Copigmentation effect of phenolic compounds on red currant juice anthocyanins during storage

Copigmentation has been suggested as a main colour stabilising mechanism in plants protecting the coloured flavylium cation from the nucleophilic attack by the water molecule. In this study influence of phenolic compounds addition (catechol, 4-methyl catechol, (+)-catechin and gallic acid) on stability of red currant juice anthocyanins (copigment:pigment molar ratio 50:1 and 100:1) during 30 days of storage at 4 °C was investigated. Stability of anthocyanins was evaluated through determination of anthocyanins, total colour difference (ΔE*), kinetic parameters and anthocyanin retention. The initial anthocyanin content of red currant juice was 44.34 mg/100 g. During storage degradation of anthocyanins occurred. After storage anthocyanin content of red currant juice was 38.87 mg/100 mL. However, in samples with addition of phenolic compounds degradation was less pronounced due to formation of pigment-copigment complex (i.e. copigmentation). Anthocyanin content in samples with addition of phenolic compounds ranged from 39.2 to 43.83 mg/100 mL, depending on phenolic compound, its concentration and storage time. The lowest degradation was observed when gallic acid was added. Monitoring only λmax of absorption spectrum of juices, one can get incomplete picture of colour stability of red currant juice. It was important to monitor total colour change (ΔE*) with CIELAB colour system since all parameters are taken into account. The lowest ΔE*, after 30 days of storage, had samples with addition of catechol and (+)-catechin (0.83 and 0.86, respectively), while the highest values had samples with addition of gallic acid (1.26)

Potrebe potrošača za dostupnom hranom dobre kakvoće

Food has a powerful impact on human physical, mental, emotional and spiritual well-being and this is reflected on in many new nutritional approaches. Consumers expect a steady increase in quality, safety and diversity of food. Consumers’ perception of food quality is a dinamic variable. It might focus on products, processes, process management or on management issues such as fairness in trade, working conditions, environmental consciousness, or the origin of products. Despite the fact that food has never been safer, it seems that consumers are considerably uncertain, anxious and increasingly critical about the safety of their food. Both growing demand for safer, healthier and higher food quality, and at consumers’ concerns about global warming and environment protection necessiate a more intensive and closer collaboration of food scientists and technologists, engineers, and others, in order to use information from the fields of biophysics, informatics, nanotechnology, nutritiogenomics, and medicine, to address all social and economic challenges. Understanding consumer behaviour as a major factor in the competitiveness of food industry and the impact of food on health, and well-being, the focus should be placed on consumers’ perception and attitudes towards food, understanding of societal trends, and identification of food choise determinants and consumer access to food. Most of the food available to the consumers are both processed and packed. To ensure a high level of protection of human health and consumers’ interests in relation to food, the basic task should be to provide an integrated approach ‘’from fork to farm’’ covering all sectors of the food chain, including feed production, primary production, food processing, transport, and retail sale. The final goals to be required refered to new flexible enterprise relationships that will connect further food products and process development with consumers’ needs, based on research results obtained in respective fundamental disciplines.Hrana ima veliki utjecaj na fizičko, mentalno, emocionalno i duhovno stanje ljudi a to se odražava u mnogim novim pristupima prehrani. Konzumenti očekuju siguran rast kvalitete, sigurnosti i različitosti hrane. Predodžba konzumenata o kvaliteti hrane je dinamična. Ona može biti fokusirana (usredotočena) na proizvode, procese, upravljanje procesom ili na pitanja upravljanja kao što su nepristranost na tržištu, radni uvjeti, briga za okoliš, ili podrijetlo proizvoda. Unatoč činjenici da hrana nikada nije bila sigurnija, čini se da su konzumenti (potrošači) znakovito sumnjičavi, zabrinuti i sve više kritični kada je u pitanju sigurnost hrane. Rastući zahtjev za sigurnijom, ‘’zdravijom’’ i hranom najviše kvalitete, kao i briga potrošača za globalno zatopljenje i zaštitu okoliša zahtijeva intenzivniju i čvršću suradnju znanstvenika u području hrane, tehnologa, inženjera i drugih, s ciljem da se upotrijebe informacije iz područja biofizike, informatike, nanotehnologije, nutricionizma, medicine, kako bi se odgovorilo socijalnim i ekonomskim izazovima. Razumijevanjem ponašanja konzumenta (potrošača), kao glavnog čimbenika u konkurentskoj prehrambenoj industriji i utjecaja hrane na zdravlje i blagostanje, fokus bi se trebao usmjeriti ka percepciji ponašanja potrošača prema hrani, razumijevanju socijalnih trendova i identifikaciji determinanti za izbor hrane te dostupnosti hrane potrošačima. Većina hrane, dostupne potrošačima, je prerađena i upakirana. Da bi se osiguralo zdravlje potrošača kao i potrebe potrošača za hranom, osnovna zadaća morala bi biti da se osigura integrirani (sveobuhvatni) pristup ‘’od vilice do farme’’ čime bi se pokrili svi sektori lanca hrane, uključujući proizvodnju hrane za stoku, primarne proizvodnje, prerade hrane, transport i prodaja. Konačni ciljevi koji su potrebni odnose se na nove fleksibilne odnose unutar poduzeća koji će povezati buduće prehrambene proizvode i razvoj procesa s potrebama potrošača, baziranih na rezultatima istraživanja postignutih u odgovarajućim fundamentalnim disciplinama

Influence of different extracts addition on total phenols, anthocyanin content and antioxidant activity of blackberry juice during storage

The aim of this study was investigation of influence of different extracts addition on total phenols, anthocyanin content, antioxidant activity and percent of polymeric colour of blackberry juice during storage of 52 days at 4 °C. Anthocyanin content of control sample (blackberry juice without extracts addition) was 149.91 mg/L. Samples with addition of extracts (olive leaf, pine bark PE 5:1, pine bark PE 95 %, green tea, red wine PE 30 %, red wine PE 4:1 and bioflavonoids had higher anthocyanin content (from 152.42 to 161.19 mg/L) in comparison to control sample. Sample with addition of bioflavonoids had the highest anthocyanin content. Samples with addition of extracts had much higher total phenol content and antioxidant activity than control sample, what was expected since extracts are rich in phenols. During storage decrease of phenols, anthocyanins and antioxidant activity occurred in higher or lesser extent, depending on extract type addition. Anthocyanin content in control sample was 119.85 mg/L. Samples with addition of bioflavonoids, olive leaf, pine bark PE 5:1 and red wine PE 4:1 had lower (from 103.44 to 118.84 mg/L), while other samples had higher (from 131.99 to 135.57 mg/L) anthocyanin content than control sample. After storage, decrease of anthocyanins was followed with increase of percent of polymeric colour, with exception of samples with addition of green tea