Improving antioxidant activities of water-soluble lignin-carbohydrate complex isolated from wheat stalk through prolonging ball-milling pretreatment and homogeneous extraction

Water-soluble lignin-carbohydrate complex(LCC)rich in polysaccharides exhibits benign in vitro antioxidant activities and distinguishes high biocompatibility from lignin-rich LCC and lignin.However,the antioxidant activity of water-soluble LCCs remains to be improved and its structure-antioxidant relationship is still uncertain.Herein,structurally diversified water-soluble LCCs were isolated under different ball-milling pretreatment durations(4,6,8 h),extraction pathways(ho-mogeneous and heterogeneous),and isolation routines(water extracts and residues after water extraction).Their structures were characterized by wet chemistry,chromatography and spec-troscopies.Antioxidant activities were evaluated by ferric reducing antioxidant power and 1,1-diphenyl-2-picrylhydrazyl radicals scavenging rate(RDPPH).Results show that altering ball-milling duration and isolation procedures cause varied structures and antioxidant activities of the water-soluble LCCs.Specifically,prolonging ball-milling duration to 8 hours and homogeneous extrac-tion can enhance their antioxidant activity through releasing more phenolic structures and pro-moting the extraction of high-molecular-weight LCCs via reducing mass-transfer resistance,re-spectively.As a result,the RDPPH of water-soluble LCCs reaches up to 97.35%,which is associated with the arabinan content with statistical significance(P<0.05).This study provides new insights into the structure-antioxidation relationship of herbaceous LCC as potential antioxidants.

Homogeneous Liquid-Liquid Extraction (HoLLE) of Palladium in Real Plating Wastewater for Recovery

On the basis of homogeneous liquid-liquid extraction (HoLLE) with Zonyl FSA to plating water containing 1 mg palladium, 96.6% of the palladium was extracted into the sedimented liquid phase. After phase separation, the volume ratio (Va/Vs) of the aqueous phase (Va) and the sedimented liquid phase (Vs) was 556 (50 mL → 0.09 mL). The assessment of the potential implementation of this procedure to wastewater treatment showed that HoLLE was satisfactorily achieved when the volume was scaled up to 1000 mL. Moreover, HoLLE was conducted to real palladium plating wastewater generated in the plating industry. 94.5% of the palladium was extracted into the sedimented liquid phase. After phase separation, the volume ratio (Va/Vs) of the aqueous phase (Va) and the sedimented liquid phase (Vs) was 500 (50 mL → 0.1 mL). In addition, HoLLE could separate palladium from coexisting metals in real plating wastewater. This knowledge is expected to lead to the development of new separation and concentration technologies of rare metals from real plating wastewater.

Epigallocatechin gallate content change of the fresh tea leaf homogenates extracted by different methods in extraction and preservation

The fresh leaves of China green tea, Camellia sinensis, were collected from Fuyang, Zhejiang Province, China, in April. The tea polyphenols was extracted by four different methods （homogenized with distilled water at room temperature, homogenized with 0.3% citric acid （w/v） at room temperature, 5- min boiling and homogenized with distilled water at room temperature, homogenized with 85℃ distilled water）, and after preserving at room temperature, the change of the Epigallocatechin gallate （EGCG） contents of the extracts was investigated. Results indicated that the EGCG content of homogenate extracted with 85℃ distilled water was the highest before the extract was preserved, followed by that of the extract homogenized with 0.3% citric acid at room temperature. During preservation, EGCG content changed obviously. The EGCG contents of homogenates extracted with distilled water at room temperature and 85℃ distilled water declined quickly and separately reduced to 21.52% and 54.6% of their initial contents after preservation for 12 h. The EGCG contents extracted by 0.3% citric acid （w/v） solvent at room temperature and 5- min boiling/homogenized with distilled water at room temperature declined relatively slowly ,and separately reduced to 76.9% and 85.16% of their initial contents after preservation for 12 h. It was also found that the citric acid can prevent the degradation of EGCG and the extract solution color is light green

Optimization of the main liming process for inulin crude extract from Jerusalem artichoke tubers

A three-stage homogenate extraction was used as a new method for inulin extraction from Jerusalem artichoke tubers. Compared with the results from conventional hot water extraction, the three-stage homogenate extraction gave higher yields and caused less degradation of the inulin. The inulin crude extract was then clarified by a carbonate-precipitation method, during which three variables -- the quicklime mass, the reaction temperature and the reaction time were optimized for the main liming process to give the best clarification effect. A Plackett- Burman design, the path of steepest ascent method, a Box- Behnken design and response surface methodology （RSM） were employed in the experimental design. The optimal conditions for the main liming process were determined to be 12.0g/L, 71.4℃ and 8min. The confirmatory tests proved that the best clarification efficiency （92.74%） was achieved at these conditions and this was approximately equal to the value predicted by the model.