Bioethanol Production from Renewable Raw Materials and Its Separation and Purification: A Review.

Production of biofuels from renewable feedstocks has captured considerable scientific attention since they could be used to supply energy and alternative fuels. Bioethanol is one of the most interesting biofuels due to its positive impact on the environment. Currently, it is mostly produced from sugar- and starch-containing raw materials. However, various available types of lignocellulosic biomass such as agricultural and forestry residues, and herbaceous energy crops could serve as feedstocks for the production of bioethanol, energy, heat and value-added chemicals. Lignocellulose is a complex mixture of carbohydrates that needs an efficient pretreatment to make accessible pathways to enzymes for the production of fermentable sugars, which after hydrolysis are fermented into ethanol. Despite technical and economic difficulties, renewable lignocellulosic raw materials represent low-cost feedstocks that do not compete with the food and feed chain, thereby stimulating the sustainability. Different bioprocess operational modes were developed for bioethanol production from renewable raw materials. Furthermore, alternative bioethanol separation and purification processes have also been intensively developed. This paper deals with recent trends in the bioethanol production as a fuel from different renewable raw materials as well as with its separation and purification processes.

The Potential of Combined Emulsification and Spray Drying Techniques for Encapsulation of Polyphenols from Rosemary (Rosmarinus officinalis L.) Leaves.

The present study evaluates the potential of encapsulation of polyphenolic antioxidants from rosemary (Rosmarinus officinalis L.) leaves by combining emulsification and spray drying techniques. To stabilize the emulsions and prepare samples suitable for use in dry products, double emulsions encapsulating rosemary polyphenolic extract and containing polyglycerol polyricinoleate (4%), whey protein isolates (2 and 4%) as emulsifiers, and maltodextrins (MDE 10 and 21) as enhancing coatings were subjected to spray drying. The obtained results show insignificant (p>0.05) effect of used maltodextrin type and protein content on mean particle size of double emulsions containing rosemary polyphenols. Morphology analyses showed that double emulsions were successfully prepared, spherical microcapsules were obtained after spray drying of double emulsions and double emulsion form was still preserved after rehydration of spray-dried microcapsules. Regardless of used maltodextrins, significantly (p>0.05) higher encapsulation efficiencies (EE) of total polyphenols (39.57 and 42.83%) in rehydrated samples were achieved when higher protein content (4% whey protein isolate) was used, indicating the major impact of protein content on EE of rosemary polyphenols. Also, using HPLC analysis, rosmarinic and caffeic acids, apigenin and luteolin derivatives were detected among specific polyphenols, where rosmarinic acid had notable encapsulation efficiency ranging from 62.15 to 67.43%. In this way, the obtained microcapsules encapsulating rosemary polyphenols could be easily blended with various dry mixtures, and serve for delivery in different functional products.

Recent Trends in Biodiesel and Biogas Production.

Biodiesel and biogas are two very important sources of renewable energy worldwide, and particularly in the EU countries. While biodiesel is almost exclusively used as transportation fuel, biogas is mostly used for production of electricity and heat. The application of more sophisticated purification techniques in production of pure biomethane from biogas allows its delivery to natural gas grid and its subsequent use as transportation fuel. While biogas is produced mostly from waste materials (landfills, manure, sludge from wastewater treatment, agricultural waste), biodiesel in the EU is mostly produced from rapeseed or other oil crops that are used as food, which raises the 'food or fuel' concerns. To mitigate this problem, considerable efforts have been made to use non-food feedstock for biodiesel production. These include all kinds of waste oils and fats, but recently more attention has been devoted to production of microbial oils by cultivation of microorganisms that are able to accumulate high amounts of lipids in their biomass. Promising candidates for microbial lipid production can be found among different strains of filamentous fungi, yeast, bacteria and microalgae. Feedstocks of interest are agricultural waste rich in carbohydrates as well as different lignocellulosic raw materials where some technical issues have to be resolved. In this work, recovery and purification of biodiesel and biogas are also considered.

Novel Approach to the Development of Functional Goat's Milk-Based Beverages Using Medicinal Plant Extracts in Combination with High Intensity Ultrasound Treatment.

Regardless of its highly valuable nutritive composition, goat's milk is less preferred by consumers due to its specific sensory characteristics that are very often regarded as undesirable. On the other hand, traditional medicinal plants from Lamiaceae family, due to their rich bioactive composition, especially polyphenols, and desirable aroma profile, can be used to enhance and improve bioactive and sensory properties of food. In the present study nutritively valuable beverages were produced by enrichment of goat's milk with medicinal plant extracts derived from the Lamiaceae family and stabilized by homogenization with high intensity ultrasound treatment. The impact of plant species (lemon balm, mint, lavender, rosemary and sage) and ultrasound treatment duration (5 or 10 min) on the physicochemical, bioactive and sensory characteristics of enriched beverages was evaluated. The addition of plant extracts to goat's milk significantly increased the concentration of bioactive components (rosmarinic acid, hydroxycinnamic acid derivatives and luteolin derivatives), in dependence of the added plant extract. The prolongation of the ultrasound homogenization markedly decreased the fat globule size and thus beneficially affected the product stability. Apart from the achieved bioactive enrichment and stability, the developed beverages exhibited significantly improved sensory properties in comparison to plain goat's milk, with the highest overall acceptability determined for samples enriched with mint and rosemary.

Consumer acceptability of liquorice root (Glycyrrhiza glabra L.) as an alternative sweetener and correlation with its bioactive content and biological activity.

Consumer acceptability and sensory properties of liquorice root (Glycyrrhiza glabra L.) were evaluated. Quantitation of total polyphenolics and glycyrrhizic acid (GA), as well as the antioxidant capacity of liquorice extracts, was conducted and their biological effects (cytotoxic, antioxidative/pro-oxidative activity, lipid peroxidation on human laryngeal carcinoma cell line) compared to the ones of their predominant bioactive compound - GA. Conducted consumer survey revealed poor familiarity with liquorice (12.37% of correspondents), but willingness towards its use as an alternative sweetener (77.32% of consumers). Polyphenolic content of evaluated extracts ranged from 1018.18 to 1277.27 mg gallic acid equivalents (GAE)/l while GA content varied between 2179.53 and 2944.13 mg/l. The most pronounced cytotoxic effect (60%) and lipid peroxidation were exerted by treatment with the highest applied extract concentrations (10 mg/ml). Pure GA exhibited cytotoxic and pro-oxidative effects at concentrations of 0.12-0.6 mg/ml. Due to high GA content, coupled with its pronounced cytotoxic activity, the intake of liquorice root should be limited.

Nettle (Urtica dioica L.) extracts as functional ingredients for production of chocolates with improved bioactive composition and sensory properties.

Pursuant to the tendencies of producing functional foods, attractive to a wide range of consumers, in this study chocolates enriched with freeze dried (FD) and concentrated (CE) nettle extracts were formulated, and their polyphenolic and antioxidant capacity stability evaluated during 12 months of storage. A simple aqueous extraction procedure of nettle was developed, and the defined extract evaluated for its cytotoxic and antioxidant/prooxidant activity on human colon cancer cell line (SW 480). An increase in total polyphenolic content, chlorogenic acid and flavonoid derivatives (originating from nettle extract) contents was achieved in enriched chocolates. Implementation of FD extract enabled higher increase of polyphenolic content in comparison to CE extract. During storage, fluctuations of polyphenolic content were observed, but the final bioactive parameters did not differ (or increased) from the initial ones. Nettle enriched chocolates exhibited more intense bitterness and astringency, while dark chocolates were preferred over milk and semisweet ones.

Structuring new alginate network aimed for delivery of dandelion (Taraxacum officinale L.) polyphenols using ionic gelation and new filler materials.

Alginate hydrogels are often used for immobilization of plant-derived bioactive compounds by fast and simple ionic gelation technique. However, the structure of alginate gel network is very porous and mostly result with high-diffusion rates of encapsulated compound, what limits its application as delivery vehicle. In order to prevent losses of bioactives and prepare efficient encapsulation systems, the aim of this study was to evaluate a potential of new natural fillers, cocoa powder (CP) and carob (C) for structuring alginate network aimed for encapsulation of aqueous dandelion (Taraxacum officinale L.) leaf extract using ionic gelation. Whey protein isolates served as a standard filler. The influence of different concentrations of gelling medium (2% and 3% calcium chloride) on encapsulation properties of alginate systems was also evaluated. Calcium concentration affected morphological properties (more acceptable when using 3% CaCl2), while textural properties and encapsulation efficiency of polyphenols and retained antioxidant capacity were more influenced by selected delivery materials. Alginate-whey protein isolates beads were scored with the highest loading capacity of polyphenols (>93%), while newly formulated binary mixtures (alginate-cocoa powder and alginate-carob) also enabled highly efficient entrapment of polyphenols (>88%). The slowest release of polyphenols in simulated gastrointestinal fluids were obtained when alginate was combined with CP and C, where system alginate-cocoa powder prepared with lower concentration of calcium chloride (2% CaCl2) enabled the most extended release of total polyphenols and hydroxycinnamic acids. Obtained results strongly justified implementation of new plant-derived functional fillers (cocoa powder and carob) for encapsulation purposes and opened new directions for designing of binary carrier's.

Compositional evaluation of selected agro-industrial wastes as valuable sources for the recovery of complex carbohydrates.

Re-utilization of various agro-industrial wastes is of growing importance from many aspects. Considering the variety and complexity of such materials, compositional data and compliant methodology is still undergoing many updates and improvements. Present study evaluated sugar beet pulp (SBP), walnut shell (WS), cocoa bean husk (CBH), onion peel (OP) and pea pods (PP) as potentially valuable materials for carbohydrate recovery. Macrocomponent analyses revealed carbohydrate fraction as the most abundant, dominating in dietary fibres. Upon complete acid hydrolysis of sample alcohol insoluble residues, developed procedures of high performance thin-layer chromatography (HPTLC) and high performance liquid chromatography (HPLC) coupled with 3-methyl-1-phenyl-2-pyrazolin-5-one pre-column derivatization (PMP-derivatization) were used for carbohydrate monomeric composition determination. HPTLC exhibited good qualitative features useful for multi-sample rapid analysis, while HPLC superior separation and quantification characteristics. Distinctive monomeric patterns were obtained among samples. OP, SBP and CBH, due to the high galacturonic acid content (20.81%, 13.96% and 6.90% dry matter basis, respectively), may be regarded as pectin sources, while WS and PP as materials abundant in xylan-rich hemicellulose (total xylan content 15.53%, 9.63% dry matter basis, respectively). Present study provides new and valuable compositional data for different plant residual materials and a reference for the application of established methodology.

Phytochemical attributes of four conventionally extracted medicinal plants and cytotoxic evaluation of their extracts on human laryngeal carcinoma (HEp2) cells.

The bioactive composition and cytotoxic and antioxidative/prooxidative effects of four medicinal plants: yarrow (Achillea millefolium L.), hawthorn (Crataegus oxyacantha L.), ground ivy (Glechoma hederacea L.), and olive (Olea europea L.) on human laryngeal carcinoma cell line (HEp2) were investigated. Water extracts of these plants obtained by infusion, maceration, and decoction were characterized for their polyphenol content and antioxidant capacity. Based on the extraction efficiency of polyphenols, the final extracts were obtained whose polyphenolic profile, polysaccharides, mineral content, and cytoprotective activities were determined. The overall highest content of polyphenols and antioxidant capacity was determined in hawthorn, followed by yarrow and ground ivy, and the lowest in olive leaves extract. Phytochemical screening revealed the presence of phenolic acids, as the most abundant bioactive compounds, followed by flavonoids, flavons, and flavonols. All examined medicinal plants reduced the cell viability and reactive oxygen species formation in a dose- and time-dependent manner. Ground ivy and yarrow containing a high content of phenolic acids and polysaccharides were more efficient to decrease the cell survival when compared to olive leaf and hawthorn. Experiments confirmed the importance of polyphenolic composition rather than content of investigated plants and revealed a relationship between the polyphenolic and polysaccharide contents and antioxidant/prooxidant characters of medicinal plants.

Formulating blackberry leaf mixtures for preparation of infusions with plant derived sources of sweeteners.

Herbal mixtures composed of blackberry leaf and natural sweeteners (dried apples, prunes, figs, raisins, apricots, carrot and sweet potato, stevia leaves and liquorice root) were developed. Their nutritive and bioactive profile, biological activity and sensory properties were determined. Formulated mixtures exhibited lower total polyphenol content (259.09-350.00 mg GAE/L) when compared to plain blackberry leaf, but contained higher content of chlorogenic, ferulic, p-coumaric, rosmarinic acids and quercetin, as well as some macroelements (Ca, K, Mg) and microelements (Ba, Na). Stevia addition to formulated mixtures ensured higher polyphenolic content. Dried carrot exhibited the highest (0.988 g/g) and liquorice the lowest (0.087 g/g) content of total sugars but it contributed to the sweetness with 574.48 mg/L of glycyrrhizic acid derivatives. Plain blackberry leaf extract exhibited cytotoxic and antioxidative activity on human colon cancer cells. Formulated mixtures exhibited improved flavour profile and balanced sweetness in relation to plain blackberry leaf infusion.

Comparative evaluation of CO2 drying as an alternative drying technique of basil (Ocimum basilicum L.) - The effect on bioactive and sensory properties.

In this study the potential of employing CO2 drying as an alternative to conventional drying techniques of basil was evaluated, with the aim of preservation of native bioactive and sensory properties of basil. For that purpose, optimal CO2 processing conditions were established and compared to air-dried and freeze dried basil samples. The contents of bioactive compounds (polyphenols, chlorophylls, ascorbic acid) and antioxidant capacity were determined spectrophotometrically and using high performance liquid chromatography (HPLC-PDA) analysis. Color analysis and essential oil content were also determined, while consumer evaluation of sensory properties was conducted using hedonic scale preference analysis. According to the obtained results, freeze drying was recognized as the most suitable technique for preservation of color, essential oil content, bioactive compounds and antioxidant capacity of basil. The essential oil content of basil ranged from 0.21 to 0.96%, and decreased upon prolongation of CO2 drying time. Among 4 identified phenolic acids (rosmarinic, chicoric, caftaric and caffeic), rosmarinic acid was the most abundant in all samples. Longer CO2 drying duration (4h) also exhibited the most detrimental effect on the polyphenolic compound content and antioxidant capacity of basil. The taste and appearance of CO2 dried basil were scored higher in comparison to air-dried basil, but further optimization of CO2 drying is needed to improve its aroma properties. Based on the obtained results, employing shorter CO2 drying time (2, 3h) and pressures of 80-100bar at 40°C might be a good alternative to freeze drying of basil.