Effect of l-ascorbic acid addition on quality, polyphenolic compounds and antioxidant capacity of cloudy apple juices

Polyphenols are one of the most important dietary antioxidants, and the apples, being a major source of polyphenolic compounds. There is increasing evidence that the consumption of fruit and their preserves, which are rich sources of vitamins and phenolics, is negatively associated with lung cancer and coronary heart disease. The influence of ascorbic acid addition on the quality, polyphenolic profile and antioxidant capacity in 14 selected varieties of apple juices during the 3 years of study was examined. Evaluation of changes of ascorbic acid content allowed to demonstrate the differences in susceptibility of apples on the enzymatic oxidation. The study shows that the variations of the least susceptible to oxidation of ascorbic acid are ‘Shampion’ and ‘Topaz’, and to a lesser extent, ‘Szara Reneta’, ‘Arlet’ and ‘Jonafree’ apples. A total of 17 kinds of polyphenolic compounds including catechins, procyanidins, hydroxycinnamates, flavonols, anthocyanins and dihydrochalcones were identified in apple tissues by HPLC with DAD analysis and after phloroglucinolysis and LC–MS. During the 3 years of study, the addition of ascorbic acid positively affects on the polyphenol compounds and antioxidant capacity (DPPH, ABTS and FRAP), increasing their content in the analyzed samples by 65 and 433, 328 and 300 %, respectively. The correlation coefficient between DPPH, ABTS and FRAP antioxidant capacity and ascorbic acid was 0.71, 0.71 and 0.72, respectively.     

Microstructure,chemical composition,wear, and corrosion resistance of FeB–Fe<Subscript>2</Subscript>B–Fe<Subscript>3</Subscript>B surface layers produced on Vanadis-6 steel using CO<Subscript>2</Subscript> laser

The paper presents the study results of laser modification of FeB–Fe₂B surface layers produced on Vanadis-6 steel using pack cementation method. Microstructure, x-ray phase analysis, chemical composition study using wave dispersive spectrometry method, microhardness, corrosion resistance as well as surface condition, roughness, and wear resistance were investigated. The diffusion boronizing processes were performed at 900 °C for 5 h in the EKabor® powder mixture. The boronized layers had a dual-phase microstructure composed of two types of iron borides, FeB and Fe₂B, and their microhardness ranged from 1800 to 1400 HV. The laser surface modification was carried out on specimens after diffusion boronizing process using CO₂ laser with a nominal power of 2600 W. Laser beam power used in this experiment was equal to 1040 W and was constant. While the three values of scanning speed were used: 19, 48, and 75 mm/s. During laser modification, the multiple tracks were made where distance between of axis tracks was equal to 0.5 mm. As a result of this process, microstructure consisted of remelted zone, heat-affected zone, and substrate was obtained. In remelted zone, the boron-martensite eutectic was observed. Boronized layers after laser modification were characterized by the mild gradient of microhardness from surface to the substrate and their value was dependent on the scanning speed used and was between 1700 and 1100 HV. Corrosion resistance tests revealed reducing the current of corrosion in case of laser modification process. Wear resistance of laser modified specimens was improved in comparison to diffusion boronized layers.     

Physicochemical properties and biomimetic behaviour of α-TCP-chitosan based materials

In this paper we present a complex study on the preparation and characterization of the cement-type implant material composed of α-tricalcium phosphate and chitosan. α-TCP has already been used as an initial component of bone cement formulations. In most cases, however, it was synthesized using a solid state reaction. In our studies, highly reactive α-TCP powder was obtained by a wet chemical method. Chitosan is well known as a safe and biocompatible polymer. In our studies it was used to improve the characteristic of the cements. Chitosan was introduced into the bone cements in the form of acetic acid solution and acted as a binder for agglomerates of calcium phosphate grains but at the same time the impeded creation of interconnections inside the agglomerates. The concentration of acetic acid influenced the pore size distribution. In vitro investigations proved the high bioactive potential of the examined materials.     

Studies of levels of biogenic amines in meat samples in relation to the content of additives

The impact of meat additives on the concentration of biogenic amines and the quality of meat was studied. Fresh white and red meat samples were fortified with the following food additives: citric and lactic acids, disodium diphosphate, sodium nitrite, sodium metabisulphite, potassium sorbate, sodium chloride, ascorbic acid, α-tocopherol, propyl 3,4,5-trihydroxybenzoate (propyl gallate) and butylated hydroxyanisole. The content of spermine, spermidine, putrescine, cadaverine, histamine, tyramine, tryptamine and 2-phenylethylamine was determined by capillary isotachophoretic methods in meat samples (fresh and fortified) during four days of storage at 4°C. The results were applied to estimate the impact of the tested additives on the formation of biogenic amines in white and red meat. For all tested meats, sodium nitrite, sodium chloride and disodium diphosphate showed the best inhibition. However, cadaverine and putrescine were characterised by the biggest changes in concentration during the storage time of all the additives. Based on the presented data for the content of biogenic amines in meat samples analysed as a function of storage time and additives, we suggest that cadaverine and putrescine have a significant impact on meat quality.     

Drying of Garlic Slices Using Convective Pre-drying and Vacuum-Microwave Finishing Drying: Kinetics, Energy Consumption, and Quality Studies

Garlic slices were dehydrated by convective drying (CD) and by a combined method consisting of convective pre-drying followed by vacuum-microwave finishing drying (CPD-VMFD). Drying of garlic using VMFD led to samples with high values of lightness and slightly lower values of the coordinates a* and b*. The treatment CPD-VMFD significantly decreased the drying time from 630 min for CD to 49 min and contributed to an important energy saving compared with CD (54.4–86.3 %). The total drying time was shorter when vacuum microwaves were introduced earlier and microwave power was higher. The highest temperature (114 °C) was found for samples pre-dried to a moisture content of 60 % and then dried at 360 W while showing the lowest energy consumption (98?±?1 kJ?g^?1). In general, the total antioxidant capacity increased after drying of garlic slices; however, the content of total phenolic compounds showed the opposite trend, and thus other compounds, such as allicin, should be involved in the antioxidant capacity of dried garlic. Garlic slices were CP dried until 30 % of moisture content followed by VMFD at 240 or 360 W showed the best results in terms of energy consumption and antioxidant capacity.