Comparison of ambient solvent extraction methods for the analysis of fatty acids in non-starch lipids of flour and starch

Abstract

BACKGROUNDLipids are minor components of flours, but are major determinants of baking properties and end-product quality. To the best of our knowledge, there is no single solvent system currently known that efficiently extracts all non-starch lipids from all flours without the risk of chemical, mechanical or thermal damage. This paper compares nine ambient solvent systems (monophasic and biphasic) with varying polarities: Bligh and Dyer (BD); modified Bligh and Dyer using HCl (BDHCL); modified BD using NaCl (BDNaCl); methanol–chloroform–hexane (3:2:1, v/v); Hara and Radin (hexane–isopropanol, 3:2, v/v); water-saturated n-butanol; chloroform; methanol and hexane for their ability to extract total non-starch lipids (separated by lipid classes) from wheat flour (Triticum aestivum L.). Seven ambient extraction protocols were further compared for their ability to extract total non-starch lipids from three alternative samples: barley flour (Hordeum vulgare L.), maize starch (Zea mays L.) and tapioca starch (Manihot esculenta Crantz).RESULTSFor wheat flour the original BD method and those containing HCl or NaCl tended to extract the maximum lipid and a significant correlation between lipid extraction yield (especially the glycolipids and phospholipids) and the polarity of the solvent was observed. For the wider range of samples BD and BD HCl repeatedly offered the maximum extraction yield and using pooled standardized (by sample) data from all flours, total non-starch lipid extraction yield was positively correlated with solvent polarity (r = 0.5682, P < 0.05) and water ratio in the solvent mixture (r = 0.5299, P < 0.05).CONCLUSIONIn general, BD-based methods showed better extraction yields compared to methods without the addition of water and, most interestingly, there was much greater method dependence of lipid yields in the starches when compared to the flour samples, which is due to the differences in lipid profiles between the two sample types (flours and starches).

Cold plasma: A new technology to modify wheat flour functionality

“…The Bligh and Dyer lipid extraction protocol ( Bligh & Dyer, 1959 ) was used to extract non-starch lipids from cereal samples at ambient temperature. All samples were extracted three times by each extraction protocol, at ambient temperature as described by Bahrami et al (2013) . Isolates were evaporated under nitrogen, dissolved in chloroform (1 mL) and stored at −80 °C until required for lipid fractionation and the analysis of fatty acid methyl esters by gas-chromatography mass-spectrometry.…”

Evaluation of Sequential Processing for the Extraction of Starch, Lipids, and Proteins From Wheat Bran

“…Total lipid analysis was done by liquid-liquid extraction using a mixture of chloroform, methanol, and water as described by Bahrami et al (2014). Six milliliters of chloroform-methanol solution (1:2 v/v) and 1.5 mL of distilled water were added to 0.25 g wheat bran sample in a 15-mL falcon tube and the suspension was mixed for 2 min.…”

Component analysis of nutritionally rich chloroplasts: recovery from conventional and unconventional green plant species

“…The solution was then left, to ensure complete conversion, for 10 min before injection onto the GC-MS (Thermo Scientific, DSQII). GC conditions and column were based on standard protocol developed in our laboratory (Bahrami et al 2014).…”