The current disclosure provides a process for enzymatically converting a saccharide into tagatose. The invention also relates to a process for preparing tagatose where the process involves converting fructose 6-phosphate (F6P) to tagatose 6-phosphate (T6P), catalyzed by an epimerase, and converting the T6P to tagatose, catalyzed by a phosphatase.

The present invention provides a genetically modified lactic acid bacterium capable of producing diacetyl under aerobic conditions. Additionally the invention provides a method for producing diacetyl using the genetically modified lactic acid bacterium under aerobic conditions in the presence of a source of iron-containing porphyrin and a metal ion selected from Fe.sup.3+, Fe.sup.2+ and Cu2+. The lactic acid bacterium is genetically modified by deletion of those genes in its genome that encode polypeptides having lactate dehydrogenase (E.C 1.1.1.27/E.C.1.1.1.28); -acetolactate decarboxylase (E.C 4.1.1.5); water-forming NADH oxidase (E.C. 1.6.3.4); phosphotransacetylase (E.C.2.3.1.8) activity; and optionally devoid of or deleted for genes encoding polypeptides having diacetyl reductase ((R)-acetoin forming; EC: 1.1.1.303); D-acetoin reductase; butanediol dehydrogenase ((R,R)-butane-2,3-diol forming; E.C. 1.1.1.4/1.1.1.-) and alcohol dehydrogenase (E.C. 1.2.1.10) activity. The invention provides for use of the genetically modified lactic acid bacterium for the production of diacetyl and a food product.

The invention relates to preparation of food ingredients enriched with a low-glycemic sugar replacement through enzymatic conversion. Food ingredients may be enriched with, for example, D-tagatose, D-allulose, D-allose, D-mannose, D-talose, and/or inositol by enzymatically converting saccharides found in flour, meal, ground tuber, ground pulse, ground bark, starch, malted grain or malt extract, maltodextrin, cellulose, cellodextrin, any of their derivatives (e.g., amylose, amylopectin, dextrin, cellobiose, etc.), and/or sucrose into D-tagatose, D-allulose, D-allose, D-mannose, D-talose and/or inositol. The enriched material can be used as a food ingredient instead of the low-glycemic sugar being purified for use as a food ingredient.

The current disclosure provides a process for enzymatically converting a saccharide into tagatose. The invention also relates to a process for preparing tagatose where the process involves converting fructose 6-phosphate (F6P) to tagatose 6-phosphate (T6P), catalyzed by an epimerase, and converting the T6P to tagatose, catalyzed by a phosphatase.

Disclosed herein are improved processes for making tagatose including the steps of converting F6P to T6P, catalyzed by a F6PE; and converting the T6P to tagatose, catalyzed by a T6PP, using enzymes with higher activities compared to F6PEs and T6PPs previously used in a process to produce tagatose.