Effect of <Emphasis Type=Italic>Carica papaya</Emphasis> and <Emphasis Type=Italic>Cucumis melo</Emphasis> seed oils on the soybean oil stability

This study aimed to evaluate the oils of soybean (S), papaya (Pa) and melon (Me) seeds and compounds oils SPa (80:20 w/w); SMe (80:20 w/w); and SPaMe (60:20:20 w/w/w) subjected to thermoxidation. Compound oils showed lower percentages of free fatty acids in relation to others, after 20 h. With the heating process, there was an increase in the quantity of saturated and monounsaturated acids. The quantity of carotenoids decreased, except in papaya seed oil that presented significant amount of carotenoids in 20 h. In relation the tocopherols, highlighted the presence of γ-tocopherol, except in the papaya oil. In 20 h, SMe and SPa still showed high amounts of tocopherols, with 76 and 85% of retention, respectively. With the thermoxidation, the amounts of phytosterols decreased. A great potential can be verified for the use of papaya and melon seed oils, in order to increase the oxidative stability of the soybean oil.     

Volatile flavor composition of <Emphasis Type=Italic>gamguk</Emphasis> (<Emphasis Type=Italic>Chrysanthemum indicum</Emphasis>) flower essential oils

The volatile composition of the essential oil from fresh gamguk (Chrysanthemum indicum) flowers was investigated. The volatile constituents were extracted by the hydro distillation method. Volatile compositional changes of gamguk prepared via different drying methods (shade- and freeze-drying methods) were also determined. Total 36, 63, and 55 volatiles constituents were confirmed in the essential oil from fresh and shade-, and freeze-dried flowers. Ketones were predominant in the volatiles of gamguk flowers (%): fresh, 43.8; shade dried, 30.3; and freeze dried, 36.1. Camphor was the most abundant volatile component in all samples, and the content of borneol was also remarkable. The content of camphor was higher in fresh sample than those of dried samples while borneol concentration was significantly increased in the dried samples.     

<Emphasis Type=Italic>In vitro</Emphasis> characterization study of <Emphasis Type=Italic>Bacillus mojavensis</Emphasis> KJS-3 for a potential probiotic

The identification and characterization of Bacillus mojavensis KJS-3 was performed by in vitro tests. A 16S rDNA sequence and phylogenetic tree demonstrated that this isolate belongs to the B. mojavensis group. B. mojavensis KJS-3 supplies nutrients by synthesizing several vitamins. B. mojavensis KJS-3 produces α-amylase and protease. B. mojavensis KJS-3 is cultured well under aerobic conditions without gas production. B. mojavensis KJS-3 allows for assimilation of cholesterol and bile salt hydrolase activity. Finally, adhesion experiments using Caco-2 cells revealed that the adherence of B. mojavensis KJS-3 to Caco-2 cells was approximately 51.2±8.14%.     

Disinfection effect and its mechanism of electrolyzed oxidizing water on spores of <Emphasis Type=Italic>Bacillus subtilis</Emphasis> var. <Emphasis Type=Italic>niger</Emphasis>

A study was carried out on the disinfection efficiency of electrolyzed oxidizing water (EOW) on spores of Bacillus subtilis var. niger. The results showed a remarkable fungicidal rate of 100% after 20 min duration of 191 mg/L active available chlorine (ACC). The disinfection effect was improved with increased ACC or prolonged disinfection time, while organic interferents exerted a strong concentration-dependent inhibition against the disinfection. The disinfection mechanism was also investigated at bio-molecular level. EOW decreased dehydrogenase activity, intensified membrane permeability, elevated suspension conductivity, and caused leakage of intracellular K⁺, proteins, and DNA, indicating a damage of cell walls and membranes. Effects of EOW on microbiological ultra-structures were also verified by transmission electronic microscopy (TEM) images, showing that EOW destroyed protective barriers of the microbe and imposed some damages upon the nucleus area.     

Analysis of Intracellular pH in <Emphasis Type=Italic>Escherichia coli</Emphasis> O157:H7 to Determine the Effect of Chlorine Dioxide Decontamination

The aim of this study was to investigate the response of Escherichia coli O157:H7 when exposed to different concentrations of sanitation agent chlorine dioxide (ClO₂) by determining intracellular pH (pH_i). For this purpose, fluorescence ratio imaging microscopy was used together with pH-sensitive, ratiometric green fluorescent protein that was introduced in E. coli O157:H7 cells. Along with pH_i, colony counts were determined during the treatment with ClO₂. Results revealed several post-treatment subpopulations with different physiological states, as judged by their pH_i. The fraction of cells with no pH gradient increased, and the colony count decreased as the concentration of ClO₂ increased.     

Optimization of carotenoids by <Emphasis Type=Italic>Rhodotorula glutinis</Emphasis>

Response surface methodology was applied to maximize the yield and productivity of carotenoids by Rhodotorula glutinis strain 1151 using supplemented tomato waste based medium. Higher concentration of tomato waste extract and yeast extract favored the production of carotenoids. In contrast to carotenogenesis higher concentration of yeast extract negatively affected the formation of biomass whereas higher amount of glucose in the medium favored biomass indicating that carotenogenesis is not correlated to biomass. The optimal concentration of medium components for maximum total carotenoids and corresponding biomass production as obtained from model were calculated to be as 660 mL/L, 1.5, 4.5, 7.4, and 10 g/L for tomato extract, malt extract, yeast extract, peptone, and glucose, respectively.     

Cold-adapted structural properties of trypsins from walleye pollock (<Emphasis Type=Italic>Theragra chalcogramma</Emphasis>) and Arctic cod (<Emphasis Type=Italic>Boreogadus saida</Emphasis>)

Complementary DNA clones encoding trypsins were isolated from pyloric ceca of cold-adapted fish, walleye pollock (Theragra chalcogramma) (WP-T) and Arctic cod (Boreogadus saida) (AC-T). The isolated full-length cDNA clones of WP-T and AC-T were 852 and 860 bp, respectively, and both cDNAs were contained an open reading frame of 726 bp. WP-T and AC-T seemed to be synthesized as preproenzyme that contains a signal peptide, an activation peptide, and a mature trypsin. Although the amino acid sequence identities of WP-T and AC-T to that of bovine trypsin were 64 and 63%, respectively, they completely conserved the structural features for catalytic function of trypsin. On the other hand, WP-T and AC-T possessed the four Met residues (Met135, Met145, Met175 and Met242) in their molecules and the deletion of Tyr151 and substitution of Pro152 for Gly in their autolysis loops when aligned with the sequences of tropical-zone fish and bovine trypsins. In addition, the contents of charged amino acid residues at the N-terminal regions (positions 20–50) of WP-T and AC-T were extremely higher than those of other fish and bovine trypsins. Moreover, one amino acid (Asn72) and two amino acids (Asn72 and Val75) coordinating with Ca²⁺ in bovine trypsin were exchanged for another amino acids in WP-T (His) and AC-T (His and Glu), respectively, and the contents of negative charged amino acids at their Ca²⁺-binding regions were lower than those of tropical-zone fish and bovine trypsins. Therefore, it was considered that these structural characteristics of WP-T and AC-T are closely related to their lower thermostability.     

<Emphasis Type=Italic>In silico</Emphasis> phylogenetic analysis of lactic acid bacteria and new primer set for identification of <Emphasis Type=Italic>Lactobacillus plantarum</Emphasis> in food samples

Lactic acid bacteria (LAB) include species very closely related both physiologically and genotypically. Therefore, the identification of this bacteria group using conventional phenotypic methods is ambiguous and cumbersome. In this study, we have analyzed a recA gene fragment from 30 bacteria, including LAB and species common in the human gastrointestinal tract, aiming to evaluate the gene conservation among them and the development of primers and PCR conditions able to discriminate Lactobacillus plantarum strains from LAB closely related. The fragment with 995 bp of recA gene has grouped LAB, enterobacteria and bifidobacteria, in different clusters. A novel primer pair, LPrecAF and LPrecAR with 23 and 18 bp, respectively, has allowed the single amplification of a 108 bp fragment of L. plantarum strains contained in culture broth and fermented dairy samples. The observed detection limit for food samples and for cultures broth were 1 × 10³ and 7 × 10² CFU mL⁻¹, respectively. This approach proved to be a simple and efficient method for the identification and monitoring of L. plantarum in food, feeds, and culture broth. Moreover, the assay could be used in the studies from human or environmental microbiota.     

Influence of Pretreatments on Quality Parameters and Nutritional Compounds of Dried Galega Kale (<Emphasis Type=Italic>Brassica oleracea</Emphasis> L. var. <Emphasis Type=Italic>acephala</Emphasis>)

The objective of this work was to evaluate the effect of six pretreatments on quality and nutritional contents of sliced Galega kale submitted to convective drying. Among all treatments, steam blanching was the most favourable, allowing improvements in retention of vitamin C, total antioxidant capacity and chlorophylls in comparison to the absence of pretreatment. Total phenolic losses were not reduced by steam blanching, but the retention was improved by combining this approach with a previous immersion in a metabisulphite solution. Moreover, steam blanching improved the colour parameters and appearance, providing a final dried product more similar to the fresh sample.     

Effect of pH,solar irradiation,and semiconductor concentration on the photocatalytic disinfection of <Emphasis Type=Italic>Escherichia coli</Emphasis> in water using nitrogen-doped TiO<Subscript>2</Subscript>

Photocatalytic activity of UV+visible-activated nitrogen-doped titanium dioxide catalyst was tested for Escherichia coli ATCC 25922 inactivation. A further aspect of this work was to evaluate the effect of selected parameters (pH, irradiation type, and nitrogen-doped TiO₂ concentration) on the disinfection efficiency. The following conditions were tested: complete solar radiation (UV–visible) and visible solar radiation alone, four different concentrations of catalyst (0.0, 0.10, 0.25, and 0.5 mg/mL), and six pH values (6.0, 6.5, 7.0, 7.5, 8.0, and 8.5). Dark conditions were used as control experiments. Disinfection process was enhanced under irradiation when the nitrogen-doped photocatalyst was added into the solution. Lower accumulated energy along with higher inactivation rates was observed in the experiments testing nitrogen-doped TiO₂ in comparison with the results obtained on the samples without the catalyst. The disinfection effect of the photocatalyst was found depending on the radiation type. pH value has an important role in the inactivation mechanisms that seems to be related with the cell wall permeability and with particle’s surface charge. pH values 6.5 and 8.0 improve the antimicrobial efficiency of the catalyst tested, whereas pH 7 was identified as the less favorable conditions for microbial inactivation.     

Identification of European commercial cockles (<Emphasis Type=Italic>Cerastoderma edule</Emphasis> and <Emphasis Type=Italic>C. glaucum</Emphasis>) by species-specific PCR amplification of the ribosomal DNA ITS region

We present a novel one-step PCR method for the identification of Cerastoderma edule and C. glaucum. Sequence differences found in the internal transcribed spacer region (ITS) of the ribosomal DNA of the two cockles allowed us to design two species-specific reverse primers. These two primers were used in a multiplex reaction, together with a forward universal primer to amplify specific fragments with different lengths in each cockle (190 and 470 bp in C. edule and C. glaucum, respectively). The successful and specific amplifications obtained for two natural populations in each species as well as in canned products lend support to the usefulness of these markers.     

Effect of ionic liquid-containing system on betulinic acid production from betulin biotransformation by cultured <Emphasis Type=Italic>Armillaria luteo</Emphasis>-<Emphasis Type=Italic>virens</Emphasis> Sacc cells

The aim of this study is to develop an ionic liquid-containing system for efficient production of betulinic acid by cultured cells Armillaria luteo-virens Sacc ZJUQH100-6. Several parameters affecting betulinic acid formation in the IL-containing system were investigated. The addition of [EMIM][BF₄] in hexane-containing reaction medium gave rise to better betulinic acid formation in comparison with other ILs used. The optimal concentration of IL in IL-containing co-solvent system is 50% (v/v). As a co-substrate, butanol is found to be useful for intracellular betulin-28-monooxygenase synthesis during the whole phase. The concentrations of substrate and resting cells have been found to exert a significant effect on betulinic acid. Moreover, the reaction time in this IL-containing system was less than that in the conventional one. The effect of the constructed IL-containing system on cell membrane structure was comparatively observed. Under the developed IL-containing system, the highest yield of product observed was 11.14% at 18 h, higher than that in monophase aqueous one (P < 0.05), whereas the activity of monooxygenase showed the same variation as betulinic acid formation.     

Selection of elderberry (<Emphasis Type=Italic>Sambucus nigra</Emphasis> L.) genotypes best suited for the preparation of juice

Experiments with elderberry genotypes, ripening stage and pectinolysis were carried out in order to investigate the possibility to improve different quality characteristics of elderberry juice. Raw juice was processed using either an optimised method with respect to enzyme concentration and treatment time or produced directly without any enzymatic treatment. Neochlorogenic acid, chlorogenic acid, cyanidin-3-sambubioside-5-glucoside, cyanidin-3,5-diglucoside, cyanidin-3-sambubioside, cyanidin-3-glucoside, quercetin-3-rutinoside (rutin) and quercetin-3-glucoside (isoquercitrin) were identified in the raw juice by liquid chromatography-mass spectrometry (LC-MS) and quantified by high-performance liquid chromatography-diode array detection (HPLC-DAD). The content of phenolic acids and flavonoids in elderberries were shown to be affected by berry development stage at harvest (ripening stage). Furthermore, a considerable variation in juice yield and physicochemical properties such as turbidity, soluble solids, titratable acidity, and content of phenolic acids and flavonoids was found between juices processed from elderberries by pectinolysis of different elderberry genotypes. Pectinolysis appeared not to have any major effect on juice yield and the content of phenolic acids and flavonoids in the juice compared to non-enzymatic processed juice. Factor analysis revealed correlations among quality characteristics such as soluble solids, titratable acidity, turbidity, and content of phenolic acids and flavonoids and it is shown that these correlations may be useful for the selection of elderberry genotypes best suited for the preparation of juice.     

Purification of <Emphasis Type=Italic>S</Emphasis>-Alk(en)yl alka/enethiosulfinates of garlic (<Emphasis Type=Italic>Allium sativum</Emphasis> L.) by using recycling preparative HPLC

S-Alk(en)yl alka/enethiosulfinates formed in crushed garlic were purified by using recycling preparative HPLC. Allyl 2-propenethiosulfinate and methyl methanethiosulfinate were effective separated because no other thiosulfinates were coeluted with them. Allyl methanethiosulfinate and methyl 2-propenethiosulfinate, trans-1-propenyl methanethiosulfinate and methyl trans-1-propenethiosulfinate, (cis)- and (trans)-1-propenyl 2-propenethiosulfinate were eluted as 1 peak, respectively, and further separated by using additional kinds of column. Since the quantity of trans-1-propenyl trans-1-propenethiosulfinate (PPTHS) was small in garlic, PPTHS was isolated from a mixture of blanched onion homogenate and garlic alliinase and purified. Purified thiosulfinates can be employed for the study of antimicrobial activity, flavor, and greening of garlic.     

Investigation of dyes degradation intermediates with <Emphasis Type=Italic>Scytalidium thermophilum</Emphasis> laccase

Scytalidium thermophilum laccase was able to successfully decolourise Congo Red, Bromo-Cresol Green, Malachite Green, Phenol Red and Indigo Carmine under optimised conditions. The cited dyes belonging to three different classes were named azo, triarylmethane and indigoid. The decolourisation rates were 100, 95, 76, 57 and 22 mg h⁻¹ U⁻¹ for Indigo Carmine, Malachite Green, Bromo-Cresol Green, Congo Red and Phenol Red, respectively. The degradation products were characterised by UV–vis and FT-IR techniques, and their cytotoxicity was monitored. UV–visible absorption spectra and FT-IR analysis showed a complete degradation of Congo Red, Bromo-Cresol Green and Malachite Green, a partial degradation of Phenol Red and a transformation of Indigo Carmine. Toxicity study revealed that most of the treated dyes were less toxic than those before treatment, especially for Malachite Green. In fact, Scytalidium thermophilum laccase degraded Malachite Green into non-toxic products. Scytalidium thermophilum laccase constitutes a powerful tool for effective bioremediation of rich-dye textile effluents and was, therefore, found worthy of investigation for potential applications in restoration work and other biotechnological uses.     

Effect of Centrifugation Conditions on the Cryotolerance of <Emphasis Type=Italic>Lactobacillus bulgaricus</Emphasis> CFL1

As the concentration step is usually considered to be responsible for cell damage, the objective of this work was to quantify the effect of centrifugation conditions (speed, duration, temperature, and pH) on the quality of Lactobacillus bulgaricus CFL1 starters. These effects were analyzed on the specific acidification activity of the cells, according to experimental designs. It is surprising to note that centrifugation conditions did not significantly affect the loss of specific acidification activity during the concentration step. In contrast, centrifugation speed and duration slightly altered cell resistance to freezing and frozen storage. No difference was observed when centrifugation was conducted at 4 or 15 °C. Finally, combining good centrifugation conditions to an acidification of the cells in their fermented broth strongly improved their cryotolerance. These results may have an impact for industrial starter production as they allowed modifying centrifugation conditions to better match the specificity and the viscosity of the medium.