Limit of the solid fat content modification of butter

Three ways have been undertaken to modify solid fat content of butter oil: (i) interesterification, (ii) adjunction of high-melting glycerides and (iii) joint effect of adjunction of high-melting glycerides and interesterification. A solvent-free interesterification, carried out with 1,3-specific lipase fromMucor miehei, resulted in an increase of the solid fat content (SFC) by about 114% after 48 h of interesterification. The changes in triglyceride composition induced by this method were followed by quantitative determination of triglycerides of different equivalent carbon number (ECN) and different theoretical carbon number. The major changes in the triglyceride composition occurred mainly in the concentration of three groups of triglycerides with the same ECN (ECN=38). Adding high-melting glycerides trimyristin (MMM) and tripalmitin (PPP) led to an increase of the SFC measured at 20°C as these proportions increased in the mixture. The joint effect of the addition of MMM or PPP and interesterification was quite significant, mainly for triglycerides that included myristic and palmitic acids. As far as the increase of SFC is concerned, the effect of interesterification decreases when both substrate amounts increase.     

Soda—Oxygen bleaching of kraft bagasse pulp

Soda—oxygen bleaching of commercially available kraft bagasse pulp has been investigated. Alkali charge, temperature and oxygen pressure are important factors in controlling brightness and physical properties of the pulps produced. Pulp yields, lignin and degree of polymerisation of the bleached pulps decreased with increasing alkali charge from 2 to 6%. Strength properties as well as brightness increased by increasing alkali charge at 368 K, whereas optimum strength properties are obtained with 4% alkali at 383 K. In the range of oxygen pressure used, 5–8 kg cm^?2, DP as well as strength properties of the bleached pulps increased with increasing oxygen pressure. Brightness up to 61% was reached by soda-oxygen alone. To obtain higher brightness an afterbleaching step is necessary. The soda—oxygen—hypochlorite and soda—oxygen—chlorite pulps prepared have strength properties comparable with those of conventionally bleached pulps.     

The effect of Egyptian honeybee propolis on the growth of Aspergillus versicolor and sterigmatocystin biosynthesis in Ras cheese

Propolis is a natural product collected by honeybee workers. The product was tested for its antifungal effect against Aspergillus versicolor ATCC 12996 as well as biosynthesis of sterigmatocystin during ripening of Egyptian Ras cheese. The use of different concentrations of aqueous propolis extract 250, 500 and 1000 part per million (ppm) on the cheese surface was investigated. Mould growth and toxin production were completely inhibited at the highest concentration 1000 ppm, while the lower concentrations exhibited definite fungistatic activity during 90 days of ripening. Control cheese demonstrated that the amount of sterigmatocystin produced was proportional to the growth of Asp. versicolor during three months of ripening. It could be concluded that propolis concentration of 1000 ppm could prevent mould growth and sterigmatocystin production in Ras cheese. The economic as well as the public health importance of propolis as a natural preservative in cheese manufacture is discussed.     

Effect of Plant Originated Coagulants and Chymosin on Ovine Milk Coagulation

The coagulation of ewe's milk was studied by using plant source coagulants namely the artichoke, Cynara scolymus L. cv. Blanca, and latex from the fig tree (Ficus carica L.). A turbidimetric method was used to evaluate and compare the coagulation properties of the novel coagulants with chymosin treated samples. Syneresis capacity and sensory evaluation of resultant cheese samples were studied and it was found that both cynara and chymosin produced sigmoidal increase in turbidity to the milk with three distinct phases. The coagulation kinetics was affected substantially by both coagulants. Plant coagulant induced shorter gelation time compared to chymosin however required longer time for restructuration (end of coagulation). The coagulum obtained with the latex of Ficus carica had a higher yield, owing to its high water retention capacity. With the exception of color, the overall sensory attributes did not show significant differences among coagulants.     

Natural occurrence of ochratoxin A in Tunisian cereals

Ochratoxin A (OTA) is a mycotoxin produced by several fungal species from Aspergillus and Penicillium genera. It is widespread in food and feed and its occurrence has been reported in cereals, cereal-derived products, dried fruits and spices. This mycotoxin was implicated in several human and animal pathologies such as the Balkan Endemic Nephropathy (BEN) and the Tunisian Chronic Interstitial Nephropathy (CIN) of unknown cause. In Tunisia, a clear correlation has been established between the consumption of OTA contaminated food and the induction of specific pathologies. Thereby, OTA was detected in human blood and tissues. The aim of our study was to investigate the presence of OTA in widely consumed cereals commercialized in Tunisia. The analytical methods used in our study involved the extraction of OTA by acidified toluene, immunoaffinity (IAC) clean-up and HPLC quantification with fluorescence detection. Levels and percentages of OTA contamination in different types of cereals, 110 wheat, 103 barley, 113 sorghum and 96 rice samples, were evaluated with incidences of 38%, 40%, 38% and 28%, respectively. The average of contamination by OTA found were 55, 96, 44 and 117 μg/kg, respectively, for wheat, barley, rice and sorghum. Our results showed that contamination percentages and levels in the period from 2004 to 2005 were higher then usual norms (5.0 μg OTA/kg) established by the European commission in 2002. The present report is the first one ever carried out on the natural occurrence of OTA in cereals, largely consumed by the Tunisian population.     

Evolution of ochratoxin A content during red and rose vinification

BACKGROUND: This work aims to investigate the effects of the common vinification steps on the fate of the ochratoxin A (OTA) during wine making. Two assays of red and rose microvinification, with artificially contaminated grapes, were performed. The content of this mycotoxin was also monitored throughout the process of red wine making from naturally contaminated grapes in a winery. RESULTS: The results from the different assays revealed that the maceration of pomace have a significant effect on the increase of OTA content in red wine (P < 0.05) whereas the alcoholic fermentation had a reducing effect. However, the spontaneous malolactic fermentation showed no significant effect on the OTA content in wine (P > 0.05). Storage of red wine in tanks followed by draining caused a significant decrease of OTA of about 55%. Clarification with a gelatin oenological fining agent contributed to the removal of up to 58% of OTA from red wine. CONCLUSION: Overall, a consistent decrease in OTA concentration was noticed throughout either red or rose vinification. This work has contributed to the understanding of the fate of OTA during different vinification processes, especially from naturally contaminated grapes. Copyright © 2008 Society of Chemical Industry     

Optimized Gated Recurrent Unit for Mid-Term Electricity Price Forecasting

Electricity price forecasting (EPF) is important for energy system operations and management which include strategic bidding, generation scheduling, optimum storage reserves scheduling and systems analysis. Moreover, accurate EPF is crucial for the purpose of bidding strategies and minimizing the risk for market participants in the competitive electricity market. Nevertheless, accurate time-series prediction of electricity price is very challenging due to complex nonlinearity in the trend of electricity price. This work proposes a mid-term forecasting model based on the demand and price data, renewable and non-renewable energy supplies, the seasonality and peak and off-peak hours of working and non-working days. An optimized Gated Recurrent Unit (GRU) which incorporates Bagged Regression Tree (BTE) is developed in the Recurrent Neural Network (RNN) architecture for the mid-term EPF. Tanh layer is employed to optimize the hyperparameters of the heterogeneous GRU with the aim to improve the model’s performance, error reduction and predict the spikes. In this work, the proposed framework is assessed using electricity market data of five major economical states in Australia by using electricity market data from August 2020 to May 2021. The results showed significant improvement when adopting the proposed prediction framework compared to previous works in forecasting the electricity price.     

A quantum mechanics-based algorithm for vessel segmentation in retinal images

Blood vessel segmentation is an important step in retinal image analysis. It is one of the steps required for computer-aided detection of ophthalmic diseases. In this paper, a novel quantum mechanics-based algorithm for retinal vessel segmentation is presented. The algorithm consists of three major steps. The first step is the preprocessing of the images to prepare the images for further processing. The second step is feature extraction where a set of four features is generated at each image pixel. These features are then combined using a nonlinear transformation for dimensionality reduction. The final step is applying a recently proposed quantum mechanics-based framework for image processing. In this step, pixels are mapped to quantum systems that are allowed to evolve from an initial state to a final state governed by Schrödinger’s equation. The evolution is controlled by the Hamiltonian operator which is a function of the extracted features at each pixel. A measurement step is consequently performed to determine whether the pixel belongs to vessel or non-vessel classes. Many functional forms of the Hamiltonian are proposed, and the best performing form was selected. The algorithm is tested on the publicly available DRIVE database. The average results for sensitivity, specificity, and accuracy are 80.29, 97.34, and 95.83 %, respectively. These results are compared to some recently published techniques showing the superior performance of the proposed method. Finally, the implementation of the algorithm on a quantum computer and the challenges facing this implementation are introduced.     

Alumina physically loaded by thiosemicarbazide for selective preconcentration of mercury(II) ion from natural water samples

The multifunctional ligand, thiosemicarbazide, was physically loaded on neutral alumina. The produced alumina-modified solid phase (SP) extractor named, alumina-modified thiosemicarbazide (AM-TSC), experienced high thermal and medium stability. This new phase was identified based on surface coverage determination by thermal desorption method to be 0.437+/-0.1 mmol g(-1). The selectivity of AM-TSC phase towards the uptake of different nine metal ions was checked using simple, fast and direct batch equilibration technique. AM-TSC was found to have the highest capacity in selective extraction of Hg(II) from aqueous solutions all over the range of pH used (1.0-7.0), compared to the other eight tested metal ions. So, Hg(II) uptake was 1.82 mmol g(-1) (distribution coefficient log K(d)=5.658) at pH 1.0 or 2.0 and 1.78, 1.73, 1.48, 1.28 and 1.28 mmol g(-1) (log K(d)=4.607, 4.265, 3.634, 3.372 and 3.372), at pH 3.0, 4.0, 5.0, 6.0 and 7.0, respectively. On the other hand, the metal ions Ca(II), Fe(III), Co(II), Ni(II), Cu(II), Zn(II), Cd(II) and Pb(II) showed low uptake values in range 0.009-0.720 mmol g(-1) (log K(d)<3.0) at their optimum pH values. A mechanism was suggested to explain the unique uptake of Hg(II) ions based on their binding as neutral and chloroanionic species predominate at pH values < or =3.0 of a medium rich in chloride ions. Application of the new phase for the preconcentration of ultratrace amounts of Hg(II) ions spiked natural water samples: doubly distilled water (DDW), drinking tap water (DTW) and Nile river water (NRW) using cold vapor atomic absorption spectroscopy (CV-AAS) was studied. The high recovery values obtained using AM-TSC (98.5+/-0.5, 98.0+/-0.5 and 103.0+/-1.0) for DDW, DTW and NRW samples, respectively based on excellent enrichment factor 1000, along with a good precision (R.S.D.% 0.51-0.97%, n=3) demonstrate the accuracy and validity of the new modified alumina sorbent for preconcentrating ultratrace amounts of Hg(II) with no matrix interference.