Influence of the time of bilberry (Vaccinium myrtillus L.) addition on the phenolic and protein profile of beer

Abstract

Background. In recent years, there has been an increased fruit addition to the brewing process, especially in craft breweries. Fruit addition leads to changes in the organoleptic characteristics and chemical composition of beers. Bilberries are rich in phenolic compounds and possess significant antioxidant capacity. The effects of bilberry addition and brewing process parameters on the changes in the phenolic and protein profile of beer have not been sufficiently studied. The aim of this research was to investigate the changes in the individual phenolic compounds and the protein fractions in beer when bilberries were added at different maturation stages. Materials and methods. An infusion mashing method was applied for the purpose of obtaining wort with an original extract of 14°P after boiling. Pilsner malt, bitter and aromatic hops 60/40 (Perle and Cascade, respectively), dry yeast Saccharomyces pastorianus (carlsbergensis) Saflager W 34/70, and bilberries (Vaccinium myrtillus L.) were used. All processes were conducted in a Home Brew 50 all-in-one 50 dm 3 brewing system. The fermentation was carried out in a stainless steel cylindroconical fermenter at a temperature of 14°C. The "green beer" was transferred to small stainless-steel fermenters after 60% of the original wort extract had been fermented. The maturation continued for 14 days at 14°C, and the beer lagering for 5 days at 2°C. The bilberries were pasteurised in a water bath for 10 minutes at 70°C. After cooling, they were added to small fermenters at a concentration of 167 g/dm 3 at the beginning and on the seventh day of beer maturation. All variants were carried out in duplicate. After lagering, the beer was bottled using a "beer gun". The beer samples from the experiments were filtered on the day of bottling and frozen until analysis. HPLC/UV-VIS and electrophoresis were used to determine the phenolics and proteins, respectively. The total monomeric anthocyanins were determined by the pH differential method. The original wort extract and alcohol concentration were evaluated, and the sensory analysis was performed according to EBC standard methods. Results. The changes in 10 phenolic acids, 7 flavonoids, and 10 protein fractions in beer with bilberries added at the beginning and on the seventh day of maturation were studied. The addition of bilberries led to an increase in the phenolic acid (3-fold) and flavonoid (6.2-fold) concentrations. The highest enrichment was observed in terms of rutin, chlorogenic, caffeic, and 3,4-dihydrobenzoic acids. Rosmarinic acid and monomeric anthocyanins were only detected in the bilberry beers. Chlorogenic and neochlorogenic acids, rutin, and catechin dominated in the bilberry beers. Neochlorogenic and gallic acids, epicatechin, and catechin dominated in the bilberry-free beers. The addition of bilberries reduced the protein content by 93 to 96%. The number of protein fractions decreased from 10 to 4. The influence of the bilberry addition time on the phenolics and proteins was different, and it affected the individ...

Impact of the Addition of Fruits of Kamchatka Berries (L. caerulea var. kamtschatica) and Haskap (L. caerulea var. emphyllocalyx) on the Physicochemical Properties, Polyphenolic Content, Antioxidant Activity and Sensory Evaluation Craft Wheat Beers

“…The ethanol content in raspberry beers was between 2.8–3.5% v/v [ 9 ]. In a study by Baigts-Allende et al [ 7 ] beers with sour cherries were characterised by an alcohol content of 3.2–8.0% v / v , with raspberries 2.5–5.7% v/v and with blackcurrant 7.1% v / v , while Nedyalkov et al [ 25 ] obtained barley beers with blueberry added with an ethanol content of 5.13% v / v . The energy value of the fruit wheat beers was between 50.53 and 61.13 kcal/100 mL and, with the exception of BW beer, was on average 8.86% higher than that of the control beer (CB; Table 1 ).…”

The Effect of the Addition of Ozonated and Non-Ozonated Fruits of the Saskatoon Berry (Amelanchier alnifolia Nutt.) on the Quality and Pro-Healthy Profile of Craft Wheat Beers

“…In the study by Baigts-Allende et al [ 10 ], cherry beers were characterised by an alcohol content in the range of 3.2–8.0% v / v , with raspberries being 2.5–5.7% v / v and blackcurrants being 7.1% v / v . In contrast, Nedyalkov et al [ 25 ] obtained an ethanol content of 5.13% v / v in the barley beer with bilberry, whereas beers produced with the addition of mango juice and pulp were found with a calorific value of 34.13–36.73 kcal and alcohol contents of 4.13–4.27% v / v [ 26 ]. The fruit wheat beers’ characterised caloric content of the finished product was at the level of 48.88–52.34 kcal/100 mL ( Table 1 ).…”

“…The caffeic acid in beers is generally in the range of 0.00–23.50 mg/L [ 43 ]. In barley beers with bilberry (fruit addition in the amount of 167 g/L), the content of caffeic acid was 13.01 mg/L, chlorogenic acid was 90.19 mg/L and neochlorogenic acid was 52.24 mg/L [ 25 ]. Wheat beers enriched with fruits of the cv.…”

Geographic Variability of Berry Phytochemicals with Antioxidant and Antimicrobial Properties

“…Bilberries have beneficial effects in the prevention of cancer, cardiovascular disease, obesity, diabetes, diseases caused by aging, urinary tract infections and periodontal disease [ 19 ], Bilberries show antimicrobial effects, too, especially against E. coli and Bacillus subtilis [ 20 ]. In order to be more accessible to consumers, bilberries were added in several foods (i.e., beer) [ 21 , 22 ]. Gooseberries ( Ribes grossularia L.) are a source of phenolic compounds, such as flavonols (quercetin, kaempferol and myricetin) and phenolic acids (caffeic, coumaric, ellagic and hydroxybenzoic acids).…”