Activity Of Berries Research Articles

Components of antioxidant activity in berries of black currant varieties from the Russian Research Institute of Fruit Crop Breeding

Components of antioxidant activity in berries of black currant varieties from the Russian Research Institute of Fruit Crop Breeding

Introduction pages, NBHA-CN 51(1), 2023

The papers published in Notulae Botanicae Horti Agrobotanici Cluj-Napoca, Issue 1, Volume 51, 2023 represent new exciting research in different topics of life science, respectively in plant science, horticulture, agronomy, and crop science. Among the interesting articles we invite you to find news about: Climate change, its impact on crop production, challenges, and possible solutions; The use of phytotherapy in hepatocellular carcinoma – a systematic review; Anticancer effects of Rhinacanthus nasutus and Acanthus ebracteatus extracts against human cervical cancer cells; Iodine application in Vitis vinifera L. cv. ‘Cabernet Sauvignon’ improve bioactive compounds and enzymatic activity in berries; Arbuscular mycorrhizal fungi promote photosynthesis in Antirrhinum majus L. under low-temperature and weak-light conditions; Biocontrol of the root-knot nematode Meloidogyne incognita with Purporeocillum lilacinum and liquid bio-formulates in tomato (Solanum lycopersicum); Impacts of heat shock on productivity and quality of Triticum aestivum L. at different growth stages.

Iodine application in Vitis vinifera L. cv. ‘Cabernet Sauvignon’ improve bioactive compounds and enzymatic activity in berries

Iodine (I) deficiency disorders represent a worldwide public health problem, with at least 1.9 million people estimated to have an unsatisfactory intake of this trace element. I content in plant foods is particularly low; however, it can be improved by biofortification. In this study, the effect of foliar fertilization with I (0, 0.25, 0.5, 0.75, 1.0, and 1.25 mg L-1) on yield, bioactive compound content, and bioaccumulation in grapevine berries was evaluated. Biofortification with I has positively modified yield, bioactive compound content and bioaccumulation. Intermediate doses (0.75 mg L-1) increased yield (57%), while high doses (1.25 mg L-1) decreased yield (28%) and incremented the phenols, flavonoids, antioxidant capacity, vitamin C, anthocyanin (50,34,31,71,26% respectively), catalase (73%) and peroxidase activity (57%), and their bioaccumulation in berries (59%). Agronomic biofortification with I is an alternative to increase yield, enzymatic and non-enzymatic antioxidants, as well as the concentration of this trace element in grape berries.

Exposure to the Endophytic Fungi Regulates the Anthocyanin Profiles in the Post-Veraison Grape Berries of ‘Cabernet Sauvignon’

The potential of endophytes to initiate changes in host secondary metabolism is expected to be applied to improve the biochemical qualities of the crop. Our previous study revealed the significant impacts of fungal endophytes on the biochemical properties and the anthocyanin profiles in grape berries of the local cultivar ‘Rose Honey’ (RH). To validate the effects, our present work further assessed the impacts of the same fungal endophytes on grape berries of the worldwide planted grapevine cultivar ‘Cabernet Sauvignon’ (CS). Consistent with the results of RH, exposure to most of the used endophytic fungi shaped the biochemical traits and anthocyanidin profile of the CS grape berries. Among the detected biochemical traits, the phenylalanine ammonia-lyase (PAL) activity in berries had the strongest response to endophytic fungal exposure, and the fungal strains RH32, RH36, and MDR1 had the greatest biochemical impacts on the grape berries. Interestingly, the most anthocyanidin species were detected in the two grape berry varieties when exposed to fungal strains MDR36 and RH34. In both varieties, the total anthocyanin concentrations were quantitatively promoted by strains RH36, RH44, MDR1, and MDR36, but suppressed by strain RH7. Malvidin derivatives and delphinidin derivatives accounted for the majority of the relative abundance of the total detected anthocyanins in CS berries. The acylation degree of anthocyanins in grape berries was also significantly promoted by exposure to fungal endophytes. In CS grape berries, a seldom-distributed anthocyanidin, pelargonidin-3-O-glucoside, as well as the diglucoside anthocyanidin were detected when exposed to fungal strains as RH32, RH34, RH36, MDR1, MDR4, and MDR36. Overall, the endophytic fungal strains MDR36, RH36, and RH34 have the ability to promote metabolite profiles in both grape varieties. This work confirms the possibility of using certain endophytic fungal strains as a strategy for shaping grape pigmentation in vinification at the post-veraison or post-harvest stages.

Relationship between Phenolic Compounds and Antioxidant Activity in Berries and Leaves of Raspberry Genotypes and Their Genotyping by SSR Markers.

The red raspberry is one of the world’s most popular berries. The main direction of its breeding has switched to nutritional quality, and the evaluation of raspberry germplasm for antioxidant content and activity is very important. As berries, raspberry leaves contain valuable bioactive compounds, but the optimal time for their collection is unknown. We evaluated 25 new breeding lines and standard raspberry cultivars for their polyphenolic content and antioxidant capacity. The antioxidant activity of berries correlated better with the content of total phenolics (0.88 and 0.92) and flavonoids (0.76 and 0.88) than with anthocyanins (0.37 and 0.66). Two breeding lines were significantly superior to the standard cultivars and can be used in further breeding. Leaves collected in three phenological phases of the raspberry contained more phenolics (5.4-fold) and flavonoids (4.1-fold) and showed higher antioxidant activities (2.4-fold in FRAP assay, 2.2-fold in ABTS) than berries. The optimal time for harvesting raspberry leaves is the fruit ripening stage, with exceptions for some cultivars. Genetic diversity analysis using microsatellite (SSR) markers from flavonoid biosynthesis genes divided the genotypes into five clusters, generally in agreement with their kinships. The relationship between genetic data based on metabolism-specific SSR markers and the chemical diversity of cultivars was first assessed. The biochemical and genetic results show a strong correlation (0.78). This study is useful for further the improvement of raspberry and other berry crops.

Dynamics of 137Cs Accumulation by Cranberry on Sphagnum Bogs of Polissia of Ukraine

Oligotrophic and mesotrophic bogs are common ecosystems in Polissia of Ukraine. After the Chernobyl accident, these ecosystems were contaminated with radionuclides. A common berry plant in these bogs is the cranberry, which is widely used in food industry. The aim of research is to establish dynamics of migration of 137Cs in cranberries during the last 30 years. The obtained results of monitoring studies are necessary for prognosis of radioactive contamination of cranberry. Investigation was conducted on stationary experimental plots (SEP) in Zhytomyr Polissia. 137Cs specific activity was measured on spectrum analyzers with scintillation and semiconductor detectors. Obtained results testify about intensive 137Cs migration on sphagnum bogs of Polissia of Ukraine. Results of investigation conducted after 34 years of Chornobyl accident showed low values of 137Cs specific activity in cranberry (Vaccinium oxycoccus L.) on all stationary experimental plots. This index in 2020 in fresh berries hesitate from 871±82.6 to 286±16.9 Bq/kg (at the permissible level 500 Bq/kg), and in dry shoots – from 1492 (SEP 15) to 6197 Bq/kg (SEP 12). It was found that in the first period (1991-1996) rather significant decreasing of 137Cs specific activity was observed in fresh berries of cranberry – from 3.8 times on SEP 11 to 2.2 times on SEP 12. In the next period (1996-2002) this decreasing was in the limits 1.4-2.9 times that is lower than in previous one. In the following period decreasing of 137Cs specific activity in berries was significantly lower. Revealed regularities of decreasing of 137Cs specific activity in berries during 1991-2020 also confirmed by decreasing of this index in the plant shoots. Total decreasing of this index in dry shoots on the whole period of investigation was: on SEP 11 – from 94590±4236 to 6099±366 Bq/kg (15.5 times), on SEP 12 – from 31800±2325 to 6197±242 Bq/kg (5.1 times), on SEP 15 – from 12120±898 to 1492±112 Bq/kg (8.1 times), on SEP 18 – from 14732±1126 to 1854±112 Bq/kg (7.9 times). Сontinuation of monitoring on stationary experimental plots will allow to predict levels of radioactive contamination of cranberry on the base of mathematical modeling

Berries and Leaves of Actinidia kolomikta (Rupr. & Maxim.) Maxim.: A Source of Phenolic Compounds.

Berries of Actinidia kolomikta (A. kolomikta) are known for high ascorbic acid content, but the diversity of phenolic compounds has been little studied. The present research aimed to investigate phenolic compounds and antioxidant activity in berries and leaves of twelve A. kolomikta cultivars. The UHPLC-ESI-MS/MS technique was used to determine differences among cultivars in the quantitative composition of individual phenolic compounds. Antioxidant activity was determined by DPPH• free radical scavenging and CUPRAC methods. In the present study, 13 phenolic compounds were detected in berries, whereas leaves contained 17 phenolic compounds. Flavonols were the primary class found in both berries and leaves; other identified phenolic compounds were flavan-3-ols, flavones and, phenolic acids; and dihydrochalcone phloridzin was identified in the leaves. The amount and variety of phenolic compounds in berries and leaves and antioxidant activity were found to be cultivar-dependent. The highest total content of phenolic compounds was found in the leaves of the cultivar ‘Aromatnaja’ and in the berries of the cultivar ‘VIR-2’. Results of this study have confirmed that berries and leaves of A. kolomikta could be a valuable raw material for both food and pharmaceutical industries.

Phenolic Compounds, Antioxidant and Cytotoxic Activity in Berry and Leaf Extracts of Black Currant (Ribes nigrum L.) as affected by Soil Management Systems

This experiment evaluated the effect of soil management systems (bare fallow, sawdust mulch and black plastic mulch) on the contents of phenolic compounds (total phenolics, flavonoids, gallotannins and condensed tannins), antioxidant activity (DPPH free radical scavenging activity, hydroxyl radical scavenging activity, lipid peroxidation) and cytotoxic activity in berry and leaf extracts of seven black currant cultivars. Soil management systems and cultivars showed highly significant differences in the content of phenolic compounds, antioxidant and cytotoxic activity. Sawdust mulch and bare fallow treatments had a significant positive effect on the synthesis of phenolic compounds and antioxidant activity in both berries and leaves. On the other hand, black currants grown on black plastic mulch had the highest cytotoxic activity. The tested extracts showed strong antioxidant and cytotoxic potential. Antioxidant activity expressed as the 50% inhibition concentration (IC50 value) ranged from 31.62 to 59.13 µg/mL and from 64.06 to 81.90 µg/mL, while cytotoxic activity varied from 15.91 to 37.89 µg/mL and from 26.28 to 38.18 µg/mL for berries and leaves extracts, respectively. Generally, the results suggested that black currants grow well under varied soil management systems, and indicated that soil management systems had a significant effect on the synthesis and accumulation of the tested parameters.

ВПЛИВ ЕСФОНУ НА БІОХІМІЧНІ ЗМІНИ В ПЕРІОД ДОЗРІВАННЯ ЯГІД, УРОЖАЙНІСТЬ ТА ЯКІСТЬ ПЛОДІВ АҐРУСУ

The effect of pre-harvest treatment of gooseberry bushes (GROSSULARIA RECLINAT (L.) MILL) of cv. Mashenka with a 0.3% aqueous solution of ethylene product on the yield and quality characteristics of berries, quantitative changes in the content of structural polysaccharides during ripening were studied. The experiments were carried out in the field from 2015 to 2017. The experimental sites were randomly chosen, there were five bushes in a row, the repetition of the field experiment was fivefold. The plants were treated with 0.3% aqueous esphone two weeks prior to berry harvesting using an OP-2 backpack. The berries under analysis were selected every four days after treatment with the preparation. The polysaccharide content was determined on a fixed material. The berries were fixed in the field with liquid nitrogen, dried in a drying oven at 70º C to air - dry state. The determination of cellulose and pectin content was carried out by weight method, hemicellulose and non-structural carbohydrates (sugars and starch) in gooseberry fruits were carried out by iodometric method. To evaluate the quality of the berries, their analysis for total acidity was performed by potentiometric titration, ascorbic acid was determined using potassium hexacyanoferrate. The analytical replicability of the studies is fivefold. Statistical processing of the results was performed using the computer program ‘Statistica-6’. The significance of the difference between the control and experiment indicators was determined by Student's t-test. It is found out that on the fourth, eighth and twelfth days, the content of reducing sugars, sucrose and their amounts in the berries treated with ethyleneproducer plants was higher than in the control sample. A more intense decrease in the total acidity of the berries of the experimental sample was observed, while the ascorbic acid content did not change significantly. A higher amylase activity in berries due to ethylene products during ripening was also established, resulting in a faster decrease in the starch content in the berries and an increase in the sugar content. Pre-harvesting of gooseberry with ethylene product esphone leads to increased accumulation of pectic substances in the products, a more intensive hydrolysis of structural polysaccharides in comparison with the control sample, which serves as an indicator of more intense maceration of fetal tissues. The use of pre-harvest processing of gooseberry with ethylene product esphone has led to increased yields and higher quality of gooseberry crop production and has many prospects for the development of mechanized harvesting technologies.

Quality and antioxidant potential of ‘BRS Magna’ grapes harvested in the first half of the year under different training systems and rootstocks in a tropical region

ABSTRACT The Submedium São Francisco Valley is renowned for its particular conditions for cultivating grapes for different uses. The production of grapes for juice is relatively recent, and thus, knowledge is still limited on components of the production system. The aim of this study was to characterize the quality and antioxidant activity of ‘BRS Magna’ grapes in irrigated crops of the Submedium São Francisco River Valley under the influence of training systems and rootstocks, in production cycles of the first half of the year. The experiment was conducted in the Experimental Field of Bebedouro/Embrapa Semiárido, in Petrolina, Pernambuco, Brazil. The following were studied: overhead trellis, lyre, and vertical shoot positioning (VSP) systems and rootstocks ‘IAC 572’ and ‘IAC 766’, in the production cycles corresponding to the first halves of 2017 and 2018. Experimental design was in randomized blocks, with sub-subplots through time and four replicates. Overall, responses depended on training systems, rootstocks, and production cycles, which determined specific traits of the grapes. Production in the first half of 2018 was characterized by high anthocyanin contents, high total extractable polyphenols, and higher antioxidant activity, and responses were differentiated according to training system and rootstock. Plants trained to overhead trellis and grafted on ‘IAC 572’ had higher accumulation of total extractable polyphenols and antioxidant activity in berries. Plants trained to VSP had increased sugar, yellow flavonoid, and anthocyanin contents in berries while lyre training system led to higher bunch mass.

Biochemical composition and antioxidant activity affected by spraying potassium sulfate in black grape (Vitis vinifera L. cv. Rasha).

The physiological and metabolic processes involved with grapevine growth and production are influenced by key macro- and micronutrients. Potassium is an essential plant nutrient that affects growth and fruit quality. In this study, the impact of foliar spraying of potassium sulfate (K2 SO4 ) on qualitative characteristics of grape berries was evaluated in the cultivar 'Rasha', a commonly cultivated cultivar in Kurdistan province of Iran. Leaves of the fully grown vines were sprayed with each of the 1.5 and 3 g L-1 K2 SO4 solutions once (1 month after petal senescence) and twice (15 days after first spraying). The control plants were sprayed with distilled water. Various biochemical contents and enzyme activities on the ripe berries were analyzed. Significant increases in anthocyanin, total protein content, and antioxidant enzyme activities were observed in the berries treated twice with 3 g L-1 K2 SO4 . Concentrations of total carbohydrate, phenol, and antioxidant activity in berries sprayed with K2 SO4 were higher than in the controls. We observed a strong correlation between antioxidant activity and different phenolic compounds. These findings suggest that K2 SO4 treatment influences biosynthesis of phenolic compounds and antioxidant enzymes. Thus, treatment by K2 SO4 could improve nutritional and qualitative attributes of grape. © 2018 Society of Chemical Industry.

Changes in sugar content and related enzyme activities in table grape (Vitis vinifera L.) in response to foliar selenium fertilizer.

Spraying selenium (Se) fertilizer is an effective method for Se-enriched fruit production. Sugar content in fruit is the major factor determining berry quality. However, changes in sugar metabolism in response to Se fertilizer are unclear. Hence, this study was conducted to identify the effects of Se fertilizer on sugar metabolism and related enzyme activities of grape berries. Additionally, production of leaves with and without Se fertilizer was also investigated. Acid invertase (AI) activity, total soluble sugar and Se content in berries, and photosynthetic rate in leaves produced under Se fertilizer treatments were higher than that of control. Glucose and fructose were the primary sugars in berries, with a trace of sucrose. In both berries and leaves, neutral invertase activity was lower than AI, there was no significant difference in neutral invertase, sucrose synthase and sucrose phosphate synthase between Se fertilizer-treated and control. In berries, AI showed a significant positive correlation with glucose and fructose; also Se content was significantly correlated with sugar content. AI played an important role in the process of sugar accumulation in berries; high AI activity in berries and photosynthetic rate in leaves could explain the mechanism by which Se fertilizer affected sugar accumulation in berries. © 2017 Society of Chemical Industry.

Food-mediated modulation of immunity in a phytophagous insect: An effect of nutrition rather than parasitic contamination

Inherent to the cost of immunity, the immune system itself can exhibit tradeoffs between its arms. Phytophagous insects face a wide range of microbial and eukaryotic parasites, each activating different immune pathways that could compromise the activity of the others. Feeding larvae are primarily exposed to microbes, which growth is controlled by antibiotic secondary metabolites produced by the host plant. The resulting variation in abundance of microbes on plants is expected to differentially stimulate the insect antimicrobial immune defenses. Under the above tradeoff hypothesis, stimulation of the insect antimicrobial defenses is expected to compromise immune activity against eukaryote parasites. In the European grape berry moth, Eupoecilia ambiguella, immune effectors directed towards microbes are negatively correlated to those directed towards eukaryotic parasites among host plants. Here, we hypothesize this relationship is caused by a variable control of the microbial community among host plants by their antibiotic metabolites. To test this hypothesis, we first quantified antimicrobial activity in berries of several grape varieties. We then measured immune defenses of E. ambiguella larvae raised on artificial diets in which we mimicked levels of antimicrobial activity of grape berries using tetracycline to control the abundance of growing microbes. Another group of larvae was raised on artificial diets made of berry extracts only to control for the effect of nutrition. We found that controlling microbe abundance with tetracycline in diets did not explain variation in the immune function whereas the presence of berry extracts did. This suggests that variation in immune defenses of E. ambiguella among grape varieties is caused by nutritional difference among host plants rather than microbe abundance. Further study of the effects of berry compounds on larval immune parameters will be needed to explain the observed tradeoff among immune system components.

Carbohydrate metabolism in grape cultivars that differ in sucrose accumulation

Sugar concentrations and sucrose-metabolism related enzyme activities in berries and leaves were investigated during berry development using grape cultivars with different sucrose concentrations. Sucrose concentration was significantly negatively related to acid invertase activity in berries. Acid invertase showed the lowest activities in berries of high-sucrose cultivars, ‘Honey Juice’ and ‘B180’, and the highest in tracesucrose cultivars, ‘Concord’, ‘Jingxiu’, and ‘Jingya’. Acid invertase activities in berries of low-sucrose cultivar ‘Canadice’ were between high- and trace-sucrose cultivars. There was no significant difference in glucose and fructose concentrations, the activities of neutral invertase, sucrose synthase and sucrose phosphate synthase in berries among high-, low- and trace-sucrose cultivars as acid invertase. Sugar concentrations and sucrose-metabolism related enzymes activities in leaves also did not show such difference among all cultivars. The results suggest that differences in sucrose concentration in berries among grape cultivars mainly be due to acid invertase activity. In addition, the final sucrose concentration in berries at maturity for a grape cultivar might be decided at veraison, and veraison is the key period for sucrose accumulation.

Antimicrobial activity of berries and leaves essential oils of Macedonian Juniperus foetidissima Willd. (Cupressaceae)

Chemical composition and antimicrobial activity of leaves and berries essential oils from Juniperus foetidissima Willd. (Cupressaceae) grown in R. Macedonia (RM) was investigated. GC/FID/MS analysis was carried out and 93 components were identified, representing 89.7-96.5% of the oils. The major components of the berries essential oil were α-pinene (19.2%), limonene (24.9%) and cedrol (23.1%), followed by smaller amounts of b-funebrene, trans-caryophyllene, germacrene D and d-cadinene. The composition of the leaves essential oil was variable depending on the region of collection. Accordingly, samples originated from southeastern RM contained essential oil with α-pinene (67.6%) and limonene (10.0%), from central part of RM with limonene (17.9-27.1%) and cedrol (28.8-33.9%), while samples from southwestern RM contained oil with terpinen-4-ol (19.1%), cis-thujone (8.3%), germacrene D (11.0%) and d-cadinene (6.3%) as predominant components in the oil. Antimicrobial screening of the essential oils was made by disc diffusion and broth dilution method against 16 bacterial strains of Gram-positive and Gram-negative bacteria and one strain of Candida albicans. The leaves essential oil showed stronger antimicrobial activity against Staphylococcus aureus, Streptococcus pyogenes and Haemophilus influenzae (MIC = 125 ml/ml) and moderate activity against Campylobacter jejuni (MIC > 500 ml/ml). Other investigated bacterial strains and Candida albicans were completely resistant to the antimicrobial activity of J. foetidissima essential oils.

The effects of bud load and regulated deficit irrigation on sugar, organic acid, phenolic compounds and antioxidant activity of Razakı table grape berries

This study aims at assessing the effects of increased bud load and irrigation applications on berry quality of the Razaki table grape. Two Regulated Deficit Irrigation (RDI) having different irrigation levels (RDI-I and RDI-II) based on the growth stages, in addition to a non-irrigated control treatment together with two different bud load practices (K-normal and 2K-two-fold buds of the normal) were examined for their effects on quality attributes such as sugar and organic acids contents, phenolic compounds as well as antioxidant capacity of the berries. The non-irrigated vines had highest sugar level (198.86 g/kg) in the first year (2013) of the experiment whilst the sugar content of the berries was increased with irrigation (RDI-II) in 2014. However the highest organic acid (7.10 g/kg) was recorded from the RDI-II treatment in 2013 whereas those of from non-irrigated vines were highest (7.81 g/kg) in 2014. Considering the sugar and organic acid content of the berries, bud load effects were not significant. The total phenolic acids were higher under non-irrigated and 2K bud load conditions. Antioxidant activity of berries was increased with RDI-I irrigation and 2K practices in the first year (2013) although no significant effect was recorded in the second year of the experiment. In all applications, glucose among the sugars, tartaric acid among the organic acids, catechin and epicatechin among the phenolic compounds were detected to be higher compared to other components in berries.

Polyphenolic Compounds and Antioxidant Activity in Berries of Four Russian Cultivars of Lonicera kamtschatica (Sevast.) Pojark

Nowadays increasing attention has been focused on polyphenolic compounds as the main representants of antioxidants in horticultural crops including fruits. The edible honeysuckle has an unique position among lesser known fruits due to its high level of antioxidants. In the present study we determined polyphenolic profile and antioxidant capacity of four Russian cultivars of edible honeysuckle including ‘Gerda 25’, ‘Amfora’, ‘Morena’, ‘Lipnicka’, which found together in a single location in Mendel University in Brno, The Czech Republic. Polyphenolic compounds were detected by high performance liquid chromatography coupled with electrochemical detector (HPLC-ED). The antioxidant capacity was measured by DPPH test. According to the results there were differences among cultivars in terms of polyphenolic content and antioxidant activity and Lonicera kamtschatica ‘Gerda 25’ were found to be possessed the highest content of phenolic compounds corresponding to the highest value of antioxidant activity.

In Vitro Studies on the Relationship Between the Antioxidant Activities of Some Berry Extracts and Their Binding Properties to Serum Albumin

The aim of this study was to investigate the possibility to use the bioactive components from cape gooseberry (Physalis peruviana), blueberry (Vaccinium corymbosum), and cranberry (Vaccinium macrocarpon) extracts as a novel source against oxidation in food supplementation. The quantitative analysis of bioactive compounds (polyphenols, flavonoids, flavanols, carotenoids, and chlorophyll) was based on radical scavenging spectrophometric assays and mass spectrometry. The total phenolic content was the highest (P < 0.05) in water extract of blueberries (46.6 ± 4.2 mg GAE/g DW). The highest antioxidant activities by 2,2-diphenyl-1-picrylhydrazyl radical scavenging assay and Cupric reducing antioxidant capacity were in water extracts of blueberries, showing 108.1 ± 7.2 and 131.1 ± 9.6 μMTE/g DW with correlation coefficients of 0.9918 and 0.9925, and by β-carotene linoleate assay at 80.1 ± 6.6 % with correlation coefficient of 0.9909, respectively. The water extracts of berries exhibited high binding properties with human serum albumin in comparison with quercetin. In conclusion, the bioactive compounds from a relatively new source of gooseberries in comparison with blueberries and cranberries have the potential as food supplementation for human health. The antioxidant and binding activities of berries depend on their bioactive compounds.

Effect of drying techniques on the retention of antioxidant activities of Saskatoon berries

The main objective of this research was to compare the retention of antioxidant activity and total anthocyanin content of Saskatoon berries dried by freeze drying, microwave-vacuum drying, thin layer hot air drying and vacuum drying. Antioxidant activity of berry samples was determined by DPPH radical scavenging and ABTS radical scavenging, and the pH differential method was used to determine total anthocyanin content of the berry samples. The results showed that the freeze dried Saskatoon berries exhibited the highest retention of anthocyanin and antioxidant activity among the dried samples, followed by microwave-vacuum dried berries, thin layer hot air dried berries and vacuum dried berries. There were significant differences between the berry samples at P&lt;0.05. DPPH radical scavenging and ABTS radical scavenging were correlated linearly with an R2 value of 0.99 at P&lt;0.05 showing their effectiveness for the determination of the antioxidant activity of the Saskatoon berries. However, the DPPH radical scavenging assay was more effective than the ABTS radical scavenging assay. The results also showed that antioxidant activity of the berries was highly correlated with the total anthocyanin content of the fruit. The reduction of anthocyanin in dried berry samples was linearly correlated with the reduction of DPPH radical scavenging with an R2 value of 0.97 at P&lt;0.05 and, also, linearly correlated with the reduction of ABTS radical scavenging with an R2 value of 0.88 at P&lt;0.05.

Influence of Anthocyanins, Flavonols and Phenolic Acids on the Antiradical Activity of Berries and Small Fruits

One fraction enriched with flavonols and phenolic acids; and the fraction enriched with anthocyanins, were isolated from red raspberry, blackberry, sour cherry, strawberry, chokeberry, elderberry, and blueberry to study their antiradical activity using the free radical, 2,2-diphenyl-1-picrylhydrazyl, test. The phenol content was determined using high-performance liquid chromatography. The antiradical activity of anthocyanins was 7 to 25 times higher than the antiradical activity of flavonols and phenolic acids. High correlations were found between the content of anthocyanins, flavonols, phenolic acids, quercetin derivatives, caffeic acid derivatives, and the antiradical activity (r = 0.99, 0.93, 0.83, 0.93, 0.94, respectively). Among the phenols studied in this work, anthocyanins showed the highest influence on the antiradical activity in all fruits. Other phenolics with relatively strong influence on the antiradical activity of fruits were quercetin derivatives and caffeic acid derivatives (chlorogenic acid) in chokeberries and blueberries, quercetin derivatives in blackberries, quercetin derivatives and caffeic acid derivatives (chlorogenic acid) in elderberries, and hydroxycinnamic acids in sour cherries.