Adding value to grape must by using it as co-substrate for the synthesis of fructo-oligosaccharides

M MICAELA URETA; NELSON ROMANO; KAKISU EMILIANO; ANDREA GÓMEZ ZAVAGLIA

Congreso; 2nd Food Chemistry Conference; 2019

Grape must market has beenrising and there is an increasing interest to use it as a "natural"replacement for traditional sugars. Food or beverages with prebiotic compounds,including fructo-oligosaccharides (FOS), emerge as an alternative for the newhealth style trend.The aim of this work was toinvestigate whether the combination of grape must with sucrose was a suitableraw material for the synthesis of FOS. This way, a prebiotic syrup containingfructose and FOS, potentially useful for the formulation of foods andbeverages, could be obtained. The main process consisted of three stages,namely conditioning of grape must (oxidation of the initial glucoseconcentration, stage 1), synthesis of FOS [incorporation of 20, 30 and 55%(w/w) sucrose, and 3.5% v/v Viscozyme L -4.2 U/mg-stage 2] and conditioning of the final product (oxidation of the glucose generatedduring the synthesis, stage 3).At stage 1, glucoseconcentration decreased from 222.8 mg/mL to 47.2 mg/mL, representing a decay ofabout 80% regarding the initial concentration of glucose. At stage 2, incorporating 20% (w/w) sucrose was not enough to impulse FOS synthesis. In turn, although 30 and 55% (w/w) sucrose produced very similarconcentrations of total FOS (DP3+DP4), 55% (w/w) sucrose led to higher glucosegeneration and less DP4 formation. Hence, 30% (w/w) sucrose was the conditionselected for the synthesis and further conditioning of the obtained product(stage 3). In these conditions, the final product consisted of more than 30% ofshort chain FOS (19% and 13% of DP3 and DP4, respectively), 55% fructose andless than 11% of glucose and sucrose.Considering that fructose has approximatelydouble sweetening power than glucose, the obtained syrup has a bigger sweetening power incomparison with the original grape must, also providing the prebiotic benefits of FOS.It represents an adequate functional ingredientto sweeten different beverages, without interfering with their qualityattributes (palatability, flavor, body, and mouthfeel), improving thenutritional composition and entailing gastrointestinal health benefits.