Effect of cultivar and storage temperature on identification and stability of polyphenols in strawberry cloudy juices

The effect of strawberry (Fragaria x ananassa Duchesne) cultivars (cvs) and storage temperature on the stability of polyphenols in cloudy juices was determined. Identification of phenolic compounds by ultra performance liquid chromatography-electrospray ionization/mass spectrometry (UPLC–ESI/MS), as well as quantitative analysis by ultra-performance liquid chromatography–photodiode array–fluorescence (UPLC–PDA–FL), were carried out on fresh and stored products (6 months, 4 °C and 20 °C) from 7 different strawberry cvs. A total of 32 polyphenolic compounds were identified: flavan-3-ols (6), anthocyanins (8), flavonols (4) and flavones (3), hydroxycinnamic acids (4), and ellagic acid derivatives (7). Total polyphenol content ranged from 642.08 mg/L in fresh ‘Florence’ cv. juice to 296.72 mg/L in ‘Honeoye’ cv. juice after 6 months of storage at 20 °C. Anthocyanins (max. 161.40 mg/L in ‘Honeoye’ juice) demonstrated the greatest degree of degradation (31–100%, depending on the molecular structure and temperature). Cyanidin-3-malonylglucoside was less labile than 3-glucoside. In the case of pelargonidin glycosides, 3-glucoside was more stable. The degradation process was the least advanced in ‘Kimberly’ cv. juice (58.53% at 4 °C). Storage conditions also influenced the decrease in p-coumaroyl-hexose, and quercetin-glucuronide content. However, low temperatures limited this process. This was especially noticeable in ‘Florence’ and ‘Honeoye’ cvs. In turn, proanthocyanidins showed the most stability and were the main polyphenols identified in juices (212–434 mg/L). Generally, it was observed that the total content of polyphenols and their stability in juices was dependent on the cultivar, and the duration of storage conditions.     

Phenolic and polysaccharidic composition of applesauce is close to that of apple flesh

Apple fruit is well known for its health properties, ascribed to its content in both phenolics and fibres. As more and more apples are consumed after processing, there is a need to understand the impact of the conventional process on the nutritional potential of applesauce. We have investigated the variation in composition between fresh and processed apples of 12 cultivars, focussing on polysaccharides and polyphenols. The polysaccharide content estimated in the alcohol insoluble solid (AIS) of the apple flesh varied from 17 (cv. Greensleeves, obtention TMR 7 A 82) to 25 (cv. Jolyne) mg/g fresh weight. The AIS contents varied from 15 to 32 mg/g fresh weight in applesauce. The applesauces were fractionated into serum, containing low concentrations (<5 mg/g) of soluble fibres, and particles concentrating the fibres (40–60 mg/g) and the cellulose (>30% of the AIS). Total phenolic concentrations varied in the flesh from 578 (cv. Golden Delicious) to 1596 mg/kg fresh weight (cv. 3535), and in the peel from 1658 (cv. Greensleeves) to 7658 mg/kg fresh weight (cv. Sinta). The applesauces contained flavonols, coming from the skin, and slightly higher concentration of dihydrochalcones coming from the pips than the flesh. A dihydrochalcone oxidation product was also detected. The concentration of hydroxycinnamic acids and flavan-3-ols was decreased in proportions depending on the cultivar. The flavan-3-ols were concentrated in the particles of the applesauce. The composition of applesauce thus appeared to be very close to that of apple flesh.     

The influence of nitrogen and potassium fertilisation on the content of polyphenolic compounds and antioxidant capacity of coloured potato

The effect of fertilisation rates of nitrogen: 0 (control treatment—no soil fertilisation), 40, 80 and 120 kg/ha and potassium: 0 (control treatment), 120, 150 and 180 kg/ha on the content of anthocyanins, phenolic acids and antioxidant capacity in purple–blue potato cv. ‘Blue Congo’ was examined. Anthocyanins and phenolic acids were identified and quantified by LC–MS and UPLC–PDA. Nitrogen was more effective in increasing the anthocyanin content—their quantity in tubers after nitrogen application was twice as much as that found after potassium application. Among phenolic acids, the dominant one was chlorogenic acid, the content of which significantly increased after nitrogen fertilisation at 120 kg/ha, in line with the increase in total concentration of phenolic acids and antioxidant capacity. The adjustment of nitrogen and potassium fertilisation levels during the growth of purple–blue potatoes seems to be an effective way to increase the expression of polyphenolic compounds in these cultivars. Therefore, fertilisation with N at 120 kg/ha and K at 120 and 150 kg/ha is recommended as a way to improve the content of biologically active compounds and antioxidant properties, and consequently, to enhance the nutritional value and the functionality of purple–blue potatoes.     

Application of non-supervised pattern recognition techniques to classify Cabernet Sauvignon wines from the Balkan region based on individual phenolic compounds

Phenolic compounds in sixteen Cabernet Sauvignon wines from different wine-growing sub-regions in the Balkan region were investigated using HPLC with DAD and fluorescence detector and spectroscopic analysis, as well as statistical PC/F and cluster analysis. The HPLC analysis of investigated red wines showed that the content of total hydroxybenzoic acids, detected at 280 nm, was the highest in wines from Tikveš wine-growing subregion, Macedonia (127–140 mg L⁻¹). Total hydroxycinnamic acids, detected at 320 nm, were the highest in wines from Župa wine-growing subregion, Serbia (43–45 mg L⁻¹). The concentration of total flavonoids (flavan-3-ols, flavonols, flavons and flavanon), detected at 280, 360 and 322/275 nm, respectively, was the highest in wine from Katarzyna Estate wine-growing subregion, Bulgaria (167 mg L⁻¹). Finally, the concentration of total anthocyanins, detected at 520 nm, was the highest in wine from Šumadija wine-growing subregion, Serbia (1463 mg L⁻¹). The results of PCA and cluster analysis together confirmed that the content of phenolic compounds in Cabernet Sauvignon wines depends on agro-climatic factors, oenological practice in different wineries and the growing season in the Balkan region that were investigated. The areas in the Balkan region in this study with similar agro-climatic characteristics showed shorter clustering distance, indicating similar phenol profiling in the red wines tested.     

HPLC analysis of diverse grape and wine phenolics using direct injection and multidetection by DAD and fluorescence

This paper proposes an HPLC method for analysing a great variety of phenolic compounds from vine and wine products with UV-Vis photodiode array (DAD) and fluorescence detection. In order to obtain a good chromatographic separation, a ternary solvent gradient that combines changes in polarity and pH was used. The pH changes from 2.6 to 1.5 to promote the elution of anthocyanins in their flavylium cationic form. The fluorescence detector enables the limit of quantification of flavan-3-ols to be reduced, and also prevents interferences caused by other phenolics that force the use of time-consuming fractionating protocols. With this method, it was possible to separate and quantify up to 48 phenolic compounds in a single, direct injection: 2 benzoic acids (DAD set at 280 nm), 9 hydroxycinnamic acids and GRP (DAD set at 320 nm), 7 flavan-3-ols (5 with fluorescence detector set at excitation/emission of 280/320 nm, and 2 with DAD set at 280 nm), 12 flavonols (DAD set at 360 nm), 15 anthocyanins (DAD set at 520 nm), and 2 stilbens (DAD set at 320 nm). Studies were performed to determine the precision, accuracy, and detection limits and data are provided on the concentration of the phenolics found in grape seed and skin extracts, as well as in wines prepared from the Vitis vinifera cultivar Cencibel.     

Ancient apple varieties from Croatia as a source of bioactive polyphenolic compounds

Several ancient apple varieties and a wild apple variety grown in Croatia were analysed for the polyphenol content and compared to two varieties grown in USA. In the flesh, flavanols, dihydrochalcones and phenolic acids (24 to 137, 23 to 109, 3 to 238 mg kg⁻¹ of fresh weight (FW), respectively) were found. Peel contained flavanols, dihydrochalcones, phenolic acids, flavonols and anthocyanins (65 to 690, 21 to 141, 0 to 107, 205 to 1223, 0 to 213 mg kg⁻¹ FW, respectively). The wild apple was characterized by much higher flavanol and phenolic acid content in the flesh (301 and 734 mg kg⁻¹ FW, respectively) while the peel was similar to other apples. The polyphenol profile was similar to apples from USA. The varieties Zimnjara, Lještarka and Adamova zvijezda could be highlighted as sources of polyphenols. Varieties are categorized by the content of dihydrochalcones and flavanols in the flesh (whether that content is high or low), and by the relative portion of phenolic acids and flavanols in the flesh (high phenolic acid proportion, lower flavanol proportion and vice versa). There was not observed to be as strong a pattern for categorizing differences in the peel.     

Phenolic and antioxidant composition of cider

Forty-four Asturian ciders were analysed for total phenolic content, phenolic profiles, and antioxidant capacity by the FRAP and the DPPH radical assays. The Folin index of ciders ranged between 446 and 1180 mg gallic acid/L. The phenolic profile of Asturian cider is mainly constituted by phenolic acids, flavan-3-ols, volatile phenols and dihydrochalcones. The methods to determine the antioxidant activity of ciders were optimised in terms of suitable reaction times, within-day and between-day repeatability. Thus, time courses of ciders in the DPPH and the FRAP assays were performed. Mean values for antioxidant activity of cider, expressed in ascorbic acid equivalents were 2.9 mM (as determined by the DPPH assay). When the FRAP assay was used, the antioxidant capacity of cider increased with the reaction time from 3.8 mM (4 min) to 5.4 mM (40 min). Multivariate approaches based on phenolic composition can be useful to predict the antioxidant capacity of cider. Folin index and flavanols and hydrocaffeic acid contents were the best predictors for antioxidant activity.     

Nutritive value,antioxidant activity and phenolic compounds profile of brewer’s spent yeast extract

Spent yeast is the second major by-product from brewing. Mechanical disruption of yeast cell wall can be used to obtain β-glucan rich ingredients and separate inner yeast content, both with potential applications as food and nutraceutical ingredients. In this work, the nutritional composition, including minerals and B-complex vitamins, together with the antioxidant activity and phenolic compounds profile of yeast extract, prepared by mechanic disruption of brewer’s spent yeast and removal of yeast cell wall, was investigated. The lyophilised yeast extract presented 64% of proteins with high proportion of essential amino acids and 4% of RNA; macrominerals (Na, K, Ca, Mg), trace elements such as Zn (11.9 mg/100 g dw), Fe (1.76 mg/100 g dw), and Mn (0.564 mg/100 g dw), and vitamins B3 (77.2 mg/100 mg dw), B6 (55.1 mg/100 g dw) and B9 (3.01 mg/100 g dw). Two phenolic compounds were quantified as free forms, gallic acid and (±) catechin, whereas other bounded phenolic compounds were also quantified. The nutrients content, antioxidant properties and phenolic composition of the lyophilised brewer’s spent yeast extract indicates that it can be an interesting food or nutraceutical ingredient. Thus, its recovery will be beneficial in terms of sustainability and environmental impact.     

Seed composition of ten industrial hemp cultivars approved for production in Canada

The objective of this study was to determine the seed chemical composition of ten industrial hemp cultivars grown in Québec. The fatty acid and tocopherol composition, as well as the concentrations of crude protein, oil, ash, cellulose, hemicellulose and lignin were quantified. The seed oil concentration varied between 269 and 306 g/kg, while the crude protein concentration ranged between 238 and 280 g/kg. The hemp seed oil is mainly composed of unsaturated fatty acids, and the dominant fatty acids are linoleic acid (597 g/kg) and α-linolenic acid (170 g/kg). For all ten cultivars, γ-tocopherol was present at a much higher concentration than δ-tocopherol (2481 vs. 774 μg/g). Out of the ten cultivars analyzed, Anka was the richest in phenolics (5.16 g/100 g), whereas CRS-1 had the lowest phenolic content (1.37 g/100 g). Seed ash concentration ranged between 51 and 58 g/kg, while neutral detergent fibre and acid detergent fibre concentrations ranged between 327 and 388, and 259 and 298 g/kg, respectively. In conclusion, our results reveal noticeable differences among cultivars in terms of the essential fatty acid, oil, protein, and antioxidant content of industrial hemp seed. Collectively, this study suggests that the seed of Canada-grown hemp is a balanced health product.     

Oxalate content of New Zealand grown and imported fruits

Total and soluble oxalate contents of 21 locally grown and 9 imported fruits commonly consumed in New Zealand were determined by extracting total oxalates with 2 M HCL for 20 min and soluble oxalates with nanopure water for 20 min at room temperature (21 °C). The extracted oxalates were analysed by ion exchange HPLC. Total oxalate content of locally grown fruit ranged from 2.0 to 640.2 mg/100 g fresh weight (FW) while the soluble oxalate ranged from not detected to 431.3 mg/100 g FW. The total oxalate content of a selection of imported fruits ranged from 2.9 to 7566.5 mg/100 g FW and the soluble oxalate content ranged from 1.2 to 3855.4 mg/100 g FW. Very high levels of total oxalates were measured in 2 imported fruits, Indian gooseberry (Phyllanthus emblica L.) and carambola (Averrhoa carambola L., star fruit), and in New Zealand-grown rhubarb (Rheum rhabarbarum L.), at 7566.5, 436.1 and 640.2 mg/100 g FW, respectively, and their soluble oxalates were also the highest measured of all the fruits.     

Phenolic and mineral profiles of four Balkan indigenous apple cultivars monitored at two different maturity stages

Some primary and secondary metabolites, as well as mineral nutrients in pulp, peel and juice obtained from four Serbian indigenous apple cultivars (Kožara, Kolačara, Budimka and Šumatovka) collected at two different developmental stages were studied. With advanced maturation soluble solids content, total and reducing sugars increased, while l-ascorbic acid content and titratable acidity decreased. Thirteen phenolic compounds were quantified using LC–MS/MS. The total phenolic content (TPC) ranged from 9.37 to 1440 mg/100 g fw, and 0.83 to 7.84 mg/100 g fw in peel and pulp samples, respectively. Quercetin derivatives were the major detected polyphenolic group. Majority of determined phenolic compounds were influenced by cultivar and the best sources were cultivars Kolačara and Budimka. The content of flavonols (with the exception of quercitrin) varied significantly depending on maturity at harvest. With regard to mineral analysis, K was the most abundant ranging from 104 to 158 mg/100 g fw in peel, 74.4 to 93.3 mg/100 g fw in pulp, and 77.1 to 91.5 mg/100 g fw in juice samples. Obtained results provide detailed information on nutritional potential and chemical composition of tested apple cultivars and thereby could encourage their wider cultivation and consumption.     

Microgreens of Brassicaceae: Mineral composition and content of 30 varieties

The mineral element composition was analyzed for 30 varieties of microgreens, representing 10 species within 6 genera of the Brassicaceae family. Brassicaceae microgreens were assayed for concentrations of macroelements, including calcium (Ca), magnesium (Mg), phosphorous (P), sodium (Na), potassium (K), and of microelements, including copper (Cu), iron (Fe), manganese (Mn), and zinc (Zn). Determinations of mineral elements in microgreen samples were performed using an inductively coupled plasma optical emission spectrophotometer (ICP OES). Potassium was the most abundant macroelement ranging from 176 to 387 mg/100 g fresh weight (FW), followed by P (52–86 mg/100 g FW), Ca (28–66 mg/100 g FW), Mg (28–66 mg/100 g FW), and Na (19–68 mg/100 g FW). Among the microelements, Fe tended to be most abundant (0.47–0.84 mg/100 g FW), followed by Zn (0.22–0.51 mg/100 g FW), Mn (0.17–0.48 mg/100 g FW), and Cu (0.041–0.13 mg/100 g FW). Based upon the analysis of 30 varieties, the results demonstrate that microgreens are good sources of both macroelements (K and Ca) and microelements (Fe and Zn.). Consumption of microgreens could be a health-promoting strategy to meet dietary reference intake requirements for essential elements beneficial to human health.     

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.     

Mineral and phenolic concentrations of mungbean [Vigna radiata (L.) R. Wilczek var. radiata] grown in semi-arid tropical India

Mungbean [Vigna radiata (L.) R. Wilczek var. radiata] is an important pulse crop grown in south, east and southeast Asia. Mungbean seed samples harvested from field trials conducted in two environments in Hyderabad, India were utilized to determine genetic variation in the concentrations of minerals Fe, Ca, Mg, Zn, Cu, Mn, Se, Na, K and P and to determine the concentrations of phytic acid (PA) and phenolic compounds. Significant variations in Fe (35–87 mg/kg), Ca (1190–1580 mg/kg), Mg (970–1700 mg/kg), Zn (21–62 mg/kg), Cu (7.5–11.9 mg/kg), Mn (9.8–19.6 mg/kg), Se (0.21–0.91 mg/kg), K (8670–14,100 mg/kg) and P (2760–5170 mg/kg) were recorded in mungbean lines commonly grown in South Asia. The effect of the environment on the concentration of minerals in mungbean lines was observed. The Fe concentration of lines CN 9-5 and Harsha doubled when grown in soil with increased availability of Fe. The low PA concentration (2.6–3.8 g/kg) and the presence of phenolic compounds such as ferulic acid (1540–3400 μg/g) in mungbean may lead to increased bioavailability of micronutrients. Nutrient-rich mungbean should be included in diets to combat micronutrient malnutrition.     

Essential and non-essential/toxic elements in rice available in the Portuguese and Spanish markets

Eighty-six rice samples, representing the most common rice brands sold in Portuguese and Spanish markets (either locally produced or imported), were analyzed for their content of 35 essential and non-essential/toxic elements using inductively coupled plasma-mass spectrometry (ICP-MS). The mean content of essential elements was: 1189 mg/kg (P), 746 mg/kg (K), 294 mg/kg (Mg), 84.7 mg/kg (Ca), 13.3 mg/kg (Zn), 8.8 mg/kg (Na), 8.3 mg/kg (Mn), 7.5 mg/kg (Fe), 1.9 mg/kg (Cu), 0.55 mg/kg (Mo), 0.18 mg/kg (Se) and 0.12 mg/kg (Co). However, significant differences exist between the different types of rice, with brown rice showing the highest content of most essential elements. The daily intake of essential elements resulting from the average Iberian (Portugal and Spain) per capita consumption of rice was calculated and its contribution to the Recommended Dietary Allowance (RDA) or Adequate Intake (AI) was estimated. Data showed that rice can be an important dietary source of P, Zn, Mn, Cu, Mo and Se but does not significantly contribute to the daily dietary intake of Ca, Na and Fe. The content of toxic elements was very low, indicating that rice can be regarded as a very safe food.     

Comparative study of the nutritional and bioactive compounds content of four walnut (Juglans regia L.) cultivars

The proximate and mineral composition, fatty acid profile, total polyphenol, melatonin and serotonin contents were assessed in four walnut (Juglans regia L.) cultivars (cv. Serr, Hartley, Chandler and Howard). The aim was to decide which cultivar is the most suitable from a nutritive, but also commercial, point of view. Proteins and fats accounted for more than 70% of the walnut kernel weight. Due to their content in bioactive compounds such as melatonin, serotonin and total phenols, their high content in magnesium (up to 443 mg 100 g⁻¹ FW) and other minerals, their high contents in polyunsaturated fatty acids (up to 78.0% of total fatty acids) and their favorable n−6/n−3 ratio, among other healthful properties, consumption of all the studied cultivars would be potentially beneficial to health. According to its fatty acid profile, Howard would be the most healthful cultivar, but also it would be theoretically the most sensitive to rancidity, and thus the cultivar with the shortest shelf life. Nonetheless, this cultivar showed the highest content in the antioxidants melatonin and total polyphenols.     

Effects of varieties and cultivation conditions on the composition of strawberries

Mineral elements, vitamin C and pesticides of frozen strawberries (Fragaria x ananassa Duch.) grown in Finland were studied. ‘Senga Sengana’, ‘Jonsok’, ‘Korona’, ‘Polka’, ‘Honeoye’ and ‘Bounty’ were cultivated applying normal farming practices and harvested analogously in 1997 and 1998. Organically cultivated ‘Polka’, ‘Jonsok’ and ‘Honeoye’ were also analysed. The variation of components in the ‘Senga Sengana’ fruit of two domestic and two imported origins was investigated. Ca, Mg, K, Fe, Zn, Cu, and Mn were determined using an atomic absorption spectrometer applying the flame technique, Cd and Pb applying the graphite furnace technique. Vitamin C was measured by using high-pressure liquid chromatography. The average concentration of vitamin C ranged from 32.4 mg/100 g to 84.7 mg/100 g. Strawberries were found to be a good source of potassium (1.55–2.53 g/kg), magnesium (0.11–0.23 g/kg) and calcium (0.16–0.29 g/kg). The lead content was in general below its detection limit (0.004 mg/kg). The cadmium level in the Finnish berries was lower than 0.016 mg/kg. In all samples levels of pesticides were below their maximum residue limits. In general, genotype and origin proved to have a greater effect than the cultivation techniques on parameter levels.     

Antioxidant activity,quality parameters and mineral content of Portuguese monofloral honeys

Physicochemical properties (pH, free, lactonic and total acidity, electrical conductivity and moisture), main mineral content (potassium, sodium, calcium, magnesium and iron) and antioxidant activity (total phenolics, 1,1diphenyl-2-picrylhydrazyl radical scavenging and ferric reduction antioxidant power) were determined for 39 Portuguese monofloral honeys (rosemary, orange, thyme, arbutus, locust podshrub and heather) with different geographical origins. Portuguese honeys showed good chemical and nutritional qualities fulfilling the criteria described in Directive 2001/110/CE. Potassium was the main mineral component representing 85% of total minerals. The mineral composition of sodium (4.63–200.60 mg/kg), calcium (0.43–72.30 mg/kg), magnesium (3.05–82.20 mg/kg) and iron (below 7.06 mg/kg) were higher for heather, eucalypt and arbutus honeys. Monofloral honeys of arbutus (Arbutus unedo), locust podshrub (Ceratonia siliqua L.) and heather (Erica umbellata) showed higher antioxidant activity with phenolic contents higher than 600 mg gallic acid equivalents (GAE)/kg, a DPPH scavenging activity higher than 50% and a ferric reduction antioxidant power above 600 μM Fe²⁺. Furthermore, the chemometric analysis revealed that total phenolic content was a crucial variable explaining the antioxidant activity of arbutus and locust podshrub honeys characteristic of the south of Portugal.     

Changes in tannins,ascorbic acid and sugar content in astringent persimmons during on-tree growth and ripening and in response to different postharvest treatments

Changes in tannins, ascorbic acid and sugars in astringent persimmons ‘Rojo Brillante’ and ‘Kaki Tipo’ were investigated during fruit maturation and after postharvest treatments. Soluble tannins exhibited a significant initial increment, followed by a marked constant decrease that led to values between 0.2 and 0.3 g/100 g fresh weight (FW) in the last stage of maturity studied. During the entire period monitored, insoluble tannins represented the minor component of the total tannic fraction, accounting for 9–27% (Rojo Brillante) and 17–32% (Kaki Tipo) of total tannins; levels of insoluble tannins were comparable to or higher than the soluble tannins in softer fruits. Total vitamin C decreased from 0.18–0.20 to about 0.08 g/100 g FW during fruit development owing to fruit growth rather than to degradation processes. Total sugars increased from about 4 g/100 g FW at the early stage of fruit development to 17 g/100 g FW after reaching the commercial stage of maturity. Glucose and fructose increased during the entire period monitored, while sucrose reached a maximum and then gradually decreased, probably owing to a strong invertase activity. Antiradical activities were significantly related to the corresponding tannic fraction. In both ‘Rojo Brillante’ and ‘Kaki Tipo’, postharvest treatment with CO₂ was more effective than with ethylene in reducing soluble tannin concentration (0.031–0.067 and 0.220–0.262 g/100 g FW, respectively).     

Phenolic acids,flavonols and anthocyanins in Corema album (L.) D. Don berries

Phenolic compounds of Corema album (Ericaceae) wild edible berries were determined by LC–DAD–MS/MS. Fifteen compounds were identified and quantified, including phenolic acids (2268.1 ± 229.2 mg/kg of dried weight, DW) such as chlorogenic and neochlorogenic acids, flavonols (638.3 ± 80.1 mg/kg DW) including quercetin 3-O-hexoside and rutin, and the anthocyanins (19. 6 ± 2.4 mg/kg DW) cyanidin 3-O-glucoside, cyanidin 3-O-pentoside and delphinidin 3-O-hexoside. Phenolic acids, the main phenolic compounds in this fruit, were fractionated into their free and bound forms, and analysed by GC–MS after hydrolysis. Eleven compounds (benzoic, salicylic, t-cinnamic, p-hydroxybenzoic, vanillic, gentisic, syringic, p-coumaric, gallic, ferulic and caffeic acids) were identified on the basis of GC retention times and simultaneously recorded mass spectra, namely caffeic, benzoic, ferulic and vanillic acids as the major phenolic acids in Corema album berries.