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Kefir Immobilized on Corn Grains as Biocatalyst for Lactic Acid Fermentation and Sourdough Bread Making

Authors

  • Stavros Plessas,

    1. Authors Plessas, Alexopoulos, and Bezirtzoglou are with Faculty of Agriculture Development, Laboratory of Microbiology, Biotechnology and Hygiene, Democritus Univ. of Thrace, 193 Pantazidou St., GR-68200 Orestiada, Greece. Author Bekatorou is with Food Biotechnology Group, Dept. of Chemistry, Univ. of Patras, GR-26500 Patras, Greece. Direct inquiries to author Plessas (E-mail: splessas@agro.duth.gr).
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  • Athanasios Alexopoulos,

    1. Authors Plessas, Alexopoulos, and Bezirtzoglou are with Faculty of Agriculture Development, Laboratory of Microbiology, Biotechnology and Hygiene, Democritus Univ. of Thrace, 193 Pantazidou St., GR-68200 Orestiada, Greece. Author Bekatorou is with Food Biotechnology Group, Dept. of Chemistry, Univ. of Patras, GR-26500 Patras, Greece. Direct inquiries to author Plessas (E-mail: splessas@agro.duth.gr).
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  • Argyro Bekatorou,

    1. Authors Plessas, Alexopoulos, and Bezirtzoglou are with Faculty of Agriculture Development, Laboratory of Microbiology, Biotechnology and Hygiene, Democritus Univ. of Thrace, 193 Pantazidou St., GR-68200 Orestiada, Greece. Author Bekatorou is with Food Biotechnology Group, Dept. of Chemistry, Univ. of Patras, GR-26500 Patras, Greece. Direct inquiries to author Plessas (E-mail: splessas@agro.duth.gr).
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  • Eugenia Bezirtzoglou

    1. Authors Plessas, Alexopoulos, and Bezirtzoglou are with Faculty of Agriculture Development, Laboratory of Microbiology, Biotechnology and Hygiene, Democritus Univ. of Thrace, 193 Pantazidou St., GR-68200 Orestiada, Greece. Author Bekatorou is with Food Biotechnology Group, Dept. of Chemistry, Univ. of Patras, GR-26500 Patras, Greece. Direct inquiries to author Plessas (E-mail: splessas@agro.duth.gr).
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Abstract

Abstract:  The natural mixed culture kefir was immobilized on boiled corn grains to produce an efficient biocatalyst for lactic acid fermentation with direct applications in food production, such as sourdough bread making. The immobilized biocatalyst was initially evaluated for its efficiency for lactic acid production by fermentation of cheese whey at various temperatures. The immobilized cells increased the fermentation rate and enhanced lactic acid production compared to free kefir cells. Maximum lactic acid yield (68.8 g/100 g) and lactic acid productivity (12.6 g/L per day) were obtained during fermentation by immobilized cells at 37 °C. The immobilized biocatalyst was then assessed as culture for sourdough bread making. The produced sourdough breads had satisfactory specific loaf volumes and good sensory characteristics. Specifically, bread made by addition of 60% w/w sourdough containing kefir immobilized on corn was more resistant regarding mould spoilage (appearance during the 11th day), probably due to higher lactic acid produced (2.86 g/Kg of bread) compared to the control samples. The sourdough breads made with the immobilized biocatalyst had aroma profiles similar to that of the control samples as shown by headspace SPME GC-MS analysis.

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