Phytostanols and phytosterols distributions in corn kernel

Recently, industry has focused attention on plant matrices rich in phytosterols and phytostanols for their ability to reduce serum cholesterol levels. Therefore, the objective of this study was to examine the phytosterols and phytostanols contents of different fractions (endosperm, pericarp, germ) of corn kernel. The germ fraction contained more oil (24.2–30.7%) than endosperm and pericarp fractions (0.4–1.2%). Endosperm oil had the highest levels of phytostanols and 4,4-dimethylsterols, while pericarp oil had the greatest amounts of 4-desmethylsterols and 4-monomethylsterols. In the oil extracted from three corn kernel fractions sitostanol was the predominant phytostanols (77–87%), followed by campestanol (13–23%). The high percentages of 24–methylencycloartanol and cycloartenol were detected in the endosperm and pericarp parts, respectively. Citrostadienol was detected in corn germ oil as the main component of the 4-monomethylsterols fraction. In different parts of corn kernel, β-sitosterol (62–69%) was the major 4-desmethylsterol, followed by campesterol (11–18%) and stigmasterol (5–13%).     

An evidential fusion approach for activity recognition in ambient intelligence environments

With the growing emergence of ambient intelligence, ubiquitous computing, sensor networks and wireless networking technologies, “ubiquitous networked robotics” is becoming an active research domain of intelligent autonomous systems. It targets new innovative applications in which robotic systems will become part of these networks of artifacts to provide novel capabilities and various assistive services anywhere and anytime, such as healthcare and monitoring services for elderly in Ambient Assisted Living (AAL) environments. Situation recognition, in general, and activity recognition, in particular, provide an added value on the contextual information that can help the ubiquitous networked robot to autonomously provide the best service that meet the needs of the elderly. Dempster–Shafer theory of evidence and its derivatives are an efficient tool to handle uncertainty and incompleteness in smart homes and ubiquitous computing environments. However, their combination rules yield counter-intuitive results in high conflicting activities. In this paper, we propose a new approach to support conflict resolution in activity recognition in AAL environments. This approach is based on a new mapping for conflict evidential fusion to increase the efficiency and accuracy of activity recognition. It gives intuitive interpretation for combining multiple sources in all conflicting situations. The proposed approach, evaluated on a real world smart home dataset, achieves 78% of accuracy in activity recognition. The obtained results outperform those obtained with the existing combination rules.     

Heat Capacity Calculation of Some Semiconductor Compounds Using Lambert W Function

Silicon - Based on the Lambert-Boltzmann distribution, a simple and efficient expression for the determination of the heat capacity of some semiconductor compounds is proposed. The new expression...     

Unknown Input Fault Detection and Isolation Observer Design for Neutral Systems

This paper deals with actuator fault diagnosis of neutral delayed systems with multiple time delays using an unknown input observer. The main purpose is to design an observer that guarantees the asymptotic stability of the estimate error dynamics and the actuator fault detection. The existence conditions for such an observer are established. The main problem studied in this paper aims at designing observer‐based fault detection and isolation. The designed observer enhances the robust diagnosis performance, including rapidity and accuracy, and generates residuals that enjoy perfect decoupling properties among faults. Based on Lyapunov stability theory, the design of the observer is formulated in terms of linear matrix inequalities, and the diagnosis scheme is based on a bank of unknown input observers for residual generation that guarantees fault detection and isolation in the presence of external disturbances. A numerical example is presented to illustrate the efficiency of the proposed approach.     

Characterization of two prickly pear species flowers growing in Tunisia at four flowering stages

Opuntia flowers belonging to two species of prickly pear were evaluated at four flowering stages: vegetative, initial flowering, full flowering and post-flowering stage, for possible use as a potential source in the food enrichment. Chemical composition including moisture, ash, protein, fat, soluble sugars, total fibers, mineral amounts and fatty acid profiles of Opuntia ficus-indica and Opuntia stricta flowers were investigated. Functional properties (swelling capacity (SWC), water holding capacity (WHC), water solubility index (WSI) and oil holding capacity (OHC)) were also studied. Results showed that during the maturation of flowers, there is a decrease in protein contents whereas fat contents increase, for both species. High minerals amounts were noticed in Opuntia flowers and they can be considered as an excellent source of minerals. The fatty acids profiles were dominated by the palmitic acid (38–59%). The techno-functional properties (SWC, WSI, WHC and OHC) were found to be important and they can be modulated according to the temperatures. Owing to its chemical profile and functional properties, Opuntia flowers could be used as an ingredient to improve different physical and nutritional properties of foods.     

Chemical Composition and Antioxidant Activities of Tunisian Thymus capitatus L. Methanolic Extract

Thymus capitatus has traditionally been considered as an anthelmintic, antispasmodic, carminative, emmenagogue, expectorant, rubefactient, sedative, stimulant, and tonic. This work was carried out to determine total polyphenol and total flavonoids chemical composition of phenolics and to evaluate the antioxidant activities of the methanolic extract. Total phenolic contents were assayed using the Folin–Ciocalteu reagent, total flavonoid content was measured spectrophotometrically and phenolics were analyzed by reverse phase–high performance liquid chromatography. The 1,1-diphenyl-2-picrylhydrazyl and reducing power were calculated. Total phenols and total flavonoids varied significantly among the studied regions. Chromatographic analysis by reverse phase–high performance liquid chromatography showed that phenolic acids: tannic, gallic, chlorogenic hemihydrate, caffeic, syringic, ferulic, p-coumaric acid, and trans-cinnamic rosmarinic were the main compounds. The anti-radical activity was region-dependent and could be summarized as follows in ascending order: Boukornine > Kef > Bizerte > Grombelia. Reducing power in the four studied regions was stronger than positive control (ascorbic acid). From these results we have conclude that thyme methanolic extract may have a role in pharmaceutical preparations and preservatives as an antioxidant.     

Gas chromatographic–mass spectrometric characterisation of triterpene alcohols and monomethylsterols in developing Olea europaea L. fruits

Five triterpene alcohols and four 4-monomethylsterols were identified by GC–MS during the ripening of Picholine olive. The quantitative characterisation of these compounds was performed using GC–FID. The results showed that the maximum level of total triterpene alcohols (263.68 mg/100 g oil) was reached at 26th week after the flowering date (WAF) of olive; whilst the highest level of total 4-monomethylsterols (234 mg/100 g oil) was attained at 24th WAF of fruit. The percentage of these two classes represented 20–33% of total phytosterols during olive maturity. 24-Methylene cycloartenol (12–207 mg/100 g oil) and cycloartenol (27–198 mg/100 g oil) were the predominant triterpene alcohols during the ripening of Picholine olive; whereas citrostadienol (30–161 mg/100 g oil) and cycloeucalenol (11–74 mg/100 g oil) were the main 4-monomethylsterol compounds followed by obtusifoliol and gramisterol. β-Amyrin, δ-amyrin and traroxerol were less present in Picholine olive and they accounted for 14% of total triterpene alcohols at complete maturity of fruit. The level of these methylsterols was overwhelmed by the amount of 4-desmethylsterols at each stage of Picholine olive maturity.     

Chemical composition and oxidative stability of Tunisian monovarietal virgin olive oils with regard to fruit ripening

The chemical composition of virgin olive oil may be influenced by genotype and different agronomic (i.e. fruit ripeness degree, water supply) and technological factors. This article reports the evaluation of the influence of the olive ripening stage on the quality indices, the major and the minor components and the oxidative stability of the two main monovarietal Tunisian cultivars (cvv. Chétoui and Chemlali) virgin olive oils. Moreover, the olives cv. Chétoui were tested in a rain-fed control and an irrigation regime. The oils sampled at five different ripeness stages were submitted to liquid chromatographic determination (HPLC-DAD/MSD) of their quali-quantitative phenolic and tocopherolic profiles. Moreover, the triacylglycerol and fatty acid compositions, and minor components such as squalene, pigments and their relation with the oil oxidative stability were evaluated. The tested oils showed very good correlation between the oxidative stability and the concentrations of total phenols, practically secoiridoids and α-tocopherol.