.

Roasting enhances the flavor, color, taste and crunchy texture of the peanut.

Advantages of peanut processing:

  • Peanut butter production has little or no effect on the vitamin content of the end-product
  • Fat-soluble vitamins, such as vitamin E, are not lost during blanching (according to one study)
  • Reduces the bacteria load and aflatoxin-producing fungi of the raw peanut
  • Vitamin B2 (riboflavin) may not be destroyed by peanut roasting as it is stable at high temperature
  • Vitamin B3 (niacin) is heat resistant and is the most stable among vitamins in the peanuts

Disadvantages of peanut processing:

  • Blanching and roasting are the main processes that may result in vitamin loss
  • Decreases its shelf stability due to an increase in oxidation
  • Vitamin E and B vitamins are very sensitive to heat and might be lost during roasting
  • Roasting had a diminishing effect on thiamine, carotenoids and tocopherols. It can be lost through rapid boiling (high temperature) and ultraviolet irradiation (sunlight)
  • The loss of vitamin B1 (thiamine) is significant through rapid boiling
  • The loss of vitamin B1 (thiamine) during roasting is observed
  • Vitamin B2 (riboflavin) is sensitive to UV light. Thus it can be lost when exposed to air and light for long period
  • Vitamin B3 (niacin) can be destroyed by air and light
  • Pyridoxine (vitamin B6) can also be quickly destroyed by light
  • Fats in peanut butter may be oxidized (spoiled) quickly by air, heating and light

The conclusions drawn and the assessment of the health benefits/risks are restricted to information appearing in the scientific literature

Subtopics about peanut allergies and aflatoxins are coming in the future posts. Stay tuned!


  1. Aflatoxins, Department of Food Safety and Zoonoses, World Health Organization, February 2018, online source: https://www.who.int/foodsafety/FSDigest_Aflatoxins_EN.pdf
  2. Health aspects of peanuts as an outcome of its chemical composition. Rabiatu Bonku, Jianmei Yu. Food Science and Human Wellness 9 (2020) 21–30

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