Changes of quality characteristics of pepino fruit (Solanum muricatum Ait) during convective drying

Quality assessment of pepino fruit preserved through convective dehydration was investigated in this work. The effect of process temperature (50, 60, 70, 80 and 90 °C) on physicochemical properties, colour, non‐enzymatic browning, vitamin C, total phenolic content, antioxidant activity and firmness of the fruit were considered. When comparing the fresh with the corresponding dehydrated pepino samples, it was shown that the drying conditions resulted in important reductions of proteins and crude fibres. Discoloration of fruit was noticeable for all treatments due to effects of non‐enzymatic browning and changes in chromatic coordinates leading to a modification of the original colour. Regarding vitamin C and total phenolic content, an increase of drying temperature resulted in a considerable reduction of both initial compounds contents. Antioxidant activity showed an important decrease especially at low temperatures (e.g. 50 °C). Softening of the dried product was observed for all the treatments indicating structural modifications of the fruit due to thermal process.     

Impact of volatile compounds generated by essential oils on Aspergillus section Flavi growth parameters and aflatoxin accumulation

BACKGROUND: The advantage of essential oils is their bioactivity in the vapour phase, a characteristic that makes them attractive as possible fumigants for stored grain protection. In this study the antifungal and antiaflatoxigenic effects of the volatile fractions of five essential oils (EOs) were evaluated by vapour contact on Aspergillus section Flavi isolates. RESULTS: In maize meal extract agar the volatile fractions of Pimpinella anisum L. (anise), Pëumus boldus Mol. (boldus), Hedeoma multiflora Benth. (mountain thyme), Lippia turbinata var. integrifolia (Griseb.) (poleo) and Syzygium aromaticum L. (clove) were able to decrease the growth rate and lag phase of aflatoxigenic isolates. Boldus EO showed the best antifungal effect on Aspergillus section Flavi growth rate. In sterilised maize grains, boldus and poleo EOs showed antifungal effects on growth rate and aflatoxin accumulation. The volatile fraction of boldus EO completely inhibited the growth of isolates at water activity (a_w) levels of 0.955, 0.930 and 0.900, while poleo EO showed this effect only at the lower a_w levels (0.930 and 0.900). All aflatoxigenic isolates showed reduced total aflatoxin accumulation in the presence of boldus EO under all a_w conditions. CONCLUSION: These findings clearly indicate that the volatile fraction of boldus EO could be used to control aflatoxigenic fungi in stored maize. Copyright © 2009 Society of Chemical Industry     

Coexistence of phosphatidylcholine-specific phospholipase C and phospholipase D activities in rat cerebral cortex synaptosomes

DAG derived from phosphatidylcholine (PtdCho) acts as a lipid second messenger. It can be generated by the activation of phospholipase D (PLD) and the phosphatidic acid phosphohydrolase type 2 (PAP2) pathway or by a PtdCho-specific phospholipase C (PtdCho-PLC). Our purpose was to study PtdCho-PLC activity in rat cerebral cortex synaptosomes (CC Syn). DAG production was highly stimulated by detergents such as Triton X-100 and sodium deoxycholate. Ethanol and tricyclodecan-9-yl-xanthate potassium salt decreased DAG generation by 42 and 61%, respectively, at 20 min of incubation. These data demonstrate that both the PLD/PAP2 pathway and PtdCho-PLC contribute to DAG generation in CC Syn. PtdCho-PLC activity remained located mainly in the synaptosomal plasma membrane fraction. Kinetic studies showed K _m and V _max values of 350 μM and 3.7 nmol DAG × (mg protein × h)⁻¹, respectively. Western blot analysis with anti-PtdCho-PLC antibody showed a band of 66 KDa in CC Syn. Our results indicate the presence of a novel DAG-generating pathway in CC Syn in addition to the known PLD/PAP2 pathway.     

Effects of probiotic administration in swine

In the present work we evaluated the effects of probiotic strains administration in pigs. On the 35th day of age, 30 pigs were distributed into 2 groups: the non-treated control group (initial average BW: 8.3 ± 0.6 kg) and a probiotic supplemented fed group (initial average BW: 8.7 ± 0.4 kg). Each experimental group was fed ad libitum on a commercial diet with free access to tap water for 35 days. A mixed probiotic culture (10⁸ CFU/ml) was orally delivered, every day, to the animals of the probiotic supplemented fed group. Body weight (BW), feed intake (FI), efficiency (BW: Feed), and faecal microflora, were studied before and throughout the experimental trial. At the end of the fifth week, 5 animals of each dietary treatment were slaughtered and intestinal samples were taken for histology. The results obtained showed that the group receiving probiotic bacteria exhibited lower FI values and better efficiency than control group (P ≤ 0.05), but mean final BW values were not significantly different. Only significant changes (P ≤ 0.05) were found in enterobacteria population between control and probiotic supplemented fed group during the experimental period. By histological techniques it was observed that the treatment group has intestinal morphological structures more preserved than control group. These results suggest that probiotic bacteria administrated in this study could be used widespread as a way to improve growth performance parameters of animals avoiding the use of antibiotics as growth-promoting factors.     

HPLC-DAD characterisation of phenolic compounds from Andean oca (Oxalis tuberosa Mol.) tubers and their contribution to the antioxidant capacity

A qualitative and quantitative characterisation of the main non-anthocyanin phenolic compounds from two different colored oca (Oxalis tuberosa Mol.) genotypes with potential antioxidant capacity was carried out by high performance liquid chromatography with photodiode array detection (HPLC-DAD). Phenolic compounds were fractionated in two main fractions: an aqueous (Faq) and a ethyl acetate fraction (Fea). In addition, the contribution of these phenolic fractions to the antioxidant capacity was evaluated. The Faq revealed the presence of caffeic, vanillic and cinnamic acid derivatives, flavan-3-ols and flavones derivatives, as the main non-anthocyanin phenolic compounds for both genotypes. Anthocyanins for the purple genotype were significantly present in this fraction. Acid hydrolysis revealed the presence of vanillic, caffeic and cinnamic acids and malvidin in Faq. The Fea was composed mainly of caffeic and cinnamic acid derivatives as well as flavan-3-ols, flavones and flavanone derivatives. Based on their UV–Vis spectral data the flavan-3-ols, flavones and flavanones detected in both fractions seem to correspond to bound forms of catechin, luteolin and apigenin and naringenin, respectively. The Faq fractions were the major contributors to the ABTS antioxidant capacity (77–82%). The results obtained in the present study suggest that oca tubers could potentially be considered beneficial for human health and for potential industrial applications.     

HoloFlows: modelling of processes for the Internet of Things in mixed reality

Software and Systems Modeling - Our everyday lives are increasingly pervaded by digital assistants and smart devices forming the Internet of Things (IoT). While user interfaces to directly monitor...     

A comparison of simplex and simulated annealing for optimization of a new rear underrun protective device

In this paper, two optimization approaches to improve the product design process have been analysed. Through the analysis of a case study, concerning the designing of a new High Energy Absorption Rear Underrun Protective Device (HEARUPD), two different optimization approaches (simplex and simulated annealing) have been compared. In the implemented optimization processes, the crash between an economy car and the rear part of a truck has been simulated by dynamic numerical (FEM) analyses. Moreover, authors have proposed the use of a suitable linear function of four variables with the purpose of reducing the multi-objective optimization processes to mono-objective ones. That has been made to simplify the analysis procedures without affecting the quality and the completeness of the optimization processes. The obtained results, as well as showing the high effectiveness of the integrated use of numerical crash analyses and optimization methods, demonstrate that simplex method is more effective than simulated annealing one for optimization problems where the single analysis loop requires much time. Even if the solutions are quite similar in terms of calculated values of the objective function, design and state variables, simplex method needs shorter computational time than simulated annealing to obtain an optimized solution.     

Degeneracy of the EM algorithm for the MLE of multivariate Gaussian mixtures and dynamic constraints

EM algorithms for multivariate normal mixture decomposition have been recently proposed in order to maximize the likelihood function in a constrained parameter space having no singularities and a reduced number of spurious local maxima. However, such approaches require some a priori information about the eigenvalues of the covariance matrices. The behavior of the EM algorithm near a degenerated solution is investigated. The obtained theoretical results would suggest a new kind of constraint based on the dissimilarity between two consecutive updates of the eigenvalues of each covariance matrix. The performances of such a “dynamic” constraint are evaluated on the grounds of some numerical experiments.