Reduction of acidity in northern region berry juices

• Main Author: Viljakainen, Sanna
• Other Authors: Department of Chemical Technology, Kemian tekniikan osasto, Laboratory of Biochemistry and Microbiology, Biokemian ja mikrobiologian laboratorio, Aalto-yliopisto, Aalto University
• Format: Doctoral or Postdoctoral Thesis
• Language: English
• Published: Helsinki University of Technology 2003
• Subjects: Environmental science; Biotechnology; northern region berries; organic acids; soluble sugars; acid reduction; malolactic fermentation; Oenococcus oeni; yeast uptake; alcoholic fermentation; berry wine; sensory quality; Crowberry
• Online Access: https://aaltodoc.aalto.fi/handle/123456789/2080

Northern region berries may be used for wide variety of product alternatives as well as serving as a supply of many nutritionally valuable components. However, there are only rare, fragmentary and inconsistent scientific data available on the chemical composition of northern region berries. Therefore, comprehensive information was gathered on organic acid and soluble sugar concentrations of juices of six wild berries (bilberry, lingonberry, cranberry, cloudberry, red raspberry, black crowberry) and five cultivated berries (black currant, white currant, red currant, gooseberry (red), strawberry) all grown in Finland. The main acids of the berry juices were invariably citric and malic acid even though their concentrations varied widely from one berry variety to another (2.9 - 16.2 g/l and 3.3 - 24.7 g/l, respectively). In addition, juices of lingonberry, cranberry, cloudberry and black crowberry contained benzoic acid (0.1 - 0.7 g/l). The main sugars of the investigated berry juices were fructose (18.0 - 57.2 g/l) and glucose (22.2 - 50.0 g/l). Most of the berries contained also sucrose (0.2 - 5.1 g/l). The data enable direct comparison of northern region berries and underline the wide variation in their organic acid and soluble sugar content, which offers possibilities for the production of numerous sensory profiles. Accordingly, the selection of the right berry for individual purposes is enhanced. Due to their acid and sugar composition, fermentation of northern region berry juices into wines faces challenges that are not normally met when using grape juices. In berry juices the fermentations should maintain or alleviate the often rich berry aroma under conditions where the content of organic acids is high and that of fermentable sugars low. Prior to fermentation the juices have to be diluted and sugar has to be added. This causes significant weakening of the aroma and body of the wine. To reduce the acidic mouthfeel of grape wines malolactic fermentation (MLF) is widely used. However, it is not known whether ...