Benefits of β-xylanase for wheat biomass conversion to bioethanol

BACKGROUND: The efficiency of bioethanol production from wheat biomass is related to the quality of end products as well as to safety criteria of co‐products such as distiller's dried grains with solubles (DDGS). The inclusion of a new biocatalyst for non‐starch polysaccharide degradation in fermentation processes could be one of the solutions. The objective of this study was to evaluate the influence of β‐xylanases in combination with traditional amylolytic enzymes on the efficiency of bioethanol production and DON detoxification during fermentation of Fusarium‐contaminated wheat biomass with high concentration of deoxynivalenol (DON; 3.95 mg kg^?1). RESULTS: The results showed that the negative effect of Fusarium spp. on yield and quality of bioethanol could be eliminated by the application of Trichoderma reesei xylanase in combination with amylolytic enzymes. This technological solution allowed to increase the concentration of ethanol in the fermented wort by 35.3% and to improve the quality of bioethanol by decreasing the concentrations of methanol, methyl acetate, isoamyl and isobutyl alcohols. Mass balance calculations showed that DDGS was the main source of DON contamination, comprising 74% of toxin found in wheat biomass. By using new enzyme combination for wheat biomass saccharification, a higher level of detoxification (41%) of DON was achieved during the fermentation process. CONCLUSION: The addition of Trichoderma reesei xylanase played a positive role in bioethanol production from Fusarium‐contaminated wheat biomass, indicating that the yeast‐growing medium was enriched during the enzymatic treatment. Copyright © 2011 Society of Chemical Industry     

Comparison of rheological and colorimetric measurements to determine α-amylase activity for malt used for the beverage Bozo

In the current study, rheological and colorimetric methods were compared for determination of α-amylase activity of grain malt, used for Kyrgyz traditional fermented beverage Bozo. The highest α-amylase activity determined by colorimetric method was found in barley malt (32.83 A), followed by wheat (32.09 A), and was lowest in millet malt (10.82 A) and maize malt (10.76 A). Rheological parameters of millet porridge without and with malt were studied. The liquefaction effect of millet porridge after addition of malt was determined with rotational and oscillatory measurements. Results from statistical analysis (partial least squares regression) revealed that oscillatory rheological parameters (yield stress τ, deformation γ, and storage modulus G′) could be an effective indicator to predict the α-amylase activity of the investigated malt with R² = 0.9572. Consequently, rheological oscillatory measurements were recommended as an alternative tool to determine α-amylase activity of grain malt.     

Selenium toxicity to invertebrates: will proposed thresholds for toxicity to fish and birds also protect their prey?

Efforts to manage the environmental risks of selenium (Se) in freshwater ecosystems have focused primarily on fish and birds, with invertebrates most often considered only as dietary sources of Se to higher trophic levels. Relatively little attention has been given to the risk of Se toxicity to invertebrates. Based on a review of 156 aqueous, dietary, or internal Se concentrations associated with toxic effects in 29 macroinvertebrate species, we found that water concentrations associated with acute lethality varied > 1000-fold among taxa, whereas toxic dietary concentrations varied approximately 100-fold and toxic internal concentrations varied about 30-fold. Sublethal effects occurred at approximately 10-fold lower concentrations than lethality. Sublethal effects occurred at 1-30 microg Se/g dry weight in invertebrate tissue, a range that encompasses proposed dietary thresholds for toxicity to fish and water birds, suggesting that Se may cause toxic effects in some invertebrate species at concentrations considered to be "safe" for the organisms consuming them.     

How does animal welfare taste? Combining sensory and choice experiments to evaluate willingness to pay for animal welfare pork

Although consumers show considerable interest in higher animal welfare, the market share for such products remains low. To provide consumers with a choice regarding different levels of animal welfare, animal welfare labels have been developed. Such product options are intended to serve as intermediate products between conventional products and more expensive organic options that are often associated with high animal welfare standards. This study aims to evaluate whether information about animal welfare practices affects consumers’ liking and willingness to pay (WTP) for a pork product. Using a within-subject design with three evaluation rounds (blind, expectation, and full information) we combine hedonic liking where subjects rate four different types of ham with a choice experiment. Hams differ in the animal husbandry conditions during the rearing and fattening process: conventional rearing, a specific treatment of mother sows, a general animal welfare label, and organic production. Results show an effect of information on consumers’ sensory evaluation of the different products, although products were evaluated to be similar in the blind condition. Consumers rated the organic product higher than those with animal welfare labels while the conventional option had the lowest liking scores. Results from the choice experiment concur with the hedonic rating. Estimates indicate that consumers are willing to pay more for ham bearing a general animal welfare or organic label in the expectation and full information condition. Consequently, information regarding animal welfare affects both consumers’ hedonic liking and WTP for ham.     

Are questionnaires the best way to measure emotions for food products and beverages?

There is a growing awareness in the field of consumer and sensory research to include emotional measurements when evaluating food products and beverages. The present paper provides an overview of the recent measures used for emotional measurements within the context of food products and beverages. Further, it discusses to what extent questionnaires might be the best measurement to capture consumer’s emotions in the field of food science by focusing on three aspects of emotion measurement, namely (i) what do we want to measure, (ii) how do we measure it and (iii) what is the added value of the measurement.     

A novel method using a silicone diffusion membrane for continuous ²²²Rn measurements for the quantification of groundwater discharge to streams and rivers

222Rn is a natural radionuclide that is commonly used as tracer to quantify groundwater discharge to streams, rivers, lakes, and coastal environments. The use of sporadic point measurements provides little information about short- to medium-term processes (hours to weeks) at the groundwater-surface water interface. Here we present a novel method for high-resolution autonomous, and continuous, measurement of 222Rn in rivers and streams using a silicone diffusion membrane system coupled to a solid-state radon-in-air detector (RAD7). In this system water is pumped through a silicone diffusion tube placed inside an outer air circuit tube that is connected to the detector. 222Rn diffuses from the water into the air loop, and the 222Rn activity in the air is measured. By optimizing the membrane tube length, wall thickness, and water flow rates through the membrane, it was possible to quantify radon variations over times scales of about 3 h. The detection limit for the entire system with 20 min counting was 18 Bq m?3 at the 3σ level. Deployment of the system on a small urban stream showed that groundwater discharge is dynamic, with changes in 222Rn activity doubling on the scale of hours in response to increased stream flow.     

A new colour assay for [URE3] prion in a genetic background used to score for the [PSI⁺] prion

Most scoring assays for yeast prions are dependent on specific genetic markers and constructs that differ for each prion. Here we describe a simple colour assay for the [URE3] prion that works in the 74D-964 strain frequently used to score the [PSI(+)] prion. Although this assay can only be used to score for [URE3] in the [psi(-)] version of the strain, it makes it easier to examine the effects of host mutations or environmental changes on [URE3] or [PSI(+)] using a colour assay in the identical genetic background.     

Dietary advanced glycation end products--a risk to human health? A call for an interdisciplinary debate

Physiological consequences resulting from protein-bound Maillard compounds in foods must be discussed carefully. This was the idea behind the debate, which is put for discussion by the papers by Sebekova and Somoza, who argued for the motion that dietary advanced glycation end products (AGEs) are a health risk, and by Ames, who provided evidence against the motion. In this two excellent reviews, numerous arguments based on papers published in high-impact journals are given for each of the opinions. The fact that no final conclusion can be drawn, may reflect the need for a more comprehensive examination of this issue in the future. For a deeper understanding of biological consequences resulting from heated foods, the relationships between well-defined biological effects and well-characterized chemical structures must be studied. Prerequisite for this is profound chemistry--pure compounds, exact concentrations, and unambiguous analytical techniques. A real "risk assessment" is much too complex than to leave it up to one discipline alone. It must be a comprehensive and interdisciplinary approach, joining the resources of biology, medicine, and chemistry.     

Codex dietary fibre definition – Justification for inclusion of carbohydrates from 3 to 9 degrees of polymerisation

The main controversy about the DF definition, adopted by the commission of Codex Alimentarius, refers to the inclusion of carbohydrates of 3–9 degrees of polymerisation (DP), decision which may be made individually by the authorities of each country. Due to the possibility of having two definitions and the negative impact it would cause over the harmonisation of nutritional information, a bibliographic review was carried, from 2009 to 2011, aiming to gather justifications for the inclusion of carbohydrates of 3–9 DP in the definition. The current review presents scientific bases that are directed to three topics: physiological aspects; repercussion over the analytical method; and impact on consumers and other users. The decision of including unavailable carbohydrates of 3–9 DP in the definition of DF may cause effective global harmonisation in the nutritional labelling, considering that the main goal is to help consumers choose healthy foods.     

Using participant ratings to construct food image paradigms for use in the Australian population – A pilot study

In human research, images of food are often used as cues in place of real foods. To elicit anticipatory responses in targeted populations (e.g. prompting changes in metabolic hormones, invoking food cravings), cultural differences and population norms with regard to food preferences need to be considered. This pilot study aimed to construct two image paradigms (healthy vs. hyperpalatable foods) for experimental use within the Australian population. A dataset of 200 images (from the licenced database Food-pics and internet sources), representative of healthy and hyperpalatable foods commonly consumed in Australia, was compiled by research dietitians. Ten male and female adults volunteered to view the images. Participants categorised each image as either healthy food or ‘junk food’ (i.e. hyperpalatable food), and rated each image according to three criteria: 1) familiarity of the food displayed; 2) recognisability of the food; and 3) appetisingness of the food. Overall, agreement with a priori categories was high for both healthy and hyperpalatable food images, 87.3% and 87.7% respectively. The food images with the lowest overall ratings (score <7 out of possible 9) were removed from the dataset and the final paradigms each contain 75 images. The healthy food paradigm contains foods from the five core food groups (fruit, vegetables, grains and cereals, meat and meat alternatives, dairy foods), and the hyperpalatable food paradigm contains non-core foods (sweet and savoury discretionary choice foods). The paradigms represent a broad range of commonly consumed foods that will be relevant for prospective projects utilising food cues in Australian adults.     

Do pig farmers preferences bias consumer choice for pork? Response to critique of the pork preference studies

Québec consumers and pig farmers selected their preferred chop from 16 images that had been modified to give 16 treatments: two levels each of fat cover, colour, marbling and drip. The selection process was repeated eight times from different groups of chops. Fat cover (47% preferred lean) and colour (44%, light red) were the most frequently chosen characteristics. No significant differences were observed between farmers and consumers preferences (χ² test, P < 0.05). Two preference-based clusters were found; 41% preferring dark red, lean meat and 59%, light red, lean meat, without marbling or drip. Choice-based clusters showed no significant links with either individual socio-demographic items, including pig farmer as occupation, or the three socio-demographic-based clusters observed (χ² test, P < 0.05). No evidence was found to suggest that the choices of pig farmers differed from those of consumers and, therefore, inclusion of pig farmers in consumer panels would not bias consumer choice for pork.     

Automated Systems Based on Machine Vision for Inspecting Citrus Fruits from the Field to Postharvest—a Review

Computer vision systems are becoming a scientific but also a commercial tool for food quality assessment. In the field, these systems can be used to predict yield, as well as for robotic harvesting or the early detection of potentially dangerous diseases. In postharvest handling, it is mostly used for the automated inspection of the external quality of the fruits and for sorting them into commercial categories at very high speed. More recently, the use of hyperspectral imaging is allowing the detection of not only defects in the skin of the fruits but also their association to certain diseases of particular importance. In the research works that use this technology, wavelengths that play a significant role in detecting some of these dangerous diseases are found, leading to the development of multispectral imaging systems that can be used in industry. This article reviews recent works that use colour and non-standard computer vision systems for the automated inspection of citrus. It explains the different technologies available to acquire the images and their use for the non-destructive inspection of internal and external features of these fruits. Particular attention is paid to inspection for the early detection of some dangerous diseases like citrus canker, black spot, decay or citrus Huanglongbing.     

On-line Solid-Phase Extraction Coupled to Liquid Chromatography–Ion Trap Tandem Mass Spectrometry for Determination of Penicillins in Catfish

A highly selective method was developed for the simultaneous determination of eight penicillins in catfish using automated on-line solid-phase extraction coupled to liquid chromatography–tandem mass spectrometry (XLC–MS/MS). The type of cartridge, equilibration sample volume, volume of solvent to carry the sample into the cartridge, and elution times were studied in order to optimize the XLC operating conditions. MS/MS conditions were also adjusted for better peak resolution. The present method was validated in agreement with the criteria of Commission Decision 2002/657/EC, showing a linear range from 2 to 350 μg kg⁻¹ and regression coefficient higher than 0.995 for the studied penicillins. Decision limits, calculated in the case of substances with no permitted limit, were lower than 0.6 μg kg⁻¹, and detection capability values were lower than 2.0 μg kg⁻¹. Samples spiked at 2.0, 10.0, and 50.0 μg kg⁻¹ showed high recovery (72–92%) and precision values lower than 20% except for amoxicillin. The present method was also applied for the analysis of penicillins in 30 catfish samples bought in local markets.