Bahrami, Niloufar and Yonekura, Lina and Linforth, Rob S.T. and Carvalho da Silva, Margarida and Hill, Sandra and Penson, Simon and Chope, Gemma and Fisk, Ian D.
Comparison of ambient solvent extraction methods for the analysis of fatty acids in non-starch lipids of ﬂour and starch.
Journal of the Science of Food and Agriculture, 94
BACKGROUND: Lipids 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).
RESULTS: For 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).
CONCLUSION: In 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).
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