RECENT ADVANCES ON STABILITY OF ANTHOCYANINS

Since Neolithic era, natural pigments have been added to foods and colour of food products is still one of the major concerns of food industry. Anthocyanins are the most noticeable group among coloured flavonoids, widely existing in the roots, stems and leaves as well as flowers and fruits of the vascular plants. They have a high potential for use as natural colorants instead of synthetic pigments because of their attractive colour and pharmacological properties. Stable and attractive colours are a highly valued attribute in competitive food industry. Considerable studies have been done on the effects of the most important chemical and physical factors involved in the stability of anthocyanins (temperature, light, pH, SO2, metal, sugar, ascorbic acid and oxygen), their concentrations, chemical structures, and matrix food compositions. Furthermore, the effects of separation technologies including microwave/ultrasound assisted extraction (MAE, UAE), and Colloidal Gaz Aphron (CGA) fractionation on the stability of anthocyanins are reviewed

Kinetic Modeling of Convective and Microwave Drying of Potato Peels and Their Effects on Antioxidant Content and Capacity

This study deals with drying properties and focuses on the drying kinetics of potato peels (PP) by two processes, namely convection drying (CD) at various temperatures (40, 60, 80, 100, and 120 °C) and microwave drying (MD) at different powers (200, 400, 600, and 800 W). In addition, the effectiveness of the adopted processes was evaluated in terms of antioxidant contents and antioxidant capacity. A total of 22 mathematical models were undertaken to predict the drying kinetics, and the best model was selected based on the highest R2 values and the lowest χ2 and RMSE values. The Sledz model was the more appropriate for both methods with values of 0.9995 ≤ R2 ≤ 0.9999, χ2 = 0.0000, and 0.0054 ≤ RMSE ≤ 0.0030 for CD, and the results of MD were 0.9829 ≤ R2 ≤ 0.9997, 0.0000 ≤ χ2 ≤ 0.0010, and 0.0304 ≤ RMSE ≤ 0.0053. The best drying rates (DR) of PP were assigned to a temperature of 120 °C and a power of 600 W with values of 0.05 and 0.20 kg water/kg dw min, respectively. A potential explanation is that as PP’s moisture content decreased during the drying process, there was a drop in absorption, which led to a reduction in the DR. The energy consumption of both processes was assessed, and it rose with increasing temperature or power. The microwave process reduced the drying time, consumed lower energy, and presented a higher drying efficiency at a moderate power level compared to the convection process. Furthermore, MD preserved antioxidants better compared to CD and improved the antioxidant capacity. Therefore, the proposed microwave process for drying PP is suggested for its expected use in various fields, including the food processing industries.Depto. de Producción AnimalFac. de VeterinariaTRUEpu

Ziziphus lotus (L.) Lam. plant treatment by ultrasounds and microwaves to improve antioxidants yield and quality: An overview

The purpose of this review is to compile the literature published about different aspects of microwave-assisted extraction (MAE) use and ultrasound-assisted extraction (UAE) applied on jujube worldwide and to compare the results on the antioxidant activity obtained for each extraction method. As a result of the increased consumers demand for natural products, as well as for those of agro-food, nutraceutical, cosmetic industries, and green extraction techniques are nowadays trending to be potential alternatives that can improve antioxidant yield and its quality from an economical and environmental point of view by reducing time, energy, and solvent consumption. Ultrasounds and microwaves are widely used methods in the extraction of active principles due to their cavitation and dipolar rotation effect, respectively. These two techniques provide efficiency of extraction while minimizing the time and preserving the quality of the food matrix, overcoming the disadvantages of conventional techniques characterized by their consumption of large quantities of solvents and providing a sparse quantity of extraction. Jujube, a shrub with a high antioxidant potential, which can be affected by various extraction conditions can be the target of UAE and MAE to increase the antioxidant extraction yield. Exploiting the beneficial properties such as the antioxidant activity can lead to an industrialization process, replacing therefor synthetic antioxidants with natural compounds. These can also help in the development of new nutraceuticals and can be used, for instance, in agro-food industries as preservatives

Modeliranje adsorpcijskog fenomena određenih fenola metodom potpornih vektora Dragonfly pomoću vlakana aktivnog ugljena

The objective of this research was to build a mathematical model based on a Support Vector Machine (SVM) capable of predicting the amount adsorbed at equilibrium (qe). Activated carbon fibres (ACF) were used for the adsorption of certain phenols (phenol, 2-chlorophenol, 4-chlorophenol, 2,4,6-trichlorophenol, 4-nitrophenol, and 2,4-dinitrophenol). An experimental dataset of 129 points was collected from previously published papers. The inputs considered for modelling were temperature (T), concentration at equilibrium (ce), and two descriptors (boiling point (BP) and density (d)) to differentiate between the pollutants studied. The data used were pre-processed by the statistical analysis to ensure that they were adequate for modelling. The results showed a superiority of the Gaussian kernel function DA-SVM model demonstrated by its determination coefficient (R2 = 0.997) and root mean squared error (RMSE = 0.027 mmol l–1). This work is licensed under a Creative Commons Attribution 4.0 International License.Cilj ovog istraživanja bio je izraditi matematički model zasnovan na metodi potpornih vektora (SVM) koji može predvidjeti količinu adsorbiranu u ravnoteži (qe). Vlakna s aktivnim ugljenom (ACF) upotrijebljena su za adsorpciju određenih fenola (fenol, 2-klorofenol, 4-klorofenol, 2,4,6-triklorofenol, 4-nitrofenol i 2,4-dinitrofenol). Eksperimentalni skup podataka od 129 bodova prikupljen je iz prethodno objavljenih radova. Ulazi parametri koji su uzeti u obzir za modeliranje bili su temperatura (T), koncentracija u ravnoteži (ce) i dva deskriptora (točka vrenja (BP) i gustoća (d)) za razlikovanje ispitivanih onečišćujućih tvari. Korišteni podatci prethodno su obrađeni statističkom analizom da bi se osigurala njihova primjerenost za modeliranje. Rezultati su pokazali superiornost modela DA-SVM Gaussove kernel funkcije demonstriranog njegovim koeficijentom determinacije (R2 = 0,997) i srednjom kvadratnom pogreškom (RMSE = 0,027 mmol l–1). Ovo djelo je dano na korištenje pod licencom Creative Commons Imenovanje 4.0 međunarodna

Ultrasound Assisted Extraction of Phenolic Compounds from a Jujube By-Product with Valuable Bioactivities

Jujube plant is a potential source of polyphenols with biological propreties. The purpose of this study was to investigate the application of ultrasound technique for extracting phenolic compounds (TPC) from seeds of Zizyphus lotus under optimization conditions based on response surface methodology. A maximum TPC, total flavonoids content (TFC), and total condensed tannins content (TTC) of 2383.10 ± 0.87 mg GAE/100g, 486.50 ± 0.38 mg QE/100g and 15,787.10 ± 0.10 mg CE/100g, respectively obtained under ethanol concentration 50.16%, sonication temperature 29.01 °C, sonication time 15.94 min and solvent-to-solid ratio 34.10:1 mL/g. The optimized extract was then evaluated for its antioxidant, antiacethylcholinesterase, antihypercholesterolemia, and antiproliferative activities. The results showed that ultrasound method is a green and safe method that can be used to effectively extract TPC from jujube seeds. The biological activity of Zizyphus extract exhibited a very good antioxidant against DPPH (EC50 = 0.39 µg/mL) and FRAP (1670.42 ± 6.5 mg/100 g). Additionally, it possesses acetylcholinesterase (AChE) inhibitory effect (IC50 = 0.93 ± 0.01 mg/mL) and HMGR inhibition (45.41%) using 100 µg/mL. The extract significantly inhibits cell proliferation on the MCF-7 and HepG2 tumor cell lines with an IC50 values of <0.05 and 3 ± 0.55 mg/mL, respectively. Therefore, the ultrasound method can be considered a method for obtaining a significant anticancer activity with respect to the lines and therefore makes it possible to recover a maximum of phenolic compounds in less time with an AChE and HMGR inhibitory activity. Thus, it can be suggested that Zls extract is a promising fruit for the development of supplementary dietary due to its potential behaviour as nutraceutical

Extraction, characterization and gelling behavior enhancement of pectins from the cladodes of Opuntia ficus indica

International audienceTotal Pectins Fraction (TPF) was extracted at room temperature from dried cladodes of Opuntia ficus indica. TPF is constituted of three pectic fractions WSP, CSP and ASP, which are made up of 66.6%, 44.3% and 81.1% (w/w) of galacturonic acid, respectively. The antioxidant ability of TPF increased with the concentration increasing. It scavenged hydroxyl radical by 90% and chelated 90% of ferrous ions at 5 g/L. FTIR study was carried out. Strong characteristic absorption peaks at 1618 cm−1 assigned to the vibration of COO– group of galacturonic acid. In the fingerprint region, we noticed three well-defined peaks at 1054, 1085, and 1154 cm−1 characteristic of pectic polysaccharides. TPF are non-gelling pectins. The co-crosslinking of TPF with carrageenan was carried out and the gelling behavior was successfully improved. Thermo-sensitive hydrogel was obtained with 82% of TPF and 18% of carrageenan (w/w)

Optimization of the recovery of phenolic compounds from Algerian grape by-products

International audienceGrape seeds and skin are by-products of wine making or juice making operations which are considered as a good source of bioactive compounds. In this study, the total phenolic content (TPC) from Vitis vinifera L. cv. Ahmar Bou-Amar seeds and skin was optimized by conventional solvent extraction (CSE) and microwave-assisted extraction (MAE) using response surface methodology (RSM), then a comparative study was carried out. The optimal conditions for seeds extracted by CSE were: 74.33% v/v of ethanol concentration, 65.23 mm extraction time, 0.1 g/70.86 ml solid/liquid ratio, and for those extracted by MAE were: 59.88 s irradiation time and 373.15W microwave power. The extract obtained under these conditions showed a TPC of 96.56 +/- 1.29 mg GAE/g and 73.15 +/- 0.20 mg GAE/g DW for CSE and MAE, respectively. Concerning skin, the optimal conditions for CSE were: 51.46% v/v of acetone concentration, 89.80 mm extraction time, 0.1 g/32.25 ml solid/liquid ratio and for MAE were: 113.74s irradiation time and 384.44W microwave power. The extract obtained under these conditions showed a TPC of 39.57 +/- 0.23 mg GAE/g and 54.84 +/- 0.41 mg GAE/g DW for CSE and MAE, respectively. The TPC of seeds extract obtained with MAE was 24% lower than that of the CSE extract; also, the antioxidant activity of CSE extract is better than that of MAE extract. While, the TPC of skin extract obtained with MAE was 28% higher than that of the CSE extract and the antioxidant capacity was significantly higher than that of the CSE extract. The results indicate that the extracts of cv. Ahmar Bou-Amar seeds and skin contain a high quantity of polyphenols; therefore, they can be considered as a good source of natural antioxidants

Effect of Sonication on Microwave Inactivation Kinetics of Enterococcus faecalis in Dairy Effluent

The aim of this study is to inactivate Enterococcus faecalis ATCC 29212 present in dairy wastewater effluent using microwave (MW) waves and/or ultrasound waves (US). The ultrasonic bath treatment (35 kHz) had no significant effect on the reduction of the survival rate (predominant declumping effect). At 650 W of microwave treatment, the total destruction was completed at 75 s, while at 350 W a 3 log reduction was achieved. The Weibull model was fitted to the survival curves to describe the inactivation kinetics, and the effect of the combined microwave-ultrasound treatments was evaluated. The scaling parameter α that was estimated from the inactivation kinetics for the microwaves combined with the ultrasound waves in pre-treatment was found to be lower than the scaling parameters obtained in post-treatment, which were in turn lower than those estimated for microwaves or ultrasound waves alone. The use of the ultrasound waves in pre-treatment was more effective than in post-treatment; a total reduction was achieved using a combination of US (30 min) followed by MW (650 W) with α = 28.3 s, while 4.0 log was obtained by reversing all processes with α = 34.5 s. The results from the protein assays indicate that the bacterial wall was damaged and that holes were formed from which protein leakage occurred

Antioxidant effects of extra virgin olive oil enriched by myrtle phenolic extracts on iron-mediated lipid peroxidation under intestinal conditions model

International audienc