Antioxidant activities of sicilian prickly pear (Opuntia ficus indica) fruit extracts and reducing properties of its betalains: betanin and indicaxanthin

Sicilian cultivars of prickly pear (Opuntia ficus indica) produce yellow, red, and white fruits, due to the combination of two betalain pigments, the purple-red betanin and the yellow-orange indicaxanthin. The betalain distribution in the three cultivars and the antioxidant activities of methanolic extracts from edible pulp were investigated. In addition, the reducing capacity of purified betanin and indicaxanthin was measured. According to a spectrophotometric analysis, the yellow cultivar exhibited the highest amount of betalains, followed by the red and white ones. Indicaxanthin accounted for about 99% of betalains in the white fruit, while the ratio of betanin to indicaxanthin varied from 1:8 (w:w) in the yellow fruit to 2:1 (w:w) in the red one. Polyphenol pigments were negligible components only in the red fruit. When measured as 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid (Trolox) equivalents per gram of pulp, the methanolic fruit extracts showed a marked antioxidant activity. Vitamin C did not account for more than 40% of the measured activity. In addition, the extracts dose-dependently inhibited the organic hydroperoxide-stimulated red cell membrane lipid oxidation, as well as the metal-dependent and -independent low-density lipoprotein oxidation. The extract from the white fruit showed the highest protection in all models of lipid oxidation. Purified betanin and indicaxanthin were more effective than Trolox at scavenging the [2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid)] diammonium salt cation radical. Cyclic voltammetric measurements show two anodic waves for betanin and indicaxanthin, and differential pulse voltammetry shows three anodic waves for betanin, with calculated peak potentials of 404, 616, and 998 mV, and two anodic waves for indicaxanthin, with peak potentials of 611 and 895 mV. Betanin underwent complex formation through chelation with Cu(2+), whereas indicaxanthin was not modified. These findings suggest that the above betalains contribute to the antioxidant activity of prickly pear fruits.     

Chemical characterization and biological effects of Sicilian Opuntia ficus indica (L.) mill. Fruit juice: antioxidant and antiulcerogenic activity

The juice of whole fruits of Sicilian cultivars of prickly pear (Opuntia ficus indica (L.) Mill.) was investigated, and the contents of ascorbic acid, total polyphenols, and flavonoids were determined. In the juice, ferulic acid was the chief derivative of hydroxycinnamic acid and the mean concentration of total phenolic compounds was 746 microg/mL. The flavonoid fraction, analyzed by high-performance liquid chromatography-diode array detection, consisted of rutin and isorhamnetin derivatives. The juice showed antioxidant activity in the DPPH(*) test, probably due to the phenolic compounds that are effective radical scavengers. The preventive administration of the juice inhibited the ulcerogenic activity of ethanol in rat. Light microscopy observations showed an increase in mucus production and the restoration of the normal mucosal architecture. The juice is nutritionally interesting, and its dietary intake could provide protection against oxidative damage.     

Hydrolytic activity and ultrastructural changes in fruit skins from two prickly pear (Opuntia sp.) varieties during storage

The activity of four cell wall hydrolases, pectinmethylesterase (PME), polygalacturonase (PG), cellulase, and beta-galactosidase (beta-Gal), was measured in fruit skins of two prickly pear varieties, Naranjona and Charola, during storage at 18 degrees C and 85-95% relative humidity (RH). In Naranjona (Opuntia ficus indica), of short postharvest life (ca. 2 weeks), PG, cellulase, and beta-Gal increased their activity more than twice, whereas PME activity tended to increase only slightly during storage. In Charola (Opuntia sp.), of long postharvest life (ca. 2 months), only beta-Gal increased its activity (77%), showing a high PG activity from the beginning of storage. Transmission electron microscopy observations showed middle lamella dissolution at the end of storage for both varieties. Naranjona showed a higher cell wall enzymatic activity than Charola, in agreement with their storability differences. Our results suggest that PG and cellulase in Naranjona and PG and beta-Gal in Charola are the main enzymes responsible for cell wall hydrolytic and ultrastructural changes in skins of stored prickly pears.     

Biothiols, taurine, and lipid-soluble antioxidants in the edible pulp of Sicilian cactus pear (Opuntia ficus-indica) fruits and changes of bioactive juice components upon industrial processing

Biothiols, taurine, and flavonols, as well as tocopherols and carotenoids have been assessed in the edible pulp of Sicilian red (Sanguigna), yellow (Surfarina), and white (Muscaredda) cultivars of cactus pear. The yellow cultivar has the highest level of reduced glutathione (GSH, 8.1 +/- 0.78 mg/100 g pulp), whereas the white cultivar showed the highest amount of cysteine (1.21 +/- 0.12 mg/100 g pulp). Taurine accounted for 11.7 +/- 1.0 mg/100 g in the yellow pulp, while lower levels were measured in the others. With the exception of kaempferol in the yellow cultivar (2.7 +/- 0.2 microg/100 g pulp), the edible pulp of cactus pear was not a source of flavonols. Very low amounts of lipid-soluble antioxidant vitamins such as vitamin E and carotenoids were measured in all cultivars. As a consequence of industrial processing, a total loss of GSH and beta-carotene and a net decrease of vitamin C and cysteine were revealed in the fruit juice, whereas betalains, taurine, and vitamin E appeared to be less susceptible to degradation.     

超高压处理对砀山梨汁中过氧化物酶活性的影响

该文研究了超高压处理对砀山梨汁中过氧化物酶活性的影响。试验压力为0.1～500 MPa，温度为20～60℃。此外，考察了不同pH值(3～7)和保压时间(2～34 min)超高压处理对酶活性的影响。试验结果表明：在处理温度为50℃、保压时间为10 min和梨汁pH 5的条件下，300 MPa以下压力范围内高压处理酶被激活，其活性增加；大于300 MPa时酶的活性随压力增大而下降。高压处理时，温度低于40℃对酶的活性影响不大；有效影响高压处理的最小温度为40℃。保压时间超过10 min后时间延长对酶的活性影响     

Color, betalain pattern, and antioxidant properties of cactus pear (Opuntia spp.) clones

Total phenolics, ascorbic acid, and betalain contents of differently colored cactus pear clones (nine Opuntia ficus-indica [L.] Mill. clones and one O. robusta Wendl. clone) were investigated and related to their respective antioxidant potential assessed by Trolox-equivalent antioxidant capacity (TEAC) and oxygen radical absorbance capacity (ORAC) assays. TEAC and ORAC values were very highly correlated with each other and also with values for total phenolics, betalain contents, and ascorbic acid concentrations. Total phenolics had the greatest contribution to ORAC and TEAC values. High-performance liquid chromatography (HPLC)-diode array detector (DAD)-tandem mass spectrometry (MS/MS) measurements of cactus pear juices permitted the differentiation of the clones based on variations in pigment patterns and betalain concentrations. The red and yellow betalains were absent in lime green colored cactus fruits. The ratio and concentration of these pigments were responsible for the yellow, orange, red, and purple colors in the other clones. Progeny of purple and lime green colored parents were characterized by 12% and 88% of plants bearing lime green and purple fruit, respectively. This implies that the genes for betalain production were lacking in the lime green fruits but could be provided by a parent with a complete set of genes, that is, purple fruits. Besides known pigments typical of Cactaceae, two unexpected betalains were identified. Whereas gomphrenin I was found for the first time in tissues of cactus plants, methionine-betaxanthin has never been described before as a genuine betalain. In addition to their alleged health-promoting properties, various combinations of yellow betaxanthins and red-purple betacyanins may allow the development of new food products without using artificial colorants.     

Liquid chromatographic methodology for the characterization of orange juice

Liquid chromatographic (LC) methodology potentially useful for the characterization of orange juice, with particular regard to detecting adulteration of orange juice by computer pattern recognition analysis, has been developed. After dilution with methanol the juice is extracted with hexane to remove the carotenoids, which are chromatographed on a C18 column with an acetonitrile-methanol-methylene chloride mobile phase and detection at 450 nm. Further extraction of the juice with methylene chloride isolates the methoxylated flavones, which are chromatographed by reverse phase LC with an acetonitrile-methanol-water mobile phase and detection at 280 nm. The flavanone glycosides remaining in solution are chromatographed on a C18 column with an acetonitrile-water mobile phase and detection at 280 nm. The precisions of the heights of the 32 LC peaks selected for pattern recognition analysis were determined from 5 replicate analyses of a single juice. Coefficients of variation of the replicates ranged from 0.3 to 4.5%, with an average of 2.1%. Adulteration of products with sodium benzoate-fortified pulpwash or grapefruit juice can be detected by this method. Pattern recognition analysis of the data obtained for 80 authentic and 19 adulterated orange juices showed that the method is potentially useful for distinguishing between authentic and adulterated products.     

Changes in the volatile compounds and chemical and physical properties of Kuerle fragrant pear (Pyrus serotina Reld) during storage

Volatiles from stored Kuerle fragrant pears (Pyrus serotina Reld) were studied using high-resolution gas chromatography and the solid-phase microextraction (SPME) method of gas chromatography/mass spectrometry (GC/MS). The dominant components were hexanal, ethyl hexanoate, ethyl butanoate, ethyl acetate, hexyl acetate, ethanol, alpha-farnesene, butyl acetate, and ethyl (E,Z)-2,4-decadienoate. By using GC-olfactometry, it demonstrated that the volatile compounds from SPME were responsible for the aroma of the Kuerle fragrant pear. The levels of sugars, organic acids, and phenolic acids in Kuerle fragrant pears were investigated using high-performance liquid chromatography (HPLC). Fructose was the dominant sugar, followed by glucose and sucrose. With increasing storage time, sucrose levels decreased; however, changes in fructose and glucose levels were not remarkable. There was a slight decrease in flesh firmness during storage. The general soluble solids concentration (SSC) declined slightly after 5 months storage. Some aroma-related volatile components increased during storage, while others decreased, especially the esters. The organic acids and phenolic acids also changed. The flavor of the Kuerle fragrant pears was affected by the change of volatile compounds and changes in chemical and physical properties.     

Nutritional reference values for Opuntia ficus‐indica determined by means of the boundary‐line approach

Optimum concentrations and/or sufficiency ranges of nutrients are useful for a correct diagnosis and improvement of nutrient status of cultivated plants. To develop boundary‐line approach (BLA) standards for Opuntia ficus‐indica L., a database of N, P, K, Ca, and Mg concentrations in 1‐year‐old cladodes and cladodes fresh‐matter yield was used. The BLA optimum concentrations (associated with estimated maximum yield) for O. ficus‐indica were: N = 13.1 g kg^–1, P = 3.2 g kg^–1, K = 44.4 g kg^–1, Ca = 38.1 g kg^–1, and Mg = 17.3 g kg^–1. The BLA sufficiency ranges at 95% yield were 8.4–20.3 g kg^–1 for N, 2.4–4.2 g kg^–1 for P, 38.2–50.8 g kg^–1 K, 31.8–45.2 g kg^–1 for Ca, and 14.3–20.9 g kg^–1 for Mg. The BLA standards are comparable to those obtained in a previous study using compositional‐nutrient‐diagnosis (CND) approach.     

Statistical characterization of sicilian olive oils from the Peloritana and Maghrebian zones according to the fatty acid profile

This paper deals with the characterization of 475 Sicilian virgin olive oils (VOO) produced in 10 different crop years (from 1993 to 2004), according to the cultivar and the geographical origin by means of multivariate statistical analysis applied to fatty acids. In particular, the studied VOOs came from the Peloritana and Maghrebian geological zones. The fatty acid composition was determined by using the official gas chromatographic method. The results suggest that although the effect of the cultivar is significant in the olive oil classification based on the fatty acid composition, a predominant and well-defined geographic effect is also present. This study demonstrated that it is possible to employ an official and inexpensive analytical method coupled with the statistical analysis to ascertain the geographical origin and the cultivar of an extra virgin olive oil.     

Thiabendazole uptake and storage performance of cactus pear [Opuntia ficus-indica (L.) Mill. Cv Gialla] fruit following postharvest treatments with reduced doses of fungicide at 52 degrees C

The storage response of cactus pears [Opuntia ficus-indica Miller (L.) cv. Gialla] was investigated over 6 weeks at 6 degrees C, plus an additional week of simulated marketing period (SMP) at 20 degrees C, after a 3-min dip treatment with thiabendazole (TBZ) at 1000 mg/L at 20 degrees C or 150 mg/L TBZ at 52 degrees C. Untreated fruits were used as control. Following TBZ treatments at 20 and 52 degrees C, total residues were recovered from the peel of cactus pear, as the concentration of residues in the pulp was negligible. Treatments with 1000 mg/L TBZ at 20 degrees C resulted in a 2.82 mg/kg residue uptake (active ingredient, whole-fruit basis), whereas treatment at 150 mg/L TBZ left 1.09 mg/kg. TBZ showed great persistence over both storage and SMP: on average, in the fruits treated at 20 and 52 degrees C, over 72 and 68%, respectively, of TBZ was still present after SMP. Postharvest treatments with 1000 mg/L TBZ at room temperature did not affect the expression of slight-to-moderate chilling injury (CI), but reduced severe CI by approximately 50% and decay development by 63.4% in comparison to those of untreated fruit after SMP. The effectiveness of TBZ was much higher with the treatment at 150 mg/L TBZ at 52 degrees C, providing 91% control of severe CI and approximately 89% suppression of decay; no treatment damage occurred during storage and SMP. External appearance was better in fruit treated with 150 mg/L TBZ at 52 degrees C. Respiration rate, titratable acidity, soluble solids concentration, and acetaldehyde in the flesh were not significantly influenced by treatments. Ethylene production rate and ethanol levels in the flesh were significantly higher in the TBZ-treated fruit as opposed to those in the untreated control fruit.     

Abundant class III acidic chitinase homologue in tamarind (Tamarindus indica) seed serves as the major storage protein

The phyla Leguminosae contains protease inhibitors, lectins, chitinases, and glycohydrolases as major defense proteins in their seeds. Electrophoretic analysis of the seed proteins of tamarind ( Tamarindus indica L.), an agri-waste material, indicated the unusual presence of two major proteins comparable to overexpression of recombinant proteins. These proteins were identified by amino-terminal analysis to be (1) Kunitz-type trypsin inhibitor and (2) class III endochitinase (34000 Da). These two proteins were purified to apparent homogeneity by a single-step chitin bead affinity chromatography and characterized. The Kunitz inhibitor was specific toward inhibiting trypsin with a stoichiometry of 1:1. The 33000 +/- 1000 Da protein, accounting for >50% of the total seed protein, is an acidic glycoprotein exhibiting a very low endotype hydrolytic activity toward chitin derivatives. SDS-PAGE followed by densitometry of tamarind seed germination indicates the disappearance of the chitinase with the concomitant appearance of a cysteine endopeptidase. On the basis of its abundance, accumulation without any pathogenesis-related stimulus, temporal regulation, amino acid composition, and very low enzyme activity, this 34000 Da protein designated "tamarinin" physiologically serves as the major storage protein.     

乙二醇蓄冷库性能及其在黄冠梨保鲜上的应用

为解决果蔬贮藏保鲜设施运行成本高的问题,促进产地冷藏设施建设,研制了以乙二醇为载冷剂的蓄冷库,并对该库的性能、贮藏保鲜效果和运行成本进行了分析,探讨该冷库用于果品贮藏保鲜的可能性。研究发现乙二醇蓄冷库的平均温度为0.18~0.32℃,测温点间最大温差为0.8℃,好于对照冷藏库。结果说明乙二醇蓄冷库的温度稳定性和均匀性较好,有利于保障果品贮藏品质。乙二醇蓄冷库和对照冷藏库用于贮藏黄冠梨,贮藏效果差异不大。一个贮藏周期一间容量30t的乙二醇蓄冷库,用电量略高于对照冷藏库;但因实行峰谷电价,运行电费仅是对照冷库的75%。总体来说,与对照冷藏库相比,研制的乙二醇蓄冷库性能优良,保鲜效果理想,运行成本更低,是实施峰谷电价地区适宜的果品贮藏保鲜设施。     

Identification and quantification of betalains from the fruits of 10 mexican prickly pear cultivars by high-performance liquid chromatography and electrospray ionization mass spectrometry

Qualitative and quantitative analyses of betalain pigments in 10 cultivars/lines of prickly pear (Opuntia spp.) fruit grown in Mexico were conducted with reverse phase high-performance liquid chromatography-diode array detection (HPLC-DAD) coupled with electrospray mass spectrometry (ESI-MS). Betacyanins and betaxanthins were identified by comparison with the UV/vis and mass spectrometric characteristics as well as the retention times of semisynthesized reference betaxanthins. Data revealed that the ratio and concentration of betalain pigments are responsible for the color in the different cultivars, showing the highest betalains content in the fruit of purple colored Camuesa (O. robusta Wendl.) (8.1 mg/g dry fruit), which is comparable to that found in red beet Beta vulgaris L. ssp. Var. Pablo) (8.6 mg/g dry tissue). Yellow betalains were absent in Reyna (O. alba-carpa) prickly pear cultivar. A total of 24 known/unknown betalains were present in the prickly pear fruit samples studied, including 18 betaxanthins and 6 betacyanins. Our results indicate that prickly pear cultivars can be considered as a potential source of yellow and red natural colorants.     

硼对砀山酥梨营养生长和果实品质的影响

为改善砀山酥梨树体营养状况,提高果实品质,在其新梢生长期（3～7月份）,叶面喷施不同浓度水平（0.2%,0.3%,0.4%）的硼肥（硼砂）,研究不同处理对砀山酥梨叶片硼含量及其变化动态、砀山酥梨营养生长和果实品质的影响。结果表明:砀山酥梨叶片硼含量随新梢生长而上升,在新梢停长期含量最高,之后开始下降,呈现低高低的变化趋势;叶面喷施不同浓度水平的硼肥后,在0.2%～0.3%范围内,叶片含硼量随喷施浓度的提高而增加;适量施硼促进了砀山酥梨的新梢生长,显著增加了单叶面积、百叶重、叶片叶绿素含量;提高了砀山酥梨果实的可溶性糖、可溶性固形物含量和果肉硬度,降低了果实含酸量。综合果树生长状况、果实品质和生产成本等因素,砀山酥梨树体缺硼时,在新梢生长期的3～7月份,叶面喷施2～3次0.3% 的硼肥效果最好。     

Chemical and physical changes in milk protein concentrate (MPC80) powder during storage

The solubility and chemical changes due to the Maillard reaction were investigated in milk protein concentrate powder containing 80% protein (MPC80) during storage at temperatures and relative humidities in the ranges of 25-40 °C and 44-84%, respectively. The Maillard reaction was studied by measuring furosine (a product of lactosylated protein after digestion with acid) and free hydroxymethylfurfural (HMF) contents by HPLC and L*, a*, b* values with a color-meter. Furosine, free HMF, and browning in MPC80 increased during storage, whereas the solubility decreased. The correlation between the Maillard reaction and solubility loss was explored in modified MPC80 to which glucose was added to enhance the rate of the Maillard reaction. More furosine and brown pigments were observed in the glucose-containing MPC80 than in MPC80 with added lactose. The opposite trend occurred for solubility, suggesting that the Maillard reaction may be a cause of solubility loss in MPC powder.     

五九香梨贮藏期间挥发性化合物和理化性状的变化(英)

利用高效液相色谱法测定贮藏期间五九香梨的糖和有机酸的组成及变化,采用固相微萃取方式（SPME）进行萃取,并结合气相色谱和质谱（GC/MS）分析检测梨果实中的挥发性香气成分。得出以下主要结论：果糖是五九香梨的主要糖类,其次是葡萄糖和蔗糖。随着贮藏期的延长,果糖先有增加的趋势,在贮藏的第三个月内,果糖含量处于最高,而蔗糖和葡萄糖减少趋势不明显。五九香梨果实中的主要有机酸是苹果酸和柠檬酸,整个贮藏期间,柠檬酸和酒石酸含量处于上升趋势,苹果酸和奎宁酸含量在第一、二月贮藏期间增加,而后开始下降;莽草酸含量在贮藏期第一到第三阶段上升,而后略下降;琥珀酸含量在第一到第二阶段变化不明显,接着有上升的趋势,在第三阶段含量达到最高,第四和第五阶段略低于第三阶段;乙酸含量变化不明显。梨果实的硬度略有下降,贮藏的前3个月,可溶性固形物含量有上升的趋势,随后开始缓慢下降。五九香梨的主要香气成分化合物有乙酸己酯 (49.35%),乙酸丁酯 (19.56%),己酸乙酯 (5.16%),丁酸乙酯 (4.92%),乙酸乙酯 (1.08%),(E,Z)-2,4-癸二烯酸乙酯 (0.84%)等。在整个贮藏期间,部分香气成分随着贮藏期的延长而略有增加,尤其是酯类化合物。结果显示：果实硬度、可溶性固形物、糖、有机酸和香气的组成与变化对五九香梨果实的品质都有一定的影响。     

Chemical characterization of lignin and lipophilic fractions from leaf fibers of curaua (Ananas erectifolius)

The chemical composition of leaf fibers of curaua (Ananas erectifolius), an herbaceous plant native of Amazonia, was studied. Special attention was paid to the content and composition of lignin and lipophilic compounds. The analysis of lignin in the curaua fibers was performed in situ by pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) and showed a lignin composition with a p-hydroxyphenyl:guaiacyl:syringyl units (H:G:S) molar proportion of 30:29:41 (S/G molar ratio of 1.4). The presence of p-hydroxycinnamic acids (p-coumaric and ferulic acids) in curaua fibers was revealed upon pyrolysis in the presence of tetramethylammonium hydroxide. On the other hand, the main lipophilic compounds, analyzed by GC/MS, were series of long-chain n-fatty acids, n-fatty alcohols, alpha- and omega-hydroxyacids, monoglycerides, sterols, and waxes. Other compounds, such as omega-hydroxy monoesters and omega-hydroxy acylesters of glycerol, were also found in this fiber in high amounts.     

Identification of betalains from yellow beet (Beta vulgaris L.) and cactus pear [Opuntia ficus-indica (L.) Mill.] by high-performance liquid chromatography-electrospray ionization mass spectrometry

Betaxanthins, the yellow-orange water-soluble pigments from yellow beet (Beta vulgaris ssp. vulgaris cv. Bejo Zaden) and cactus pear (Opuntia ficus-indica cv. Gialla) have been investigated using an HPLC system compatible with mass spectrometry. Five novel betaxanthins were found and characterized as the immonium adducts of betalamic acid with serine, gamma-aminobutyric acid, valine, isoleucine, and phenylalanine. To enable concentration of betalain samples, desalting was performed by solid-phase extraction. With this technique, betacyanins could be separated from the betaxanthins using the pH-dependent retention characteristics of red and yellow betalains. The betaxanthin fraction was taken for the preparation of betalamic acid as a precursor for semisynthetic standards. The HPLC method was applied to yellow beet and cactus pear, revealing a more complex betalain profile than described earlier, thus proving its suitability for screening of betaxanthin-containing plants as potential sources for natural food colors.