88D-12 |
Lactic acid production in sour doughs made from wheat-amaranth mixtures |
L. VÁZQUEZ CHÁVEZ, L. C. Fernández Linares, and I. Guerrero Legarreta. Departamento de Biotecnologia, Universidad Autonoma Metropolitana-Iztapalapa, Ap. Postal 55-535, Mexico City, 09340, Mexico Sour dough breads are traditional from several parts of the world, they are prepared from cereals and other starchy materials. Amaranth is a pseudo-cereal traditionally used in Mexico as a food grain. Its main characteristic is high protein quantity and quality. The objective of this work was to evaluate the fermentation ability of wheat-amaranth mixtures inoculated with lactic acid bacteria and yeast. Wheat and amaranth flour were mixed in different proportions and inoculated with three starter cultures: a commercial starter, L. plantarum and L. lactis. In addition a yeast, Saccharomyces cerevisiae, was used. The dough was prepared with various wheat-amaranth proportions and incubated at 37oC during 8 hours. Inoculations with starter cultures were carried out in two subsequent steps: lactic acid bacteria at time 0 and yeast 4 hours after incubation (lactic-alcoholic fermentation), or yeast at time 0 followed by lactic acid bacteria after 4 hours of incubation (alcoholic-lactic fermentation). The sources of variation were: wheat-amaranth proportion and order of starter addition (lactic-alcoholic or alcoholic-lactic fermentation). pH reached lower levels when the commercial inoculum was used. Lower lactic acid concentrations and higher pH values were found in doughs prepared with higher amaranth proportions. Acid production has an important contribution in sour dough aroma; from this point of view it is expected that if amaranth is included in high proportions in sour doughs the flavor will be bland. Loaf volumes were lower and flavor more intense in lactic-alcoholic fermentations due to lower carbon dioxide amount produced by yeasts. In alcoholic-lactic fermentations loaf volumes were larger and acid flavor was less intense. Depending on the starter, flour proportion and fermentation sequence, sour doughs prepared with wheat amaranth mixtures will have different quality characteristics such as loaf volume and flavor intensity. Protein supplementation was achieved by adding amaranth to the formulation.
Session 88D, Food Microbiology: General
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