Variations of Total Phenolic Content in Honey Samples Caused by Different Calibration Lines

In the review of total phenolic contents (TPCs) of acacia, lime, and chestnut honey samples from several literature sources, large differences were noticed, which cannot be attributed only to seasonal or geographical variations. The dependence of TPC on the process of construction of the calibration line is illustrated in the measurement of acacia, lime, and chestnut honey types from Croatia and neighbouring countries (Serbia, Italy, and Hungary). TPCs are determined for 39 uni-floral honey samples by four calibration lines and four TPC values are obtained for each honey sample. Obtained results are compared mutually, as well as with the literature results for honey samples of the same type. For each honey type, the average of all determined TPCs determined in this study is in the middle of literature values. The average TPC values for chestnut honey samples were found to be 1.5 and 3 times higher than those for lime and acacia, respectively. The effects of two factors regularly considered in the determination of calibration lines are analyzed: (1) the concentration range of the standard chemical and (2) whether the calibration line is drawn through the origin, or not. The final results strongly depend on these two factors that should be considered in future TPC estimations. This work is licensed under a Creative Commons Attribution 4.0 International License

Influence of the Beehive Type on the Quality of Honey

Agricultural producers apply numerous technological procedures, and enlarging efforts to produce the high-quality products. This initiative is present in the beekeeping, too. The quality of the honey produced by the honey bee colonies depends of various factors, but prevailing are the ecological conditions and the floristic composition of the honeyfull plants. The aim of our research was to discover the influence of the beehive type on the quality of honey, which is produced at apiaries under the similar environmental conditions. The whole studied honey bee colonies belong to the European race, Apis mellifera carnica, and they used the same honeyfull plants pastures. The results indicate that different beehive type used at apiaries influenced on the quality of honey

Structure-Radical Scavenging Activity Relationships of Flavonoids

The relationship between the structural characteristics of 29 flavonoids and their antiradical activity was studied. The obtained results suggest that the free radical scavenger potential of these polyphenolic compounds closely depends on the particular substitution pattern of free hydroxyl groups on the flavonoid skeleton. The possible mechanism of action of flavonoids lacking B ring OHs as free radical scavengers has been proposed

Influence of the Beehive Type on the Quality of Honey

Agricultural producers apply numerous technological procedures, and enlarging efforts to produce the high-quality products. This initiative is present in the beekeeping, too. The quality of the honey produced by the honey bee colonies depends of various factors, but prevailing are the ecological conditions and the floristic composition of the honeyfull plants. The aim of our research was to discover the influence of the beehive type on the quality of honey, which is produced at apiaries under the similar environmental conditions. The whole studied honey bee colonies belong to the European race, Apis mellifera carnica, and they used the same honeyfull plants pastures. The results indicate that different beehive type used at apiaries influenced on the quality of honey

Vitisin-Type Pigments: Possible Novel Food Colors

Spectral properties of different forms of several vitisin-type pigments, recently found in red wines and grapes, were studied. These orange-red tone compounds seem to be promising anthocyanin based food colors

Vitisin-Type Pigments: Possible Novel Food Colors

Spectral properties of different forms of several vitisin-type pigments, recently found in red wines and grapes, were studied. These orange-red tone compounds seem to be promising anthocyanin based food colors

Structure-Radical Scavenging Activity Relationships of Flavonoids

The relationship between the structural characteristics of 29 flavonoids and their antiradical activity was studied. The obtained results suggest that the free radical scavenger potential of these polyphenolic compounds closely depends on the particular substitution pattern of free hydroxyl groups on the flavonoid skeleton. The possible mechanism of action of flavonoids lacking B ring OHs as free radical scavengers has been proposed

A Simple QSAR Model for Trypsin Aminopeptidase Inhibitory Flavonoids

A simple QSAR model of the trypsin aminopeptidase inhibitory flavonoids has been developed which enables prediction of the inhibitory potency of flavonoids as a function of their molecular properties. Based upon the results obtained, a possible mode of interaction between the flavonoid and its target receptor is proposed

OXIDATIVE STRESS UNDER INTENSE PHYSICAL EXERTION IN HUMANS AND ANIMALS

Poremećaj ravnoteže u organizmu između proizvodnje reaktivnih kisikovih radikala (ROS) i antioksidansa nazivamo oksidacijskim stresom. Do pomaka ravnoteže dolazi ukoliko je smanjena antioksidacijska obrana organizma ili ako je povećano stvaranje slobodnih radikala. Antioksidansi su sve one tvari koje u maloj količini u kratkome vremenu neutraliziraju djelovanje slobodnih radikala i drugih oksidansa. Oni nastaju u stanici ili se u organizam unose hranom ili u obliku dodataka. Antioksidansi onemogućuju stvaranje slobodnih radikala u organizmu, uništavaju stvorene slobodne radikale ili popravljaju oštećenja u stanici nastala djelovanjem slobodnih radikala.U radu su prikazani biomarkeri oksidacijskog stresa u ljudi i životinja, prema podjeli na enzimske, neenzimske, te ostale biomarkere s naglaskom na biomarkere umora perifernih mišića. Biomarkeri umora perifernih mišića u ljudi i životinja su markeri staničnog mišićnog oštećenja i pokazatelji mišićnog stresa, a koriste se za uvid u mehanizme iscrpljenosti tijekom vježbanja kako bi se otkrio povećani umor ili se otkrili manjkavi metabolički putevi. Utvrđivanje oksidacijskog stresa važno je zbog mogućnosti pravovremenog uključivanja antioksidacijskih tvari koji povećavaju antioksidacijski kapacitet ljudskog i životinjskog organizma.Oxidative stress indicates an imbalance in the body between pro-oxidant and antioxidant in favor of a pro-oxidant. To shift the balance may occur if the reduced antioxidant defense of the body or if the increased production of free radicals. Antioxidants are those substances that in a small amount in a short time can neutralize free radicals and other oxidants. They are produced in the cell or organism in food intake or in the form of dietary antioxidants in food or liquid to drink. Antioxidants prevent the formation of free radicals in the body, destroying free radicals created or repair damage in cells caused the action of free radicals. Paper showed biomarkers of oxidative stress in humans and animals, divided to enzymatic, non-enzymatic and other. Biomarkers of peripheral muscle fatigue in humans and animals are markers of cellular muscle damage and muscle stress indicators, and are used for insight into the mechanisms of fatigue during exercise to detect increased fatigue or found deficient metabolic pathways. The determination of oxidative stress is important because of the possibility of timely inclusion of antioxidant substances that increase the antioxidant capacity of human and animal organism

Estimation of Random Accuracy and its Use in Validation of Predictive Quality of Classification Models within Predictive Challenges

Shortcomings of the correlation coefficient (Pearson's) as a measure for estimating and calculating the accuracy of predictive model properties are analysed. Here we discuss two such cases that can often occur in the application of the model in predicting properties of a new external set of compounds. The first problem in using the correlation coefficient is its insensitivity to the systemic error that must be expected in predicting properties of a novel external set of compounds, which is not a random sample selected from the training set. The second problem is that an external set can be arbitrarily large or small and have an arbitrary and uneven distribution of the measured value of the target variable, whose values are not known in advance. In these conditions, the correlation coefficient can be an overoptimistic measure of agreement of predicted values with the corresponding experimental values and can lead to a highly optimistic conclusion about the predictive ability of the model. Due to these shortcomings of the correlation coefficient, the use of standard error (root-mean-square-error) of prediction is suggested as a better quality measure of predictive capabilities of a model. In the case of classification models, the use of the difference between the real accuracy and the most probable random accuracy of the model shows very good characteristics in ranking different models according to predictive quality, having at the same time an obvious interpretation