Evaluation of phenolic compounds in commercial fruit juices and fruit drinks

The total phenolic content of 13 commercially available fruit juices and juice drinks, selected to represent the most popular juice flavors in the United Kingdom, were analyzed using the Folin-Ciocalteu assay. Individual phenolic compounds were identified and quantified using HPLC-PDA-MS2. The catechin content and degree of polymerization of proanthocyanidins were also analyzed. Purple grape juice contained the largest number of individual phenolic compounds and also the highest concentration of total phenolics. The main components were flavan-3-ols, anthocyanins, and hydroxycinnamates, which accounted for 93% of the total phenolic content. In contrast, white grape juice, which contained principally hydroxycinnamates, had the lowest total phenolic content. Antioxidant activity was measured using the ORAC and FRAP assays, and the data obtained were in broad agreement with total phenol content. In view of the recent findings of the Kame project indicating that long-term fruit juice consumption can provide protection against Alzheimer's disease (Dai et al. Am. J. Med. 2006, 379, 464-475), it is suggested that the protective effects may be enhanced by consumption of a combination of juices rich in phenolics and containing a diverse variety of individual phenolic compounds, namely, juices derived from purple grapes, grapefruit, cranberries, and apples.     

Ammonium reduces growth,fruit yield and fruit quality of watermelon

Watermelon (Citrullus lunatus Thunb.) plants cv ‘Sugar Baby’ were grown hydroponically in a greenhouse under NO₃:NH₄ ratios of 3:1, 1:1, and 1:3. Plants receiving the high ammonium treatment expressed symptoms of NH4‐toxicity and declined rapidly after bloom. Reducing NO₃:NH₄ from 3:1 to 1:1 significantly reduced growth, water use, fruit yield, flesh soluble solids and uptake of NO₃, NH₄, K, Ca and Mg.     

Significance of fruit transpiration on calcium nutrition in developing apricot fruit

The first objective of this study was to search for a possible correlation between accumulation of calcium (Ca), potassium (K), and magnesium (Mg) and fruit transpiration in developing apricot (Prunus armeniaca L.) fruit. Secondly, the work aimed to determine the significance of transpirational flux on Ca nutrition. We hypothesized that if the fruit transpiration is the determining factor of Ca accumulation (phloem‐immobile element) then the import of Ca would be suppressed by restriction of fruit water loss, while the import of phloem‐mobile nutrients (i.e., K and Mg) would not be. To test this hypothesis, the seasonal changes of transpiration and of Ca, K, and Mg concentration/accumulation were assessed in fruits left to naturally transpire or under restricted transpiration (bagged fruits). Fruit transpiration was measured on detached fruits using a portable gas‐exchange equipment (ADC‐LCA4, ADC BioScientific Ltd, Hoddesdon, England). Results demonstrated that 83% of total fruit Ca content was gained within the first 4 weeks after fruit‐set, and that Ca import ceased concomitantly to a reduction of transpiration. In spite of the limitation of fruit transpiration, Ca entered the nontranspiring fruits, and its concentration was about 45% of that in control fruits suggesting that other factor(s) operated for Ca accumulation. This study provides the evidence that fruit transpiration accounted for 55% of total Ca that entered a fruit. We conclude that optimal soil Ca availability and apportioning to the fruit during the early 4 weeks of growth are essential to sustain the fruit demand of this nutrient and that some cultural practices (e.g., summer pruning, irrigation) should be tested as possible tools to improve fruit Ca nutrition via increasing fruit transpiration.     

Radiocesium transfer into the fruit of deciduous fruit trees contaminated during dormancy

Following the accident at the Tokyo Electric Power Company, Fukushima Daiichi Nuclear Power Plant (FDNPP), radiocesium (¹³⁴Cs + ¹³⁷Cs) concentrations in deciduous mature fruits were determined in orchards in the northern area of Fukushima Prefecture. At the time of the nuclear accident, most deciduous fruit trees were in the dormant stage prior to bud burst. To evaluate the relationship between radiocesium deposition in the soil and fruit contamination, radiocesium concentrations were measured from the 5-cm topsoil and from six fruit species across 17 orchards in 2011. The vertical distribution of radiocesium in the topsoil (0–30 cm in depth) and its spatial distribution in the 5-cm topsoil underlying the tree canopy of a peach, Prunus persica (L.) Batsh, orchard (“Akatsuki” cultivar) were also investigated. Significant correlations between the radiocesium concentration in the mature fruit and that in the 5-cm topsoil layer were observed for the 17 orchards as well as for the trees of the peach orchard. However, 93% of the ¹³⁷Cs found in the 30-cm soil core was retained within the top 3 cm of the soil in the peach orchard. Considering the profile of the root of this deciduous fruit tree, we assumed a negligible level of radiocesium uptake via the roots. However, the possibility of inward migration via the bark was undeniable, because some radiocesium adhered to the tree canopy before bud burst while depositing on the soil surface. Additionally, transfer factors for peach and grape, hybrid of Vitis labrusca L. and Vitis vinifera L., from young, uncontaminated trees cultivated with contaminated soil were lower than those previously reported.     

Modifications of strawberry fruit antioxidant pools and fruit quality under NaCl stress

The responses of fruit antioxidants in two strawberry cultivars differing in their sensitivity to NaCl stress were studied. The sensitive cv. Elsanta and the less sensitive cv. Korona were treated with NaCl solutions of 40 and 80 mmol/L in the nutrient solution. In general, moderate salinity resulted in increases of antioxidant capacity. In cv. Korona, salt stress increased the activity of superoxide dismutase and the contents of glutathione, phenols, and anthocyanins, while that of ascorbic acid decreased. In cv. Elsanta, changes of superoxid dismutase activity and of ascorbic acid concentration were comparable to those of cv. Korona, but the decrease of ascorbic acid was more distinct. The contents of anthocyanins decreased, and those of phenols remained similar. The glutathione content was reduced at the highest NaCl level. The results indicate that less salt-sensitive strawberry cultivars may be grown under moderate salinity stress to optimize fruit quality.     

模拟酸雨对龙眼落果及果实品质的影响研究

试验研究模拟酸雨对 8年生龙眼落果及果实品质的影响结果表明 ,pH≤ 3 5的酸雨处理显著增加落果率 ,果实可溶性固形物、固酸比和糖酸比显著下降。pH为 2 5的酸雨处理果实出现伤斑 ,单果重和可食率显著降低。     

果实采前套袋对龙眼果实品质和耐贮性的影响

以福建省主栽龙眼品种“福眼”果实为材料，研究果实采前套袋对龙眼果实品质和采后耐贮性的影响。结果表明：果实采前套袋可明显改善龙眼果实的外观品质；但降低了果肉可溶性固形物、可滴定酸、维生素C和总糖等营养物质含量，导致龙眼果实甜度下降、风味变淡。果实采前套袋降低了与龙眼果皮褐变密切相关的酚类物质(包括花色素苷、类黄酮和总酚)含量和多酚氧化酶、过氧化物酶的活性，减少了龙眼果实在贮藏期间果皮褐变的发生；同时，果实采前套袋明显减轻由采前病原菌潜伏侵染所致的采后龙眼果实病害，提高果实耐贮性，延长果实贮藏期。     

Water uptake through sweet cherry (Prunus avium L.) fruit pedicels: Influence of fruit surface water status and intact fruit skin

A modified potometer consisting of a water-filled glass tube mounted in parallel with a metric scale and connected to a fruit was used to study water uptake into detached fruits of sweet cherry. Results describing quantities of imported water from some introductory studies were in the same range as in previously published studies conducted with alternative methods. Water uptake was measured in fruits of four cultivars kept in air of approximately 50±5% RH followed by immersion in water 1–2 h into the experimental period. This caused a significant decrease in water uptake. However, the fruits continued to accumulate water at a reduced rate. When the fruits were dried, the water uptake immediately increased to the same level as before the immersion in water. The fruit skin of two cultivars was exposed to normal air after being ruptured with four shallow cuts to simulate cuticular fractures or shallow cracks. These two treatments did not give statistically different water uptake through the pedicel, although there was a tendency to an increased rate of water uptake in fruits with ruptured fruit skin.     

猕猴桃籽油微胶囊化技术研究

猕猴桃籽油中不饱和脂肪酸含量较高,特别是亚麻酸含量高达63.99%.为防止猕猴桃籽油的氧化,采用喷雾干燥法对猕猴桃籽油进行微胶囊化研究,并对产品进行了电镜观察和氧化试验.结果表明:壁材采用1∶1的大豆分离蛋白与麦芽糊精,芯材与壁材的配比为1∶1.5,料液总固形物含量为25%,在30～35 MPa压力下均质处理,喷雾干燥进风温度180℃,出风温度80℃,制得的微胶囊结构理想,抗氧化性较好.     

Phenolic composition of litchi fruit pericarp

Litchi (Litchi chinensis, Sapindaceae) is a nonclimacteric subtropical fruit that, once harvested, loses its red pericarp color because of browning reactions probably involving polyphenols. Low-pressure chromatography, high-pressure liquid chromatography, UV-visible spectral analysis, mass spectrometry, and nuclear magnetic resonance studies have allowed the determination and quantification of the polyphenolic composition of litchi pericarp. Litchi skins contain significant amounts of polyphenolic compounds. The principal characteristic of the litchi skin polyphenolic compounds is their ortho-diphenolic structure, which gives them high oxidability. Four major pigments were formally identified as cyanidin 3-rutinoside, cyanidin glucoside, quercetin 3-rutinoside (rutin), and quercetin glucoside. The tannin content was characterized after the depolymerization thiolysis reaction. Tannins (polymeric proanthocyanidins) are mainly constituted with epicatechin units linked by A- and B-type bonds. The different phenolic compounds of litchi cv. Kwai Mi were quantified by HPLC. Condensed tannins were the most abundant (4 mg x g(-1) of fresh skin), followed by epicatechin and procyanidin A2 (1.7 and 0.7 mg x g(-1) of fresh pericarp, respectively). The amount of anthocyanins was found to be comparable to that of flavonols, with a value of approximately 0.4 mg x g(-1) of fresh pericarp.     

水果果袋自动撑开机构的研究

水果套袋技术可以减少水果的农药残留,提高果品品质,是生产无公害水果的重要手段之一。人工套袋劳动强度大、危险性高。该文根据人工套袋的步骤,自主开发了自动化套袋装置。整个装置分为：果袋自动撑开机构和套袋机构,该文主要介绍果袋自动撑开机构。包括果袋分开机构、果袋撑开机构和撑好果袋的输送机构,采用单片机控制,用气力驱动,采用两个转动块和一对真空吸盘将成叠的果袋逐个分开;采用弧形手指,将果袋的内腔撑开到最大容积,满足水果套袋的要求,实现了果袋撑开过程的自动化,作业速度达到3个/min,为套袋作业做好了准备。     

Edible coatings influence fruit ripening, quality, and aroma biosynthesis in mango fruit

The effects of different edible coatings on mango fruit ripening and ripe fruit quality parameters including color, firmness, soluble solids concentrations, total acidity, ascorbic acid, total carotenoids, fatty acids, and aroma volatiles were investigated. Hard mature green mango (Mangifera indica L. cv. Kensigton Pride) fruits were coated with aqueous mango carnauba (1:1 v/v), Semperfresh (0.6%), Aloe vera gel (1:1, v/v), or A. vera gel (100%). Untreated fruit served as the control. Following the coating, fruits were allowed to dry at room temperature and packed in soft-board trays to ripen at 21+/-1 degrees C and 55.2+/-11.1% relative humidity until the eating soft stage. Mango carnauba was effective in retarding fruit ripening, retaining fruit firmness, and improving fruit quality attributes including levels of fatty acids and aroma volatiles. Semperfresh and A. vera gel (1:1 or 100%) slightly delayed fruit ripening but reduced fruit aroma volatile development. A. vera gel coating did not exceed the commercial mango carnauba and Semperfresh in retarding fruit ripening and improving aroma volatile biosynthesis.     

Relationships between leaf and fruit minerals and fruit quality attributes of apples grown under northern conditions

Field experiments were conducted during 1994–1995 in seven apple (Malus spp.) orchards located in the southwest of Finland (the mainland and the Åland Islands). The cultivars were ‘Transparente Blanche’, ‘Samo’, ‘Melba’, ‘Raike’, ‘Red Atlas’, ‘Åkerö’, ‘Aroma’, and ‘Lobo’. Leaf samples from branches bearing fruits (BF) and not‐bearing fruits (BNF) were collected two times during the growing seasons. Fruit samples were picked about one week before commercial maturity. Macronutrient concentrations in fruits and leaves, fruit diameter and juice pH, titratable acidity (TA) and soluble solids concentrations (SSC) were determined. Leaf nitrogen (N), phosphorus (P), and potassium (K) were higher, but calcium (Ca) and magnesium (Mg) were lower in BNF. Branch types (BF and BNF) were closely related in leaf N, P, and Ca, but not in leaf K and Mg at the first sampling time. Fruit N, P, K, and Mg were closely related to each other but not to fruit Ca. Mean fruit N and Ca and leaf P and Mg were low compared with the recommended levels. Relationships between fruit and leaf nutrient concentrations were found only in P and Mg. Fruit diameter increased and juice SSC decreased with increasing leaf N concentration. Fruit P declined with increasing fruit diameter and juice TA increased and SSC/TA decreased with increasing leaf P and Ca concentrations.     

Sweet passion fruit yield and fruit quality related to fertilization with urea and cattle manure

An experiment was conducted in Campos dos Goytacazes in the State of Rio de Janeiro, Brazil, in order to evaluate the applying effect of nitrogen and cattle manure doses on sweet passion fruit yield and quality. The experimental outline used was complete block, in a 5 × 2 factorial arrangement, five nitrogen doses (0, 50, 150, 250 and 350g plant^?1 year^?1) and two types of organic fertilization (with and without cattle manure), with 4 replications. Sweet passion fruit yield presented an increase of 44.4% due to the application of the best nitrogen doses in comparison with the treatment which did not receive nitrogen fertilization. The treatments that did not receive cattle manure presented higher average weight, diameter and thickness of the fruit skin, while the addition of cattle manure presented greater juice concentration and higher percentage of seeds in sweet passion fruit fruits. The increase in nitrogen doses allowed an increase in concentration and total titratable acidity of the fruits.     

Characterization of alcohol acyltransferase from olive fruit

Alcohol acyltransferase catalyzes the esterification of volatile alcohols with acyl-CoA derivatives to produce volatile esters typically present in the aroma of some fruits. This enzyme was detected in extracts from the pericarp tissues of ripe olive fruits using hexanol and acetyl-CoA as the substrates. Alcohol acyltransferase showed a very low activity level in these fruits, with an optimum pH value at 7.5 and high K(m) values for hexanol and acetyl-CoA. The substrate specificity of this enzyme for various alcohols was also studied. The involvement of the studied enzyme in the biogenesis of the volatile esters present in the aroma of virgin olive oil was discussed.     

Potassium fertilization enhances pepper fruit quality

The effect of potassium (K⁺) concentration on the nutritional quality and yield of pepper fruits was evaluated. Pepper plants were grown in a controlled-environment greenhouse under hydroponic conditions with different nutrient solutions obtained by modifying the Hoagland solution to achieve different K⁺ concentrations. Potassium nutrition affected fruit yield parameters more than vegetative biomass in pepper plants. The maximum fruit yield was obtained with 7 mM K⁺ in the nutrient solution. However, it is possible to improve the bioactive compounds of pepper fruits with a higher application of K⁺ without reducing yield. The increase of K⁺ in the nutrient solution improved pepper fruit quality by increasing fruit firmness, TSS content, soluble sugars and ascorbic acid concentration. Therefore, the fruit quality improvements obtained with adequate K⁺ nutrition resulted in nutritionally enriched fruits, which, at little or no extra cost, benefits the consumer.     

Tryptophan-N-glucoside in fruits and fruit juices

In extracts prepared from various fruits as well as in fruit juices a single tryptophan glycoconjugate was detected by HPLC-MS analysis. Product ion spectra demonstrated the N-glycosidic linkage of a hexose moiety to the indole nitrogen. For structure elucidation, the novel tryptophan glycoside was isolated from pear juice and identified as N(1)-(beta-D-glucopyranosyl-(4)C(1))-L-tryptophan by (1)H, HH-COSY and (13)C NMR spectroscopy. Finally, we disclosed the biosynthetic origin of the novel tryptophan metabolite by demonstrating the enzymatic glycosylation of deuterium-labeled tryptophan, which was applied to pear fruit.