Levels Of Soluble Phenolics Research Articles

Mutagenic effects of sodium azide on pineapple micropropagant growth and biochemical profile within temporary immersion bioreactors

Sodium azide (NaN3) is widely used to induce mutagenesis within in vitro plant systems. However, since this mutagenesis is undirected, its unintended effects demand characterization. This study investigated the mutagenic effects of sodium azide (0-0.45 mM) on selected growth (shoot multiplication rate and shoot cluster fresh weight) and biochemical (aldehydes, chlorophylls, carotenoids and phenolics) parameters in pineapple micropropagants within temporary immersion bioreactors (TIBs). The content of soluble phenolics in the culture medium was also evaluated. Irrespective of the concentration NaN3 decreased shoot multiplication rate (by 87% relative to the control at 0.45 mM) and fresh weight (by 66% relative to the control at 0.45 mM). Levels of chlorophyll a and b, and soluble phenolics in the culture medium were also negatively correlated with NaN3 concentration. Interestingly, NaN3 application increased shoot carotenoid and soluble phenolic levels but had no significant effect on a range of established plant stress biomarkers: cell wall-linked phenolic levels, malondialdehyde and other aldehydes. Given that 0.19 mM NaN3 decreased shoot multiplication rate by 50% and resulted in propagants that displayed no morphologically abnormalities, increased levels of photoprotective pigments (relative to the control) and no significant increase in lipid peroxidation products, the mutagen can be used at this concentration to induce pineapple mutagenesis in TIB based studies aimed at producing agriculturally-useful mutants.

열처리 보리수 과즙과 식초의 이화학적 특성, phytochemicals 및 생리활성

In this study, vineger was produced after heat treatment of Elaeagnus multiflora juice and its fermentative characteristics were investigated. The heat-treated juice and vinegar of E. multiflora were similar in fruit color, with b values (redness) of 39.48 (juice) and 37.56 (vinegar). After 10 days of fermentation of E. multiflora fruit, the acetic acid bacteria viable cell number, pH, acidity, reducing sugar content, and alcohol content were 4.59-4.62 log CFU/mL, 3.14-3.45, 0.2-2.12%, 0.69-35.24 mg/mL, and 0.2%, respectively. The heat-treated juice and vinegar showed significantly higher radical scavenging and digestive enzyme inhibitory activities than untreated samples, and the levels of soluble phenolics, soluble flavonoids, flavan-3-ol derivatives, and phenolic and derivatives were increased. Additioinally, the heat-treated vinegar contained major organic acids, such as acetic acid (21.82 mg/mL), and major flavan-3-ols and phenolic acids, such as catechin (72.24 μg/mL), catechin gallate (273.36 μg/mL), epigallocatechin gallate (68.35 μg/mL), protocatechuic acid (12.84 μg/mL), and salicylic acid (42.29 μg/mL). At 25 μL/mL treatment, DPPH and ABTS radical scavenging activities and α-glucosidase and pancreatic lipase inhibitory activities were 79.66%, 93.99%, 90.12%, and 64.85%, respectively. This result suggested that it is possible to produce new types of vinegar and beverages, using heat-treated E. multiflora juice.

Potassium phosphites in the protection of common bean plants against anthracnose and biochemical defence responses

AbstractThe aim of this study was to investigate the effectiveness of potassium phosphites for the control of anthracnose and the mode of action of these products on common bean plants against Colletotrichum lindemuthianum, comparing it with the standard resistance inducer acibenzolar‐S‐methyl. The protection of plants against anthracnose was evaluated in greenhouse after treatment with potassium phosphites (Phosphite A and B, 5.0 ml/L), acibenzolar‐S‐methyl (0.25 g/L), or no treatment (control). Two sprayings of the treatments were performed, respectively, at V4 stage (three trifoliate leaves) and at the R5 stage (flower buds present). The inoculation with C. lindemuthianum was performed 5 days after the first spraying. Phosphite formulations A and B reduced the severity of anthracnose by 68.7% and 55.6%, respectively, and the presence of phosphites in the leaf tissues were detected at concentrations between 1 and 3 mm by 7 days after spraying. These same concentrations of phosphites reduced the mycelial growth of C. lindemuthianum in vitro by 15.0% to 25.7%. In addition, the activities of defence enzymes and the levels of phenolic compounds and lignin were assessed. Phosphite treatments enhanced the activity of various enzymes, including superoxide dismutase, peroxidase, chitinase, and β‐1,3‐glucanase, and increased the lignin and a small increase in the levels of soluble phenolics. This study provides evidence that phosphite treatments control anthracnose by acting directly on C. lindemuthianum and by inducing the production of defence responses.

In-Vitro Antioxidant Capacity and Bioactive Compounds Preservation Post-Drying on Berrycacti (Myrtillocactus geometrizans)

Berrycactus is a cactus which does not require special agronomic attention, the berries are consumed locally and its commercialization is rather scarce because of the extremely short shelf-life. The significance of the application of any drying methods used to extend the shelf-life on the berrycacti is currently unknown. The aim of this work was to preserve berrycacti (Myrtillocactus geometrizans) and test the bioactive compounds and antioxidant capacity using two distinctive drying methods, freeze-drying (FD) and Instant Controlled Pressure Drop (DIC). Ripe berrycacti was chosen for the drying procedures because the antioxidant capacity and levels of soluble phenols and betalains were at their peak. Colour, phenols, non-extractable polyphenols, tannins, betalains, and antioxidant capacity were considered as factors to determine drying efficacy. Only colour parameters could discriminate between FD and DIC, concluding that both methods are suitable and efficient for preservation of antioxidant properties and retention of bioactive compounds. Both drying methods demonstrated higher in-vitro antioxidant capacity compared to the fresh fruit; highlighting the increase of non-extractable polyphenols and condensed tannins, and good retention of betalains and ascorbic acid after the drying treatments. This research points to use this sustainable crop to provide added value to berrycacti while considering this fruit as functional food due to the antioxidant capacity present even after being processed.

Phosphites for the control of anthracnose in common bean

Abstract: The objective of this work was to evaluate the effect of phosphites in the protection of common bean (Phaseolus vulgaris) against anthracnose. Different phosphite formulations were evaluated by quantifying peroxidase and polyphenol oxidase activity, total phenols, and lignin content. The treatments consisted of sprayings, in the V4, R5, and R7 stages, with: the K, Zn, Mn, K+Mn, K+salicyclic acid, and Cu phosphites; salicylic acid; acibenzolar-S-methyl; the fungicide azoxystrobin; besides a control, without sprayings. The area under the disease progress curve was lower in plants that received applications of the K and Mn phosphites, whose values ranged between 74 and 81%, compared with the control. The K, Zn, and K+salicyilic acid phosphites were effective in controlling the disease. In addition, disease severity was lower with the application of the K, Zn, and Mn phosphites than with the control. Enzyme (peroxidases and polyphenol oxidases) activity and levels of soluble phenols were higher in common bean plants treated with the K and Mn phosphites, although no change was detected in the levels of soluble lignin in the same tissue. Phosphite application reduces the severity of the disease, can enhance enzymatic activity, and is an effective alternative for the control of anthracnose in common bean.

Effect of increased copper ion content in the medium on the regeneration of androgenetic embryos of carrot (Daucus carota L.)

The study was conducted to determine the effect of elevated concentrations of copper in the medium on the regeneration of androgenetic embryos of the carrot cultivar ‘Kazan F<sub>1</sub>’ obtained in anther cultures and to determine the level of soluble phenols produced in the regenerates under copper stress. Green embryos were laid out on 4 regeneration media based on B5 medium (G a m b o r g et al. 1968) without hormones, containing 0.1 – control, 1, 10, and 100 μM CuSO<sub>4</sub>×5H<sub>2</sub>O. The plant material was passaged 3 times, after 4, 9 and 15 weeks. During these passages the emerging structures were examined; they were classified in terms of growth and development <i>in vitro</i>, weighed and counted. The levels of soluble phenols in the freeze-dried regenerates were determined. The elevated concentrations of copper in the regeneration media affected positively the formation of complete plants (rooted rosettes) and secondary embryos during the first 4 weeks of culture. After a longer regeneration time (9, 15 weeks), the elevated concentrations of copper caused negative effects: deformation of rosettes. After 15 weeks, the number of rooted rosettes decreased. The 9-week culture subjected to copper stress brought about an increase in the amounts of soluble phenols. The highest values were recorded in the rosettes treated with 10 μM CuSO<sub>4</sub>. Prolonged exposure to media containing elevated concentrations of CuSO<sub>4</sub> caused a reduction in the accumulation of phenolic compounds in the rosettes.

Hydrogen peroxide scavenging mechanisms are components of Medicago truncatula partial resistance to Aphanomyces euteiches

The biochemical processes underlying the expression of resistance in the roots of Medicago truncatula against Aphanomyces euteiches infection was investigated, with emphasis on oxidative stress. The levels of H2O2, superoxide dismutase, peroxidase, ascorbate peroxidase, catalase, soluble phenolics and lignin were measured in the roots of two lines, A17 partially resistant and F83005.5 susceptible to A. euteiches at three infection stages; penetration of the epidermis (1 dpi), colonization of the cortex (3 dpi) and invasion of the root stele (6 dpi). A rapid and large decrease of the H2O2 levels in A17 roots occurred. However, in F83005.5 roots, the decrease in H2O2 levels was delayed until 3 dpi. In A17 roots, the activities of ascorbate peroxidase, peroxidase and catalase were induced as early as 1 dpi, whereas a general decrease in the activity of the four antioxidant enzymes was observed in F83005.5 roots. The levels of soluble phenolics and lignin were increased in A17 roots at 3 and 6 dpi, respectively. The H2O2 levels were negatively correlated to ascorbate peroxidase, catalase and lignin production at 1, 3 and 6 dpi, respectively in A17 roots. Physiological concentrations of H2O2 found in M. truncatula infected roots had no detrimental effect on the in vitro growth of this oomycete. Our data suggest that H2O2 does not have a direct antimicrobial effect on M. truncatula resistance to A. euteiches, but is involved in cell wall strengthening around the root stele, preventing pathogen invasion of the vascular tissues.

BROWNING OF FRESH-CUT SWEET CORN KERNELS AFTER COOKING IS PREVENTED BY CONTROLLED ATMOSPHERE STORAGE

Reduced O2 plus elevated CO2 (2% O2 + 10% CO2) was very beneficial in maintaining the visual quality of fresh-cut sweet corn kernels and reduced sugar and flavor losses during 10 days storage at 5 °C compared with storage in air. The main benefit of this controlled atmosphere (CA) was to prevent after cooking browning. Preliminary results indicate that after cooking browning is not associated with a Maillard reaction since 5-hydroxymethylfurfural (HMF), the characteristic intermediate compound produced during the Maillard reaction, is not present in cooked sweet corn kernels exhibiting browning. There were no significant changes in the total soluble phenolics content during storage in air or CA, but the soluble phenolic levels decreased with cooking, which suggests that the after cooking brown color may be due to as yet unidentified insoluble phenolic-protein complexes in the cooked sweet corn tissue The total aerobic microbe count increased with storage and the increase was significantly greater in air. This suggests that the browning could be a response of the sweet corn tissue to the microorganisms, or it may be associated with some product of microbial enzyme activity. INTRODUCTION Fresh-cut sweet corn is a very perishable product since the kernels have a very high respiration rate that increases the rate of deterioration compared to intact sweet corn. Previous work with fresh-cut sweet corn showed that this product can be stored for 10 days in low temperature (0-1 °C). Using atmosphere modification (2% O2 plus 10% CO2) allows storage even at higher temperature (5 °C) without much loss in visual or chemical quality (Brecht, 1999; Riad and Brecht, 2001). There are two main problems associated with this product: loss of sugar and flavor (dimethyl sulfide, the main component of sweet corn aroma), and browning that can occur after cooking when the cut kernels are stored in air at higher than optimum temperatures (Riad and Brecht, 2001). Blanchard et al. (1996) described a similar after cooking browning problem in air-stored diced onion, which was eliminated by storage in 10% CO2. After-cooking browning as a result of the Maillard reaction (a nonenzymatic reaction between sugars and free amino acids usually associated with thermal processing) is common in the food processing industry. This reaction produces 5-hydroxymethylfurfural (HMF) (Bayindirli et al., 1995; Gogus et al., 1998). In the case of sweet corn, the possibility of Maillard reaction would seem to be very high since sweet corn has high levels of free amino acids and sugars (Courter et al., 1988; Grunau and Swiader, 1991), and because the brown color does not develop until the kernels are cooked. Another possibility for this browning is the autooxidation of phenolic compounds that cause polymerization of polyphenolic compounds (Talcott and Howard, 1999). It is well known that phenolic acids increase after wounding (Babic et al., 1993a,b; Howard and Griffin, 1993; Ramamurthy et al., 1992). Brecht (1999) noticed that the browning is severe in cut kernels but there is no browning in intact kernels, which also suggests that the cutting or injured tissues in the kernels might result in elevated levels of phenolics that may play a role in the after cooking browning. Fresh-cut products may have high microbial loads (circa 10 to 10 CFU/g) and these populations may increase during storage and reach high levels (e.g., 10 CFU/g) in Proc. XXVI IHC – Issues and Advances in Postharvest Hort.

Componentes fenólicos e enzimas oxidativas em clones de Theobroma cacao resistentes e suscetíveis a Crinipellis perniciosa

Os níveis de fenóis solúveis totais e a atividade das enzimas oxidativas polifenoloxidases e peroxidases foram estudados em tecidos foliares sadios dos clones de cacaueiro (Theobroma cacao) SCA 6, TSH 1188, TSH 565, TSH 516, EET 397, EET 62, TSA 641, SIAL 505, RIM 106, RIM 52, SIC 24 e UF 613, com o objetivo de estudar possível(is) mecanismo(s) de resistência de cacaueiro a Crinipellis perniciosa. Os níveis de fenóis solúveis totais foram mais elevados em clones de cacaueiro com resistência a C. perniciosa, e podem estar contribuindo na resposta de defesa contra o patógeno. A atividade de polifenoloxidases foi menor nos clones resistentes do que nos clones suscetíveis. A atividade de peroxidases em folhas maduras foi menor nos clones resistentes, mas em folhas jovens não foi possível estabelecer uma relação da atividade de peroxidase com os clones resistentes. Os níveis de fenóis e a atividade das enzimas oxidativas correlacionaram-se de forma inversa na maioria dos clones estudados, o que pode indicar uma inibição das enzimas peroxidases e polifenoloxidases pelos compostos fenólicos.

Biochemical Parameters as Biomarkers for the Early Recognition of Environmental Pollution in Scots Pine Trees. I. Phenolic Compounds

Abstract Pinus sylvestrish., Catechin, Ferulic Acid, p-Coumaric Acid, Picein Within a series of regular projects investigating the suitability of biochemical parameters as biomarkers for the early recognition of environmental pollution, the levels of selected phenolic compounds were determined in Scots pine needles (Pinus sylvestris L.) from young and adult trees at three field sites with different SO2 pollution (Rösa>Taura>Neuglobsow). Young trees showed no differences in the levels of soluble phenolics in case of increasing loads of SO2, whereas the concentration of the soluble phenolic component catechin in previous needles of adult trees altered significantly. In current year’ needles, differences were only found in the presence of high SO2 deposition. In contrast to catechin, picein and total phenolics remained unaffected. The concentration of catechin in the previous year’s needles of adult trees correlated positively with needle necroses. The phenolic components of the cell walls of pine needles were also analysed. The main phenolic compounds were identified as p-coumaric acid and ferulic acid. Differences in the levels of p-coumaric acid were detected in the needles of adult trees between the three sites, with the highest levels being measured at the site with the lowest pollution (Neuglobsow). However, changes in the p-coumaric acid content in young trees were low. No site-related differences were found regarding ferulic acid in adult and young pines. The findings are discussed and compared with data reported in the literature.

Genetic variation in the feeding value of cereal straw

Modern cereal varieties tend to have higher grain yields, improved harvest indices, be shorter and earlier maturing than their traditional counterparts. Since neither higher grain yields nor harvest indices appear to be consistently associated with reduced straw digestibility, the potential exists for breeding or selecting varieties combining these characteristics. Shorter varieties of barley and wheat contain higher proportions of leaf blade in the straw than taller material. In rice, conversely, more leaf blade is found in taller varieties. In barley and wheat, leaf blade is more digestible in vitro than either leaf sheath and stem and thus, straw from shorter varieties is more digestible. In rice, leaf blade is less digestible than the stem fraction. Thus, in rice, as well as barley and wheat, shorter material is likely to result in higher feeding value. Stem diameter does not influence straw quality in barley. A greater number of days from planting to either flowering or grain maturity results in increased leaf-blade content in barley and rice straw. In barley, selection for early maturity is likely to lead to reduced straw digestibility but in rice, straw digestibility could be expected to improve. Feeding trials suggest that early maturity in barley results in lower straw voluntary intake. Proportions of leaf and stem appear to explain variations in cellulase solubility of straw from different barley genotypes more closely than levels of soluble phenolics, residual phenolics or titratable groups. However, levels of soluble phenolics or titratable groups were effective in differentiating between untreated straw and straw treated with sodium hydroxide. The effect of variation in straw morphology on the feasibility of chemical treatment to improve straw quality is discussed. In barley straw, leaf sheath responded more to sodium-hydroxide treatment than other straw fractions, suggesting that varieties with greater proportions of leaf blade and stem are likely to show poorer responses to treatment. Aqueous ammonia had only a small effect on the cellulase solubility of leaf blade, compared with sodium-hydroxide treatment. Straw from varieties with a high leaf-blade content and good initial digestibility is likely to show a smaller improvement in digestibility upon treatment with aqueous ammonia compared with straw from varieties with lower initial value.

Peroxidase involvement in lignification in water‐impermeable seed coats of weedy leguminous and malvaceous species

Abstract. The development of water impermeable seed coats of two members each of the leguminoseae family [Crotalaria spectabilis Roth, Sesbania exaltata (Raf) Cory] and the malvaceae family [Anoda cristata (L.) Schlecht, Abutilon theophrasti Medic.] was investigated. Highest peroxidase (POD) activity of Anoda and Abutilon seed coat extracts was highly correlated with the developmental stages when soluble phenolics were maximally converted into lignin. Although extensive lignification occurred during seed coat development in both legumes, the patterns of POD activity, soluble phenolic levels and time of lignification were different from those of the malvaceous species. POD activity levels in developing coats of the malvaceous seeds increased as phenolics decreased. Both POD activity and phenolic levels decreased during seed coat development of the legumes. POD was immunocytochemically and immunochemically detected in seed coats of all four species; however, results for polyphenol oxidase were negative. The results confirmed POD involvement in lignification of leguminous and malvaecous species and support and extend our earlier view that POD is involved in lignin formation during development of impermeable seed coats.

The Effects of Selected Aryloxyalkanecarboxylic Acids on the Growth and Levels of Soluble Phenols in Cultured Cells of Rosa damascena

Summary Cell suspension cultures of Rose damascena cease growth and accumulate soluble phenols when 2,4-dichlorophenoxyacetic acid (2,4-POA), normally supplied at 1 mg 1 −1 is omitted from the culture medium. 2,4-POA can be effectively replaced by the active auxins 2,4,5-trichlorphenoxyacetic acid (2,4,5-POA) and 4-chlorophenoxyacetic acid (4-POA) at 1 mg 1 −1 . The weak auxin, 2-chlorophenoxyacetic acid (2-POA) is less active in promoting growth and a poor suppressor of soluble phenol accumulation even at 10 mg 1 −1 . α-(2-chlorophenoxy) isobutyric acid (2-POiB), which is inactive in the standard auxin bioassays, is very effective in suppressing accumulation of soluble phenols particularly at concentrations within the range 3–10 mg 1 −1 and enables the cells to continue growth although at a lower rate than in the presence of the active auxins. It is concluded that the activity of aryloxy-alkanecarboxylic acids as growth regulators for cells in culture involves their effects on cell metabolism not related to their activity as auxins.