The possibility of in vitro multi-enzymatic method application for the assessment of the influence of thermal treatments on organic matter digestibility of feed for ruminants

In vitro multi-enzymatic method is a two-step procedure that uses exogenous enzymes for incubation of feed that aim to imitate digestive processes in the animal. It is used for determination of organic matter digestibility (OMD) of various feedstuffs and complete mixtures used in ruminant nutrition. The aim of the present work was to determine whether this in vitro multi-enzymatic method can be applied for the assessment of the influence of thermal treatments on OMD of feed for ruminants. Samples of corn and complete mixture for cows (based on corn) were subjected to pelleting, steam flaking, micronization and extrusion. Statistical analysis of the results did not show significant increase of corn and complete mixture OMD after various thermal treatments compared to untreated samples, which can be explained by high digestibility of corn itself (exceeds 90%). Based on obtained results it can be concluded that applied in vitro method is not suitable for the assessment of the influence of thermal treatments on OMD of corn and corn based mixture, while future research should be broadened to analysis of samples with lower OMD, such as sorghum, oats and barley

Simple correlations for bubble columns and draft tube airlift reactors with dilute alcohol solutions

Simple empirical correlations were developed to predict gas holdup, liquid circulation time, downcomer liquid velocity and volumetric mass transfer coefficient in dilute alcohol solutions in bubble columns and draft tube airlift reactors with single orifice sparger. Also, new experiments were conducted with diluted alcohol solutions to n-octanol, expanding the experimental data from C1 up to C8. The proposed empirical correlations include, beside the superficial gas velocity, the alcohol chain length as the only factor to characterize the liquid phase. The suggested correlations have shown good agreement between the calculated and the experimental data

Conductometric method for determining water stability and nutrient leaching of extruded fish feed

Water stability of eight samples of extruded salmon feeds was first determined by applying two gravimetric methods developed by the authors: gravimetric static and wet sieving method. Then, the conductometric method, primarily developed for investigation of nutrient leaching of feed into the water by the authors, was used for each sample. The aim of this study was to evaluate the potential of the conductometric measurement as a technique for determining water stability of extruded fish feed. In order to find any correlation between the results of two gravimetric tests and conductometric method, correlation analysis was employed. The results of static and wet sieving method were expressed as water stability index, which was expressed as the percent of remained dry matter of sample after being disintegrated in the water. The results of conductometric method were shown as conductivity curves for each sample, giving the insight in rate of nutrient leaching during the time. The obtained values of water conductivity showed no significant (p < 0.05) correlation with the results of static water method, while there was a negative significant (p < 0.05) correlation with the results of wet sieving method during first four hours of pellets soaking in water. The highest correlation coefficients were obtained within the first hour of conductivity measurement, demonstrating that proposed conductometric method had a potential to be applied as a rapid and simple method for determination and relative comparison of salmon feed water stability.[ Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. III46012 and Grant no. TR31011

Reduction of cyanogenic glycosides by extrusion - influence of temperature and moisture content of the processed material

Тhe paper presents results of the investigation of the influence of extrusion temperature and moisture content of treated material on the reduction of cyanogenic glycosides (CGs) in linseed-based co-extrudate. CGs are the major limitation of the effective usage of linseed in animal nutrition. Hence, some technological process must be applied for detoxification of linseed before its application as a nutrient. Extrusion process has demonstrated several advantages in reducing the present CGs, since it combines the influences of heating, shearing, high pressure, mixing, etc. According to obtained results, the increase in both temperature and moisture content of the starting mixture decreased the content of CGs in the processed material. HCN content, as a measurement of GCs presence, ranged from 25.42 mg/kg, recorded at the moisture content of 11.5%, to 126 mg/kg, detected at the lowest moisture content of 7%. It seems that moisture content and temperature had the impact on HCN content of equal importance. However, the influence of extrusion parameters other than temperature and moisture content could not be neglected. Therefore, the impact of individual factors has to be tested together. [Projekat Ministarstva nauke Republike Srbije, br. III 46012

Determining the degree of powder homogeneity using PC-based program

The mixing of powders and the quality control of the obtained mixtures are critical operations involved in the processing of granular materials in chemical, metallurgical, food and pharmaceutical industries. Studies on mixing efficiency and the time needed for achieving homogeneity in the powder mashes production have significant importance. Depending on the characteristic of the materials, a number of methods have been used for the homogeneity tests. Very often, the degree of mixing has been determined by analyzing images of particle arrays in the sample using microscopy, photography and/or video tools. In this paper, a new PC-based method for determining the number of particles in the powder homogeneity tests has been developed. Microtracers®, red iron particles, were used as external tracer added before mixing. Iron particles in the samples of the mixtures were separated by rotary magnet and spread onto a filter paper. The filter paper was sprayed with 50% solution of ethanol for color development and the particles counted where the number of spots presented the concentration of added tracer. The number of spots was counted manually, as well as by the developed PC program. The program which analyzes scanned filter papers with spots is based on digital image analyses, where red spots were converted through few filters into a black and white, and counted. Results obtained by manual and PC counting were compared. A high correlation was established between the two counting methods

Optimization of co-solvent addition in supercritical fluid extraction of fat with carbon dioxide

This investigation is concerned with supercritical fluid extraction (SFE) using CO2, as an analytical technique for total fat extraction from food and feed samples. Its most significant advantages are safety, cleanness, and shorter extraction time. The main limitation of this technique includes the difficulty of extracting polar lipids due to the non-polar character of the solvent (CO2) used for the extraction. The influence of ethanol as a co-solvent on the SFE of mash pig feed was investigated in this paper. Total fat content was determined by SFE and Soxhlet method for ten commercially available mesh pig feeds. Yields of the fat extracted by both methods were plotted one against the other and compared. Statistically significant difference (p ≤ 0.05) has been found only between the total fat obtained by the Soxhlet extraction and SFE by pure CO2. Based on the mathematical model, maximum yield of the extracted fat is achieved at an ethanol addition of 0.67 ml/g of sample, when the other parameters are the same as recommended by the producer’s procedure

Analysis of aflatoxins B1 and G1 in maize by quechers

A reliable and easy method has been developed for the determination of aflatoxins B1 and G2 in maize samples. High performance liquid chromatography coupled with FLD (HPLC-FLD) with photochemical derivatization was used. Mycotoxins were extracted from maize using a QuEChERS-based extraction procedure. The optimized analytical conditions were evaluated in terms of recoveries, reproducibility, LOD, LOQ and linearity for aflatoxin B1 and aflatoxin G1 in maize. Extraction, chromatographic and detection conditions were optimized in order to increase sample sensitivity. The linearity was analyzed in the range of 0.4-20 μg/kg and the correlation coefficients (R2) were higher than 0.99 for aflatoxins B1 and G1. Blank samples were spiked at 1.0, 2.0 and 4.0 μg/kg, and the average recovery for aflatoxin G1 was 96.96±1.72% and for aflatoxin B1 it was 86.80±1.24%. RSDs were lower than 25% for both mycotoxins. LOD for both aflatoxins was 0.5 μg/kg and LOQ was 1.0 μg/kg, respectively

The quality analyses of olive cake fuel pellets - mathematical approach

This article investigates the effect of processing parameters (conditioning temperature and binder content), on final quality of produced agro-pellets for heat energy generation, obtained from four different olive cultivars using different technological parameters. Technological, physical and chemical properties of pellets (carbon, hydrogen, nitrogen and sulphur content, particle density, abrasion length, moisture, ash content, higher and lower heating values, fixed carbon and volatile matter content) have been determined to assess their quality. The performance of Artificial Neural Network (ANN) was compared with the performance of second order polynomial (SOP) model, as well as with the obtained experimental data in order to develop rapid and accurate mathematical model for prediction of final quality parameters of agro-pellets. SOP model showed high coefficients of determination (r2), between 0.692 and 0.955, while ANN model showed high prediction accuracy with r2 between 0.544 and 0.994. [Projekat Ministarstva nauke Republike Srbije, br. III 46005 i br. TR-31055

Determination of multiple mycotoxins in maize using quechers sample preparation and LC-MS/MS detection

A reliable and easy method has been used for the multiple mycotoxins determination of AFs, DON, ZEA and FBs in maize samples. Liquid chromatography cou­pled mass spectrometry (LC-MS/MS) was used. Mycotoxins have been extracted from maize using a QuEChERS-based extraction procedure. All validation parameters were in accordance with Reg. (EC) No 401/2006. The analyses of eight maize seed samples showed the AFs, DON, ZEA and FBs contamination with the values below the state limit standards