‘Cyanidin volumetric index’ and ‘chromaticity coordinates ratio’ to characterize red raspberry (Rubus idaeus)

The object of this work is presented in a larger research project concerning ‘New indexes to evidence the nutritional quality of small fruits’ in progress at the Analytical Food Research Laboratories, University of Milan. The present paper contains data that contribute to the analytical characterization of 12 varieties of red raspberry through the high-performance liquid chromatography determination of the aglycon ‘cyanidin’ derived from chemical hydrolysis of berries. Even more interesting results are the proposal of the ‘cyanidin volumetric index’, by which it is possible to compare different red raspberry varieties with higher meaningfulness. A new possible correlation between the ratio of chromaticity coordinates ‘a/b’ and the cyanidin content of red raspberries has been identified.     

Phenolic composition of fruits from different cultivars of red and black raspberries grown in Poland

Fruits of 11 varieties of Rubus idaeus and 1 variety of Rubus occidentalis cultivated in Poland, were analyzed in terms of phenolic composition. The qualitative and quantitative determination of phenolics was performed by means of HPLC-DAD coupled with ESI–MS detector. Quantitative determination of anthocyanins, revealed significant differences in the levels of major anthocyanins in most red raspberry varieties, of which cyanidin 3-O-sophoroside was the most prevalent one. Black raspberries displayed 4–11 times more anthocyanin content compared to red raspberries, with the dominating anthocyanins being cyanidin 3-O-rutinoside and cyanidin 3-O-xylosyl-rutinoside.Sanguiin H-6 was the main ellagitannin identified in all varieties, with ‘Beskid’, ‘Laszka’, ‘Polana’ and ‘Litacz’ standing out as the richest sources of sanguiin H-6. Ellagic acid was at similar, low concentrations, with the highest levels observed in ‘Willamette’. A number of other compounds belonging to flavonols, flavan-3-ols and phenolic acids, were found at much lower levels than anthocyanins and ellagitannins, with the presence of procyanidins B₁ and B₂ being reported for the first time in the fruits of black raspberries. Data obtained on the variation in content of major and minor phenolic compounds between raspberry varieties highlights the most valuable cultivars to be used as a dietary source of phenolic compounds.     

The bioactive potential of red raspberry (Rubus idaeus L.) leaves in exhibiting cytotoxic and cytoprotective activity on human laryngeal carcinoma and colon adenocarcinoma

In this article, the bioactive potential of red raspberry leaves, a by-product of this widely spread plant, mostly valued for its antioxidant-rich fruits, was determined. The polyphenolic profile and antioxidative properties of red raspberry leaf extract were determined and examined for potential biological activity. Cytotoxic effect, antioxidative/prooxidative effect, and effect on total glutathione concentration were determined in human laryngeal carcinoma (HEp2) and colon adenocarcinoma (SW 480) cell lines. SW 480 cells are more susceptible to raspberry leaf extract in comparison with HEp2 cells. The antioxidative nature of raspberry leaf extract was detected in HEp2 cells treated with hydrogen peroxide, as opposed to SW 480 cells, where raspberry leaf extract induced reactive oxygen species formation. Raspberry leaf extract increased total glutathione level in HEp2 cells. This effect was reinforced after 24 hours of recovery, indicating that induction was caused by products formed during cellular metabolism of compounds present in the extract. Comparison of the results obtained on these two cell lines indicates that cellular response to raspberry extract will depend on the type of the cells that are exposed to it. The results obtained confirmed the biological activity of red raspberry leaf polyphenols and showed that this traditional plant can supplement the daily intake of valuable natural antioxidants, which exhibit beneficial health effects.     

Variability in flavonol content of grapes cultivated in two Mediterranean islands (Sardinia and Corsica)

The main abundant flavonols, myricetin, quercetin and kaempferol, were analyzed in 58 samples of native red and white grapes from two Mediterranean islands, Sardinia and Corsica, with the aim of identifying a possible correlation between the respective flavonol profile and varietal origin. Quercetin and myricetin are the most commonly represented flavonols in the red grapes. In the white varieties quercetin prevails over kaempferol, while myricetin is absent. Absolute data show that the red varieties of Nielluccio and Minustello present high total concentrations of flavonols. Among the white grape varieties it is possible to observe that the Moscato is characterized by a total flavonol content clearly higher than that of Vermentino, and comparable to, sometimes even higher than, that of the other red varieties. No differences have been found between the Vermentino samples from Corsica and Sardinia according to their geographical origin. Considering the absolute values of the compounds analyzed great variability is found among the samples belonging to the same variety, whereas variability in the flavonol profile, expressed as percentage content of each aglycon of the total, is less pronounced. Statistical techniques (ANOVA and Hierarchical Cluster Analysis) showed that the flavonol profile, rather than the absolute values, enabled good discrimination between cultivars, demonstrating that it may effectively be used for chemotaxonomic aims.     

Red fruit juice quality and authenticity control by HPLC

The present work used International Federation of Fruit-Juice Producers (IFU) Method No. 71 with minor modifications for the analysis of anthocyanins, betacyanins, synthetic red pigments, hydroxycinnamic acids, hydroxybenzoic acids and catechins present in red fruit and vegetable juices and red-purple soft-drinks. The proposed HPLC method has been implemented with simultaneous UV-Visible and fluorescence detection and offers unambiguous composition results for 9 red fruit and vegetable juices: strawberry, red raspberry, blueberry, European cranberry, blackcurrant, sour cherry, red grape, purple carrot and purple prickly pear. Twenty-eight anthocyanins, 4 betacyanins, 1 natural and 6 synthetic pigments, 11 hydroxycinnamic acids, 6 hydroxybenzoic acids and 2 catechins were determined in a 30-min chromatogram. This method is useful for quality and authentication analyses of red fruit and vegetable juices, and red-purple soft-drinks. The use of a unique analysis method for polyphenol analysis is encouraged as a helpful tool to build up an unambiguous polyphenol composition database of foods.     

Antioxidant and cyclooxygenase inhibitory activity of sorrel (Hibiscus sabdariffa)

The antioxidant activity of the hexane, ethyl acetate and methanol extracts of three varieties of sorrel (Hibiscus sabdariffa), as well as their potential for reducing blood viscosity, were studied in vitro. The samples screened were two red [(traditional red (TRED) and early bearing red (ERED)] and one white (WHTE) mature Hibiscus varieties. Antioxidant activity was measured by fluorescence spectroscopy using a model liposome system. Cyclooxygenase inhibitory activity was measured using cyclooxygenase (COX-1 and COX-2) enzymes by monitoring the rate of oxygen uptake in prostaglandin synthesis. Antioxidant activity was the highest overall in the red varieties compared to the white. The methanol extract from the three varieties had the highest activity. The methanol and ethyl acetate extracts of the three varieties of sorrel showed higher COX-1 enzyme inhibition than COX-2 and therefore had high potential to decrease blood viscosity. There was no COX-1 or COX-2 inhibition in the hexane extract. These findings support the ethnomedicinal use of H. sabdariffa in Africa and the Caribbean for the treatment of cardiovascular disease and hypertension.     

Epidemic of gastroenteritis of viral origin associated with eating imported raspberries

Several episodes of food poisoning affected the region of Quebec City in July and August 1997. In the first two episodes, the analysis of two cohorts (A and B) demonstrated that the consumption of a raspberry mousse with raspberry sauce increased the risk of contracting gastroenteritis (A, RR = 2.6 p = 0.001; B, RR = 4.7 p = 0.02). More than 200 people were sick after eating a raspberry dessert. The common ingredient of all those desserts was raspberries imported from Bosnia. Viral studies on the raspberry sauce (2) and stool samples (5) using the genome amplification method by PCR indicated the presence of genomic material compatible with a virus of the Caliciviruses family. Southern hybridization and sequence analysis showed that the nucleotide sequences found in the raspberry sauce and in the stool samples were identical. It is important to maintain active surveillance to detect and limit the spread of this kind of outbreak.     

Phytochemicals and antioxidant capacity in four Italian traditional maize (Zea mays L.) varieties

Flours of four pigmented (from orange to red and dark red) local Italian corns, studied for their soluble, soluble conjugate, and insoluble-bound phenols and flavonoids, showed a prevalence of the insoluble-bound fraction (70–80%). Correlations were found between the flours antioxidant capacity, measured with CUPRAC, FRAP, and DPPH methods, and soluble phenols and flavonoids content. A correlation was also found between ascorbic acid content and flours antioxidant power. Anthocyanins were present in small amounts in the red/dark red seeds; however, acid-alcohol assays and spectral analyses of pericarp extracts indicated the presence of red-brick phlobaphenes in these varieties. Spectrophotometrically quantified total carotenoids were significantly higher in one of the local varieties (Nano); RP-HPLC analyses indicated that the local varieties contained significantly higher amounts of zeaxanthin and β-carotene, and lower amounts of lutein, than a commercial line. Among local varieties, Nano expressed the highest levels of zeaxanthin, β-carotene, and β-cryptoxanthin.     

新疆树莓果实营养成分及其提取物抗氧化性研究

目的分析新疆野生树莓果实营养成分,并对其提取物进行抗氧化活性测定。方法进行营养保健成分含量分析,并对果实95%乙醇提取物经石油醚脱脂后,依次用乙酸乙酯、正丁醇萃取,观察不同萃取部位对DPPH·和·OH的清除能力。结果树莓鲜果中必需氨基酸含量高达320mg%,非必需氨基酸中谷氨酸含量较高(180mg%);富含维生素C(28.04mg%)和钾(147.32mg%);有机酸含量高达1.72%,以柠檬酸为主;其它如总酚、总黄酮、鞣化酸、单宁含量分别为498、125、2.2和290mg%,SOD活性高达606.93U/ml。树莓不同提取物均显示了较好的抗氧化活性,以乙酸乙酯部分最高,与清除DPPH自由基相比,清除羟自由基能力强。结论新疆野生红树莓果富含多种营养保健成分和抗氧化活性,有很好的开发价值。     

Changes in total phenolic and monomeric anthocyanin composition and antioxidant activity of three varieties of sorrel (Hibiscus sabdariffa) during maturity

Three varieties of sorrel (Hibiscus sabdariffa) were analyzed for total phenolic, monomeric anthocyanins and antioxidant activity at five stages of maturity. The varieties designated traditional red (TRED), early bearing red (ERED) and white (WHTE) were sampled at the pre-flowering stage, as well as 3 days, 7 days, 21 days and 35 days after flowering. The total phenolic composition ranged from 5 to 24 mg/g and, while found in all varieties, was highest for TRED and ERED. Anthocyanins were only observed in the red varieties and ranged from 0.5 to 3.5 mg/g. The levels of both total phenolics and monomeric anthocyanins fluctuated, initially declining then increasing with maturation. The three sorrel varieties exhibited antioxidant activity, inhibiting lipid peroxidation between 69 and 79%. Increasing maturity at harvest tended to increase antioxidant activity for all varieties. A linear relationship existed between antioxidant activity and stage of maturity (r = 0.59). This research has implications for the sorrel industry as the antioxidant phytonutrients of sorrel could add value to sorrel currently produced and consumed.     

Application of principal component and hierarchical cluster analysis to classify fruits and vegetables commonly consumed in Ireland based on in vitro antioxidant activity

The purpose of this study was to gain insights into the variations in antioxidant profiles between fruits and vegetables using pattern recognition tools; classification was achieved based on global antioxidant activity, levels of antioxidant groups (total phenolics, total anthocyanins, ascorbic acid) and quality parameters (instrumental colour, moisture). Six vegetables (broccoli, carrot [organic and intensively grown], butterhead lettuce, red onion, yellow onion) and eight fruits (blueberries, cherry tomato, cranberries, red grapes, green pepper, raspberry, red pepper and strawberry) commonly consumed in Ireland were analysed. Antioxidant activity (ARP) and concentrations of bioactive compound groups differed according to sample type. Berry fruits had the highest antioxidant activity (1.51-2.97 (g/L)⁻¹). By contrast, vegetables were quite low in antioxidant activity (0.14-0.39 (g/L)⁻¹). Interrelationships between the parameters analysed and the different fruits and vegetables were investigated by principal component analysis (PCA) and hierarchical cluster analysis (HCA). PCA revealed that the first two components represented 62% of the total variability in antioxidant activity and different antioxidant groups. HCA classified samples into four main groups on the basis of the measured parameters.     

Contents of tannins and oxalic acid in the selected forest fruits depending on the harvest site

Contents of anti-nutritional components (tannins and oxalic acid) were determined in samples of forest fruits: blueberry, raspberry and wild strawberry harvested in Lublin region from areas considered as potentially not exposed to pollution (Skierbieszów Landscape Park) and potentially polluted areas (Cement Factory Rejowiec S.A.). Study revealed that blueberry and raspberry fruits collected on potentially polluted area were characterized by higher tannins contents than those harvested on potentially not polluted area. Oxalic acid level in studied material indicated its significantly higher concentration in wild strawberry fruits collected both from not exposed and polluted areas as compared to raspberry and blueberry. Tannins and oxalic acid contents in analyzed berries may be accepted as low and safe for human's health.     

Rubus occidentalis: The black raspberry—its potential in the prevention of cancer

Rubus occidentalis is a black-fruited raspberry originating from North America. Its popularity and demand has been growing over the years, as studies outline its high anthocyanin and ellagitannin content and significance for human health. Interaction between chemical composition and pharmacological activity, mechanisms of action at cellular and molecular levels are all active areas of study. The vast majority of research concerning black raspberries is focused on chemoprevention and anticancer effects. This review summarizes the data on chemical composition and anticancer activity of black raspberry fruits throughout the years.     

The comparison of betalain composition and chosen biological activities for differently pigmented prickly pear (Opuntia ficus-indica) and beetroot (Beta vulgaris) varieties

Betalains are a group of plant originated pigments with chemopreventive potential. The aim of this study was to relate the composition of betalains and chosen biological activities (antioxidant, cytotoxic, anti-genotoxic and influence on enzymatic activities) for extracts from differently pigmented varieties of prickly pear (yellow, orange and red) and beetroot (white and red). The assumption was that phytocomplexes of tested varieties of the same plant species would exhibit generally similar chemical composition differing mostly in betalain content, which will be reflected by their biological activity. Betalain composition analysis and antioxidant profiles confirmed that the content and composition of these pigments is strongly correlated with the antioxidant activity of tested plant extracts measured by spectrophotometric methods and CAA test. However, the results of determinations of other biological activities showed that in the case of actual plant foods, there was no simple relationship between betalain content or composition and chemopreventive potential.     

Environmental and genetic variation of phenolic compounds in red raspberry

Red raspberry (Rubus idaeus L.) is an economically important berry crop that contains numerous phenolic compounds with potential health benefits. It is known that the content of phenolics is affected by processing factors, but limited information is available on the influence of cultural factors or genotype. To clarify this issue, phenolic compounds were analysed from a diverse range of raspberry cultivars grown under northern European conditions, in Finland.The content of phenolic compounds varied widely and significantly between cultivars. The quercetin content ranged from 0.32 (yellow cultivar) to 1.55 mg/100 g fresh weight (fw) (cv. Balder). The ellagic acid content varied from 38 (cv. Gatineau and cv. Nova) to 118 mg/100 g fw (cv. Ville). The total anthocyanin content varied from close to 0 (yellow cultivars) to 51 mg/100 g fw (cv. Gatineau). The content of total phenolics varied from 192 (cv. Gatineau) to 359 mg/100 g fw (cv. Ville). In addition, environment had a significant effect on the content of quercetin. Thus, breeding material should be evaluated for their potential health benefits over several regions in northern raspberry breeding.     

Application of the quechers method coupled with gas chromatography with electron capture detection (GC-ECD) in analysis of pesticide residues in food

In 2003 Anastassiades and Lehotay described the "quick, easy, cheap, effective, rugged and safe" (QuEChERS) method for the multi-class, multiresidue analysis of pesticides in fruit and vegetables. The QuEChERS method allows to obtain high quality results with a minimum number of steps and a low solvent and glassware consumption. The QuEChERS method based on liquid-liquid partitioning with acetonitrile followed by a cleanup step with dispersive-SPE (Solid Phase Extraction). The aim of this study was to check the usefulness of the QuEChERS method coupled with gas chromatography with electron capture detection (GC-ECD) in analysis of pesticide residues in food. Ready-to-use QuEChERS reagents kits and own-weighed reagents have been applied. In recovery experiment for 15 selected pesticides, three matrices belonging to different groups--carrots (high carotenoids content), raspberry (highly acidic matrix) and tomatoes (high water content)--have been used, according to the SANC0/10684/2009 guideline and PN-EN 15662:2008 requirements. Fourteen compounds showed a recovery in the range of 70-120% and only one compound (trifluralin in raspberry) presented a recovery lower than 70% at the 0.5 mg/kg fortification level. The repeatability was satisfying with a RSD lower than 20% apart from trifluralin in raspberry (27.16%).     

Antimutagenic activity of berry extracts

Plants are proven sources of useful anti-tumor and chemopreventative compounds. Hence, identification of phytochemicals useful in dietary prevention and intervention of cancer is of paramount importance. The initial step in the formation of cancer is damage to the genome of a somatic cell producing a mutation in an oncogene or a tumor-suppressor gene. Fresh juices and organic solvent extracts from the fruits of strawberry, blueberry, and raspberry were evaluated for their ability to inhibit the production of mutations by the direct-acting mutagen methyl methanesulfonate and the metabolically activated carcinogen benzo[a]pyrene. Juice from strawberry, blueberry, and raspberry fruit significantly inhibited mutagenesis caused by both carcinogens. Ethanol extracts from freeze-dried fruits of strawberry cultivars (Sweet Charlie and Carlsbad) and blueberry cultivars (Tifblue and Premier) were also tested. Of these, the hydrolyzable tannin-containing fraction from Sweet Charlie strawberries was most effective at inhibiting mutations.     

Comparison of antioxidant capacity and phytochemical properties of wild and cultivated red raspberries (Rubus idaeus L.)

We investigated some of the chemical properties and antioxidant capacities of 14 wild red raspberry accessions selected from northern Turkey. In addition, the cultivars Heritage and Tulameen were included in the study to determine the variation between wild and cultivated raspberries. Total phenolics (TP), total monomeric anthocyanins (TMA), soluble solids (TSS), individual organic acids and sugars in the fruit were examined. Antioxidant capacity of fruits was determined by both ferric reducing ability of plasma (FRAP) and trolox equivalent antioxidant capacity (TEAC) assays. The fruit color and weight were determined as well. The result of this study indicated that some of the wild accessions of red raspberries have higher antioxidant capacity and phytonutrient content than existing domesticated cultivars. Moreover, significant variability was found for antioxidant capacity, TP, TMA, organic acids and sugars of wild raspberries. Principle component analysis showed that the accessions were divided into three groups: A2, A9, A12, A14 formed the first group with high phytonutrient properties; the cultivars Heritage and Tulameen grouped together with high phytonutrients but low color values; and the rest of the accessions formed the final group. The antioxidant capacity among samples averaged 14.6 and 14.1 μmol TE/gfw using FRAP and TEAC methods, respectively.     

Discrimination of five Greek red grape varieties according to the anthocyanin and proanthocyanidin profiles of their skins and seeds

The knowledge of grapes phenolic content is proven to be critical for the vinification process and the improvement of wine quality. This study was undertaken to determine the phenolic composition and to employ the phenolic profile as a varietal discrimination tool in five Greek red grape varieties. Ninety grape samples from two seasons (2017 and 2018) were analyzed after extraction with organic solvents. Their proanthocyanidin profile, expressed as percentages of flavan-3-ols, was determined in both skins and seeds by employing phloroglucinolysis followed by HPLC-UV and MS detection, and anthocyanin profile was identified only in the skin extracts by HPLC-UV. Significant differences were observed in proanthocyanidin and anthocyanin profiles of skin extracts between the samples of different varieties, but not in seeds. (-)-Epicatechin was the main subunit in Mandilaria, Kotsifali, Agiorgitiko and Xinomavro grapes while (-)-epigallocatechin gallate in Mavrotragano. Malvidin-3-O-glucoside was the predominant pigment in all grape samples analyzed with the exception of Kotsifali skin extracts, where peonidin-3-O-glucoside was the most abundant anthocyanin. In addition, Mavrotragano skin extracts were the richest in delphinidin and petunidin-3-O-glucosides, while Agiorgitiko and Xinomavro contained the highest amount of malvidin-3-O-glucoside. The results underline the significance of the skin phenolic composition as a tool for the discrimination of the Greek red grape varieties.     

Anthocyanins and Color Variables of Bulgarian Aged Red Wines

The main sensory parameter for the quality of red wines is their color. Twenty-one Bulgarian red wines from five different grape varieties were analyzed (Cabernet-Sauvignon, Merlot, Melnik, Mavrud and Gamza) in order to determine color variables and evaluate pigment matter. The results show highest proportion of red color in Cabernet-Sauvignon (dA%=59.2–46.9%), followed by Merlot, Mavrud, Melnik and Gamza (dA%=48.1–34.4%). Total anthocyanins reach maximal level for Cabernet-Sauvignon-1998 (274mg/L) and minimal value for Melnik-1998 (22mg/L), and correlate with dA% value. The age index, polymeric anthocyanins/monomeric anthocyanins, increases from 32.6% for Cabernet-Sauvignon-1998 to 87.5% for Gamza-1994 as the polymeric pigment forms have displaced the monomeric anthocyanins during aging process.