Evaluation of spent coffee obtained from the most common coffeemakers as a source of hydrophilic bioactive compounds

The main hydrophilic antioxidant compounds (3-, 4-, and 5-monocaffeoylquinic and 3,4-, 3,5-, and 4,5-dicaffeoylquinic acids, caffeine, and browned compounds, including melanoidins) and the antioxidant capacity (Folin-Ciocalteu, ABTS, DPPH, Fremy's salt, and TEMPO) were evaluated in Arabica and Robusta spent coffee obtained from the preparation of coffee brews with the most common coffeemakers (filter, espresso, plunger, and mocha). All spent coffee grounds, with the exception of those from the mocha coffeemaker, had relevant amounts of total caffeoylquinic acids (6.22-13.24 mg/g of spent coffee), mainly dicaffeoylquinic acids (3.31-5.79 mg/g of spent coffee), which were 4-7-fold higher than in their respective coffee brews. Caffeine ranged from 3.59 to 8.09 mg/g of spent coffee. The antioxidant capacities of the aqueous spent coffee extracts were 46.0-102.3% (filter), 59.2-85.6% (espresso), and <42% (plunger) in comparison to their respective coffee brews. This study obtained spent coffee extracts with antioxidant properties that can be used as a good source of hydrophilic bioactive compounds

Influence of Roasting on the Antioxidant Activity and HMF Formation of a Cocoa Bean Model Systems

During the roasting of cocoa beans chemical reactions lead to the formation of Maillard reaction (MR) products and to the degradation of catechin-containing compounds, which are very abundant in these seeds. To study the modifications occurring during thermal treatment of fat and antioxidant rich foods, such as cocoa, a dry model system was set up and roasted at 180 °C for different times. The role played in the formation of MR products and in the antioxidant activity of the system by proteins, catechin, and cocoa butter was investigated by varying the model system formulation. Results showed that the antioxidant activity decreased during roasting, paralleling catechin concentration, thus suggesting that this compound is mainly responsible for the antioxidant activity of roasted cocoa beans. Model system browning was significantly higher in the presence of catechin, which contributed to the formation of water-insoluble melanoidins, which are mainly responsible for browning. HMF concentration was higher in casein-containing systems, and its formation was strongly inhibited in the presence of catechin. No effects related to the degree of lipid oxidation could be observed. Data from model systems obtained by replacing fat with water showed a much lower rate of MR development and catechin degradation but the same inhibitory effect of catechin on HMF formation

Electron Spin Resonance (ESR) Studies on the Formation of Roasting-Induced Antioxidative Structures in Coffee Brews at Different Degrees of Roast

The antioxidative properties of coffee brew fractions were studied using electron spin resonance spectroscopy using 2,2,6,6-tetramethyl-1-piperidin-1-oxyl (TEMPO) and Fremy¿s salt (nitrosodisulfonate) as stabilized radicals. TEMPO was scavenged by antioxidants formed during roasting and not by chlorogenic acid, whereas Fremy¿s salt was scavenged by all antioxidants tested including chlorogenic acid. The stabilized radical TEMPO allowed the exclusive measurement of roasting-induced antioxidants. The roasting-induced antioxidant activity of coffee brews increased with increasing degree of roast, and most of these antioxidants were formed during the initial roasting stage. The majority of these roasting-induced antioxidants were present in the high molecular weight fractions, indicating that the formation of these antioxidants preferably occurs at specific high molecular weight structures, likely being arabinogalactan and/or protein moieties which might be part of the melanoidin complex. It was found that chlorogenic acids most probably do not lose their antioxidant activity and phenolic characteristics upon incorporation in coffee melanoidins. The parameter fast reacting antioxidants (FRA) was introduced as an alternative for the antioxidative potential. FRA levels showed that coffee fractions rich in roasting-induced antioxidants exposed their antioxidant activity relatively slowly, which must be a consequence of its complex structure. Finally, the melanoidin content and the roasting-induced antioxidant activity showed a positive and linear correlation for the coffee brew fractions, showing that roasting-induced antioxidants are present within melanoidins. This is the first time that the formation of roasting-induced antioxidants could be directly correlated with the extent of Maillard reaction and melanoidin formation in a complex product such as coffee

POSSIBLE WAYS FOR POST‐TREATMENT OF BIOLOGICALLY TREATED WASTEWATER FROM YEAST FACTORY/GALIMI PAPILDOMI MIELIŲ GAMYKLOS BIOLOGIŠKAI VALYTŲ NUOTEKŲ VALYMO BŪDAI/ВОЗМОЖНЫЕ ПУТИ ДООЧИСТКИ БИОЛОГИЧЕСКИ ОЧИЩЕННЫХ СТОЧНЫХ ВОД ДРОЖЖЕВОГО ЗАВОДА

The effluents, which are formed from the waste in the process of production of yeast and molasses, contain a large amount of colouring substances (melanoidins, etc.) and can give dark brown painting to the effluent leading to high organic load on the wastewater treatment plant. The purpose of this study was estimation of the process of coagulation as possible method for the post‐treatment of effluents of yeast industry. The experiments on the coagulation were carried out using biologically purified effluents of Salutaguse yeast factory. This effluent had relatively high residual content of COD (with the effectiveness of treatment — 90%) and brown colour. Different coagulants and flocculants were studied under laboratory conditions. The most effective coagulants FeCl3˙6H2O and Al2 (SO4) 3 were studied additionally. The results of this experiment showed a significant decrease of colour and also concentration of COD. Economic analysis for the possible application of coagulants and ozone for the post‐treated effluents of yeast factory was also made. The obtained data showed that coagulants and ozone could be used in the process of the post‐treatment of effluents of yeast industry for the purpose of decreasing the colour and general concentration of pollutants, however, these processes are very expensive. Santrauka Nuotekų, susidarančių pramoniniuose procesuose naudojant mieles bei melasą, sudėtyje esti dideli kiekiai dažančių medžiagų (melanoidų). Jie nuotekas nudažo tamsiai rudai, o valymo įrenginiams tenka didelės organinių medžiagų apkrovos. Tyrimo tikslas buvo įvertinti koaguliacijos procesą kaip galimą papildomą mielių pramonės nuotekų valymo metodą. Koaguliacijos eksperimentams buvo naudojamos biologiškai valytos Salutaguso mielių gamyklos nuotekos. Nustatyta didelė šių nuotekų liekamoji organinių medžiagų vertė (valymo efektyvumui esant 90 %), nuotekos buvo rudos. Laboratorinėmis sąlygomis ištirta įvairūs koaguliantai ir flokuliantai. Efektyviausieji koaguliantai – FeCl3 · 6H2O ir Al2 (SO4 )3 buvo išanalizuoti papildomai. Eksperimento rezultatai – žymiai pašviesėjo nuotekų spalva, sumažėjo organinių medžiagų koncentracija. Atlikta ekonominė analizė, įvertinta koaguliantų ir ozono taikymas biologiškai išvalytoms mielių gamyklos nuotekoms valyti papildomai, kad pašviesėtų nuotekų spalva, ir suminė organinių medžiagų koncentracija būtų mažesnė. Šie procesai yra itin brangūs. Резюме Сточные воды, образующиеся от использования в процессе производства дрожжей мелассы, содержат большое количество красящих веществ (меланоидинов), которые придают сточной воде темно-коричневую окраску и приводят к высокой органической нагрузке на очистные сооружения. Целью исследования была оценка процесса коагулирования как возможного метода доочистки сточных вод дрожжевой промышленности. В экспериментах по коагулированию была использована биологически очищенная сточная вода Салутагуского завода по производству дрожжей. Сток имел относительно высокое остаточное содержание органических веществ (при эффективной очистке в 90%) и коричневый цвет. Различные коагулянты и флокулянты были изучены в лабораторных условиях. Наиболее эффективные коагулянты FeCl3 ·6H2O и Al2 (SO4 )3 были изучены дополнительно. В результате эксперимента удалось добиться значительного уменьшения интенсивности цвета и концентрации органических веществ. Был произведен экономический анализ с целью возможного применения коагулянтов и озона для процесса доочистки биологически очищенных стоков завода по производству дрожжей. Коагулянты и озон можно использовать в процессе доочистки стоков биологически очищенных вод дрожжевой промышленности для уменьшения цветности и общей концентрации органических веществ. Эти процессы, однако, очень дороги. First Published Online: 14 Oct 2010 Reikšminiai žodžiai: koaguliacija, spalva, ozonavimas, papildomas valymas, mielių pramonės nuotekos. Ключевые слова: коагуляция, цвет, озонирование, дополнительная очистка, сточные воды дрожжевой промышленности