Wheat germ: not only a by-product

Int J Food Sci Nutr. 2012 Mar;63 Suppl 1:71-4. doi: 10.3109/09637486.2011.633898. Epub 2011 Nov 11.

Abstract

The wheat germ (embryonic axis and scutellum) represents about 2.5-3.8% of total seed weight and is an important by-product of the flour milling industry. The germ contains about 10-15% lipids, 26-35% proteins, 17% sugars, 1.5-4.5% fibre and 4% minerals, as well as significant quantities of bioactive compounds such as tocopherols [300-740 mg/kg dry matter (DM)], phytosterols (24-50 mg/kg), policosanols (10 mg/kg), carotenoids (4-38 mg/kg), thiamin (15-23 mg/kg) and riboflavin (6-10 mg/kg). Oil recovery is achieved by mechanical pressing or solvent extraction, which retrieve about 50% or 90% lipids, respectively; innovative approaches, such as supercritical carbon dioxide extraction, are also proposed. The oil is rich in triglycerides (57% of total lipids), mainly linoleic (18:2), palmitic (16:0) and oleic (18:1) acids, but relevant amounts of sterols, mono- and diglycerides, phospho- and glycolipids are present. The lypophilic antioxidants tocopherols and carotenoids are also abundant. The main by-product of oil extraction is defatted germ meal, which has high protein content (30-32%), is rich in albumin (34.5% of total protein) and globulin (15.6%), and thus presents a well-balanced amino acid profile. Its principal mineral constituents are potassium, magnesium, calcium, zinc and manganese, in decreasing order. Total flavonoid content is about 0.35 g rutin equivalent/100 g DM. The wheat germ is therefore a unique source of concentrated nutrients, highly valued as food supplement. While the oil is widely appreciated for its pharmaceutical and nutritional value, the defatted germ meal is a promising source of high-quality vegetable proteins. Better nutrient separation from the kernel and improved fractioning techniques could also provide high-purity molecules with positive health benefits.

Publication types

  • Review

MeSH terms

  • Animal Feed / analysis
  • Animal Feed / economics
  • Animals
  • Dietary Supplements / analysis
  • Dietary Supplements / economics
  • Food, Fortified / analysis*
  • Food, Fortified / economics
  • Food-Processing Industry / economics
  • Humans
  • Industrial Waste / analysis
  • Industrial Waste / economics
  • Nutritive Value
  • Plant Oils / administration & dosage
  • Plant Oils / analysis
  • Seeds / chemistry*
  • Triticum / chemistry*

Substances

  • Industrial Waste
  • Plant Oils
  • wheat germ oil