Detection and assessment of citrus tristeza virus antigens by computer-aided scanning densitometry

Citrus tristeza virus (CTV) extracted from Etrog citron (C.medica L.) was immunoprecipitated. The immunoprecipitate was fractionated by SDS-PAGE and western blotted onto nitrocellulose. The CTV antigens were determined by immunoblot analysis using rabbit anti-CTV IgG, and the protein-band pattern exhibited on the nitrocellulose was assessed by soft-laser scanning densitometry. The densitometric tracing revealed the presence of bands that were not visible to the naked eye. Using the superimposition mode of the instrument, it was also revealed that the protein-band patterns of different CTV samples were not identical. Computer-aided soft-laser scanning densitometry proved to be a powerful approach in the detection and assessment of protein bands revealed on nitrocellulose immunoblots, which we were previously unable to do employing conventional methods.     

The efficacy and progress in using radiation as a quarantine treatment of tropical fruits—a case study in Hawaii

Most tropical fruits for export must be treated with an approved quarantine treatment. Three and a half decades of research have demonstrated the efficacy of irradiation as a quarantine treatment in terms of efficiency, effectiveness, and product quality retention. The USFDA and the USDA-APHIS approved irradiation to disinfest fresh foods/fresh papayas in 1986 and 1989, respectively. In early 1995, the Hawaii Department of Agriculture was granted a special permit from USDA-APHIS allowing untreated Hawaiian fruits to be irradiated on the US mainland. The objectives were to gain experience in commercial irradiation as a quarantine treatment and to gather data on shipping and handling procedures, and on product quality. In April 1995, the first shipment of Hawaiian fruit was irradiated at a minimum quarantine dose of 0.25 kGy in an Isomedix plant near Chicago, and then distributed to supermarkets in Illinois and Ohio. Continuous shipments, irradiation, and marketing of various tropical fruits in the US have shown commercial efficacy, quality retention, and excellent consumer acceptance. A commercial e-beam/converted X-ray facility was installed by Titan Corp. on the Island of Hawaii and was operational by late July 2000. Hawaii has become the first place in the world to use irradiation as a quarantine treatment of fruits.     

Novel synthesis of Planococcus citri pheromone

An effective method was proposed for synthesizing (+)-cis-1R-acetoxymethyl-3-isopropenyl-2,2-dimethylcyclobutane, a pheromone of the citrus mealybug, based on ozonolysis of verbenone that led in one step to the key synthon 1R,3S-3-acetyl-2,2-dimethylcyclobutanecarboxylic acid. __________ Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 179–180, March–April, 2006.     

Production and Purification of Pectinase from Bacillus subtilis 15A-B92 and Its Biotechnological Applications

Enzymes that degrade pectin are called pectinases. Pectinases of microbial origin are used in juice clarification as the process is cost-effective. This study screened a pectinase-producing bacterium isolated from soil and identified as Bacillus subtilis 15A B-92 based on the 16S rRNA molecular technique. The purified pectinase from the isolate showed 99.6 U/mg specific activity and 11.6-fold purity. The molecular weight of the purified bacterial pectinase was 14.41 ± 1 kD. Optimum pectinase activity was found at pH 4.5 and 50 °C, and the enzyme was 100% stable for 3.5 h in these conditions. No enzymatic inhibition or activation effect was seen with Fe²⁺, Ca²⁺, or Mg²⁺. However, a slight inhibition was seen with Cu²⁺, Mn²⁺, and Zn²⁺. Tween 20 and 80 slightly inhibited the pectinase, whereas iodoacetic acid (IAA), ethylenediaminetetraacetate (EDTA), urea, and sodium dodecyl sulfate (SDS) showed potent inhibition. The bacterial pectinase degraded citrus pectin (100%); however, it was inactive in the presence of galactose. With citrus pectin as the substrate, the Km and Vmax were calculated as 1.72 mg/mL and 1609 U/g, respectively. The high affinity of pectinase for its substrate makes the process cost-effective when utilized in food industries. The obtained pectinase was able to clarify orange and apple juices, justifying its application in the food industry.     

固相萃取气相色谱法测定水果中克菌丹和灭菌丹

采用硅镁吸附剂和硅胶作为混合固相萃取的净化方法,建立了固相萃取气相色谱法同时测定水果中克菌丹和灭菌丹的分析方法。研究了多种固相萃取柱和不同洗脱溶剂对克菌丹和灭菌丹保留行为的影响,优化了固相萃取净化方法及样品提取方法的分析条件。用GC-ECD检测,两种农药在0.05～2.0mg/L浓度范围内呈线性关系,相关系数大于0.997。苹果中4个浓度克菌丹和灭菌丹的加标回收率分别在100%～111%和104%～113%之间,RSD在3.0%～7.2%和2.8%～4.2%之间。在菠萝、草莓、梨和橙子中,克菌丹的平均回收率和RSD分别在95.6%～112%和2.5%～7.5%之间;灭菌丹在82.5%～96.4%和3.3%～8.0%之间,克菌丹和灭菌丹的方法检出限分别为0.012mg/kg和0.0056mg/kg。     

Residues Analysis of Post-Harvest Imidazole Fungicides in Citrus Fruit by H PLC and GLC

Abstract

The determination of imazalil and prochloraz fungicide residues has been carried out by HPLC with an UV detector at 204 nm and by GLC with an electron capture detector (ECD).

In both cases fungicide residues were extracted with hexane/acetone (90:10, v/v) after pH adjustment and purified by a liquid-liquid partitioning process. When HPLC was used for prochloraz and imazalil analysis, it was necessary to eliminate the interfering substances with a further clean-up process. This was also required when samples with low residue levels were analyzed by GLC.

Recovery was always higher than 70%. The detection limit was 0.04 ppm for the HPLC method and 0.02 for the GLC method.

Imazalil and prochloraz residues in “Washington Navel” oranges and “Hernandina” clementine fruits, dipped in a 1000 ppm fungicide solution, are reported.     

Antioxidative and Anti-Inflammatory Phytochemicals and Related Stable Paramagnetic Species in Different Parts of Dragon Fruit

In this study, we investigated the antioxidant and anti-inflammatory phytochemicals and paramagnetic species in dragon fruit using high-performance liquid chromatography (HPLC) and electron paramagnetic resonance (EPR). HPLC analysis demonstrated that dragon fruit is enriched with bioactive phytochemicals, with significant variations between each part of the fruit. Anthocyanins namely, cyanidin 3-glucoside, delphinidin 3-glucoside, and pelargonidin 3-glucoside were detected in the dragon fruit peel and fresh red pulp. Epicatechin gallate, epigallocatechin, caffeine, and gallic acid were found in the dragon fruit seed. Additionally, 25–100 mg × L⁻¹ of dragon fruit pulp and peel extracts containing enrichment of cyanidin 3-glucoside were found to inhibit the production of reactive oxygen species (ROS), reactive nitrogen species (RNS), inducible nitric oxide synthase (iNOS), and cyclooxygenase-2 (COX-2) in cell-based studies without exerted cytotoxicity. EPR primarily detected two paramagnetic species in the red samples. These two different radical species were assigned as stable radicals and Mn²⁺ (paramagnetic species) based on the g-values and hyperfine components. In addition, the broad EPR line width of the white peel can be correlated to a unique moiety in dragon fruit. Our EPR and HPLC results provide new insight regarding the phytochemicals and related stable intermediates found in various parts of dragon fruit. Thus, we suggest here that there is the potential to use dragon fruit peel, which contains anthocyanins, as a natural active pharmaceutical ingredient.     

Physicochemical Characterization,Antioxidant Capacity,and Sensory Properties of Murici (Byrsonima crassifolia (L.) Kunth) and Taperebá (Spondias mombin L.) Beverages

Amazonian fruits are excellent sources of bioactive compounds and can be used in beverages to improve the nutritional and sensorial characteristics. The present study aimed to develop a blend of murici (Byrsonima Crassifolia (L.) Kunth) and taperebá (Spondias Mombin L.) through experimental design and investigating the nutritional and sensorial characteristics of fruits and beverages. The murici was highlighted as higher vitamin C content (58.88 mg · 100 g⁻¹) compared to taperebá (25.93 mg · 100 g⁻¹). The murici and taperebá are good sources of total phenolic compounds (taperebá 1304.15 ± 19.14 mgGAE · 100 g⁻¹ and the murici of 307.52 ± 19.73 mg GAE · 100 g⁻¹) and flavonoids (174.87 ± 1.76 μgQE/g and 129.46 ± 10.68 μgQE/g, murici and taperebá, respectively), when compared to other Brazilian fruits. The antioxidant capacity in different methods revealed that the taperebá had a higher average in the results, only in the ORAC method and did not present a significant difference (p > 0.05) in relation to the murici. The beverage development was performed using experimental design 2³, showed through sensory analysis and surface response methodology that murici and high sugar content (between 12.5 and 14.2% of sugar) influenced in sensory acceptance. Our findings indicate that beverages with improved nutrition and a sensory acceptance can be prepared using taperebá and murici fruits.     

Superior Antibacterial Activity of Integral Lemon Pectin Extracted via Hydrodynamic Cavitation

Pectin extracted via hydrodynamic cavitation in water only from waste lemon peel and further isolated via freeze drying displays significant antibacterial activity against Staphylococcus aureus, a Gram positive pathogen which easily contaminates food. The antibacterial effect of the new IntegroPectin is largely superior to that of commercial citrus pectin, opening the way to advanced applications of a new bioproduct now obtainable in large amounts and at low cost from citrus juice industry's waste.     

Carbohydrate Hydrolase-Inhibitory Activity of Juice-Based Phenolic Extracts in Correlation to Their Anthocyanin/Copigment Profile

Red fruits and their juices are rich sources of polyphenols, especially anthocyanins. Some studies have shown that such polyphenols can inhibit enzymes of the carbohydrate metabolism, such as α-amylase and α-glucosidase, that indirectly regulate blood sugar levels. The presented study examined the in vitro inhibitory activity against α-amylase and α-glucosidase of various phenolic extracts prepared from direct juices, concentrates, and purees of nine different berries which differ in their anthocyanin and copigment profile. Generally, the extracts with the highest phenolic content—aronia (67.7 ± 3.2 g GAE/100 g; cyanidin 3-galactoside; chlorogenic acid), pomegranate (65.7 ± 7.9 g GAE/100 g; cyanidin 3,5-diglucoside; punicalin), and red grape (59.6 ± 2.5 g GAE/100 g; malvidin 3-glucoside; quercetin 3-glucuronide)—showed also one of the highest inhibitory activities against α-amylase (326.9 ± 75.8 μg/mL; 789.7 ± 220.9 μg/mL; 646.1 ± 81.8 μg/mL) and α-glucosidase (115.6 ± 32.5 μg/mL; 127.8 ± 20.1 μg/mL; 160.6 ± 68.4 μg/mL) and, partially, were even more potent inhibitors than acarbose (441 ± 30 μg/mL; 1439 ± 85 μg/mL). Additionally, the investigation of single anthocyanins and glycosylated flavonoids demonstrated a structure- and size-dependent inhibitory activity. In the future in vivo studies are envisaged.