Utilization of Mixolab<Superscript>®</Superscript> to predict the suitability of flours in terms of cake quality

The objective of this study was to determine the possibility of using Mixolab^® to predict the cake baking quality of different wheat flours. Mixolab^® data were also compared with various flour quality characteristics. The correlations between Alveoconsistograph data and the cake quality characteristics were not significant. Therefore, Alveoconsistograph test does not seem to be useful to predict the cake quality of the flour samples. Mixolab^® characteristics C2, C3, C4 and C5 were found to be significantly correlated with volume index while C5 was correlated with hardness of cakes. The parameters C2 to C5 represent the end point of the corresponding mixing stages. The flour samples which gave higher cake hardness values had higher C5 values and the samples with lower cake volumes had higher C2, C3, C4 and C5 values. It seems to be possible to estimate the texture and volume of cakes by these values. Therefore, Mixolab^® seems to be a useful tool to predict the cake making quality of flour samples.     

Four new SYBR<Superscript>®</Superscript>Green qPCR screening methods for the detection of Roundup Ready<Superscript>®</Superscript>, LibertyLink<Superscript>®</Superscript>, and CryIAb traits in genetically modified products

SYBR^®Green qPCR methods for the detection of the Roundup Ready^® “CP4-EPSPS”, LibertyLink^® “PAT” and “BAR,” and the Bacillus thuringiensis “CryIAb” traits as present in genetically modified organisms (GMO) were developed. Their specificity, sensitivity, and PCR method efficiency were determined. All methods are specific and generate amplicons of 108, 73, 109, and 69 bp, respectively, for “CP4-EPSPS,” “CryIAb,” “PAT,” and “BAR” targets. They perform well at low target levels and can detect down to 5 copies of their respective targets extracted from a sample. The PCR efficiency of the methods ranges between 91 and 109%. Due to their trait-specific nature, these methods allow an efficient screening between the different GMO. In this way, the number of possible GMO candidates present in a sample can be reduced what results in lower global costs due to limiting of further the number of analytical identification steps. The application of these methods in CoSYPS GMO analysis is illustrated using two GEMMA proficiency test samples and a reference material from the GM rapeseed event RF3. This set of SYBR^®Green qPCR trait-specific methods represents a very interesting novel set of GMO analysis methods allowing cost-effective identification of GM materials in products.     

Predicting the cookie quality of flours by using Mixolab<Superscript>®</Superscript>

The objective of this study was to determine the possibility of using Mixolab^® to predict the cookie baking quality of different wheat flours. Mixolab data was also compared with various flour quality characteristics. There were significant correlations (P < 0.001) between Mixolab stability and some of the flour quality characteristics (protein and wet gluten contents, Zeleny sedimentation value). Alveoconsistograph T value was negatively correlated with Mixolab C3, C4 and C5 values. The cookie diameter gave highly significant correlations with protein content, Zeleny sedimentation value and damaged starch content. Mixolab C3 and C4 values were highly correlated (P < 0.001) with both cookie diameter and spread ratio. A significant correlation coefficient (r = 0.556) was determined between the cookie diameter and C1–C2 value which is an indication of protein quality. The dependence of cookie diameter and spread ratio on Mixolab C3 value, damaged starch content and Zeleny sedimentation value were analyzed with multiple regression analysis and high multiple correlation coefficients were found between these parameters (r = 0.948 and 0.861, respectively).     

Species identification in food products using the bioMerieux FoodExpert-ID<Superscript>®</Superscript> system

Animal feeds and meat mixtures were analysed using the bioMerieux FoodExpert-ID^® system. The system utilises a reverse dot technique on a DNA microarray to allow the identification of over 30 species of fish, birds and mammals. DNA is amplified by PCR (polymerase chain reaction) then hybridised to the microarray chip. Using this technique, turkey and chicken were correctly identified in 100% of feed samples that contained these species above a level of 0.1%. Pig, lamb and cow could not be reliably detected below a level of 1% in feed samples. For meat mixtures, a level of 0.2% pork or chicken could be correctly identified when mixed with 50% beef or pork, respectively. When a baked or canned meat mixture was investigated, a level of 5% pork, beef or chicken could be correctly identified, following either process. The bioMerieux FoodExpert-ID^® system can therefore be used as a general screen to identify likely species present in a sample, the level of which can be confirmed using other methods.     

Mathematical quantification of total carotenoids in Sioma<Superscript>®</Superscript> oil using color coordinates and multiple linear regression during deep-frying simulations

Sioma^® is a variety of red palm oil produced in Ecuador; it is mainly unsaturated, has no flavor, odor, nor cholesterol, and it is GMO-free and free of trans fatty acids. The main objectives of this study were: (a) to study changes in fatty acids, color coordinates, total carotenoids and carotenoid composition during deep-frying simulations; (b) to develop a mathematical model that allows quantification of total carotenoids (antioxidant compounds) using routine color measurements. Two different deep-frying temperatures were assayed 180 and 240 °C. The main fatty acids and carotenoids found in this oil were: (a) oleic, palmitic, and linoleic acids, and (b) α-, β-, and δ-carotenes. During these deep-frying simulations, Sioma^® oil became lighter and more yellowish (L* and b* values increased) and more greenish (a* values decreased); these changes were more evident for higher temperatures. At 180 °C, total carotenoids decreased linearly, from almost 500 mg L^?1, at a rate of 5 mg /kg¹ min^?1; however, at 240 °C the degradation of carotenoids was almost complete after 40 min. Finally, the mathematical models developed using multiple linear regressions allowed an easy and fast quantification of total carotenoids using color measurements.     

Effects of <Superscript>60</Superscript>Co-γ and Electron Beam Irradiation on Storage Quality of <Emphasis Type="Italic">Panax ginseng</Emphasis>

Fresh ginseng was irradiated with ⁶⁰Co-γ or an electron beam at the dose of 2 and 4 kGy and stored at 2 °C. The quality of ginseng was evaluated after 60 and 120 days. Results suggest that when the storage time was 120 days, 2 kGy EI-treated ginseng had the lowest decay rate. During the 2 storage periods, the amounts of most of 9 ginsenosides decreased with an increase in the irradiation dose. The total saponin content of both ⁶⁰Co-γ-irradiated and EI-treated samples decreased with an increase in the irradiation dose. Significant (P <?0.05) upregulation of total polysaccharide content was observed in the 4 kGy EI samples after storage. Samples irradiated at 2 or 4 kGy by electron beam irradiation had the highest concentration of total saponin and ginseng polysaccharides, respectively. Levels of most of 17 amino acids decreased with the increasing irradiation dose. Exposure to irradiation doses up to 4 kGy affected the amino acid content of fresh ginseng. Ginseng irradiated at 4 kGy by ⁶⁰Co-γ irradiation and stored for 120 days had a significantly higher activity of superoxide dismutase (P <?0.05). A significant difference was observed in the total concentration of nucleosides and nucleobases between irradiated and un-irradiated ginseng samples (P <?0.05). These data suggest that the combination of a lower irradiation dose and low temperature is an optimal condition for extending the shelf-life of fresh ginseng without detriment to its ingredients.     

The trend of reduced hop‐content in Pilsner‐type beer in Germany. A change in taste?

A time series analysis of the development of bitterness units (BU) of a collective of 1,202 Pilsner beer samples analysed between 1983 and 2013 shows a small but statistically significant decline from values of around 30 BU in the 1980s to values of around 27 in the last years. The results confirm a trend to lower hopped Pilsner beers, which could derive from economic pressures on the breweries combined with a lack of regulations, or a change in consumer preference. So–called Pilsner beers with extremely low BU values are judged as a being misleading to the consumer, which is an offence against European food law. Copyright © 2015 The Institute of Brewing & Distilling     

Voltammetric Determination of Thymol in Oregano Using CeO<Subscript>2</Subscript>-Modified Electrode in Brij® 35 Micellar Medium

Glassy carbon electrode (GCE) modified with CeO₂ nanoparticles dispersed in 0.01 M Brij® 35 (CeO₂-Brij® 35/GCE) has been developed for the determination of thymol in micellar medium. Scanning electron microscopy (SEM) data confirm immobilization of the nanomaterial on the electrode surface. The electrooxidation of thymol on CeO₂-Brij® 35/GCE is an irreversible diffusion-controlled process with participation of two electrons and two protons. Differential pulse voltammetry has been used for the quantification of thymol. The linear dynamic range of the thymol determination is 0.700–10.1 and 10.1–606 μM with the limits of detection and quantification 0.20 and 0.65 μM, respectively. The approach developed has been applied for the quantification of thymol in oregano spices using preliminary micellar extraction with Brij® 35. The results of voltammetric determination are in good agreement with the data of standard spectrophotometric method.     

Six years of wearer experience in children participating in a myopia control study of MiSight® 1 day

PurposeTo evaluate the experience of children wearing soft contact lenses (CLs) during a trial of MiSight® 1 day (omafilcon A, CooperVision, Inc.), a dual-focus myopia-control daily disposable CL.MethodsA 3-year, double-masked, randomised trial (Part 1) comparing experiences with MiSight 1 day and a single-vision control (Proclear® 1 day, omafilcon A, CooperVision, Inc.) of neophyte, myopic children (ages 8–12). Treatment (n = 65) and control (n = 70) participants received lenses at sites in Canada, Portugal, Singapore, and the UK. Successful participants completing Part 1 were invited to continue for a further 3 years wearing the dual-focus CL (Part 2), and 85 participants completed the 6-year study. Children and parent questionnaires were conducted at baseline, 1 week, 1 month, and every 6 months until the 60-month visit, with children only also completing questionnaires at 66 and 72 months.ResultsThroughout the study, children reported high satisfaction with handling (≥89% top 2 box [T2B]), comfort (≥94% T2B), vision (≥93% T2B for various activities), and overall satisfaction (≥97% T2B). Ratings for comfort and vision were not significantly different between lens groups, visits, or study parts and did not change when children switched to dual-focus CLs. Ratings for ‘really easy’ or ‘kind of easy’ application improved from the outset for the neophytes (57% at 1-week follow-up and 85% at 1-month follow-up) and remained high throughout the study (visit: P = 0.007; part: P = 0.0004). Overall satisfaction improved in Part 2 (P = 0.04). Wearing times increased in Part 2 (14 vs. 13 hrs/weekday; 13 vs. 12 hrs/day on weekends; P < 0.001); there were no differences between groups.ConclusionsChildren adapted rapidly to full-time wear, rated lenses highly, and rarely reported issues. The dual-focus optics included in the MiSight® 1 day lenses successfully achieved myopia control without lowering subjective ratings when fitted to neophytes or children refitted from single-vision CLs.     

Continuous cultivation of <Emphasis Type="Italic">Dunaliella salina</Emphasis> in photobioreactor for the production of β-carotene

A helix tube photobioreactor with a volume of 10 L was designed and manufactured. The facade of the reactor was designed as three-layer frame. The illumination helixes units were 16, illumination area volume was 1.5 L, illuminate specific area was 95 m⁻¹. A marine micro-alga Dunaliella salina was used as a model organism in this study. Results showed that the optimum inoculum concentration was OD₆₃₀ = 0.15 and the optimum circulation rate of culture fluid was 630 mL/h for the bioreactor. In continuous cultivation, in order to determine the optimum collection of alga solution for the highest yield of β-carotene, three different alga solution collection and addition fresh culture medium volumes were applied: 0.8, 1.5, 2.0 L/day. The biomass and extraction of β-carotene were determined in different cultivation periods. The result suggested that the optimum daily harvest of alga solution was 1.5 L/day for the cultivation of D. salina to obtain the highest production of β-carotene.     

Temperature-dependent dynamics of bovine casein micelles in the range 10–40 °C

Milk is a complex colloidal system that responds to changes in temperature imposed during processing. Whilst much has been learned about the effects of temperature on milk, little is known about the dynamic response of casein micelles to changes in temperature. In this study, a comprehensive physico-chemical study of casein micelles in skim milk was performed between 10 and 40 °C. When fully equilibrated, the amount of soluble casein, soluble calcium and the pH of skim milk all decreased as a function of increasing temperature, whilst the hydration and volume fraction of the casein micelles decreased. The effect of temperature on casein micelle size, as determined by dynamic light scattering and differential centrifugation, was less straightforward. Real-time measurements of turbidity and pH were used to investigate the dynamics of the system during warming and cooling of milk in the range 10–40 °C. Changes in pH are indicative of changes to the mineral system and the turbidity is a measure of alterations to the casein micelles. The pH and turbidity showed that alterations to both the casein micelles and the mineral system occurred very rapidly on warming. However, whilst mineral re-equilibration occurred very rapidly on cooling, changes to the casein micelle structure continued after 40 min of measurement, returning to equilibrium after 16 h equilibration. Casein micelle structure and the mineral system of milk were both dependent on temperature in the range 10–40 °C. The dynamic response of the mineral system to changes in temperature appeared almost instantaneous whereas equilibration of casein was considerably slower, particularly upon cooling.     

Determination of <Emphasis Type="Italic">Bacillus cereus</Emphasis> Emetic Toxin in Food Products by Means of LC–MS²

Cereulide is the heat-stable toxin produced by certain strains of Bacillus cereus. It is the main virulence factor of emetic B. cereus strains, which causes the emetic food poisoning syndrome, including rare fatal cases of food intoxications. Due to presumably low intoxication doses, a sensitive, specific, and robust technique is needed for its detection. In 2002, a LC–MS method was developed which allowed absolute quantification of cereulide using valinomycin as standard. This study describes the validation, according to the Commission Decision 2002/657/EC, of the LC–MS2 method, a tandem mass spectrometry technique, which guarantees lower detection limit and higher specificity. The LC–MS2 method, calibrated with valinomycin, was validated in rice and tested on various matrices (i.e., red beans, spices, and chili con carne) containing cereulide. The process combines a simple extraction step from the food matrix followed by LC–MS2 analysis and detection by ion trap mass spectrometer. The detection limit for cereulide in rice was 0.5 ng eq/g, which is 20 to 2,500 times lower than currently understood intoxicative doses between 10 and 1.280 ng/g previously reported for cereulide. The validated method was specific, sensitive, repeatable, and reproducible with recoveries ranging from 77% to 101%.     

Effects of coenzyme Q10, α-tocopherol and ascorbic acid on oxidation of cholesterol in chicken liver pâté

The aim of this study was to determine whether supplemental addition of coenzyme Q₁₀ and ascorbic acid or α-tocopherol, either alone or together, can prevent oxidative damage in chicken liver pâté, as reflected by reduced formation of cholesterol oxidation products (COPs) and by preservation of sensorial quality. Separate groups of chicken liver pâtés had no supplements (control) or were supplemented with coenzyme Q₁₀ (0.2 g/kg) and either ascorbic acid (2 g/kg) or α-tocopherol (0.2 g/kg), or both. All products were pasteurised (82 °C) or sterilised (121 °C). Four COPs were found: 7α-, 7β-, 20α- and 25-hydroxycholesterol. The COP radical scavenger function of coenzyme Q₁₀ (control, 5.16 mg/kg; plus Q₁₀, 3.94 mg/kg) and the synchronous actions of coenzyme Q₁₀ and α-tocopherol (2.6 mg/kg) were confirmed in sterilised pâtés. Generally, in pasteurised and sterilised pâtés, the most efficient scavenger function was with ascorbic acid either alone or together with α-tocopherol, where the formation of COPs was below the limit of detection. An increase of 1.9 mg/kg in COP production during heating was also seen in samples without added antioxidants. There was a weak interdependence between the content of COPs and the sensory parameters of the pâté. For addition of antioxidants, in the pasteurised pâté, colour and smell were slightly improved, but flavour deteriorated; in the sterilised pâté, colour was slightly worse, with a more tender texture. Overall, instrumentally measured colour and sensory properties (except texture) showed no significant differences between pasteurisation and sterilisation.     

Analytical Methods for the Evaluation of α-<Emphasis Type="SmallCaps">l</Emphasis>-Fucosidase Activity in Sheep Milk

The lack of analytical methods for measuring the activity of highly thermolable endogenous enzymes in sheep milk is a factor that hampers the protection of typical Protected Designation of Origin (PDO) dairy products made from raw milk. In order to provide a solution, this study assesses, tests, and fully validates analytical procedures for the determination of α-l-fucosidase activity in sheep milk. While the UV–VIS method has been optimized for this matrix in order to solve clarification problems before the spectrophotometric reading, a reversed phase high-performance liquid chromatography literature method proposed for bovine milk has been successfully applied also to sheep milk. Both methods have been fully validated in terms of sensitivity, linearity, precision, and accuracy, displaying low detection and quantification limits, excellent linearity over a wide enzymatic activity interval, very good repeatability and reproducibility, and the lack of any bias. The analysis of a number of real samples of whole sheep milk has allowed the evaluation of an average value (46.78 ± 5.49 U mL⁻¹) and range (from 29.27 ± 2.60 to 72.64 ± 1.17 U mL⁻¹) of α-l-fucosidase activity. Such activity does not seem to differ substantially from those measured for bovine milk. Finally, marked seasonal variability has been observed in this preliminary dataset.     

Modeling the effect of γ-irradiation on reducing total bacterial populations in <Emphasis Type="Italic">gochujang</Emphasis> intended for consumption by astronauts in space programs

This study modeled the effect of γ-irradiation on reducing bacterial populations in space gochujang (Korean red pepper paste). The gochujang samples were γ-irradiated at 0, 5, 10, 15, and 20 kGy, and stored under accelerated storage condition (35°C for 10 days). During storage, total bacterial populations in gochujang samples were enumerated on plate count agar (PCA) on day 0, 1, 3, 5, 7, and 10. To calculate maximum specific growth rate (μ_max; log CFU/g/day), lag phase duration (day), low asymptote (Y ₀; log CFU/g), upper asymptote (Y _max; log CFU/g), and surviving cell counts recovered with PCA were fitted to the Baranyi equation. The parameters then were further expressed as a function of irradiation dose. Total bacterial populations in gochujang were decreased to below detection limit (1 log CFU/g) after irradiation (5–20 kGy). The samples irradiated at 5, 10, and 15 kGy then had bacterial cell recovery, but no growth was observed in 20 kGy irradiated samples during accelerated storage. After validation of models, acceptable model performances (B factor=1.15, A factor=1.29, RMSE=1.044, R ²=0.862) were observed. These results indicate that the developed models may be useful in predicting irradiation doses to produce space gochujang.     

Antimicrobial effect of κ-carrageenan-based edible film containing ovotransferrin in fresh chicken breast stored at 5 °C

The antimicrobial activity of κ-carrageenan-based film (κCF) containing ovotransferrin (OTf) against Escherichia coli, Salmonella typhimurium, Staphylococcus aureus, and Candida albicans was investigated. The effects of packaging with κCF–OTf on fresh chicken breast were also investigated during storage at 5 °C. The κCF–OTf showed a slight antimicrobial activity against E. coli (diameter of inhibition zone was <2 mm), but the effect was increased synergistically in the presence of 5 mM EDTA (diameter of inhibition zone is 2–5 mm). However, there were only weak inhibitory effects against S. aureus and S. typhimurium (diameter of inhibition zone was <2 mm). The growth of total microbes and E. coli in fresh chicken breast wrapped with κCF showed 1.8 and 2.7 decimal reductions by the addition of 5 mM EDTA or 5 mM EDTA in combination with 25 mg of OTf (P < 0.05), respectively, when compared to that of control at day 7. The chicken breast wrapped with κCF–PS–EDTA was also inhibited the growth of total microbes and E. coli during storage period. However, the addition of either 25 mg of OTf alone or 10 mg of potassium sorbate alone slightly inhibited the growth of microorganisms in chicken breast. Based on the obtained results, the κ-carrageenan-based film containing ovotransferrin combined with EDTA can be used for extending shelf life of fresh chicken breast.     

Simultaneous Voltammetric Determination of Synthetic Colorants in Foods Using a Magnetic Core–Shell Fe<Subscript>3</Subscript>O<Subscript>4</Subscript>@SiO<Subscript>2</Subscript>/MWCNTs Nanocomposite Modified Carbon Paste Electrode

This paper reports the production of a novel magnetic nanocomposite based on multi-walled carbon nanotubes (MWCNTs) decorated with magnetic core–shell Fe₃O₄@SiO₂ nanoparticles which were used to fabricate a modified carbon paste electrode (Fe₃O₄@SiO₂/MWCNT-CPE). The Fe₃O₄@SiO₂/MWCNT-CPE was investigated for the simultaneous determination of sunset yellow (SY) and tartrazine (TT) in 0.1 mol/L phosphate buffer solution (pH 6.0) using square wave voltammetry (SWV). The synthesized nanocomposite was characterized by transmission electron microscopy, scanning electron microscopy, energy dispersive spectroscopy and Fourier transform infrared spectroscopy. The proposed electrode exhibits linear ranges of 0.5–100 μmol/L SY and TT with detection limits of 0.05 and 0.04 μmol/L for SY and TT, respectively. The novel proposed voltammetric method was successfully applied in the simultaneous determination of SY and TT in food products, with results similar to those obtained using a HPLC method at 95 % confidence level.

Open image in new window

Graphical Abstract A magnetic nanocomposite based on MWCNTs decorated with core–shell Fe₃O₄@SiO₂ was prepared and showed good ability to distinguish the response of SY and TT

     

Batch drying of banana pieces — effect of stepwise change in drying air temperature on drying kinetics and product colour

Slices of banana were dried in a two-stage heat pump dryer capable of producing stepwise control of the inlet drying air temperature while keeping absolute humidity constant. Two stepwise air temperature profiles were tested. The incremental temperature step change in temperature of the drying air about the mean air temperature of 30°C was 5°C. The total drying time for each temperature-time profile was 240 min. The drying kinetics and temporal colour change of the products dried under these stepwise variation of the inlet air temperature were measured and compared with constant air temperature drying. The effects of the profile starting temperature and cycle time on both drying kinetics and product quality were also studied. It was observed that by employing stepwise-varying drying air temperature with appropriate starting temperature and cycle time, it was possible to reduce significantly the drying time to reach the desired moisture content with improved product colour.