Koponen et al. studied the fate of black currant (Ribes nigrum L.) and bilberry (Vaccinium myrtillus L.) flavonols in enzyme-aided processing. The enzyme preparations were dosed based on their polygalacturonase activity from 1 to 100 nkat/g of berry mash. The flavonols were quantified and characterized by high-performance liquid chromatography equipped with a diode array detector and an electrospray ionization mass spectrometer. A tentative identification for 14 black currant and 19 bilberry flavonols is presented representing 11 previously unpublished conjugates. The enzyme-aided processing affected the flavonol extractability, elevating the yield in juices and decreasing that in press residues as compared to non-enzymatic treatment. Importantly, no significant loss of the berry flavonols was observed during the experiments, although some hydrolysis of flavonol conjugates was recorded. To maximize the effect on flavonol extractability, higher enzyme dosages were needed for black currants than for bilberries.

Koponen et al. processed bilberries (Vaccinium myrtillus L.) and black currants (Ribes nigrum L.), dark blue berries rich in anthocyanins, with an aid of commercial pectinolytic enzyme preparations. In addition, they investigated the effect of processing on berry anthocyanins.The enzyme preparations were dosed based on their polygalacturonase activity from 1 to 100 nkat/g of berry mash. The juice yields were determined by weighing, and anthocyanin analyses were performed with HPLC. The bilberry and black currant juice yields increased significantly in enzyme-aided treatments with comparison to non-enzymatic treatment, even with the lowest (1 nkat/g) polygalacturonase dosage. The anthocyanin yield increased by up to 83 % for bilberries and up to 58 % for black currants in enzyme-aided treatments as compared to non-enzymatic treatment.

Ercili Cura et al. investigated the effects of a novel tyrosinase from Trichoderma reesei in structure modification of chemically acidified sodium caseinate and skim milk gels. Enzyme-aided structure engineering of dairy products has taken much interest since the introduction of transglutaminase (TG), a transferase capable of forming inter- or intramolecular isopeptide bonds in protein systems. TG-aided crosslinking of caseins has been reported to lead to milk protein gels with increased firmness and less syneresis. Tyrosinase is an interesting alternative to TG, due to its different mode of action. In the presence of oxygen, tyrosinase is capable of oxidizing tyrosine residues in protein molecules, resulting in the formation of protein-protein crosslinking.

Ma et al. investigated the possibility to improve the suitability of sodium caseinate as emulsifier in o/w emulsions at broad range of pH values. Proteins, such as casein and whey protein, are widely used as emulsifiers in various industrial application areas, e.g. food products, cosmetics and pharmaceuticals. A drawback with proteins as emulsifiers is their low solubility and low net charge at pH values close to their isoelectric points (pI). As a result of this, their emulsifying activity in that pH range is considerably reduced. In the case of caseins with an average isoelectric point around 4.5, reduction of its emulsifying activity at pH values 4-5 has been a severe limitation in its applications in the acidic pH range.