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Abstract

Minimal processing technologies, like High Hydrostatic Pressure (HHP), heat treatments at low temperatures have an increasing role in food industry. Eggs are considered as functional foods, but for high retention of biological active compounds adequate minimal processing technologies are needed during preservation procedure. In our study, liquid egg yolk (LEY) was examined to meet consumer's expectations.

Combinations of pasteurization (57–63 °C, 5–7 min) and HHP (350–400 MPa, 5 min) were used to provide microbiological stability of LEY. After these treatments samples were examined for mesophyll aerobes and Enterobacteriaceae cell counts (using Nutrient agar an incubation of 30 °C, 48 h) and viscosity attributes (Anton Paar MCR 92).

Our results show that microbiological stability is significantly influenced by the different parameters of heat treatments and HHP. Heat treatment effected at least 3 orders of magnitude decrease in cell count. Viscosity attributes point out that higher pressure of HHP have a stronger effect on viscosity than the temperature of pasteurization.

The results point out a great opportunity for industrial use of minimal processing technologies for LEY. Microbiological safety is strongly influenced by the order of treatments, but viscosity may be independent from the order of the treatments.

Open access
Progress in Agricultural Engineering Sciences
Authors:
Emna Ayari
,
Csaba Németh
,
Karina Ilona Hidas
,
Adrienn Tóth
,
Dávid Láng
, and
László Friedrich

Abstract

Starting from mechanical revolution, each day new methods and new equipment have emerged. Today, the Ultra Heat Treatment (UHT) is one of the important technologies that permits to the industry to reduce processing time while maintaining the same quality of the products. Egg and egg products are known as heat-sensitive products, so the UHT enables us to preserve their qualities after a heat treatment.

Our aim is to study the effect of UHT treatment (approximately 67 °C for 190 s) on the Liquid Egg Yolk (LEY). For twenty-one days, the color and the apparent viscosity were measured every seven days, we also studied the damage of protein using DSC (Differential Scanning Calorimetry).

Comparing the two graphs of DSC, the denaturation of protein is distinct. The endothermic peak decreased. This could be seen also on the rheological curves. The apparent viscosity is diminished from 231 mPa.s on the 1st day of storage to 224 mPa.s on 21st day. However, the treated LEY could be stored for longer period than the raw LEY.

Open access
Progress in Agricultural Engineering Sciences
Authors:
Katalin Badak-Kerti
,
Viktória Zsom-Muha
,
Tamás Zsom
,
Dávid Nagy
, and
József Felföldi

Abstract

In the experiments, the sound generated during the breaking of chocolate samples was examined. The fracture was performed by a precision penetrometer, the breaking sound was recorded. Texture index (TI) was calculated from the resulting signal. First the change of the resulting TI was monitored as a function of the samples' temperature. The sample groups of the same dark chocolate with different temperatures were completely separated from each other with statistical tool (LDA, linear discriminant analyses), but no trend was found to describe the change. Secondly, based on the TI, we could identify and classify the chocolate samples in the appropriate groups (based on cocoa content from 40 to 85%). According to linear discriminant analyses chocolates with different cocoa content were completely separated and showed a certain pattern. Based on the obtained results, it can be stated that the cocoa content of chocolate can be determined on the basis of TI obtained by acoustic method.

Open access

Abstract

Grapevine berry shape has important marketing value in the table grape commerce, hence variability evaluation of this characteristic is highly important. In this study berry shape of 5 table grape genotypes: “Fanny”, “Lidi”, “Hamburgi muskotály”, “Moldova”, and “Orsi” were compared. To evaluate the shape variability graphic reconstruction and elliptic Fourier analysis have been carried out. Shape outlines have been investigated and Principal Component Analysis (PCA) has been performed with the SHAPE software package. PCA of the contours showed that 6 out of the 77 principal components were effective to describe shape attributes. The first 6 PCs explained 94.51% of the total variance. PC1 associated with the width and length of the berry. PC2 related to the shape of the top and bottom of the berries, while PC3 linked to the ratio of the top and the bottom width. ANOVA of the principal component scores revealed significant difference among the genotypes. Results suggest that morphology of the berry is a variable not only among but within the accessions. Our findings confirmed that elliptic Fourier descriptors (EFDs) would be a powerful tool for quantifying grapevine berry morphological diversity.

Open access

Abstract

The engineering application's design process starts with a concept, based on our theoretical knowledge and continues with a numerical simulation. In our paper, we review the finite volume method (FVM) which is used generally for heat and fluid dynamic simulations.

We compare three different computational fluid dynamics (CFD) software (based in the fine volume method) for validating a NACA airfoil, which can be used for example in the aerospace industry for an airplane's wing profile, and it can be used for example in the renewable industry for a wind turbine's blade or a water turbine's impeller profile. At the end of this paper, the result of our simulations will be compared with a validation case and the difference between the CFD software and the measured data will be presented.

Open access

Abstract

This research aims to determine whether the treatment of food products in a microwave electromagnetic field is advantageous or disadvantageous compared to conventional technologies. In household practice, microwave energy transfer is used mostly for heating. One of the most important tangible benefits of microwave heat treatment is that it causes less damage to the nutritional value of the product due to its speed.

Despite the fact that microwave technology was introduced more than 70 years ago, it is still not clear whether its application results in equivalent products in terms of quality and food safety.

This study demonstrates how heat-treated wines with microwave energy transmission and with convective heating in a thermostatic water bath are affected. In the white, rose and red wine samples pasteurized at a temperature of 74 ± 0.5 °C, significant differences between the two heating methods regarding colour characteristics could be indicated.

Open access

Abstract

Industrial wastewater is a growing environmental challenge due to its high concentrations of organics and its limited biological degradability. Up to date, however, no published work discussed industrial wastewater characterization, which is the focus of this study. Moreover, the effect of hydrothermal treatment on the chemical oxygen demand (COD) removal and the soluble chemical oxygen demand (SCOD) release was investigated in this work. Wastewater samples were collected from different industrial sites and characterized in order to determine their initial properties. It was summarized that the salinity of wastewater estimated by EC was relatively low, and its pH values were in the acceptable range. On the other hand, however, high values of sodium absorption ratio (SAR) were obtained in all samples post to hydrothermal treatment. Nonetheless, our results revealed higher SCOD release post to hydrothermal treatment suggesting better efficiency of COD removal obtained by this treatment technique.

Open access

Abstract

In milling industry, the object of milling is to separate endosperm and bran parts of wheat, and to recover flour. The most important and the highest energy requirement operation is grinding. The quantity and quality of flour depends on: the variety of wheat that will be milled, the type of grinding equipment and the condition used before the grinding. During our experiments two different grain structured varieties of wheat were milled in laboratory conditions with disk, stone grinder and roller miller in air-dry, and conditioned states. The performance of the equipment and the particle size distribution (PSD) of the produced grist were measured, then the energy requirements of the grinders were calculated. In the milling experiments the ash contents of the different particle sized fractions were compared to map particular properties of wheat cultivars.

Open access
Progress in Agricultural Engineering Sciences
Authors:
Tamás Zsom
,
Petra Polgári
,
Lien Phuong Le Nguyen
,
Géza Hitka
, and
Viktória Zsom-Muha

Abstract

Broccoli's high perishability and its sensitivity to negative quality changes (i.e., mass loss, ethylene induced degreening, abscission of leaves, and florets) generates quality problems during postharvest. Freshly harvested samples were stored at 5 and 21 °C after separately treated for 24 h with 625 ppb 1-methyl-cyclopropene (1-MCP), 24 h with 2 ppm ethylene and 1-MCP followed by ethylene. Quality maintenance effectivity of 1-MCP was investigated during cold and room storage by non-destructive optical methods (chlorophyll fluorescence and DA-index®) and by the evaluation of the visual physiological symptoms. The highly positive effects of 1-MCP treatment combined with cold storage were obviously proven on quality maintenance providing better retention of initial quality related to the initial mature green stage as chlorophyll content related DA-index®; F m , F v , F v /F m , and F m /F 0 chlorophyll fluorescence values. From the practical point of view, the rapid, and easy-to-use Sintéleia FRM01-F Vis/NIR DA-meter® could be applied relatively easy for the quality measurement of broccoli. The reproducibility of quality determination could be increased by the enhanced number of measuring points or using computer aided imaging methods (i.e., chlorophyll fluorescence imaging, machine vision system) providing global and more reliable information about quality changes.

Open access
Progress in Agricultural Engineering Sciences
Authors:
Judit Perjéssy
,
Ferenc Hegyi
,
Magdolna Nagy-Gasztonyi
,
Rita Tömösközi-Farkas
, and
Zsolt Zalán

Abstract

Nowadays, demand for products which beyond the overall nutritional value have a feature that protects the consumer health, have increased. Several studies have proved that fruit juices can become a suitable carrier or medium for probiotic organisms. Therefore, the aim of our study was to investigate the possibility of the probiotication of sour cherry juice (SCJ) by fermentation with probiotic starter culture. During the fermentation 9 Lactobacillus strains were used and Újfehértói fürtös sour cherry species as raw material. To reach the recommended probiotic cell count we investigated the pH adjustment, supplementation of nutrients, the effect of dilution, and strain adaptation to SCJ. In our study the properties of the strains – such as reproduction and metabolism – and its effect on the raw material were investigated. A significant difference was observed between the number of viable cells of certain Lactobacillus strains, that is important in point of view of the development of probiotic-containing products. Furthermore, the lactic acid fermented SCJ can enhance the polyphenol content and antioxidant activity to promote the health of consumers.

Open access