Screening of antioxidant properties of the apple juice using the front-face synchronous fluorescence and chemometrics

Fluorescence spectroscopy is gaining increasing attention in food analysis due to its higher sensitivity and selectivity as compared to other spectroscopic techniques. Synchronous scanning fluorescence technique is particularly useful in studies of multi-fluorophoric food samples, providing a further improvement of selectivity by reduction in the spectral overlapping and suppressing light-scattering interferences. Presently, we study the feasibility of the prediction of the total phenolics, flavonoids, and antioxidant capacity using front-face synchronous fluorescence spectra of apple juices. Commercial apple juices from different product ranges were studied. Principal component analysis (PCA) applied to the unfolded synchronous fluorescence spectra was used to compare the fluorescence of the entire sample set. The regression analysis was performed using partial least squares (PLS1 and PLS2) methods on the unfolded total synchronous and on the single-offset synchronous fluorescence spectra. The best calibration models for all of the studied parameters were obtained using the PLS1 method for the single-offset synchronous spectra. The models for the prediction of the total flavonoid content had the best performance; the optimal model was obtained for the analysis of the synchronous fluorescence spectra at Delta lambda = 110 nm (R (2) = 0.870, residual predictive deviation (RPD) = 2.7). The optimal calibration models for the prediction of the total phenolic content (Delta lambda = 80 nm, R (2) = 0.766, RPD = 2.0) and the total antioxidant capacity (Delta lambda = 70 nm, R (2) = 0.787, RPD = 2.1) had only an approximate predictive ability. These results demonstrate that synchronous fluorescence could be a useful tool in fast semi-quantitative screening for the antioxidant properties of the apple juices.info:eu-repo/semantics/publishedVersio

Zmiany związków polifenolowych w miazdze jabłkowej

The content of polyphenolic compounds and the colour of apple must obtained from the apple pulp being storea before pressing was studied. Changes in the polyphenolic compounds were intensive in the first minutes after apple comminution. Especially susceptible to the reaction were procyanidins and flavanols. The changes in polyphenolic compounds were accompanied by the must browning process being more intensive in case of turbid than clear must.W pracy badano dynamikę zmian zawartości związków polifenolowych i barwy moszczy pozyskiwanych z miazgi jabłkowej przetrzymywanej 0, 3, 5, 15, 30, 60, 120 i 24-0 min przed tłoczeniem. Stwierdzono, że przemiany związków polifenolowych zachodzą intensywnie w pierwszych minutach po rozdrobnieniu jabłek. Statystycznie istotne zmiany procyjanidyn nastąpiły w czasie 15 min pozostawienia miazgi przed tłoczeniem, flawanoli w czasie 30 min, flawonoidów i polifenoli w ciągu 60 min. W pomiarach barwy moszczy mętnych stwierdzono, że w miarę wydłużania czasu przetrzymywania miazgi przed tłoczeniem wzrasta ich zbrunatnienie. Natomiast dla moszczy klarownych, brunatnienie barwy rosło do 15 min przetrzymywania miazgi, a następnie od 30 do 240 min następowało pojaśnienie barwy. W otrzymywaniu moszczy mętnych w celu zachowania jasnej barwy należy zapobiegać procesom utleniania w chwili rozdrabniania. Natomiast dla moszczy klarownych jasną barwę uzyskuje się również przez przedłużanie czasu przetrzymywania miazgi przed tłoczeniem, ale otrzymuje się produkty ubogie w związki polifenolowe

Chemical composition, phenolic compounds and antioxidant activity of three varieties of apple from organic and conventional farming

Celem niniejszej pracy było porównanie składu chemicznego, w tym zawartości związków fenolowych i aktywności przeciwutleniającej trzech odmian owoców jabłoni pochodzących z uprawy konwencjonalnej i certyfikowanej uprawy ekologicznej. W owocach oznaczono sucha masę, ekstrakt ogółem, kwasowość ogólną oraz zawartość kwasu askorbinowego. Dodatkowo oznaczono zawartość związków fenolowych metodą chromatografii cieczowej (HPLC) i aktywność przeciwutleniającą. Na poszczególne analizowane wyróżniki chemiczne wpływ miał nie tylko system uprawy tych owoców, ale i badana odmiana. Wyniki badań wskazują, że owoce z produkcji ekologicznej charakteryzowały się wyższą zawartością ekstraktu ogólnego, kwasowością ogólną i pektyn. Natomiast owoce ekologiczne odmiany 'Topaz' i 'Szampion' w przeciwieństwie do odmiany 'Pinova' charakteryzowały się także wyższą zawartością związków biologicznie czynnych, w tym związków fenolowych i kwasu askorbinowego, czego efektem była wyższa aktywność przeciwutleniająca tych odmian.The aim of this paper was to compare chemical composition, including a content of phenolic compounds, and antioxidant activity of three varieties of apple: Topaz','Szampion', Pinova' from conventional and certified organic farming. There were determined dry matter, total soluble solids, total acidity, ascorbic acid in the fruit. In addition, there was determined a content of phenolic compounds by the high performance liquid chromatography method (HPLC), and antioxidant activity. Separate analysed chemical determinants were influenced not only by the fruit cultivation system, but also the studied variety. The study results show that ecological fruit comprised a higher level of soluble solids, total acidity, pectins. In organic fruit 'Topaz' i 'Szampion', opposite to 'Pinova' cultivars, possess Higher content of bioactive compounds, including phenolic compounds and ascorbic acid occurs in organic fruit 'Topaz' i 'Szampion', opposite to 'Pinova' cultivars. It was reflected in the antioxidant activity

Chemical composition, phenolics, and firmness of small black fruits

Black fruits either cultivated as chokeberry (Aronia melaanocarpa (Michx) Elliot), highbush blueberry 'Duke' (Vaccinium corymbosum L.), lowbush blueberry 'Putte' (Vaccinium corymbosum x Vaccinium angustifolium), and blue honeysuckle (Lonicera caerulea L.), or collected in the wild as bilberry (Vaccinium myrtillus L.), elderberry (Sambucus nigra L.), and wild blackberry (Rubus sp. L.) were assayed for nutritionally valuable components and phenolic composition. On fresh weight basis, lowest acidity was found for elderberry (0.83 g citric acid/l00 g) and the highest for honeysuckle 2.86 g citric acid/ 100 g. Soluble solids content ranged from 16.0% (chokeberry) to 7.4% (blackberry). Honeysuckle berries showed the highest content of L-ascorbic acid (47 mg/100 g), while bilberries the lowest (7 mg/100 g). The berries also showed a disparate firmness ranging from 86 G/mm (bilberry) to 498 G/mm (chokeberry). Regarding total  henol, chokeberry and bilberry were predominant amounting 672.4 mg/100 g and 639.7 mg/100 g, respectively. Moreover, bilberry had the highest amount of anthocyanins (619.6 mg/100 g) and flavonoids (630.2 mg/l 00 g). The highest concentration of flavonols was observed for lowbush blueberry 'Putte' (35.2 mg/100 g), whereas, phenolic acids for chokeberry (121.9 mg/100 g). In contrast, the lowest total phenol was recorded for blackberry (137.8 mg/100 g) due to the low level of anthocyanins (129.4 mg/100 g), flavonols (5.1 mg/100 g), and phenolic acids (3.3 mg/100 g). Cyanidin 3-glucoside was the only anthocyanin occurring in the all species. The presence of chlorogenic acid and quercetin 3-glucoside was detected in the all berries except for blackberries. The 2-year study comparing black fruits of seven species out of different genera demonstrates their high nutritional value and health-promoting potential

Physiological influence of chokeberry phenolics in model diet

Seven groups of Wistar rats (8 males in each) were fed for 4 weeks diets with chokeberry products. Chokeberry juice was added every day to diets at a dose of 1.5, 3 and 6 ml per rat (corresponding to the intake of about 0.5, 1 and 2 l of juice by an adult person) or diets were supplemented with polyphenolics extract to reach the same level of phenolics. The addition of juice or extract did not affect food intake and body gain. Chokeberry juice increased stomach pH from 3.44 (control group) to 3.69–3.85, and ileal pH from 6.16 to 6.23–6.46. Alkalisation of digesta was less distinct with diets containing polyphenolics extract. Both chokeberry products decreased the concentration of caecal ammonia, especially at medium and high doses. The highest dose of chokeberry juice increased microbial α-glucosidase, decreased β-glucosidase and had no effect on β-glucuronidase activities in the caecal digesta. To compare with the control group, the highest dose of chokeberry juice and extract numerically decreased triglycerides (from 265 to 211 and 219 mg dl−1, respectively) and significantly decreased total cholesterol level in the serum (from 133 to 118 and 114 mg dl−1, respectively) and increased content of butyrate in short-chain fatty acids sum of caecal digesta. Indices of the antioxidant status of rats were similar in all treatments. Physiological results of applying relatively low amount of phenolic extract in the diet were similar as when applying high doses of chokeberry juice

Preliminary study on the influence of UV-C irradiation on microorganism viability and polyphenol compounds content during winemaking of ‘Regent’ red grape cultivar

In this study, UV-C light was tested as an alternative method to inactivate microorganisms in the must of ‘Regent’ red grape cultivar. The control sample containing the microorganism diluted in a physiological NaCl solution was prepared to take into consideration different conditions of liquids, such as turbidity and colour. Additionally, the changes in the composition of polyphenol compounds in the ‘Regent’ must after UV-C exposure were evaluated. The viability of yeasts (Saccharomyces cerevisiae) and bacteria (Oenococcus oeni) significantly decreased with time; however, the highest decline was noted after the first hour of exposure. The polyphenol compound content was significantly lower after UV-C treatment and this was mainly the result of anthocyanin decomposition. The total content of flavan-3-ols and hydroxycinnamic acids and derivatives increased after irradiation