Traditional Cereal Food as Container of Probiotic Bacteria “<i>Lb. rhamnosus</i>GG”: Optimization by Response Surface Methodology

Abstract

This research paper aims at optimizing three parameters involved in solid state fermentation (SSF) using Lactobacillus rhamnosus GG (LGG) to improve a traditional cereal food “Bsissa” in order to elaborate a new probiotic fermented breakfast cereal. A Box-Behnken experimental design was used and the optimal fermentation conditions were liquid to solid ratio: 1.2 (vw −1 ), fermentation time: 12 h, and sucrose concentration: 10.48 g (100 g DM) −1 . Under these conditions, the viable LGG cells, the free amino nitrogen content, and the total acidity were obtained to be<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M1"><mml:mn fontstyle="italic">9.1</mml:mn><mml:mo> </mml:mo><mml:mrow><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">log</mml:mi></mml:mrow><mml:mrow><mml:mn fontstyle="italic">10</mml:mn></mml:mrow></mml:msub></mml:mrow><mml:mo>⁡</mml:mo><mml:mrow><mml:mo stretchy="false">(</mml:mo><mml:mi mathvariant="normal">c</mml:mi><mml:mi mathvariant="normal">f</mml:mi><mml:mi mathvariant="normal">u</mml:mi><mml:mo> </mml:mo><mml:msup><mml:mrow><mml:mi mathvariant="normal">g</mml:mi></mml:mrow><mml:mrow><mml:mo>-</mml:mo><mml:mn mathvariant="normal">1</mml:mn></mml:mrow></mml:msup><mml:mo stretchy="false">)</mml:mo></mml:mrow></mml:mrow></mml:math>, 12.95 (mg g −1 ), and 6.46 ( μ mol g −1 ), respectively. After three weeks of refrigerated storage, the viability of LGG in the fermented Bsissa was<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M2"><mml:mn fontstyle="italic">8.23</mml:mn><mml:mo> </mml:mo><mml:mrow><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">log</mml:mi></mml:mrow><mml:mrow><mml:mn fontstyle="italic">10</mml:mn></mml:mrow></mml:msub></mml:mrow><mml:mo>⁡</mml:mo><mml:mrow><mml:mo stretchy="false">(</mml:mo><mml:mi mathvariant="normal">c</mml:mi><mml:mi mathvariant="normal">f</mml:mi><mml:mi mathvariant="normal">u</mml:mi><mml:mo> </mml:mo><mml:msup><mml:mrow><mml:mi mathvariant="normal">g</mml:mi></mml:mrow><mml:mrow><mml:mo>-</mml:mo><mml:mn mathvariant="normal">1</mml:mn></mml:mrow></mml:msup><mml:mo stretchy="false">)</mml:mo></mml:mrow></mml:mrow></mml:math>. This study shows a new possibility to make an acceptable nonfermented dairy product based mainly on cereals, leguminous plants, spices, and aromatic herbs, which are suitable substrates able to support the high probiotic viability.