Comparison of free amino acids and volatile components in three fermented milks

Free amino acids (FAAs) and volatile components were analysed in commercial samples of yoghurt and Actimel^® drink as well as laboratory‐made kefir. The lysine and cysteine were the principal amino acids and accounted for about 70% of the total FAAs in all the samples. However, the amino acid profiles in the different fermented milk products differed: on the whole values for most of the amino acids were observed to be significantly higher in the Actimel^® samples. A total of 50 volatile components were identified. The largest number of volatiles were found in the kefir. Ethanol, 2,3‐ butanodione and 3‐hidroxybutan‐2‐one were the most prevalent volatile components, with ethanol significantly higher in the kefir samples.     

Controllability of linear single-input positive discrete-time systems

Linear positive systems are utilized in various scientific areas such as economic modelling, behavioural science, stochastic processes etc. A recent study has focused on some sufficient conditions for the controllability of these systems. A full characterization is provided of the controllability for discrete-time single-input positive systems. Necessary and sufficient conditions are derived using a digraph-theoretic approach. The main results show that strong constraints are to be imposed on the digraph associated with the pair (A, b) to ensure the controllability of the system.     

Measurement of Taste Intensity and Degree of Liking of Beverages by Graphic Scales and Magnitude Estimation

Graphic scaling (GS) and magnitude estimation (ME) of hedonic and intensity responses to 4–30% sucrose in lemonade and 0–16% fat in milk gave similar conclusions about the beverages, but GS was simpler to perform and responses were influenced less by numerical and contextural effects. More restricted ranges were used for ME than for GS, and for hedonic than for intensity responses. Good reproducibility was obtained, except for GS of hedonic responses to lemonade, which were bimodally distributed. Use of a higher sucrose reference (R) in lemonade decreased ME values, and increased the intensity exponent from 0.651 when R was 4% sucrose to 0.973 when R was 10% sucrose. Individual intensity exponents varied from 0.068–0.372 for milk, and from 0.146–1.075 for lemonade when R was 4% sucrose, and from 0.373–2.635 when R was 10% sucrose.     

Effect of Water Activity of Milk upon Growth and Acid Production by Mixed Cultures of Streptococcus thermophilus and Lactobacillus bulgaricus

Acid production and growth rates were determined in pure cultures of Streptococcus thermophilus and Lactobacillus bulgaricus and cocci/ bacilli ratios in mixed cultures of both species, using milk with modified a_w as culture medium. Maximal growth rates were always at a_w lower than 0.992 for all strains whcn a_w of milk was adjusted with glycerol, while maximal acid production rates were at a_w 0.992-0.983. Glucose had an inhibitory effect additional to that caused by lowering a_w. The cocci/bacilli ratio in mixed cultures increased as a_w decreased in most cases, because of the higher susceptibility of L. bulgaricus to a_w decrease. The behavior of a mixed culture could not always be predicted from data of the component strains in a pure culture, showing some kind of symbiotic compatibility between species.     

ANALYSIS OF NATURALLY OCCURRING PHENOLIC COMPOUNDS IN AROMATIC PLANTS BY RP-HPLC AND GC-MS AFTER SILYLATION

Aromatic plants of Greek origin, Origanum dictamnus (dictamus), Eucalyptus globulus (eucalyptus), Origanum vulgare L. (oregano), Mellisa officinalis L. (balm mint) and Sideritis cretica (mountain tea) were examined for the content of phenolic substances. Reversed phase high performance liquid chromatography was used for the analysis of the plant extracts. Gas chromatography–mass spectrometry method was also used for identification of phenolic compounds after silylation. The most abundant phenolic acids were gallic acid (1.5–2.6 mg 100 g ^{− 1} dry sample), ferulic acid (0.34–6.9 mg 100 g ^{− 1} dry sample) and caffeic acid (1.0–13.8 mg 100 g ^{− 1} dry sample). ( + )-Catechin and ( − )-epicatechin were the main flavonoids identified in oregano and mountain tea. Quercetin was detected only in eucalyptus and mountain tea.

PRACTICAL APPLICATIONS

Plant-derived polyphenols receive considerable interest because of their potential antioxidant and antimicrobial properties. Undoubtedly, it is very important not only to determine those properties but also to determine each and every phenol in aromatic plants both qualitatively and quantitatively. A number of analytical methods have been proposed for the separation and determination of these compounds. Most of these protocols are based on a high performance liquid chromatography technique with ultraviolet spectrophotometry. Gas chromatography–mass spectrometry after silylation of the phenolic compounds is used in this research together with the aforementioned technique as an alternative and more sensitive method to detect and understand the compositional profile of the extracts as well as the structure and functional relationship of the components in the extracts, based on MS spectra.     

Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR): A critical overview on the most promising applications of molecular scissors in oral medicine

The scientific community is continuously working to translate the novel biomedical techniques into effectivemedical treatments. CRISPR-Cas 9 system (Clustered Regularly Interspaced Short Palindromic Repeats-9), commonlyknown as the “molecular scissor”, represents a recently developed biotechnology able to improve the quality and theefficacy of traditional treatments, related to several human diseases, such as chronic diseases, neurodegenerativepathologies and, interestingly, oral diseases. Of course, dental medicine has notably increased the use ofbiotechnologies to ensure modern and conservative approaches: in this landscape, the use of CRISPR-Cas-9 systemmay speed and personalize the traditional therapies, ensuring a good predictability of clinical results. The aim of thiscritical overview is to provide evidence on CRISPR efficacy, taking into specific account its applications in oral medicine.     

Interactive Collaborative Visualization Environment for Geometric Computing

This paper investigates the visualization of geometric computing in heterogeneous distributed environments. We show how focusing in a well-defined domain makes it possible to develop a compact system that is accessible to even naive users. We present a conceptual model and a system, GASP-II, that realizes this model in the geometric domain. The system allows the presentation and interactive exploration of three-dimensional geometric algorithms over the network.