Influence of deficit irrigation on strawberry (Fragaria × ananassa Duch.) fruit quality.

BACKGROUND: Three different irrigation regimes - upper limit of field capacity (UFC), -12 kPa); lower limit of field capacity (LFC), -33 kPa; and deficit irrigation (DI), -70 kPa) were established on silty-loam soil and monitored with tensiometers. Yield and fruit quality of 'Flamenco' and 'Eva's Delight' ever-bearing strawberry cultivars were monitored. The aim of the study was to evaluate the effect of different irrigation regimes on the content of sugars, organic acids and phenolic compounds using high-performance liquid chromatography-mass spectrometry HPLC/HPLC-MS. RESULTS: Deficit irrigation significantly increased the content of sugars (from 1.1- to 1.3 fold), organic acids (from 1.1- to 1.3-fold), their ratio (from 1.1- to 1.2-fold) and the content of most identified phenolics in cv. 'Flamenco'. Conversely, higher amounts of total sugars and organic acids (1.7- to 1.8-fold) were detected in 'Eva's Delight' strawberries at UFC and LFC irrigation. Deficit irrigation generally decreased strawberry yield of cv. 'Eva's Delight'. CONCLUSION: The results suggest superior fruit quality and taste of strawberries grown under minor deficit irrigation for cv. 'Flamenco'. © 2016 Society of Chemical Industry.

Changes in the Aroma Profile and Phenolic Compound Contents of Different Strawberry Cultivars during Ripening.

Secondary metabolites, namely, phenolic and volatile organic compounds, contribute to the nutritional and organoleptic quality of the strawberry fruit. This study focuses on the changes in the content of phenolic compounds and volatile organic compounds during the ripening, from green to overripe fruit, of five strawberry cultivars ('Asia', 'CIVN 766', 'Aprica', 'Clery', and 'Malwina'). Additionally, these changes are compared with the colour of the fruit and peroxidase and polyphenol oxidase activity. Our results show that the accumulation of secondary metabolites (phenolic and volatile organic compounds) significantly changed during the ripening process for all of the studied cultivars. As for phenolic compounds, flavanols and hydroxybenzoic acid derivatives comprised between 87 and 95% of the total phenolic compound content in unripe green fruit. In contrast, anthocyanins and hydroxycinnamic acid derivatives comprised between 64 and 77% of the total phenolic compound content in overripe fruit, except in the fruit of the cultivar 'CIVN766'. When it comes to the aroma profile, the content of aldehydes decreased by 24-49% as the fruit ripened, and the accumulation of esters increased. Our study also shows that the ripening process differs among cultivars, and it is therefore necessary to define ripening indicators separately for each cultivar.

Construction of IsoVoc Database for the Authentication of Natural Flavours.

Flavour is an important quality trait of food and beverages. As the demand for natural aromas increases and the cost of raw materials go up, so does the potential for economically motivated adulteration. In this study, gas chromatography-combustion-isotope ratio mass spectrometry (GC-C-IRMS) analysis of volatile fruit compounds, sampled using headspace-solid phase microextraction (HS-SPME), is used as a tool to differentiate between synthetic and naturally produced volatile aroma compounds (VOCs). The result is an extensive stable isotope database (IsoVoc-Isotope Volatile organic compounds) consisting of 39 authentic flavour compounds with well-defined origin: apple (148), strawberry (33), raspberry (12), pear (9), blueberry (7), and sour cherry (4) samples. Synthetically derived VOCs (48) were also characterised. Comparing isotope ratios of volatile compounds between distillates and fresh apples and strawberries proved the suitability of using fresh samples to create a database covering the natural variability in δ13C values and range of VOCs. In total, 25 aroma compounds were identified and used to test 33 flavoured commercial products to evaluate the usefulness of the IsoVoc database for fruit flavour authenticity studies. The results revealed the possible falsification for several fruit aroma compounds.

Brussels Sprout Decapitation Yields Larger Sprouts of Superior Quality.

A common technological practice in Brussels sprouts (Brassica oleracea L. var. gemmifera) production is the removal of apical plant section a few weeks before harvest in order to promote the development of auxiliary buds (sprouts) and ensure higher yields. It is well-known that this measure positively influences the size of the sprouts, but until now no study has focused on the effect of decapitation on the content of primary and secondary metabolites in Brussels sprouts. Plants were decapitated one month before harvest, and sprouts were sampled from three sections along the stem (basal, middle, top) of each plant. The sprouts were harvested, weighed, and chemically analyzed. The content of individual sugars was assessed by HPLC and the content of individual phenolics and glucosinolates by HPLC-MS. Significant interactions between the decapitation and different stem sections were detected in the weight of the sprouts, as well as in their sugar levels. The highest sugar content was determined in basal sprouts collected from decapitated plants. Conversely, basal sprouts from nondecapitated plants were characterized by the lowest sugar content. No interaction between the decapitation and stem sections was detected in the level of phenolics or glucosinolates. Decapitation promoted the accumulation of all glucosinolates and hydroxycinnamic acids. Moreover, the content of glucosinolates and flavonoids was always highest in the sprouts from the top stem section.

Fresh from the Ornamental Garden: Hips of Selected Rose Cultivars Rich in Phytonutrients.

Morphological parameters (size, weight, color), the content of sugars, organic acids, lycopene, ß-carotene, and phenolics were determined in hips of Rosa canina (RCA), Rosa sweginzowii (RSW), Rosa rugosa (RUG), and selected ornamental Rosa cultivars Fru Dagmar Hastrup (FDH), Repandia (REP), Veilchenblau (RVB), Aloha (RAL), Bonica (BON), and Golden Gate (RGG). Although traditionally used RCA hips contained the highest amount of cyanidin-3-glucoside (83 µg/g DW) and were the reddest (h° = 17.5), they did not stand out in other analyzed parameters. RGG climber had the biggest hips (8.86 g), which also contained highest sugar levels (50.9 g/100 g DW). RAL stood out as the cultivar rich in organic acids (33.9 g/100 g DW), mainly because of high quinic acid content (17.6 g/100g DW). FDH and RSW hips were characterized by particularly high ascorbic acid levels (4325 mg/100 g DW and 4711 mg/100 g DW). Other ornamental cultivars contained low amounts of ascorbic acid compared to the analyzed species. The phenolic profile was species/cultivars-specific. The greatest diversity of phenolic compounds was detected in RUG and FDH hips (55 and 54 different tentatively identified compounds with HPLC/MS). Flavanols represented the main phenolic class in most of the investigated species/cultivars and RGG hips contained the highest amount of catechin and proanthocyandin derivatives (15855 µg/g DW). Altogether RAL hips contained the highest quantity of phenolics (44746 µg/g DW) mainly due to high levels of hydrolysable tannins compared to other species/cultivars. Although small, hips of BON and REP were most abundant regarding ß-carotene and lycopene content, respectively.

Alteration of the content of primary and secondary metabolites in strawberry fruit by Colletotrichum nymphaeae infection.

The effects of infection with Colletotrichum nymphaeae , the causative agent of strawberry black spot, were studied on two strawberry cultivars: susceptible 'Elsanta' and tolerant 'Honeoye' cultivars. Four treatments were established: (1) artificial inoculation; (2) spray application of pyraclostrobin + boscalid (Signum); (3) foliar spraying with calcium (Stopit); and (4) control (spraying with water). Primary metabolites (sugars and organic acids) and secondary metabolites (phenolic compounds) were determined in strawberry fruit with the use of HPLC-MS(n). Infected fruit accumulated large amounts of total sugars and low levels of organic acids. The sugar/acid ratio was higher in the infected and in Ca-treated strawberries. The contents of ellagic acid derivatives, flavonols, oligomeric procyanidins, flavan-3-ols, and total phenolics were highest in inoculated strawberry fruit. Results indicated that fungicide and calcium sprayings did not alter polyphenolic levels in plant tissue.