Green and Efficient Processing of Cinnamomum cassia Bark by Using Ionic Liquids: Extraction of Essential Oil and Construction of UV-Resistant Composite Films from Residual Biomass

Advances in efficient extraction of essential oils from spices and its application in food industry: A critical review

With the increase of people's awareness of food safety, it is crucial to find natural and green antimicrobial agents to replace traditional antimicrobial agents. Essential oils of spices (SEOs) are low toxicity or nontoxic, which exhibited antioxidants and antimicrobial activity according to many in vitro and in situ experiments. Spices are widely available and low cost as a plant raw material for the extraction of SEOs. This review summarized highly efficient extraction techniques for SEOs, such as physical field assisted extraction technology, supercritical fluid extraction, and biological-based techniques. Furthermore, purification of SEOs and components were also recapitulated. Purification techniques of SEOs improve their utilization value due to the increased content of bioactive components. Finally, the review concentrated on the applications of SEOs in food industry, including food preservation, food active packaging by means of films or coatings, antioxidant properties. In addition, addressing the problem of unstability of SEOs and its role to inhibit the pathogenic bacteria, the encapsulation of SEOs for use in the food industrial sectors reduces the safety risk to human health.

Modification of Poly(vinyl chloride) with Bio-Based Cassia Oil to Improve Thermo-Mechanical and Antimicrobial Properties

The purpose of this study was to modify plasticised PVC to obtain a material with antimicrobial properties and selected mechanical properties. Natural cassia oil (CO) was used to modify plasticised PVC materials. The modified material was produced by extrusion. The introduced modifier had a maximum concentration of 20 phr. Rheological and mechanical properties were evaluated, and the glass transition temperature was determined. The antioxidant and antimicrobial activity of the agar diffusion method was investigated by analysing the growth inhibition zones against Enterococcus faecalis and Listeria monocytogenes. A favourable effect of the cassia oil content on the increase in antioxidant activity of the developed polymeric materials was found with an increase in the modifier content and the duration of action (30 days). The largest growth restriction zones were observed for L. monocytogenes, i.e., they showed the highest sensitivity to the modified material. The simultaneous decrease in modulus of elasticity, increase in elongation at break, and decrease in T_g indicate that the modifier has a plasticising effect on PVC. The developed material may find application as an active and/or functional material, especially as an emitter of antimicrobial agents, in the packaging used to store minimally processed food.

Influence of Metal Salts Addition on Physical and Electrochemical Properties of Ethyl and Propylammonium Nitrate

In this work, we deepen in the characterization of two protic ionic liquids (PILs), ethylammonium nitrate (EAN) and propylammonium nitrate (PAN). With this aim, we determined the influence of inorganic nitrate salts addition on their physical properties and their electrochemical potential window (EPW). Thus, experimental measurements of electrical conductivity, density, viscosity, refractive index and surface tension of mixtures of {EAN or PAN + LiNO₃, Ca(NO₃)₂, Mg(NO₃)₂ or Al(NO₃)₃} at a temperature range between 5 and 95 °C are presented first, except for the last two properties which were measured at 25 °C. In the second part, the corresponding EPWs were determined at 25 °C by linear sweep voltammetry using three different electrochemical cells. Effect of the salt addition was associated mainly with the metal cation characteristics, so, generally, LiNO₃ showed the lower influence, followed by Ca(NO₃)₂, Mg(NO₃)₂ or Al(NO₃)₃. The results obtained for the EAN + LiNO₃ mixtures, along with those from a previous work, allowed us to develop novel predictive equations for most of the presented physical properties as functions of the lithium salt concentration, the temperature and the water content. Electrochemical results showed that a general order of EPW can be established for both PILs, although exceptions related to measurement conditions and the properties of the mixtures were found.

Enzymatic Hydrolysate of Cinnamon Waste Material as Feedstock for the Microbial Production of Carotenoids

In the context of the global need to move towards circular economies, microbial cell factories can be employed thanks to their ability to use side-stream biomasses from the agro-industrial sector to obtain additional products. The valorization of residues allows for better and complete use of natural resources and, at the same time, for the avoidance of waste management to address our needs. In this work, we focused our attention on the microbial valorization of cinnamon waste material after polyphenol extraction (C-PEW) (Cinnamomum verum J.Presl), generally discarded without any additional processing. The sugars embedded in C-PEW were released by enzymatic hydrolysis, more compatible than acid hydrolysis with the subsequent microbial cultivation. We demonstrated that the yeast Rhodosporidium toruloides was able to grow and produce up to 2.00 (±0.23) mg/L of carotenoids in the resulting hydrolysate as a sole carbon and nitrogen source despite the presence of antimicrobial compounds typical of cinnamon. To further extend the potential of our finding, we tested other fungal cell factories for growth on the same media. Overall, these results are opening the possibility to develop separate hydrolysis and fermentation (SHF) bioprocesses based on C-PEW and microbial biotransformation to obtain high-value molecules.

Effect of crystallinity on pretreatment and enzymatic hydrolysis of lignocellulosic biomass based on multivariate analysis

In this work, multivariate data analysis was employed to correlate variables of pretreatment process of lignocellulosic biomass. Principal component analysis and partial least square methods were performed to get the inner-relationship and data interpretation between the crystallinity and other parameters of mechanical refining-assisted sodium hydroxide pretreatment followed by enzymatic saccharification of corn stover. The PCA and PLS models showed that Sodium hydroxide dosage, mechanical refining treatment, lignin removal rate and crystallinity had close inner-related relationship with the efficiency of pretreatment and enzymolysis. Alkaline reaction and mechanical refining treatment had strong influence on the crystallinity. Multivariate data analysis revealed that pretreated corn stover samples with lower crystallinity were more easily hydrolyzed by enzyme and could get more final reducing sugar. This work could offer a new methodology to get further understanding of effect of crystallinity on the crop residue lignocellulosic biomass conversion process.

Ionic Liquid Stabilized Gelatin-Lignin Films: A Potential UV-Shielding Material with Excellent Mechanical and Antimicrobial Properties

Significant research is currently underway to develop environmentally friendly UV-shielding materials. Herein, we have constructed choline citrate (a biobased ionic liquid, IL) stabilized homogeneous gelatin-lignin UV-shielding films with excellent antimicrobial and mechanical properties. The synthesis procedure of the films is less energy demanding, one pot, and sustainable in nature. Prepared films were characterized by mechanical and thermal analysis using UTM and TGA, respectively. ATR-IR and PXRD was employed to explore the possible formation of H-bonding between biopolymers and the IL and the change in crystallinity in films after addition of IL to the gelatin-lignin matrix. Surface morphology of prepared films has been studied using optical microscope, AFM, and field emission SEM (FE-SEM). Optical properties of prepared films were measured using UV/Vis spectroscopy. Antimicrobial activity of the prepared films was tested against Bacillus subtilis. Prepared biofilms showed a sun-protection factor (SPF) of up to ≈45.0, large elongation ≈200 %, and tensile strength ≈70 MPa, which are as good as those values exhibited by organic polymeric films, indicating a promising renewable-resources-based material for UV light blocking.