In Situ Biosynthesis of Natural Fruity Flavors in Whey and Whey Permeate during Fermentation Using Lipase

Background and Objectives: Chemical synthesis and extraction of flavorings from natural sources include disadvantages. However, biotechnology is a preferred method for biosynthesis of flavorings. The objective of this study was to synthesize natural esters with fruity flavors in whey using lipase of Palatase in combination with ethanol fermentation. Materials and Methods: Lactobacillus fermentum ATCC 14931, Lactobacillus reuteri DSM 17938, and Lactobacillus buchneri NCIMB 40788 were used as in situ ethanol producers. Ultra-high temperature (UHT) cream (30% fat) was added to the fermentation media as a fat source, which was esterified with produced ethanol by Palatase. Viable cell counts and pH were monitored at 0, 24 (Palatase addition), and 48 h (end of fermentation). Free fatty acids of up to 12 carbon chain and their ethyl esters were analyzed using gas chromatography/mass spectrometry. Results: Palatase did not affect the viable cell counts of Lactobacillus reuteri and Lactobacillus buchneri, but increased the viable cell counts of Lactobacillus fermentum. Ethyl ester and free fatty acid levels of the samples increased after Palatase addition. Lactobacillus fermentum produced higher ester levels in ultrafiltration whey permeate whereas other lactobacilli produced higher ester levels in traditional whey. Lactobacillus buchneri included the lowest ester levels and Lactobacillus reuteri included the lowest free fatty acid levels between the lactobacilli. The ester levels of Lactobacillus reuteri samples were the highest in most cases. Free fatty acid levels were higher in traditional whey than ultrafiltration whey permeate. Conclusions: This method can be recommended as an alternative to artificial flavorings with the advantage of labeling products as natural.