abstract
Broa is an example of bread that is a good candidate for inclusion in functional diets, so it deserves further in-depth study of its chemical compositionnamely with regard to evolution of the lipid profile throughout breadmaking, in order to assess whether mixing, fermentation, or baking affect its nutritional value (in terms of unsaturated fatty acids, UFA) based on the assumption that neutral lipids (NL) can be protein- or carbohydrate-bound. Hence, constituent fatty acids in NL of maize (Zea mays) and rye flour (Secale cereale), and in sourdough and final broa manufactured from a mixture therefrom were quantitated. Methodologies of esterification of fatty acids, as well as of transesterification of acyl lipids and sterol esters (SE) were improved. The n-hydrocarbons containing between 4 and 24 carbon atoms were then resolved and identified by gasliquid chromatography. Regarding total neutral lipids (TNL) in all samples, 7989% were TAGs, and 8793% were TAGs and DAGs in the case of free lipids (FL). Furthermore, 7385% of TNL in bound lipids (BL) and 6580% of TNL in starch lipids (SL) were TAG and free fatty acids (FFA). Conversely, only 45%, 616%, and 710% of TNL in FL, BL, and SL, respectively, were SE and MAGs. TAGs and DAGs underwent partial hydrolysis during fermentation and baking; palmitic, oleic, and linoleic acids were dominant as products released. The nutritional value of broa lipids was apparent owing to their proportions of SE (4%) and DAG (9%), coupled with 52% of linoleic acid in all samplesas well as to the high contents of polyunsaturated versus monounsaturated or saturated fatty acids, and to the general dominance of UFA.
keywords
QUANTITATIVE-ANALYSIS; EXOGENOUS LIPASE; CEREAL-GRAINS; METHYL-ESTERS; DOUGH; FLOUR; BINDING; BREAD
subject category
Food Science & Technology; Nutrition & Dietetics
authors
Rocha, JM; Kalo, PJ; Malcata, FX
our authors
João Rocha
Full Professoracknowledgements
The Regional Directorate of Agriculture of Entre-Douro-e-Minho (DRAEDM, Portugal) and several local farmers are hereby gratefully acknowledged for their collaboration in sampling. Financial support for author J.M.R. was through a Ph.D. fellowship within program PRAXIS XXI-ref. PRAXIS XXI/BD/16060/98, administered by Fundacao para a Ciencia e a Tecnologia (Portugal) and supervised by author F. X. M. Partial financial support for research expenses was received within program PAMAF-IED, through research grant