Development of a prebiotic strawberry preparation for the dairy industry

Abstract

Background. Food industry has been pressed to develop products with reduced sugar and caloric value, with the challenge of keeping rheological and sensory characteristics. Herein we developed a functional strawberry preparation for the dairy industry, by in-situ enzymatic conversion of sucrose into prebiotic fructo-oligosaccharides (FOS). Methodology. Two enzymatic complexes (Pectinex®Ultra SP-L and Viscozyme®L) were applied in the preparation. Operational parameters were optimized to maximize FOS yield: temperature, pH, enzyme:substrate ratio (E/S). Rheological, physicochemical and functional properties (INFOGEST gastrointestinal digestion protocol) were evaluated. Results. At optimal conditions (60 , pH 5.0), Pectinex produced 265±3 g·L1 FOS, yielding 0.581±0.006 gFOS·gin.GF1 after 7 h reaction (E/S:1/40); and Viscozyme produced 295±1 g·L1 FOS, yielding 0.664±0.004 gFOS·gin.GF1 after 5 h (E/S:1/30), both resulting in preparations with 50% (w/w) FOS. The caloric value was reduced 24%, including 80% sucrose reduction. Differences in colour, water activity and ºBrix were not relevant, while consistency and viscosity decreased 70% and pH increased from 4.4 to 4.7. FOS showed resistance to gastrointestinal digestion; only kestose was slightly hydrolysed at intestinal phase. Conclusions. A prebiotic strawberry preparation was successfully produced at lab scale, by in-situ enzymatic conversion of caloric into functional sugars. Next, the process will be scaled-up at industrial level.

Background. Food industry has been pressed to develop products with reduced sugar and caloric value, with the challenge of keeping rheological and sensory characteristics. Herein we developed a functional strawberry preparation for the dairy industry, by in-situ enzymatic conversion of sucrose into prebiotic fructo-oligosaccharides (FOS). Methodology. Two enzymatic complexes (Pectinex®Ultra SP-L and Viscozyme®L) were applied in the preparation. Operational parameters were optimized to maximize FOS yield: temperature, pH, enzyme:substrate ratio (E/S). Rheological, physicochemical and functional properties (INFOGEST gastrointestinal digestion protocol) were evaluated. Results. At optimal conditions (60 , pH 5.0), Pectinex produced 265±3 g/L FOS, yielding 0.581±0.006 g(FOS)/g(initial.GF) after 7 h reaction (E/S:1/40); and Viscozyme produced 295±1 g/L FOS, yielding 0.664±0.004 g(FOS)/g(initial.GF) after 5 h (E/S:1/30), both resulting in preparations with 50% (w/w) FOS. The caloric value was reduced 24%, including 80% sucrose reduction. Differences in colour, water activity and ºBrix were not relevant, while consistency and viscosity decreased 70% and pH increased from 4.4 to 4.7. FOS showed resistance to gastrointestinal digestion; only kestose was slightly hydrolysed at intestinal phase. Conclusions. A prebiotic strawberry preparation was successfully produced at lab scale, by in-situ enzymatic conversion of caloric into functional sugars. Next, the process will be scaled-up at industrial level.