EFFECTS OF FORMULATION AND PROCESSING CONDITIONS ON EASILY EXTRACTABLE LIPID AND NITROGEN COMPONENTS OF WHEAT SOURDOUGHS

The changes in free lipid (neutral lipids, glycolipids, and phospholip ids) and extractable nitrogen (amino acids, peptides, and proteins) co mponents of unyeasted and yeasted wheat sourdoughs started with Lactob acillus plantarum B-39 were investigated in samples under different pr ocessing conditions. A central composite surface response design was u sed with factor analysis to investigate the effect of flour extraction rate lash content), added water, presence or absence of yeast, and fe rmentation temperature on readily extractable lipid and nitrogen compo nents. Absolute values for extractable protein and non-protein compone nts were highly correlated with ash content of flour (factor 1); where as phospholipids and neutral lipids were closely connected with added water (factor 2). Sixty sourdoughs were classified into three groups: 1) high-ash fermented sourdoughs produced high (>350 mg kg(-1)) total nonprotein amino nitrogen and medium (<3 mg g(-1)) lipid levels; mid-a sh flour doughs had lower levels of both components; 2) low-ash fermen ted sourdoughs produced low (<300 mg kg(-1)) levels of amino acids and peptides and medium lipids levels, and 3) unfermented sourdoughs had low (<250 mg kg(-1)) levels of non-protein nitrogen components and mos t made with low-ash flour had medium lipid levels; most made with medi um and high-ash flours had high (>4 mg g(-1)) neutral lipid levels and were largely separated from the low-ash group. The most promising sou rdoughs for bread were those with low added water, fermented from high er ash flour with maximum levels of extractable amino acids, peptides and proteins and medium to high polar and neutral lipid levels.