Effect of Solids Concentration on the Physicochemical and Flow Properties of Cactus Pear Juices of Two Varieties (<Emphasis Type="Italic">Opuntia ficus-indica</Emphasis> and <Emphasis Type="Italic">Opuntia streptacantha</Emphasis>)

Juices from two varieties of cactus pear, a green (Opuntia ficus-indica) and a red (Opuntia streptacantha), were obtained and concentrated by evaporation. Both fruit varieties and their juices at different concentrations were characterized. Green cactus pears had significantly higher amount of pulp than red cactus pears; the peel of O. ficus-indica represented only 38 versus 52 % of the fruit for the O. streptacantha. Both varieties had no significant differences on moisture, density, pH, and titratable acidity, in contrary to soluble solids. Juice was concentrated under vacuum conditions to reach a final concentration of 42, 53–55, and 58–60 °Brix, respectively, and stored under refrigeration (10 °C) during 4 weeks. Physicochemical properties of the pears and juices were determined as fresh items (time zero) and every week for the concentrate juices through storage; similarly, flow parameters were measured at 10 and 25 °C. Concentrate density (1160–1283 kg/m³) was mainly affected by final soluble solids, while pH and acidity were affected differently depending on the variety. Concentrated juices at 42 °Brix were considered with Newtonian behavior with a viscosity of 2–22 mPa s, while those at higher concentrations were of pseudoplastic nature (n < 1.0 and K > 69 mPa sⁿ). Power Law model fitted better the flow behavior than Herschel-Bulkley model of concentrates of both varieties. Temperature, solid concentration, and/or storage time affected the consistency coefficient (K) and flow index (n) depending on the cactus pear variety. Overall, those concentrated juices from O. streptacantha were more stable and exhibited lower apparent viscosity.     

Inhibitory efficacy of Ligularia fischeri against aldose reductase and advanced glycation end products formation

The efficacy of Ligularia fischeri (LF) for managing diabetic complications was evaluated by assessing inhibitory effects against advanced glycation end product (AGE) formation, rat lens aldose reductase (RLAR), and 1,1-diphenyl-2-picryl hydrazyl (DPPH) radical scavenging. The ethyl acetate fraction from 70% ethanol extracts of LF showed the highest DPPH radical scavenging activity of 53.90% at a concentration of 3.3 μg/mL. The ethyl acetate fraction exhibited the most potent AGE formation inhibition of 73.57% at a concentration of 55 μg/mL and showed the most potent RLAR inhibition of 88.97% at a concentration of 11.11 μg/mL. The ethyl acetate fraction exhibited the most potent antioxidant and anti-diabetic effects. Nuclear magnetic resonance via bioactivity-guided fractionation of the LF ethyl acetate fraction revealed that 3,4-dicaffeoylquinic acid was the bioactive compound. This compound from LF can be effective for prevention or treatment of diabetic complications.     

Estrogenic effects of various extracts from <Emphasis Type="Italic">Chamdanggui</Emphasis> (<Emphasis Type="Italic">Angelica gigas</Emphasis> Nakai) and <Emphasis Type="Italic">sogdan</Emphasis> (<Emphasis Type="Italic">Phlomis umbrosa</Emphasis> Turcz)

The various extracts from chamdanggui (Angelica gigas Nakai) and sogdan (Phlomis umbrosa Turcz) were evaluated for estrogenic activity and characterized according to HPLC profile. Chamdanggui and sogdan were individually extracted with 4 solvents (hot water, 70% ethanol, n-butanol, and dichloromethane) of differing polarities. Estrogenic activity was determined by E-screen using an estrogen-dependent MCF-7 BUS cell. Although almost all extracts showed estrogenic effects in a concentrationdependent manner, the hot water extract from chamdanggui (250 μg/mL) had the higher effect (138%). Among 90 fractions using HPLC separation of the hot water extract from chamdanggui, fraction 21 and 28 produced the highest estrogenic effects of 178 and 163% at 10 μg/mL, respectively. The results imply that the hot water extract from chamdanggui could be useful as an alternative hormone replacement therapy.     

Conventional and Microwave-Assisted Extraction of Mucilage from <Emphasis Type="Italic">Opuntia ficus-indica</Emphasis> Cladodes: Physico-Chemical and Rheological Properties

Cactus pear cladodes processing has potential value for mainstream industries and is equally important for marginal rural communities in arid regions. This work is focused on physico-chemical and rheological properties of Opuntia ficus-indica (OFI) peeled cladodes extracted by conventional method “CE” and using microwave-assisted extraction “MAE.” MAE gave the highest yield extraction (8.13 %, w/w) within the lowest extraction time (500 W/7 min) and provided more protein (×1.03) and carbohydrates (×1.51) than CE. The monosaccharides detected by gas chromatography were arabinose, galactose, rhamnose, xylose, and galacturonic acid. The dialyzed mucilage solution characterized by SEC/MALS/VD/DRI (size-exclusion chromatography coupled with online multi-angle light scattering, viscometer detectors, and differential refractive index) revealed fractions with molecular weight (M _w ) ranging from 15.3–15.7?×?10⁶ g mol^?1 for the CE extracts and about 16.7–17.5?×?10⁶ g mol^?1 for the MAE extracts. Dynamic oscillatory testing has been used to study the rheological properties of mucilage solution within the concentration of 0.50–3.00 % (w/v) at 25 °C. The rheological profiles of CE and MAE showed similar behavior. At low frequency and low mucilage concentration (<2.00 %), the viscous component (G") predominated over the elastic component (G'), while for higher frequencies, the behavior is reversed (G'?>?G"). If safely controlled, alternative energies like microwaves could extract soluble polymers with comparable properties to commercial ones, conventionally extracted.     

Tyramine production of technological important strains of <Emphasis Type="Italic">Lactobacillus</Emphasis>, <Emphasis Type="Italic">Lactococcus</Emphasis> and <Emphasis Type="Italic">Streptococcus</Emphasis>

The aim of this paper was to study the biogenic amines (histamine, tyramine, putrescine, cadaverine, agmatine, spermine and spermidine) production of selected technological important lactic acid bacteria (strains of the genera Lactococcus, Lactobacillus and Streptococcus). Three methods (ion-exchange chromatography (IEC), PCR and cultivation method with pH indicator) were used. Within the 39 strains of lactic acid bacteria tested, the production of tyramine (formed by tyrosine decarboxylase) was detected in eight strains (3 strains of Lactococcus lactis subsp. lactis, three strains of Lactococcus lactis subsp. cremoris, 1 strain of Streptococcus thermophilus and 1 strain of Lactobacillus delbrueckii subsp. bulgaricus). The other tested biogenic amines were not detected. Cultivation in decarboxylation broth seems to be the least accurate method for the detection of biogenic amines due to enhanced risk of false-positive reactions. Therefore, in order to detect bacteria producing biogenic amines, the combination of PCR and chromatographic methods (e.g. IEC) can be recommended.     

Molecular diversity among natural populations of <Emphasis Type="Italic">Lactobacillus paracasei</Emphasis> and <Emphasis Type="Italic">Lactobacillus plantarum</Emphasis>/<Emphasis Type="Italic">paraplantarum</Emphasis> strains isolated from autochthonous dairy products

The diversity of 87 Lactobacillus paracasei and Lactobacillus plantarum/paraplantarum strains, previously identified from different autochthonous dairy products, was investigated by phenotypic and genotypic approaches. The increased resolution obtained using phenotypic and genotypic characterization allowed the level of strain heterogeneity detection to be widened. Phenotypic diversity was evaluated by studying biochemical characteristics of technological interest, including antimicrobial and proteinase activities, resistance to nisin, aggregation ability, production of exopolysaccharides, acetoin and diacetyl, citrate utilization, and antibiotic susceptibility. Genotypic diversity was generally evaluated by PCR amplification of repetitive bacterial DNA element fingerprinting using the (GTG)₅ primer [(GTG)₅-PCR]. Moreover, in cases where strains were not discriminated by (GTG)₅-PCR combined with phenotypic analysis, pulsed-field gel electrophoresis (PFGE) analysis was performed. The results indicate that L. plantarum/paraplantarum and L. paracasei natural isolates from artisanal dairy products are a gold mine in terms of diversity of strains and could be potentially interesting to dairy companies for the formulation of functional starter cultures in the production of innovative foods.     

Antioxidative effect of cactus pear fruit (<Emphasis Type="Italic">Opuntia ficus-indica</Emphasis>) extract on lipid peroxidation inhibition in oils and emulsion model systems

The lipid peroxidation inhibitory effects of cactus pear fruit (Opuntia ficus-indica) extracts (CPFE) on fish oil, fish oil-in-water emulsion and linoleic acid were studied using conjugated diene hydroperoxides (CDH), weight gaining, peroxide value (PV), and thiobabituric acid reactive substances (TBARS) assays. A modified DPPH assay was used in the characterization of CPFE antioxidants for their thermal stability. CPFE successfully controlled lipid peroxidation at different stages of the pathway in a dose-dependent manner. Inhibition of the lipid peroxidation in oils and emulsion was successfully improved by increasing the level of CPFE from 0.01 to 0.1%. CPFE controlled conjugated diene formation from lipid radicals, demonstrating lower conjugated diene hydroperoxide values than its control counterpart. Moreover, it controlled the addition of oxygen to conjugated dienes to form lipid peroxyl radicals, resulting in lower weight gain. It also recorded a lower PV than its control counterpart, indicating its inhibitory effect on peroxyl radical formation. Such multiple and integrated effects controlled the overall lipid peroxidation, resulting in lower TBARS values than the control. Characterization of the CPFE antioxidants proved that those antioxidants are heat-resistant, although the color of the CPFE pigments disappeared rapidly.     

Influence of autoclave treatment and enzymatic hydrolysis on the antioxidant activity of <Emphasis Type="Italic">Opuntia ficus</Emphasis>-<Emphasis Type="Italic">indica</Emphasis> fruit extract

The objectives of this study were to obtain Opuntia ficus-indica fruit (OFIF) extract by autoclave treatment, to convert the flavonoid glycosides in the autoclave extract (AE) to aglycones by enzymatic hydrolysis, and to compare the antioxidant activity of AE and OFIF extracts obtained by other conventional methods. It was revealed that the total polyphenol and flavonoid content and antioxidant activity of AE were higher than those of water extract but were a slightly lower than those of ethanol extract, which indicates that autoclave treatment might be an efficient extraction method for OFIF. Moreover, it was confirmed that the conversion of various flavonoid glycosides to aglycones in all the OFIF extracts does not significantly affect the antioxidant activities. Therefore, it is extrapolated that the antioxidant activity might be correlated to the intestinal absorption rates and metabolic pathway induction upon oral administration rather than the structure of compound itself.     

Thermal inactivation kinetics of quality-related enzymes in cauliflower (<Emphasis Type="Italic">Brassica oleracea</Emphasis> var. <Emphasis Type="Italic">botrytis</Emphasis><Emphasis Type="Bold">)</Emphasis>

Thermal inactivation of quality-related enzymes in both cauliflower crude enzyme extracts and fresh tissue samples was studied in temperature range 50–100 °C. For crude enzyme extracts, several parameters, reaction rate constants (k) and activation energy (E _a) as well as decimal reduction time (D) and (z) values, were used to characterize the thermal stability. The rates of inactivation were found to follow first-order inactivation kinetics. Activation energies varied between 101.18 and 208.42 kJ mol⁻¹ with z values of 10.59–24.09 °C. The examined kinetics indicated that lipoxygenase was the most heat resistant followed by peroxidase, polyphenol oxidase, pectin methyl esterase and ascorbic acid oxidase. Furthermore, the obtained results from the blanched fresh tissues indicated that inactivation of lipoxygenase secured disappearing of any other enzyme activities. Therefore, this study recommends using lipoxygenase as an indicator enzyme to optimize the thermal treatments of cauliflower products.     

A New Multiplexed Real-Time PCR Assay to Detect <Emphasis Type="Italic">Campylobacter jejuni</Emphasis>, <Emphasis Type="Italic">C. coli</Emphasis>, <Emphasis Type="Italic">C. lari</Emphasis>, and <Emphasis Type="Italic">C. upsaliensis</Emphasis>

A new rapid method based on real-time PCR was developed to detect four thermophilic Campylobacter species (Campylobacter jejuni, Campylobacter coli, Campylobacter lari, and Campylobacter upsaliensis) in food samples. The assay targeted the bipA gene for C. upsaliensis and C. lari, whereas the gene encoding the ATP-binding protein CJE0832 was used to detect C. coli and C. jejuni. These genes were chosen for this assay due to their low variability and mutation rate at a species level. The multiplex PCR showed 100% inclusivity for all 25 thermophilic Campylobacter strains tested and 100% exclusivity for 38 non-targeted strains belonging to closely related species. The newly developed real-time PCR could detect down to 10² genomes/reaction and displayed efficiency above 97% for all species except for C. upsaliensis (90.1%). The method proved to be a reliable tool for food analysis, showing 100% sensitivity, 96% efficiency, and 92.45% specificity when validated against the gold standard method UNE-EN ISO 10272:2006 using 200 diverse food samples (meat, fish, fruits and vegetables, and raw milk). In artificially spiked samples, the detection limit of the method was 10 cfu/g in salad, 5 cfu/g in turkey meat, and 1 cfu/g in the rest of meat samples tested. Consequently, the newly designed molecular tool represents a quick and safe alternative to obtain reliable results concerning the presence/absence of the main thermophilic Campylobacter in any food sample.     

In vivo study of antiallergenicity of ethanol extracts from <Emphasis Type="Italic">Sargassum tenerrimum</Emphasis>, <Emphasis Type="Italic">Sargassum cervicorne</Emphasis> and <Emphasis Type="Italic">Sargassum graminifolium turn</Emphasis>

Food allergy has becoming the serious threat in the world for which the search of an effective anti-allergic drug is the demand of time. Keeping in view of the potentiality of seaweeds, the ethanol extracts from Sargassum tenerrimum (ST), Sargassum cervicorne (SC), and Sargassum graminifolium turn (SG) have been studied in vivo for its antiallergenicity through passive cutaneous anaphylaxis (PCA) and active cutaneous anaphylaxis (ACA) in female BALB/c mice. Intraperitoneal administration of these ethanol extracts inhibit mouse PCA and ACA in a dose-dependent manner using ovalbumin (OVA) and shrimp allergen as triggering agents to induce allergenicity over mice. The extract of ST containing phlorotannin has been found most active over the suppression of PCA triggered by OVA and shrimp with IC₅₀ values of 25.64 and 40.98 mg/kg, respectively and an efficacy comparable to that of an anti-allergic drug disodiumcromoglycate. Similarly, ST inhibits ACA triggered by ova and shrimp allergen in the mouse, with 50% suppression at 25.5 and 43.53 mg/kg, respectively. The results presented here show that these extracts are active on the studied models among which ethanol extract of ST was the most potent, leading toward the promising development of a new class of anti-allergic drugs.     

Characterization and transformation of the <Emphasis Type="Italic">Opuntia ficus indica</Emphasis> fruits

Opuntia ficus indica fruits have been associated with health effects, due to their protective actions against oxidation. Nevertheless, few studies about processing of Opuntia fruits are available’; therefore, we studied the pulp characteristics and processing of a local variety, for producing beverage nectars. The pulp had an average pH of 5.64, 13.47 °Brix, with total sugars (106 g L^?1), K (1180 mg L^?1), 503.3 µg L^?1 of β carotene, 120 mg L^?1 of total phenolic compounds, 4.9 mg and 46.9 mg L^?1 respectively for betacyanins and betaxanthins and 243.4 mg L^?1 of vitamin C. The formulated nectars with 35% of pulp (N35) and 45% of pulp (N45) had respectively 14 and 15 °Brix. Minor components represent 1109 and 1112 mg L^?1 of K for N35 and N45 respectively, β carotene (318.6 µg and 362.8 µg L^?1), and vitamin C 227 and 231 mg L^?1. We confirmed the stability and acceptability of these beverages after a month of storage, after stability and panel tests. Therefore, we suggest that the pulp processing can be used as a new form of agro industrial utilization of this underutilized fruit.     

Pressurized acidified water extraction of black carrot [<Emphasis Type="Italic">Daucus carota</Emphasis> ssp. <Emphasis Type="Italic">sativus</Emphasis> var. <Emphasis Type="Italic">atrorubens</Emphasis> Alef.] anthocyanins

The anthocyanins present in black carrot were extracted with pressurized water acidified with sulfuric, citric and lactic acids. Anthocyanin degradation became significant above 100 °C and there was no improvement when extraction pressure was increased to 100 bar. Therefore, the extraction from black carrot was carried out at temperatures 50, 75 and 100 °C under 50 bar pressure. The extraction efficiencies in terms of acylated and non-acylated anthocyanins were comparable for all three acids used to acidify water at 50 °C, while similar results were observed at 75 °C for both citric and lactic acids. Water acidified with lactic acid showed significantly higher extraction efficiency at 100 °C compared to water acidified with sulfuric and citric acids. Highest degree of polymerization together with increasing degree of browning was observed within extracts when sulfuric acid was used. On the other hand, when organic acids were used to acidify water, a higher extraction efficiency of anthocyanins, accompanied with a relatively low polymerization and browning was observed, with lactic acid giving the best results.     

Effect of <Emphasis Type="Italic">Lactobacillus acidophilus</Emphasis> Bauer and <Emphasis Type="Italic">Bifidobacterium animalis</Emphasis> ssp. <Emphasis Type="Italic">lactis</Emphasis> BB12 on proteolytic changes in dry-cured loins

The effect of the potentially probiotic bacteria strain of Lactobacillus acidophilus Bauer and probiotic bacteria Bifidobacterium animalis ssp. lactis BB12 on proteolytic changes of proteins in dry-cured loins during fermentation and cold storage was studied. Results of the conducted tests demonstrated that the use of probiotic bacteria for the production of dry-cured meats impacts the generation of products of protein proteolysis with high antioxidant activity. The highest antioxidant activity of peptides after fermentation and cold storage was observed in the loin with the strain B. animalis ssp. lactis BB12 and the loin with the mixture of strains L. acidophilus Bauer and B. animalis ssp. lactis BB12. Qualitative analysis of peptides demonstrated that peptides with weight below 3.5 kDa are characterized by the highest capacity of quenching the ABTS cation radical, including the peptides in loins with the strain B. animalis ssp. lactis BB12.     

Effect of heat-treated <Emphasis Type="Italic">Nuruk</Emphasis> on the quality characteristics of aged <Emphasis Type="Italic">Yakju</Emphasis>

Long-term aging of Yakju, a traditional Korean liquor made of rice and Nuruk (a fermentation agent), causes browning and odor and flavor development. This study investigated the effects of heat-treated Nuruk (50–80 °C, 30 min) on Yakju quality. The saccharogenic powers and glucoamylase, α-amylase, and carboxypeptidase activities were similar in non-heat-treated Nuruk and that treated at 50 °C. However, acidic protease and alcohol dehydrogenase decreased above 50 °C. The content of nitrogen-containing compounds was inversely proportional to the heat-treatment temperature. Compounds that cause off-flavors decreased at 50–60 °C, but increased at 70–80 °C, whereas compounds that provide fragrance increased at 50–60 °C. Sensory evaluation indicated that bad taste attributes were higher in Yakju produced using non-heat-treated Nuruk. Therefore, heat treatment of Nuruk at 50 °C can be adopted as a method for improving Yakju quality, as enzymatic activities that affect color, aroma, and taste are regulated.     

Differences of Bactericidal Efficacy on <Emphasis Type="Italic">Escherichia coli</Emphasis>, <Emphasis Type="Italic">Staphylococcus aureus</Emphasis>, and <Emphasis Type="Italic">Bacillus subtilis</Emphasis> of Slightly and Strongly Acidic Electrolyzed Water

In the present study, the disinfection efficacy of slightly acidic electrolyzed water (SAEW) and strongly acidic electrolyzed water (AEW) was tested on three bacteria, Escherichia coli, Staphylococcus aureus, and Bacillus subtilis and the disinfection mechanism was discussed. The results showed that SAEW had a stronger antibacterial efficacy against these tested bacteria in comparison with AEW. The results also showed that both SAEW and AEW treatments could damage the cell membrane, which was demonstrated microcosmically by scanning electron microscopy (SEM), thus causing leakages of protein, DNA, RNA, and ATP, resulting in the death of microbes. Moreover, AEW treatment could not cause the degradations of DNA and RNA, and nucleic acids including DNA and RNA are not the target point of its bactericidal efficacy. However, SAEW could maybe cause the degradation of RNA, and RNA may be the target in its antibacterial activity. We suggested that the differences in antibacterial efficacy between SAEW and AEW could be explained by the different impacts on RNA of tested strains.     

Spray Chilling Microencapsulation of <Emphasis Type="Italic">Lactobacillus acidophilus</Emphasis> and <Emphasis Type="Italic">Bifidobacterium animalis</Emphasis> subsp. <Emphasis Type="Italic">lactis</Emphasis> and Its Use in the Preparation of Savory Probiotic Cereal Bars

The use of probiotic microorganisms has been limited by the difficulty of maintaining their viability during processing and throughout the product’s shelf life. This study evaluated the viability of microencapsulating Lactobacillus acidophilus (LA) and Bifidobacterium animalis subsp. lactis (BL) using the spray chilling technique to add them to savory cereal bars. The results showed that spray chilling generated a powder that was composed of smooth and continuous spheres with low moisture content and low water activity. The microencapsulated microorganisms exhibited a storage viability at least of 90 days as microparticles and in savory cereal bars, and their counts were superior to those resulting from other methods of adding activated and lyophilized probiotics to savory cereal bars. Thus, microparticles prepared by spray chilling are good vehicles for incorporating probiotics into cereal bars and have the potential to release the probiotics in the consumers’ intestines by means of fat digestion. Savory cereal bars that did and did not contain probiotics exhibited no differences in sensorial acceptance or commercial potential.     

Drying kinetics of whole and sliced <Emphasis Type="Italic">shiitake</Emphasis> mushrooms (<Emphasis Type="Italic">Lentinus edodes</Emphasis>)

Isotherms of shiitake mushroom (Lentinus edodes) at 25 and 40°C were determined and drying kinetics of whole and sliced shiitake mushrooms were tested using a convective air drying method at different drying temperature of 40, 50, 60, and 70°C. The monolayer moisture contents of the mushroom were 7.23 and 5.44 g water/100 g of dry solids at 25 and 40°C, respectively. Both mushroom samples showed falling drying rate periods with increasing drying rates with increases in drying temperature, and the drying rate of the sliced mushrooms was faster than that of the whole mushrooms at the same drying conditions. The kinetic parameters for dehydration of the mushrooms were determined using the Newton model and the Classical diffusion model. Activation energy (E _a ) values as determined using the Newton model were 22.58 and 20.48 kJ/mol for the whole and sliced mushrooms, respectively.     

Exposure assessment of <Emphasis Type="Italic">Staphylococcus aureus</Emphasis> in <Emphasis Type="Italic">Kimbab</Emphasis>, a ready-to-eat Korean food

The exposure assessment was carried out for Staphylococcus aureus in kimbab by predicting growth of S. aureus and the production of enterotoxin using Food MicroModel® program. Environmental parameters selected were pH 5.5, Aw 0.999, and storage temperatures in the range of 10 to 30°C. It was predicted that 6.3 hr could be a critical time for enterotoxin production while kimbab was stored at 30°C. Mild case scenario analysis showed that enterotoxin could not be produced if kimbab was kept at 10°C during preparation and distribution and then left at 25°C for 4 hr before consumption. In the worst case scenario, the keeping time at 25°C was assumed to be 7.0 hr. The level of S. aureus in the worst case was predicted to be 6.8×10⁶ CFU/g which is lower than the critical level (7.8×10⁶ CFU/g) for toxin production.