TL;DR: In this paper, a modified version of the TBARS method was proposed for assessing the presence of malondialdehyde (MDA) and other non-MDA compounds absorbing at 532 nm.
Abstract: The occurrence of malondialdehyde (MDA), a secondary end product of the oxidation of polyunsatu- rated fatty acids, is considered a useful index of general lipid peroxidation A common method for measuring MDA, referred to as the thiobarbituric acid-reactive- substances (TBARS) assay, is to react it with thiobar- bituric acid (TBA) and record the absorbance at 532 nm However, many plants contain interfering compounds that also absorb at 532 nm, leading to overestimation of MDA values Extracts of plant tissues including purple eggplant (Solanum melongena L) fruit, carrot (Daucus carota L) roots, and spinach (Spinacia oleracea L) leaves were assessed for the presence of MDA and other non-MDA compounds absorbing at 532 nm A method described herein corrects for these interferences by subtracting the absorbance at 532 nm of a solution containing plant extract incubated without TBA from an identical solution containing TBA The reliability and eAciency of this spectrophotometric method was assessed by altering the relative ratios of exogenous MDA additions and/or extracts of red cabbage (Brassica oleracea L) leaves containing inter- fering compounds and then measuring MDA recovery Reliability was also validated through high-performance liquid chromatography and high-performance liquid chromatography-mass spectrometry techniques Results indicated that over 90% of exogenously added MDA could be recovered through the improved protocol If there were no corrections for interfering compounds, MDA equivalents were overestimated by up to 965% Interfering compounds were not detected in vegetables such as lettuce (Lactuca sativa L) and spinach which had low or negligible concentrations of anthocyanidin derivatives Comparisons between the TBARS method presented here and two currently accepted protocols indicated that the new modified method exhibits greater accuracy for quantifying TBA-MDA levels in tissues containing anthocyanins and/or other interfering com- pounds This modified protocol represents a facile and rapid method for assessment of lipid peroxidation in virtually all plant species that contain interfering com- pounds
TL;DR: In this paper, Radish and potato extracts imparted color characteristics to model juices extremely close to those of allura red, and red potatoes stand out as potential alternatives for the use of FD&C Red No. 40 (allura red).
TL;DR: Fruit and vegetables rich in anthocyanins demonstrated the highest antioxidant activities, followed by those rich in flavanones and flavonols, while the hydroxycinnamate-rich fruit consistently elicited the lower antioxidant activities.
Abstract: Recent studies are emphasising the importance and putative modes of action of specific flavonoids as bioactive components of the diet in in vivo and in vitro models Thus, it is important to have a clear idea of the major phenolic families of which fruit and vegetables are comprised and the levels contained therein Regularly consumed fruit and vegetables of mixed varieties available on the UK market were analysed for the composition of the major individual phenolic components The total phenolic content (applying the Folin assay) and the vitamin C levels were also determined The antioxidant capacities of aqueous/methanolic extracts were comparatively assessed using the TEAC (Trolox Equivalent Antioxidant Capacity), the FRAP (Ferric Reducing Ability of Plasma) and ORAC (Oxygen Radical Absorbance Capacity) assays, which comprise contributions from polyphenols, simple phenols and the ascorbate component The results were calculated in terms of 100 g fresh weight (FW) uncooked portion sizes Fruit and vegetables rich in anthocyanins (eg strawberry, raspberry and red plum) demonstrated the highest antioxidant activities, followed by those rich in flavanones (eg orange and grapefruit) and flavonols (eg onion, leek, spinach and green cabbage), while the hydroxycinnamate-rich fruit (eg apple, tomato, pear and peach) consistently elicited the lower antioxidant activities The TEAC, FRAP and ORAC values for each extract were relatively similar and well-correlated with the total phenolic and vitamin C contents The antioxidant activities (TEAC) in terms of 100 g FW uncooked portion size were in the order: strawberry>> raspberry = red plum >> red cabbage >>>grapefruit = orange > spinach > broccoli > green grape approximately/= onion > green cabbage > pea > apple > cauliflower tomato approximately/= peach=leek > banana approximately/= lettuce
TL;DR: The very high values of antioxidant activity were found in intensely colored vegetables, and the values were very low in watery vegetables such as potato, marrow, and cucumber.
Abstract: This research studies in detail the contents of phenolic compounds determined by the Folin-Ciocalteu reagent and the antioxidant activities determined by the TEAC (Trolox equivalent antioxidant capacity), DPPH (using diphenyl-p-picrylhydrazyl radical), and FRAP (ferric reducing antioxidant power) methods, and their correlations for used standards with these methods (catechine, gallic acid, caffeic acid, ferulic acid, Trolox, ascorbic acid, and ferrous sulfate) and extracts from several species of commonly consumed vegetables were studied in detail. The comparison of absolute values of absorption coefficients for used standards and for individual methods allows one to choose optimal common standards for methods to be compared. The procedures applied for the same sets of the extracts using identical calibration procedures and common standards allowed better comparison of the results obtained by the TEAC, DPPH, and FRAP methods. The values of content of phenolic substances and total antioxidant activity of the sets of samples correlate very well for all used methods. The very high values of antioxidant activity were found in intensely colored vegetables (red cabbage, red onion, etc.), and the values were very low in watery vegetables such as potato, marrow, and cucumber.
TL;DR: In this paper, a Time-Temperature Indicator (TTI) based on a PVA/Chitosan polymeric doped with anthocyanins was used to detect changes in the pH of packaged food products when subjected to improper storage temperatures.