Valorization of Food Processing Waste to Produce Valuable Polyphenolics.

Traditional incineration and landfill of food processing waste (FPW) have polluted the environment and underutilized valuable bioactive compounds, including polyphenols in food waste. As one of the most widely occurring compounds in the FPW, polyphenols possess high utilization value in many fields such as human health, energy, and environmental protection. Extracting polyphenols directly from FPW can maximize the value of polyphenols and avoid waste of resources. However, traditional polyphenol extraction methods mostly use the Soxhlet extraction, infiltration, and impregnation method, consuming a large amount of organic solvent and suffering from long extraction time and low extraction efficiency. Emerging green extraction methods such as supercritical fluid extraction, ultrasonic-assisted extraction, microwave-assisted extraction, and other methods can shorten the extraction time and improve the solvent extraction efficacy, resulting in the green and safe recovery of polyphenols from FPW. In this paper, the traditional treatment methods of FPW waste and the application of polyphenols in FPW are briefly reviewed, and the traditional extraction methods and emerging green extraction methods of polyphenols in FPW are compared to obtain insight into the start-of-the-art extraction approaches.

Preparation of sodium cellulose sulfate oligomers by free-radical depolymerization.

Sodium cellulose sulfates with various degree of substitution (DS) and degree of polymerization (DP) were synthesized by homogeneous sulfation of cellulose with different DP by using SO3/pyridine (Py) complex in N,N-dimethylacetamide/lithium chloride (DMA/LiCl). Sodium cellulose sulfate (SCS) samples obtained were free-radically depolymerized with hydrogen peroxide and copper (II) acetate at a controlled pH value of 7.5-8.0 and without control of the pH value (pH 2.5-4.0). The depolymerization process was studied with respect to changes in molecular mass, total DS, and substituent distribution of SCS. Elemental analysis, 13C NMR- and IR spectroscopic methods indicated that primary structures of SCS were retained with insignificant decreases in total sulfate content in the depolymerization. The depolymerization of SCS was randomly and obeyed pseudo first order kinetics under the conditions applied. SCS oligomers with low DP and very narrow molecular weight distribution were prepared by the depolymerization at pH 2.5-4.0.

Preparation and anticoagulation activity of sodium cellulose sulfate.

Semi-synthesis of cellulose sulfate sodium (Na-MCS) was carried out by sulfation of microcrystalline cellulose (MCC) with chlorosulfonic acid-dimethylformamide complex as sulfating agent. As shown by FT-IR, NMR spectroscopy, and elemental analysis, the sulfation occurred mainly at C6, partially at C2, and no substitution at C3. The substitution degree ranged from 1.10 to 1.70 and the average molecular weight is between 1.1 and 3.5 x 10(4)Da. The anticoagulant efficacy and its possible mechanism were investigated using in vitro, in vivo coagulation assays and amidolytic tests in comparison with heparin. Results indicated that Na-MCS exhibited higher anticoagulation activity based on activated partial thromboplastin time (APTT) assay and prolonged the thrombin time (TT) to a lesser extent than heparin. No effect was detected on the prothrombin time (PT). Subcutaneous administration of Na-MCS to mice increased the clotting time (CT) in a moderate dose-dependent manner with a longer duration. Na-MCS exhibited anticoagulation activity mainly by accelerating the inhibition of antithrombin III (AT-III) on coagulation factors FIIa and FXa in plasma.