Róbert Romvári

NIR detection of honey adulteration reveals differences in water spectral pattern

High fructose corn syrup (HFCS) was mixed with four artisanal Robinia honeys at various ratios (0-40%) and near infrared (NIR) spectra were recorded with a fiber optic immersion probe. Levels of HFCS adulteration could be detected accurately using leave-one-honey-out cross-validation (RMSECV=1.48; R(2)CV=0.987), partial least squares regression and the 1300-1800nm spectral interval containing absorption bands related to both water and carbohydrates. Aquaphotomics-based evaluations showed that unifloral honeys contained more highly organized water than the industrial sugar syrup, supposedly because of the greater variety of molecules dissolved in the multi-component honeys. Adulteration with HFCS caused a gradual reduction of water molecular structures, especially water trimers, which facilitate interaction with other molecules. Quick, non-destructive NIR spectroscopy combined with aquaphotomics could be used to describe water molecular structures in honey and to detect a rather common form of adulteration.

Individual and combined haematotoxic effects of fumonisin B1 and T-2 mycotoxins in rabbits

Weaned rabbits were fed diets contaminated with 2 mg/kg diet T-2 toxin alone, or 10 mg/kg diet fumonisin B1 (FB1) alone, and both toxins in combination (2+10 mg/kg, resp.), as compared to a toxin free control. Samplings were performed after 2 and 4 weeks. Bodyweight of the T-2 fed group was lower after 4 weeks; the liver weight increased dramatically. Red blood cell (RBC) Na(+)/K(+) ATPase activity decreased after 4 weeks in the T-2 group, it increased in the FB1 group and antagonism was found by the combined treatment. The RBC membrane fatty acid profile was modified by both toxins similarly during the entire feeding. After 4 weeks T-2 alone and in combination (with FB1) was found to increase mean cell volume (MCV). The time-dependent alterations in the T-2 group were significant for MCV (increase) and the mean cell haemoglobin (increase). The active monovalent cation transport was altered by both mycotoxins. Most probably FB1 exerts its sodium pump activity modification via an altered ceramide metabolism (behenic acid decrease in the RBC membrane), while for T-2 toxin a moderate membrane disruption and enzyme (protein) synthesis inhibition was supposed (ca. 75% decrease of the sodium pump activity).

Effect of egg composition on hatchability and on growth and slaughter characteristics of meat-type chicks

1. Using the so-called TOBEC (Total Body Electrical Conductivity) method, which allows the determination of egg composition in vivo, correlations between egg composition, hatchability and hatched chicks’ development were studied. 2. A total of 1500 hen eggs (Ross-308) were measured by TOBEC, and eggs with extremely high (10%, n = 150), extremely low (10%, n = 150) and average (10%, n = 150) electrical conductivity values were chosen for further investigation. 3. During the incubation period, it was observed that eggs with high electrical conductivity had a significantly higher mortality than eggs with low electrical conductivity. 4. It was observed that both the increase in electrical conductivity at the same egg weight, and the increase in egg weight at the same electrical conductivity resulted in an increase in the hatching weight. 5. It was found that the dry matter, protein and fat content of the chicks hatched from eggs with low electrical conductivity was higher at hatching than that of the chicks hatched from eggs with high electrical conductivity. 6. At 42 d of age the liveweight of cocks and pullets hatched from eggs with low electrical conductivity was 3·2 and 8·2% higher than the liveweight of cocks and pullets hatched from eggs with high electrical conductivity. 7. Because of the higher liveweight at slaughter, there was a significant superiority of the chicks hatched from eggs with low electrical conductivity in the case of the examined carcase traits at slaughter. 8. Similar tendencies were found also in the ratios of carcase variables to liveweight, but the between group differences were not statistically significant in this case. 9. Based on the results it was concluded that TOBEC seems to be a useful method for separating eggs with different composition. 10. This could be a good starting point for further in vivo investigations in order to clarify the effect of egg composition on hatchability and further development.

Multicomponent blood lipid analysis by means of near infrared spectroscopy, in geese

This study provides accurate near infrared (NIR) spectroscopic models on some laboratory determined clinicochemical parameters (i.e. total lipid (5.57±1.95 g/l), triglyceride (2.59±1.36 mmol/l), total cholesterol (3.81±0.68 mmol/l), high density lipoprotein (HDL) cholesterol (2.45±0.58 mmol/l)) of blood serum samples of fattened geese. To increase the performance of multivariate chemometrics, samples significantly deviating from the regression models implying laboratory error were excluded from the final calibration datasets. Reference data of excluded samples having outlier spectra in principal component analysis were not marked as false. Samples deviating from the regression models but having non outlier spectra in PCA were identified as having false reference constituent values. Based on the NIR selection methods, 5% of the reference measurement data were rated as doubtful. The achieved models reached R(2) of 0.864, 0.966, 0.850, 0.793, and RMSE of 0.639 g/l, 0.232 mmol/l, 0.210 mmol/l, 0.241 mmol/l for total lipid, triglyceride, total cholesterol and HDL cholesterol, respectively, during independent validation. Classical analytical techniques focus on single constituents and often require chemicals, time-consuming measurements, and experienced technicians. NIR technique provides a quick, cost effective, non-hazardous alternative method for analysis of several constituents based on one single spectrum of each sample, and it also offers the possibility for looking at the laboratory reference data critically. Evaluation of reference data to identify and exclude falsely analyzed samples can provide warning feedback to the reference laboratory, especially in the case of analyses where laboratory methods are not perfectly suited to the subjected material and there is an increased chance of laboratory error.

Carbon monoxide stunning of Atlantic salmon (Salmo salar L.) modifies rigor mortis and sensory traits as revealed by NIRS and other instruments.

BACKGROUND Methods of stunning used in salmon slaughter are still the subject of research. Fish quality can be influenced by pre-, ante- and post-mortem conditions, including handling before slaughter, slaughter methods and storage conditions. Carbon monoxide (CO) is known to improve colour stability in red muscle and to reduce microbial growth and lipid oxidation in live fish exposed to CO. Quality differences in Atlantic salmon, Salmo salar L., stunned by CO or percussion, were evaluated and compared by different techniques [near infrared reflectance spectroscopy (NIRS), electronic nose (EN), electronic tongue (ET)] and sensory analysis. RESULTS Thawed samples, freeze-dried preparates and NIRS devices proved to be the most efficient combinations for discriminating the treatments applied to salmon, i.e. first the stunning methods adopted, then the back-prediction of the maximum time to reach rigor mortis and finally to correlate some sensory attributes. A trained panel found significant differences between control and CO-stunned salmon: reduced tactile crumbliness, reduced odour and aroma intensities, and reduced tenderness of CO-treated fillets. CO stunning reduced radiation absorbance in spectra of thawed and freeze-dried fillets, but not fillet samples stored in ethanol, where it may have interacted with myoglobin and myosin. CONCLUSIONS The good results in a rapid discrimination of thawed samples detected by NIRS suggest suitable applications in the fish industry. CO treatment could mitigate sensory perception, but consumer tests are needed to confirm our findings.

Clinical chemistry of farmed red deer (Cervus elaphus) yearling hinds reared on grass or papillonaceous pasture paddocks in Hungary

Abstract. Yearling red deer (Cervus elaphus) hinds of identical initial body weight were reared on a monocotyledonous grass (group 1) or on a papillonaceous plant pasture (group 2) for 212 days. At the end of the experiment (when deer were shot) blood was taken from ten animals of each group for serum biochemical analysis. Hinds of group 2 provided higher final body weight (90±3.5 vs. 101±6.6 kg) and higher daily body weight gain (105.7±10.7 vs. 153.8±26.8 g/day). Within serum nitrogenous compounds group 2 provided higher total protein concentrations, while from the lipids only serum triglyceride levels were higher in this group. Serum potassium was in both groups higher than the reference range with a superposed slight hyperkalaemia in group 2. Higher lactate dehydrogenase and alkaline phosphatase activities were found in group 2 and lower aspartate aminotransferase activity values. Inorganic phosphate concentration showed a significant difference (group 1 provides higher values). Results refer to an expressed venison growth as a result of the rich dietary protein supply of group 2. Findings were evaluated as well with discriminant factor analysis, outlining the relative importance of the single blood biochemical parameters in shaping the inter-group differences.

In vivo tracking of maturation in male European eel, Anguilla anguilla (L.), by computed tomography

The present study aimed in vivo tracking of maturation of male eel by computed tomography (CT). Additionally, individually monitored testes sizes were correlated with the conventionally used external maturity indicators (i.e. eye and nose indexes) in order to test and improve their usefulness at individual level. Testes could be clearly identified with the CT from the end of the third week of hCG administration routinely used to induce maturation in fish. The volume of testes increased exponentially during hormone treatment, and by the end of the sixth week of maturation procedure all males produced motilable spermatozoa. Present results prove that testes size can noninvasively be monitored with CT from maturity level where testes size rich 3000 mm3 volume. Eye and nose indexes are in close correlation with testes volume and thus can also be effectively used to monitor maturity level of male eel, but preferably only at stock level. However, due to their high individual variability, these indexes can be applied only with caution at individual level and should be supplemented with other noninvasive techniques such as CT.

Negative allometry of docosahexaenoic acid in the fowl lung and pulmonary surfactant phospholipids.

In a recent study (Comp. Biochem. Physiol. B. (2010)155: 301-308) we reported that the fatty acids (FA) of the avian (7 species) total lung phospholipids (PL) (i.e. lung parenchyma and surfactant together) provide allometric properties. To test whether this allometric scaling also occurs in either of the above components, in six gallinaceous species, in a body weight range from 150 g (Japanese quail, Coturnix coturnix japonica) to 19 kg (turkey, Meleagris gallopavo) the PL FA composition (mol%) was determined in the pulmonary surfactant, in native and in thoroughly lavaged lungs (referred to as lung parenchyma). In all three components docosahexaenoic acid (DHA) showed significant and negative allometric scaling (B = -0.056, -0.17 and -0.1, respectively). Surfactant PLs provided further negative allometry for palmitic acid and the opposite was found for palmitoleate and arachidonate. In the lung parenchymal PLs increasing body weight was matched with shorter chain FAs (average FA chain length) and competing n6 and n3 end-product fatty acids (positive allometry for arachidonic acid and negative for DHA). Negative allometric scaling was found for the tissue malondialdehyde concentration in the native and lavaged lungs (B = -0.1582 and -0.1594, respectively). In these tissues strong correlation was found between the MDA concentration and DHA proportion (r = 0.439 and 0.679, respectively), denoting the role of DHA in shaping the allometric properties and influencing the extent of in vivo lipid peroxidation of membrane lipids in fowl lungs.

Identification of traditionally reared Mangalica pig's meat by near infrared spectroscopy using generalised partial least squares in open source R Project-a feasibility model study

The possibility for near infrared spectroscopy-based discrimination of meats originating from the extensively reared autochthonous breed of Mangalica and intensively reared commercial genotypes (Landrace, Large White, Landrace × Large White crossbreed) was investigated. Since there was a considerable difference between the intramuscular fat content of Mangalica and intensively-reared meats (average of 19.1 DM% vs 9.3 DM%, resp.), several sample selection options were applied to explore the impact of fat content on the results of NIR analysis. The system for discrimination was able to identify the different groups even when the discriminator equation was generated on very different samples and was tested on samples with overlapping fat content. The ratio of correctly classified samples was above 90% during cross-validation or for independent test samples of all comparisons, both in fresh or freeze-dried samples. Over 90% of independent fresh pork samples were correctly identified when the discriminator equation was generated with 70 randomly selected samples. This ratio increased up to over 95% when freeze-dried samples were applied. The generalised partial least squares package of open-source R Project seems to be a useful tool for qualitative analysis of NIR data recorded from meat samples.

Influence of Partial Fat Replacement With Lecithin on the Product Characteristics of a Special Hungarian Cold Cut

Replacement of animal fat with plant oils is a very popular research field, due to the increasing prevalence of cardiovascular diseases in association with saturated fatty acid consumption. The aim of this study was to reduce amount of pig backfat in a meat product (Parizsi) and to partially replace it with soybean- (SBL) or sunflower lecithin (SFL). Between the samples difference was realized in fatty acid (FA) profile, mostly in total n6 FA content. The replacement also altered the colour compared to the control. The oxidative stability (MDA) analysis showed that SBL was more prone towards preparation technology (10 nmol MDA/g) than the Sfl(9 nmol MDA/g). The lecithin appeared as foreign taste based on the sensory test. The aromatic difference, as assessed with electronic nose, was clearly detectable between Sfland SBL. The increasing supplementation levels were also properly distinguished with discriminant analysis within the SBL and Sflseries. Summarized, Sflwas found to be a better antioxidant, but S...