Mekanisme Metabolik Jalur Pentosa Fosfat dan Pembentukan Senyawa Prekursor Flavor pada Fermentasi Sourdough Tepung Lokal (Studi Kasus: Tepung Mocaf): A Narrative Literature Review

Sourdough is a fermented product based on flour and water, involving lactic acid bacteria (LAB) and yeast. The use of Modified Cassava Flour (Mocaf) has the potential to support the diversification of local food raw materials; however, the chemical characteristics of Mocaf—specifically its high starch content, relatively low protein content, and absence of gluten—can influence microbial activity and flavor formation. This article aims to outline the relationship between the pentose phosphate pathway (PPP), carbohydrate metabolism, and the formation of flavor precursor compounds in Mocaf-based sourdough, using a literature review approach. The reviewed literature indicates that the PPP provides NADPH and biosynthetic intermediates, while glycolysis and the phosphoketolase pathway contribute to the production of lactate, acetate, ethanol, and carbon dioxide. Erythrose-4-phosphate also has an indirect link to the formation of aromatic amino acids via the shikimate pathway. Amino acids, pyruvate, acetyl-phosphate, and organic acids can subsequently contribute to the formation of volatile compounds that impart floral, fruity, malty, buttery, and toasted aromas. In the case of Mocaf, low protein content may limit the supply of amino acids—which serve as flavor precursors—while the availability of carbohydrates can support microbial metabolism. Nevertheless, some of these relationships remain mechanistic hypotheses, as the reviewed sources have not directly measured metabolite flux or volatile compounds in Mocaf-based sourdough. The selection of starter cultures, optimization of fermentation conditions, and supplementation with nitrogen sources are strategies that warrant further investigation.