Chokeberry fruits can be treated as very rich sources of bioactive compounds and, therefore, have a very high biological value. The purpose of the study was to compare selected chemical and physical properties of chokeberry fruits, both from organic and conventional cultivations located near Cracow. Chemical composition of the fruit, content of the antioxidant activity, bioactive compounds, and ultra-weak luminescence were analyzed. It was proved that chokeberry fruits are rich in bioactive compounds and that ecological crops produce fruits with a higher level of such compounds. Chokeberry fruits from organic farms were proven to have a higher content of bioactive ingredients and antioxidant activity than in traditionally grown fruits. The total amount of sugars was ambiguous because both the highest and the lowest values were determined in fruits from traditional cultivation. Photon emissivity determined on the basis of ultra-weak luminescence was higher in fruits from organic cultivations. A very high correlation was also found between the photon emissivity and the content of polyphenols as well as the antioxidant activity.

Black chokeberry (Aronia melanocarpa L.) fruit and processed berries have very high biological value because they are a rich source of bioactive compounds. The method of black chokeberry juice preservation is of key importance. One of the more recent ways in which semiliquid and liquid products can be preserved is the pulsed electric field (PEF) method. The aim of our study was to compare chosen physical and chemical properties of fresh and PEF-preserved chokeberry fruit juices derived from farms located in the vicinity of Cracow (Kraków). The analysis focused on the physical properties and chemical composition of black chokeberry juices, their bioactive compound content, and antioxidant activity. After using the PEF method, there was an increase in dry weight, sugars, and polyphenols, which could be caused by the slight evaporation of water during the process. During this process, antioxidant activity decreased, and ultra-weak luminescence slightly increased. The process of preserving juices using the PEF method is a good way to preserve the bioactive properties of the obtained aronia juices.

Concentrated microwave field (CMF) is the technology for preserving liquid food products, where the preservation factor is both a nonthermal effect and a moderate thermal effect. The term “concentrated microwave field” is traditionally used in Poland and is the equivalent to “single-mode-type microwave heating”. The aim of the research was to determine selected physical and rheological properties of liquid egg white, liquid yolk and liquid whole eggs (LWE) after CMF treatment. It was found that both the amount of energy supplied to the system and the intervals between CMF pulses had a statistically significant impact on the analyzed properties of liquid egg raw materials. In industrial practice, it would be recommended to use lower CMF treatment (at the level of 2.2–2.6 kJ) for the yolk, medium (3.2–3.6 kJ) for egg white and higher (4.0–4.4 kJ) for the liquid whole eggs. The “response surface” models presented in the paper may have a practical application in determining the influence of individual technological parameters on the final quality of various liquid food products.

The influence of selected physical and rheological properties of the egg mass after the treatment of concentrated microwave field (CMF) was analysed in the study. CMF treatment can be generated in the continuous or pulsed way where microwave field is concentrated by a special waveguide. The raw material for the research was fresh hen eggs obtained from Leghorn Brown laying hens at the age of 30-50 weeks. The study investigated the effect of CMF pulses on the raw material, where the variable parameters were intervals between single pulses of 0.5 s, 1.0 s or 1.5 s, as well as 3 different numbers of CMF pulse packets for each of these intervals (5, 7 or 9). In this way, 9 research variants were obtained, not counting the control sample. After completion of the CMF treatment, the temperature of the samples was measured, and then they were cooled down to the temperature of 20 °C, where the analysis of active acidity (pH), color measurements expressed as L*a*b* and viscosity was performed. The results were statistically processed using the analysis of variations, Duncan’s test and the so-called “Response Surface Methodology” with corresponding Pareto charts showing the significance of the analyzed variables and their interactions. It was found that both the amount of energy supplied to the system and the intervals between the CMF pulses for most of the analyzed parameters had a statistically significant effect. The “response surface” models may have practical application, eg in industrial conditions, in determining the impact of individual technological parameters on the final quality of food products, including physical and rheological characteristics.

No abstract