pyrolysis reaction, it is necessary and imperative to study the thermaldegradation of biomasses' types and evaluate their potential thermochemical valorization process. Thermogravimetric analysis is the main reliable technique used to study the thermal
Plus UV-Vis (Analytik Jena) instrument and expressed as mg cyanidin-3-O-glucoside/100 g DW. 1.4 Thermaldegradation kinetics The thermal stability was evaluated during heating the crude extract in citrate buffer pH 3.5 at 50 °C and 80 °C. Plotting lnC
In this work the influence of addition of different plant extracts (olive leaf, green tea, pine bark PE 95%, pine bark PE 5:1, red wine PE 30%, red wine PE 4:1, and bioflavonoids) to blackberry juice during heating (at 30, 50, 70 and 90 °C) on the anthocyanin and phenol contents, polymeric colour, and antioxidant activity was investigated. Also, reaction rate constant, half-lives of degradation, and activation energy were calculated. Control sample was juice without addition of extracts. The highest anthocyanin content at 30 °C was in samples with the addition of olive leaf and green tea. At 90 °C the highest anthocyanin content was measured in samples with the addition of extract of red wine and bioflavonoides. Samples supplemented with the extracts had much higher antioxidant activity in comparison to the control sample. Results showed that at 90 °C the sample with green tea supplementation had the lowest reaction rate constant and the highest half-life. Activation energy ranged from 29 to 44 kJ mol−1.
Passion fruit juice (PFJ) has a delicate flavour, very susceptible to thermal degradation. This study pursued to test the effect of sonication as non-thermal preservation method on some quality parameters of PFJ. The effect of ultrasound (20 kHz, 263 W, 89.25 μm) on the indigenous microflora, colour, pH, and ascorbic acid content of PFJ was studied. Firstly, the kinetic of microbial inactivation was determined for aerobic mesophilic bacteria and yeasts. Data was fitted to Weibull model, and a treatment time of 8 min was selected for stability studies. To this, untreated and sonicated juice was stored at 4 and 10 ºC up to 10 days and microbial quality, instrumental colour, pH, and ascorbic acid content were evaluated. In general, ultrasound kept juice microbiologically stable for up to 10 days at 4 ºC without markedly affecting other parameters evaluated. Ultrasound seems suitable to stabilize PFJ microbiologically.
In this study, addition of green tea or pine bark extracts, a rich sources of phenolic antioxidants, were tested in reduced-calorie blueberry jams regarding their effect on the anthocyanin content, polyphenol content and antioxidant activity. The results obtained during investigation demonstrated that the addition of green tea or pine bark extracts had influence not only on the total phenol content in fortified jams but also on the anthocyanin content. Addition of both extracts resulted in higher anthocyanin content. The anthocyanin content in reduced-calorie blueberry jam without an addition of extracts was 137 mg/100 g, while in samples with an addition of green tea or pine bark extracts was 146 and 154 mg/100 g, respectively. During 12 months of storage degradation of anthocyanins occurred and difference between the samples with an addition of extracts and without was not so pronounced as immediately after the preparation of jam samples. Fortification of reduced-calorie blueberry jam with extracts, rich in antioxidants, could be used as protection tool against thermal degradation of anthocyanins.
In this study, compositional analysis of the products obtained by thermal degradation of sugar cane bagasse at various pyrolysis temperatures (300, 350, 400, 450, 500, 550, 600, 650, 700, 750 and 800 °C) and heating rate (5, 10, 20 and 50 °C/min) was studied. Sugar cane bagasse was pyrolyzed in a stainless steel tubular reactor. The aim of this work was to experimentally investigate how the temperature and heating rate affects liquid and char product yields via pyrolysis and to determine optimal condition to have a better yield of these products. Liquid product (bio-oil) obtained under the most suitable conditions were characterized by elemental analysis, FT-IR, C-NMR and HNMR. In addition, column chromatography was employed to determine the aliphatic fraction (Hexane Eluate); gas chromatography and FT-IR were achieved on aliphatic fractions. For char product (bio-char), the elemental chemical composition and yield of the char were determined. The results of our work showed that the amount of liquid product (bio-oil) from pyrolysis of sugar cane bagasse increases with increasing the final temperature and decreases with increasing the heating rate. The highest yield of liquid product is obtained from the samples at 550 °C and at the heating rate of 5°C/min, the maximal average yield achieved almost 32.80 wt%. The yield of char generally decreases with increasing the temperature, the char yield passes from 39.7 wt% to 21 wt% at the heating rate of 5°C/min and from 32 wt% to 17.2 wt% at the heating rate of 50 °C/min at the same range of temperature (300–800 °C). The analysis of bio-oil showed the presence of an aliphatic character and that it is possible to obtain liquid products similar to petroleum from sugar cane bagasse waste. The solid products (bio-char) obtained in the presence of nitrogen (N2) contain a very important percentage of carbon and high higher heating values (HHV).