Prebiotic potential of barley derived β-glucan at low intake levels: A randomised,double-blinded,placebo-controlled clinical study

This randomised, double-blinded, placebo-controlled clinical study aimed to evaluate the in vivo prebiotic potential of barley β-glucan. Fifty-two healthy volunteers aged 39–70 years were randomly assigned to consume daily a cake containing 0.75 g of barley β-glucan or a placebo for 30 d. Stool samples were collected before, during and 2 weeks after the intervention for bacterial enumeration. Gastrointestinal side effects were recorded during the treatment period. In older subjects (?50 years old), barley β-glucan induced a strong bifidogenic effect and an increase of bifidobacteria into traceable range in cases of no detectable baseline levels. A concurrent significant increase in bacteroides was also observed in this age group. Ingestion of the experimental food resulted in no undesirable gastrointestinal side effects in older subjects. We concluded that the daily intake of a cake containing barley β-glucan is well-tolerated and demonstrated significant bifidogenic properties in older healthy volunteers consuming their usual diets.     

Assessing TBM performance in heterogeneous rock masses

Bulletin of Engineering Geology and the Environment - A major challenge that TBM performance is requested to deal with for a successful and effective progress is tunnelling through lithologically...     

Functional properties of egg yolk concentrate with a reduced cholesterol content prepared by treatment with supercritical CO2

A yolk protein concentrate containing ~45 and 75% less total lipids and cholesterol, respectively, than the original yolk was prepared by treating spray-dried yolk with supercritical CO₂. The yolk protein concentrate exhibited emulsion-stabilizing ability similar to that of dried yolk. A mayonnaise-like emulsion prepared with the yolk concentrate had lower consistency index and yield stress values, and less pronounced pseudoplasticity, than mayonnaise prepared with the original dried yolk. Both the foaming activity and the foam liquid stability were considerably greater in the case of yolk protein concentrate. Finally, the concentrate performed satisfactorily in cake preparation, but the texture of cake obtained, as assessed by panel tests, was different to the texture of cake prepared with dried yolk.     

Volatile Bio-ester Production from Orange Pulp-Containing Medium Using Saccharomyces cerevisiae

The dynamics of orange pulp (OP) as a fermentation feedstock for the production of volatile esters of “fruity” aroma by using a commercial wine yeast strain (Saccharomyces cerevisiae var. cerevisiae) was investigated. To achieve this goal, the kinetic behaviour of yeast (cell growth, substrate assimilation and volatile ester formation) was studied in OP complemented with nutritive medium under two different aeration conditions. The results were compared with those obtained from conventional processes in nutritive medium containing glucose as a sole carbon source. The results obtained revealed that the yeast cells were able to grow in the OP-containing medium after a 12-h lag period, probably due to the inhibitory effect of limonene. OP was found to stimulate the de novo synthesis of isoamyl acetate, phenylethyl acetate and ethyl esters (hexanoate, octanoate, decanoate and dodecanoate) by S. cerevisiae. This was strongly evident in the case of limited oxygen supply. Based on the above findings, OP appears to be a promising choice for bioflavour production by yeast.     

The formation of 2,5-dimethyl-4-hydroxy-2H-furan-3-one by cell-free extracts of Methylobacterium extorquens and strawberry (Fragaria × ananassa cv. Elsanta)

The formation of 2,5-dimethyl-4-hydroxy-2H-furan-3-one (DMHF), using the bacterial cells of Methylobacterium extorquens (strain with CABI registration number: IMI 369321) and strawberry cells (Fragaria × ananassacv. Elsanta), was studied. A combined mixture of the bacterial cell-free extract plus the strawberry extract was used as the enzymatic source. The pH of all the experimental aliquots was pH 6.0. The studied substrates were short-chain alcohols, carbohydrates and one amino acid. DMHF was analyzed by HPLC with UV detection at 280 nm. When 1,2-propanediol, 1-propanol, sucrose and fructose were used as substrates, the best production rates of DMHF were achieved, having a combined mixture of the bacterium and strawberry (minus the achenes) as the enzymic source. On the other hand, glucose, 1,2-propanediol, 2-propanol and fructose were the best substrates for the production of DMHF when a combined mixture of the bacterium and achenes served as the enzymic source. All results were obtained by comparing the production of DMHF from the strawberry extract alone and the bacterium plus the strawberry, without the achenes (in the first case) and the production of DMHF from the achene extract alone and the bacterium plus the achenes (in the second case). Moreover, the dehydrogenation activities of these three enzyme sources were determined by measuring the absorption of NADH at 340 nm. The substrate which was used for this series of the experiments was 1,2-propanediol. These results indicate the undoubted cooperation between the plant and the bacterial cells. This paper reports, for the first time, the formation of DMHF by bacterial and plant cell-free extracts.     

Acid-induced gelation of aqueous WPI–CMC solutions: Effect on orange oil aroma compounds retention

Electrostatic gelation under benign conditions of mixed whey protein isolate–carboxymethylcellulose aqueous solutions of relatively low biopolymer concentration was effected following pH reduction from neutral to values between the protein pI and the polysaccharide pK. Small deformation dynamic rheometry (time and frequency sweep measurements) was applied to determine the gel point and characterize the gel structure. State diagrams of biopolymer solutions in absence or presence of Tween 40 were also constructed to assess the contribution of interactions other than ionic ones to the development of the mixed gel structure. The findings are discussed in terms of the attainment of a stoichiometric electrical charge equivalence as the pH was moved towards acidity. As a consequence, the biopolymer molecules carried equal but opposite charges and protein–polysaccharide interactions took place. Retention of selected orange aroma compounds as a result of gel matrix formation was also investigated by applying the Headspace Solid Phase Microextraction technique, followed by gas chromatography–mass spectrometry analysis. The measurements indicated that a number of terpenic constituents of the orange oil were better retained in the matrix while the same was not observed in the case of the aldehydes.     

Teachers’ Perceptions οn the Use of Botanic Gardens as a Means of Environmental Education in Schools and the Enhancement of School Student Benefits from Botanic Garden Visits

The potential of Botanic Gardens (BGs) to contribute to environmental education is well documented. To what degree this potential is met concerning school students’ environmental education is to be considered. In Greece, Environmental Education Centres (EECs) develop Environmental Education Programmes (EEPs) for schools to implement. A questionnaire survey addressing teachers employed at the EECs in Greece investigated the use of BGs as a means of environmental education and identified their most important features in supporting school EEPs. Findings indicated that the majority of EEC teachers (90.6%) have not developed EEPs involving the use of BGs, although BGs were ranked as most suitable amongst other green spaces for conducting such programmes, particularly for primary school students. Teachers identified the need for BGs to be designed accordingly and provide the necessary infrastructure to be educationally effective that included facilitating teaching (e.g. open spaces, areas to congregate, easy access paths and indoor facilities) and plant-orientated elements as well as plant management displays. A strategy by BGs to promote their role in environmental education and a multidisciplinary design approach would maximise student benefit.