Physical attributes and chemical composition of organic strawberry fruit (Fragaria x ananassa Duch, Cv. Albion) at six stages of ripening

Changes in secondary metabolites, organic acids and soluble sugars during the development of plum fruit cv. 'Furongli' (Prunus salicina Lindl)

BACKGROUND

Organic acids, sugars and pigments are key components that determine the taste and flavor of plum fruit. However, metabolism of organic acid and sugar is not fully understood during the development of plum fruit cv. 'Furongli'.

RESULTS

Mature fruit of 'Furongli' has the highest content of anthocyanins and the lowest content of total phenol compounds and flavonoids. Malate is the predominant organic acid anion in 'Furongli' fruit, followed by citrate and isocitrate. Glucose was the predominant sugar form, followed by fructose and sucrose. Correlation analysis indicated that malate content increased with increasing phosphoenolpyruvate carboxylase (PEPC) activity and decreasing nicotinamide adenine dinucleotide-malate dehydrogenase (NAD-MDH) activity. Citrate and isocitrate content increased with increasing PEPC and aconitase (ACO) activities, respectively. Both acid invertase and neutral invertase had higher activities at the early stage than later stage of fruit development. Fructose content decreased with increasing phosphoglucoisomerase (PGI) activity, whereas glucose content increased with decreasing hexokinase (HK) activity.

CONCLUSION

Dynamics in organic acid anions were not solely controlled by a single enzyme but regulated by the integrated activity of enzymes such as nicotinamide adenine dinucleotide phosphate-malic enzyme (NADP-ME), NAD-ME, PEPC, ACO and NADP-isocitrate dehydrogenase. Sugar metabolism enzymes such as PGI, invertase and HK may play vital roles in the regulation of individual sugar metabolic processes. © 2018 Society of Chemical Industry.

Blackberry (Rubus ulmifolius Schott): Chemical composition, phenolic compounds and antioxidant capacity in two edible stages

The berries of the genus Rubus has been highlighted as important source of bioactive and health promoting constituents, however, information about chemical composition and antioxidant potential of the specie Rubus ulmifolius are still scarce. In this regard, this study aimed to assess the physicochemical characteristics, total monomeric anthocyanins (TMA), individual phenolics, minerals, sugars, and antioxidant properties of mature and fully mature R. ulmifolius. With the advance of maturation, changes in the physicochemical composition suggest pleasant characteristics for consumption especially in the fully mature stage. High levels of TMA and sugars (fructose and glucose) were also verified in the fully mature stage, as well as, expressive antioxidant potential, with values of 241.06 μM Fe⁺² g^-1 for ferric reducing antioxidant power and 28.22 mg gallic acid equivalent g^-1 for Folin-Ciocalteu reducing capacity (all expressed in dry matter, DM). In contrast, minerals (potassium, calcium, sodium) and most of the studied phenolic compounds showed the highest concentrations in mature fruits. Among the phenolics investigated, 26 compounds were identified and quercetin and isoquercitrin were the predominant phenolic compounds in the fruit. The results reinforce the nutritive and antioxidant potential of Rubus ulmifolius in both maturation stages studied.

Polyphenolic Profile and Antioxidant Activity of Leaf Purified Hydroalcoholic Extracts from Seven Mexican Persea americana Cultivars

Persea americana (avocado) is a fruit consumed worldwide; however, since avocado leaves are apparently a natural ingredient that can be used as a traditional medicine, they can be a potential source of bioactive compounds. This study aimed to analyze the antioxidant activity of seven Mexican avocado leaf extracts by DPPH^•, ABTS^•+, and lipid peroxidation (LPO), and to identify the compound profile by liquid chromatography coupled to mass spectrometry/electron spray ionization. The highest free radical-scavenging activity was observed for Platano Delgado and Criollo 6 avocado cultivars havin IC₅₀ values of 271.86 ± 13.69 and 269.56 ± 6.53 for DPPH^• and ABTS^•+ radicals, respectively, while the best result for lipid oxidation inhibition was registered in Criollo 6 cultivar extract. In this study forty-one compounds were detected in avocado leaves of the the seven cultivars analyzed, and of these compounds, eighteen phenolics were identified for first time in such plant material. The present study demonstrated that Mexican cultivars of Persea americana possess diverse polyphenolic compounds with strong antioxidant activity, which might be useful in the food and pharmaceutical industries.

Phytochemical composition of everbearing strawberries and storage quality of strawberry fruit treated by precooling

This study was conducted to investigate the nutrient composition of everbearing strawberry cultivar grown on highlands of Gangwon province after harvest. Various phytochemical compositions such as ascorbic acid, anthocyanin, malondialdehyde, and phenolic compounds were analyzed in strawberry fruits from five different cultivars (cv. Albion, Flamenco, Goha, San Andreas, and Seascape). Ascorbic acid content was similar among five cultivars at 20 mg 100 g^-1, whereas major pigment anthocyanin in Seascape was higher than in any other cultivars. Goha and San Andreas showed higher total phenolic compound contents. The effect of room or forced-air precooling on Flamenco and Goha was studied. Higher weight loss was observed in Flamenco treated with forced-air cooling, while in Goha both precooling treatments induced weight loss. Both precooling treatments were effective to maintain firmness in two strawberry cultivars. Forced air cooling maintained total phenolic contents until 12 days of storage, and the efficiency accelerated by low temperature storage.

Preharvest Ultraviolet C Treatment Affected Senescence of Stored Strawberry Fruit with a Potential Role of MicroRNAs in the Activation of the Antioxidant System

Recent studies presented preharvest ultraviolet C (UV-C) as an environmentally friendly approach for the management of horticultural crop diseases. The effect of this approach on quality preservation during postharvest storage has not yet been investigated. Strawberry fruit harvested from plants grown with supplemental UV-C were stored at room temperature for 72 h, and their postharvest shelf-life biochemical indicators were evaluated. The involvement of microRNAs (miRNAs) in the activation of UV-C-induced antioxidant systems was investigated. Preharvest UV-C contributed to the preservation of sugar and organic acid and reduced overall lipid peroxidation in strawberry fruit during storage. We found that miR159 and miR398 were downregulated by preharvest UV-C and that their respective targets were upregulated at the early stage of storage with enhancement of the activity of antioxidant enzymes. The initial burst of H₂O₂ and O₂^• - suggested that preharvest UV-C primed the fruit in an antioxidative activated state via reactive-oxygen-species-mediated feedback control with post-transcriptional involvement of miRNAs.

Berries grown in Brazil: anthocyanin profiles and biological properties

BACKGROUND

Phytochemical profiles of two Brazilian native fruits - pitanga (red and purple) and araçá (yellow and red) - as well as strawberry cultivars Albion, Aromas and Camarosa, blackberry cultivar Tupy and blueberry cultivar Bluegen cultivated in Brazil were characterized for total phenolic content and total anthocyanin content by liquid chromatography coupled to a photodiode array and a quadrupole time-of-flight mass spectrometer. Radical scavenging, antiherpes and cytotoxic activities of these berry extracts were also evaluated.

RESULTS

Blueberry presented the highest total anthocyanin content (1202 mg cyanidin-O-glucoside equivalents kg^-1 fresh fruit), while strawberry cultivar Aromas presented the highest total phenolic content (13 550 mg gallic acid equivalents kg^-1 fresh fruit). Liquid chromatographic-mass spectrometric analysis resulted in the identification of 21 anthocyanins. To the best of our knowledge this is the first report of cyanidin-O-glucoside in yellow and red Araçá fruit and the first time eight anthocyanins have been reported in pitanga fruits. DPPH and ABTS assays showed that blueberry cultivar Bluegen, blackberry cultivar Tupy and pitanga (red and purple) showed the most promising antiradical activities, respectively. No relevant cytotoxicity against three cancer cell lines or antiherpes activity was detected under the experimental conditions tested.

CONCLUSION

Total anthocyanin content of all fruits had a strong positive correlation with their free radical scavenging activity, suggesting anthocyanins contribute to the antioxidant potential of these fruits. © 2018 Society of Chemical Industry.

Rhizobium and Phyllobacterium bacterial inoculants increase bioactive compounds and quality of strawberries cultivated in field conditions

Strawberries (Fragaria × ananassa Duch.) are widely demanded by the consumers because they contain several bioactive compounds, mainly vitamin C and anthocyanins, which may be increased by biofertilization with some plant growth promoting bacteria. In this work we have analysed two bacterial strains, PEPV15 and PEPV16, from genera Phyllobacterium and Rhizobium, respectively, which under microcosms conditions were able to promote the strawberry growth, increasing the content of some bioactive compounds, such as vitamin C or organic acids. Here we have analysed the effect on bioactive compounds in strawberries from plants biofertilized with the strains PEPV15 and PEPV16 in field conditions. Under these conditions, the anthocyanin content was increased when plants were biofertilized with the strain PEPV15 and the pelargonidin-3-O-rutinoside content significantly increased. Besides, citric acid, vitamin C and epicatechin contents were significantly higher when either of the two strains was used as biofertilizer. Our results showed that the inoculation with Phyllobacterium and Rhizobium strains is a good agronomical practice, which improve the content of several bioactive compounds of strawberries increasing the beneficial effects on human health.

Health and taste related compounds in strawberries under various irrigation regimes and bio-stimulant application

Strawberry has a unique status within the fruit species in terms of health and taste related compounds. This experimental study concerned the application of a bio-stimulant at various drip irrigation levels (IR125, IR100, IR75 and IR50). The effects of the bio-stimulant (seaweed extract) on the eating quality, i.e., the taste-related (TSS, fructose, glucose, sucrose and citric, malic, l-ascorbic acid), and health-related (antioxidant activity, total phenol, myricetin and quercetin) compounds were studied in two strawberry cultivars. The 'Rubygem' with its higher sugar and lower acid content has been more preferable than the 'Kabarla' cultivar. The bio-stimulant contributes to taste by improving the TSS, fructose, sucrose and also to health by increasing the quercetin content of the fruit which is associated to the cardiovascular properties and cancer reducing agents. The experiment conducted revealed significant increases only in the TSS contents and antioxidant activity under the IR50 and IR75 deficit irrigation treatments.

Identifying Key Flavors in Strawberries Driving Liking via Internal and External Preference Mapping

Australian consumers desire the development of a more flavorsome Australian strawberry cultivar. To aid in the development of well-liked strawberries, the attributes driving liking need to be identified. The objective of this research is to apply Preference Mapping (PM) techniques to the descriptive profile of commercial and newly bred strawberry cultivars, together with consumer preference data to determine the flavors contributing to liking. A trained sensory panel (n = 12) used Quantitative Descriptive Analysis (QDA®) methodology to evaluate two appearance, seven aroma, five texture, 10 flavor and 10 aftertaste attributes of three commercial strawberry cultivars and six elite breeding lines grown in Victoria, Australia. Strawberry consumers (n = 150) assessed their liking of the same strawberry cultivars. QDA® significantly discriminated strawberries on 28 of the 34 sensory attributes. There were significant differences in hedonic ratings of strawberries (F(8,714) = 11.5, P = 0.0001), with Hierarchical Cluster Analysis (HCA) identifying three consumer clusters each displaying differing patterns of preference. Internal and external PM techniques were applied to the data to identify the attributes driving consumer acceptability. Sweet, berry, caramel, fruity and floral attributes were identified as most contributing to liking. Sour, citrus, green, astringent, firm and gritty attributes were conversely associated with a reduction in consumer liking. Elite Lines 2 and 6 have been identified as having the broadest appeal, satisfying between 60% and 70% of consumers in the population assessed, thus the introduction of these cultivars should satisfy the largest group of consumers in the Australian market.

PRACTICAL APPLICATION

The results of this research could be applied to breeding programs, to ensure newly bred cultivars express characteristics that were identified as well-liked amongst consumers. In addition, this research provides evidence for marketing strawberries by cultivar, to assist consumers in identifying those strawberries for which they have a preference.

Potential link between fruit yield, quality parameters and phytohormonal changes in preharvest UV-C treated strawberry

Preharvest ultraviolet-C (UV-C) treatment of strawberry is a very new approach, and little information is available on the effect of this treatment on plant growth regulators. In this study, the effect of preharvest UV-C irradiations at three different doses on strawberry yield, fruit quality parameters and endogenous phytohormones was investigated simultaneously. The overall marketable yield of strawberry was not affected by the preharvest UV-C treatments, although more aborted and misshapen fruits were found in UV-C treated groups than in the untreated control. The fruits in the high dose group were firmer and had approximately 20% higher sucrose content and 15% higher ascorbic acid content than the control, while fruits from the middle and low dose groups showed no significant changes in these parameters. The lower abscisic acid (ABA) content found in the fruits in the high UV-C group may be associated with those quality changes. The citric acid content decreased only in the low dose group (reduction of 5.8%), with a concomitant 37% reduction in jasmonic acid (JA) content, compared to the control. The antioxidant status of fruits that received preharvest UV-C treatment was considered enhanced based on their oxygen radical absorbance capacity (ORAC) and malondialdehyde (MDA) content. In terms of aroma, three volatile alcohols differed significantly among the various treatments with obvious activation of alcohol acyltransferase (AAT) activity. The observed synchronous influence on physiological indexes and related phytohormones suggests that preharvest UV-C might affect fruit quality via the action of plant hormones.

Enhancement of nutritional and bioactive compounds by in vitro culture of wild Fragaria vesca L. vegetative parts

In vitro culture emerges as a sustainable way to produce bioactives for further applicability in the food industry. Herein, vegetative parts of Fragaria vesca L. (wild strawberry) obtained by in vitro culture were analyzed regarding nutritional and phytochemical compounds, as well as antioxidant activity. These samples proved to have higher content of protein, polyunsaturated fatty acids, soluble sugars, organic acids (including ascorbic acid) and tocopherols (mainly α-tocopherol) than wild grown F. vesca, as well as containing additional phenolic compounds. The antioxidant activity of hydromethanolic extracts could be correlated with the content of different phenolic groups and other compounds (sugars and organic acids). It was demonstrated that in vitro culture could enhance nutritional and bioactive compounds of Fragaria vesca L. plants, providing a very interesting biotechnological tool for potential food applications.

Physicochemical and Nutritional Characterization of Brebas for Fresh Consumption from Nine Fig Varieties (Ficus caricaL.) Grown in Extremadura (Spain)

The quality characteristics of brebas for fresh consumption from nine fig varieties at different commercial ripening stages were determined. Physicochemical and nutritional parameters were analyzed for both skin and flesh, and the findings were compared among varieties and ripening stages. The results revealed that the major nutrient components in brebas are sugars, such as glucose and fructose, and mineral elements, including K, Ca, P, and Mg. Most nutrients evaluated are important elements that contribute to the commercial quality of brebas. “Brown Turkey” and “Banane” varieties showed the highest weight and width. The concentrations of the monomer sugars studied were higher in flesh than skin, and the “Cuello Dama Blanco” and “Colar Elche” varieties showed the highest content of these sugars. The early ripening stage, coinciding with a fast increase in fruit size, was also associated with a higher fiber and protein contents, TA, and firmness for “Banane,” “Brown Turkey,” and “Blanca Bétera” varieties. Conversely, the later ripening stage was related to a significant increase of TSS, MI, and color intensity. Finally, no clear changes in the concentrations of organic acids were observed between different varieties and commercial ripening stages.

The flavor and nutritional characteristic of four strawberry varieties cultured in soilless system

Strawberry fruits (cv. Benihoppe, Tochiotome, Sachinoka, and Guimeiren) were harvested and evaluated the flavor and nutritional parameters. By principal component analysis and hierarchical clustering analysis, differences were observed based on the volatile compounds composition, sugar and acid concentration, sweetness, and total soluble sugars/total organic acids of the four varieties. A total of 37, 48, 65, and 74 volatile compounds were identified and determined in cv. Benihoppe, Tochiotome, Sachinoka, and Guimeiren strawberry fruits extracted by head-space solid-phase microextraction (HS-SPME), respectively. Esters significantly dominated the chemical composition of the four varieties. Furaneol was detected in cultivars of Sachinoka and Guimeiren, but mesifuran was only found in cv. Tochiotome. Tochiotome and Sachinoka showed higher content of linalool and (E)-nerolidol. Sachinoka showed the highest content of total sugars and total acids. Guimeiren showed higher sweetness index than the other three cultivars. Firmness of Tochiotome was highest among all the varieties. The highest total soluble solids TSS value was found in cv. Sachinoka, followed by the Guimeiren and Tochiotome varieties. Sachinoka had the highest titratable acidity TA value. The content of ascorbic acid (AsA) of cv. Tochiotome was higher than the others, but there was no significant difference in cultivars of Benihoppe, Tochiotome, and Sachinoka. Fructose and glucose were the major sugars in all cultivars. Citric acid was the major organic acid in cv. Tochiotome, cv. Sachinoka, and cv. Guimeiren. Tochiotome had higher ratios of TSS/TA and total sugars/total organic acids than others, arising from its lower acid content. The order of the comprehensive evaluation score was Sachinoka>Guimeiren>Tochiotome>Benihoppe.

Antitumor, Antioxidant, and Nitrite Scavenging Effects of Chinese Water Chestnut (Eleocharis dulcis) Peel Flavonoids

The preparation, quantification, and characterization of flavonoid compounds from Chinese water chestnut peel (CWCP) flavonoid extract and ethyl acetate fraction (EF), n-butanol fraction, and water fraction were studied. Among these, EF showed the maximum free radical levels (IC₅₀ values of 0.36, 0.40, and 0.37 mg/mL for DPPH•, ABTS•⁺ , and •OH, respectively), nitrite scavenging effects (IC₅₀ = 1.89 mg/mL), and A549 cell inhibitory activities (IC₅₀ = 776.12 μg/mL) with the highest value of total flavonoid content (TFC, 421.32 mg/g). Moreover, the contents of 8 flavonoids in this fraction were quantified using high-performance liquid chromatography, and fisetin, diosmetin, luteolin, and tectorigenin were the 4 major flavonoids with levels of 31.66, 29.91, 13.69, and 12.41 mg/g, respectively. Luteolin produced a greater inhibition of human lung cancer A549 cells (IC₅₀ = 59.60 μg/mL) than did fisetin, diosmetin, and tectorigenin. Flow cytometry revealed that the cellular mechanisms of luteolin inhibition of A549 cells were achieved via the induction of cell proliferation arrest at G₁ phase and apoptosis/necrosis. Our findings suggest that flavonoids are closely associated with antitumor, antioxidant, and nitrite scavenging effects of CWCP.

Strawberry tannins inhibit IL-8 secretion in a cell model of gastric inflammation

In the present study we chemically profiled tannin-enriched extracts from strawberries and tested their biological properties in a cell model of gastric inflammation. The chemical and biological features of strawberry tannins after in vitro simulated gastric digestion were investigated as well. The anti-inflammatory activities of pure strawberry tannins were assayed to get mechanistic insights. Tannin-enriched extracts from strawberries inhibit IL-8 secretion in TNFα-treated human gastric epithelial cells by dampening the NF-κB signaling. In vitro simulated gastric digestion slightly affected the chemical composition and the biological properties of strawberry tannins. By using pure compounds, we found that casuarictin may act as a pure NF-κB inhibitor while agrimoniin inhibits IL-8 secretion also acting on other biological targets; in our system procyanidin B1 prevents the TNFα-induced effects without interfering with the NF-κB pathway. We conclude that strawberry tannins, even after in vitro simulated gastric digestion, exert anti-inflammatory activities at nutritionally relevant concentrations.

Effects of poplar buds as an alternative to propolis on postharvest diseases control of strawberry fruits

BACKGROUND

Botrytis cinerea and Rhizopus stolonifer, two main postharvest pathogens, cause great loss of strawberry fruits. Here, the effects of poplar buds extracts, a main plant source for Chinese propolis, on disease control were investigated in vitro and in vivo.

RESULTS

The HPLC profile of poplar buds ethanol extract (PBEE) was almost identical to that of propolis ethanol extract (PEE), with the active flavonoids identified as pinocembrin, chrysin and galangin. PBEE exhibited similar inhibitory activities on spore germination of both pathogens compared with PEE, and PBEE also strongly inhibited the mycelial growth of the pathogens. In vivo, PBEE could effectively reduce decay of strawberry fruits stored at 13 °C. Although the weight loss was slightly increased, the contents of total soluble solid, titritable acid, vitamin C and total anthocyanins were significantly higher in PBEE treated fruits than those of the control.

CONCLUSION

PBEE had the similar antifungal activity with propolis and had great potential as an alternative to propolis to control strawberry fruits diseases.

Wild Fragaria vesca L. fruits: a rich source of bioactive phytochemicals

Wild F. vesca fruits and the corresponding infusions could be potentially applied in functional foods (infusions) and/or nutraceuticals/pharmaceutical formulations (hydromethanolic extracts).

Transcriptome profiling of postharvest strawberry fruit in response to exogenous auxin and abscisic acid

Auxin and abscisic acid regulate strawberry fruit ripening and senescence through cross-talk of their signal transduction pathways that further modulate the structural genes related to physico-chemical properties of fruit. The physiological and transcriptomic changes in harvested strawberry fruits in responses to IAA, ABA and their combination were analyzed. Exogenous IAA delayed the ripening process of strawberries after harvest while ABA promoted the postharvest ripening. However, treatment with a combination of IAA and ABA did not slow down nor accelerate the postharvest ripening in the strawberry fruits. At the molecular level, exogenous IAA up regulated the expressions of genes related to IAA signaling, including AUX/IAA, ARF, TOPLESS and genes encoding E3 ubiquitin protein ligase and annexin, and down regulated genes related to pectin depolymerization, cell wall degradation, sucrose and anthocyanin biosyntheses. In contrast, exogenous ABA induced genes related to fruit softening, and genes involved in signaling pathways including SKP1, HSPs, CK2, and SRG1. Comparison of transcriptomes in responses to individual treatments with IAA or ABA or the combination revealed that there were cooperative and antagonistic actions between IAA and ABA in fruit. However, 17% of the differentially expressed unigenes in response to the combination of IAA and ABA were unique and were not found in those unigenes responding to either IAA or ABA alone. The analyses also found that receptor-like kinases and ubiquitin ligases responded to both IAA and ABA, which seemed to play a pivotal role in both hormones' signaling pathways and thus might be the cross-talk points of both hormones.

Composition of nonanthocyanin polyphenols in alcoholic-fermented strawberry products using LC-MS (QTRAP), high-resolution MS (UHPLC-Orbitrap-MS), LC-DAD, and antioxidant activity

In this study, the nonanthocyanin (poly)phenolic profile of an alcoholic-fermented strawberry beverage was characterized. High-performance liquid chromatography coupled with a triple-quadropole mass spectrometer and ultra-high-performance liquid chromatography coupled with a linear trap quadropole and an Orbitrap mass analyzer was used to identify nonanthocyanin phenolic compounds. Sixty-six compounds were identified, and 13 of these were identified for the first time in strawberry or its derived alcoholic fermented beverage: protocatechuic acid-4-O-β-hexoside, brevifolin carboxylic acid, ferulic acid glucuronide, dimer caffeic acid-O-hexoside, luteolin-3'-O-xyloside, isorhamnetin 3-O-glucoside, taxifolin-O-glucoside, (+)-aromadendrin rhamnoside, eriodictyol-7-O-glucoside, (+)-taxifolin, (+)-aromadendrin, eriodictyol, and homovanillic acid. The alcoholic fermentation process produced significant increases in certain compounds, such as homovanillic acid and p-hydroxybenzoic acid, while a significant decrease in galloyl bis-HHDP-glucose was observed. Linear discriminant analysis correctly classified samples initial, final, and pasteurized, which led to the conclusion that alcoholic fermentation induces significant changes in composition, mainly in relation to the 19 compounds represented in the tables of this work.

Nontargeted metabolite profiles and sensory properties of strawberry cultivars grown both organically and conventionally

Strawberry (Fragaria × ananassa Duch.) contains many secondary metabolites potentially beneficial for human health, and several of these compounds contribute to strawberry sensory properties, as well. In this study, three strawberry cultivars grown both conventionally and organically were subjected to nontargeted metabolite profiling analysis with LC-qTOF-ESI-MS and to descriptive sensory evaluation by a trained panel. Combined metabolome and sensory data (PLS model) revealed that 79% variation in the metabolome explained 88% variation in the sensory profiles. Flavonoids and condensed and hydrolyzable tannins determined the orosensory properties, and fatty acids contributed to the odor attributes of strawberry. Overall, the results indicated that the chemical composition and sensory quality of strawberries grown in different cultivation systems vary mostly according to cultivar. Organic farming practices may enhance the accumulation of some plant metabolites in specific strawberry genotypes. Careful cultivar selection is a key factor for the improvement of nutritional quality and marketing value of organic strawberries.

Changes in sugars and organic acids in wolfberry (Lycium barbarum L.) fruit during development and maturation

Wolfberry (Lycium barbarum L.) fruits of three cultivars ('Damaye', 'Baihua' and 'Ningqi No.1') were harvested at five different ripening stages and evaluated for sugars and organic acids. Fructose, glucose and total sugar contents increased continually through development and reached their maxima at 34 days after full bloom (DAF). Fructose and glucose were the predominant sugars at maturity, while sucrose content had reduced by maturity. L.barbarum polysaccharides (LBP) content was in the range of 13.03-76.86 mg g(-1)FW during ripening, with a maximum at 20DAF. Citric, tartaric and quinic acids were the main organic acid components during development, and their levels followed similar trends: the highest contents were at 30, 14 and 20DAF, respectively. The significant correlations of fructose and total sugar contents with LBP content during fruit development indicated that they played a key role in LBP accumulation.

Identification and quantification of phenolic compounds of selected fruits from Madeira Island by HPLC-DAD-ESI-MS(n) and screening for their antioxidant activity

Five fruits species commonly cultivated and consumed in Madeira Island (Portugal) were investigated for their phenolic profile by means of reversed phase high-performance liquid chromatography coupled to diode array detection and electrospray ionisation mass spectrometry (HPLC-DAD-ESI/MS(n)) and antioxidant potential. A large number of compounds were characterised, flavonoids and phenolic acids being the major components found in target samples, 39 compounds (flavonoids, phenolic acids, terpenoids, cyanogenic glycosides and organic acids) were identified in cherimoyas, lemons, papayas, passion-fruits and strawberries for the first time. Furthermore, all samples were systematically analysed for their total phenolic and flavonoid contents along with two radical scavenging methods (ABTS and ORAC) for antioxidant activity measurement. Target fruits presented high phenolic contents which is responsible for most of the antioxidant activity against radical reactive species (R(2)>0.80). Quantitative data showed that anthocyanins, in particular pelargonidin-3-O-hexoside (>300 mg/100 mL), present only in strawberries were the compounds in largest amounts but are the ones which contribute less to the antioxidant activity.

Variation in the bioactive compound content at three ripening stages of strawberry fruit

During the harvest season of two consecutive years, five strawberry cultivars (‘Arosa’, ‘Elsanta’, ‘Marmolada’, ‘Miss’ and ‘Raurica’), grown in the continental part of the Republic of Croatia, were examined. Strawberry fruits quality was evaluated by individual phenol compounds, individual anthocyanins and fruit color. Fruits were harvested in three different periods. Analyzed strawberry cultivars show very good average values of the studied phenolic acids and flavonoids with predominant caffeic acid and epicatechin content in all researched strawberry cultivars. Considering the content of individual anthocyanins, pelargonidin 3-glucoside is predominant in strawberry extract followed by cyanidin-3-glucoside and pelargonidin 3-rutinoside. The correlation between individual anthocyanin content and chromaticity parameters was detected in all strawberry cultivars, additionally correlation coefficients and statistical significance were much lower. The results show a positive association between cultivar and harvest time on strawberry pulp color, with each of the color variables, a, b, a/b ratio, C, L and h° values.

Nutritional and nutraceutical quality of strawberries in relation to harvest time and crop conditions

Three strawberry varieties cultivated in soilless systems were studied for their content of primary and secondary metabolites in relation to harvest time and crop conditions. The three varieties were chosen based on their sensitivity level to environmental stress: Palomar (very sensitive), Festival (sensitive), and Camarosa (resistant). Throughout the campaign, three samplings were performed: December (extra-early production), January, and March (early production). Differences among cultivars and harvest times were observed based on the contents of sugars, organic acids, phenolic compounds, and antioxidant capacity. The higher levels for total anthocyanins and flavan-3-ols were found in Camarosa and Festival strawberries, both in the January harvest. The Palomar variety showed higher total sugar/total organic acids ratio in the March harvest. The influence of cultivation practices and environmental conditions was assessed by nested ANOVA and PLS-DA. Differences in the sugar and phenolic content were observed depending upon variety and coverage type. TEAC was most influenced by the substrate type.

Influence of cultivar and culture system on nutritional and organoleptic quality of strawberry

BACKGROUND

Strawberries are widely appreciated and consumed as a pleasant-tasting fruit either in fresh form or as processed product. Of the many factors which can affect the quality of fruit (sensorial and nutritional), the cultivar is especially important, but it is also affected by crop conditions. The main characteristics related to the fruit quality and nutritional attributes were assessed in several varieties of strawberry grown in soilless and soil culture. The effect of different cultivars and cropping systems on selected quality parameters, were assessed by applying multivariate statistical methods, such as principal component analysis and partial least square discriminant analysis (PLS-DA).

RESULTS

Differences among cultivars were observed based on the mineral composition and glucose and fructose concentrations in both cultivation systems. However, no significant differences between cultivars were detected in sourness. Tamar and Camarosa were the sweetest cultivars among those grown in soilless and soil system, respectively. Both varieties also had the highest total sugars/total acids ratio. The comparison between strawberries cultivated in soil and soilless systems also revealed significant differences in the mineral composition, content of sugars and related parameters.

CONCLUSION

Good discrimination was observed between cultivars of conventional crops, whereas no clear separation between cultivars grown in the soilless system was achieved by PLS-DA. PLS-DA also allowed differentiation of samples by type of crop (soilless vs. conventional crop). This information could be useful for selection of growing conditions and high-quality cultivars.