Folate content and retention in selected raw and processed foods

BASSETT, M.N. ; SAMMÁN, N.C.

ARCHIVOS LATINOAMERICANOS DE NUTRICIóN

ARCHIVOS LATINOAMERICANOS NUTRICION

Lugar: Caracas; Año: 2010 vol. 60 p. 298 - 305

0004-0622

SUMMARY. Adequate intake of folate reducEd the risk of abnormalities in early embryonic brain development such as the riskof malformations of the embryonic brain/spinal cord, collectively referred to as neural tube defects (NTDs). Folate is extremely sensitive to destruction by heat, oxidation and UV light. The purpose of this study was to evaluate the use of different extraction procedures and enzymatic treatment to determine folate concentrations in variety of foods using a microbiological assay (MA) with Lactobacillus rhamnosus as the test organism. This study also aimed to evaluate the retention of folate in foods after using different cooking processes. Nine of the most commonly consumed foods in Argentina and that contain folate were analyzed: broccoli, spinach, potato, lentil, soy (raw and boiled); hen whole egg and yolks (raw, boiled and fried); beef liver (raw and cooked); strawberry (raw) and white bread. For this study, rat plasma (RP) and human plasma (HP) conjugases together with acetate and phosphate buffers were tested. In extraction step for all analyses, RP conjugase was selected since it was easily available in our laboratory and small quantities were required. The acetate buffer was chosen since better growth and more reproducible results were obtained in the different conditions assayed. The results allowed the foods to be grouped into a) rich sources of folate: hen eggs, yolks, spinach, soybean (raw) and strawberry (100 and 350μg/100g fresh weight (FW); b) good sources of folate: broccoli (raw), soybean (boiled), lentils (raw) and potato (56 to 83μg/100g FW) and c) moderate sources of folate: broccoli, lentils (boiled), white breads, onions and beef liver (15 to 30μg/100g FW). The folate retention was in the range 14–99% according to both type of food and method of processing. Contents and losses of folate vary widely according to type of food and cooking method.