Jingren He

HPLC-DAD-ESI-MS(2) analytical profile of extracts obtained from purple sweet potato after green ultrasound-assisted extraction.

Ultrasound pre-treatment (UAE) was applied to assist the extraction of valuable compounds (polyphenols (especially anthocyanins), and proteins) from purple sweet potato (PSP). Under optimum conditions (ultrasound time (40min); supplementary hot extraction (80°C) up to 120min; pH: 2.5; ethanol concentration: 58%), the highest concentrations of polyphenols (3.877mg/g), anthocyanins (0.293mg/g), and proteins (0.753mg/g) were found, with minimal specific energy consumption (8406J/mg). Moreover, anthocyanin and non-anthocyanin polyphenols in PSP extract from optimized extraction temperature were identified using HPLC-DAD-ESI-MS(2). The major identified anthocyanins were peonidin-3-caffeoyl-p-hydroxybenzoyl sophoroside-5-glucoside, peonidin-3-(6″-caffeoyl-6‴-feruloyl sophoroside)-5-glucoside, cyanidin-3-caffeoyl-p-hydroxybenzoyl sophoroside-5-glucoside, whereas the major identified non-anthocyanin molecules were quinic acid, chlorogenic acid, caffeic acid, and chlorogenic acid-3-glucose. The amount of the predominant anthocyanin and non-anthocyanin compounds from PSP extract obtained after UAE was higher than that extracted after conventional solvent extraction. The results obtained in this work demonstrated the efficiency of UAE for the recovery of anthocyanins from PSP.

Preparation and toxicological evaluation of methyl pyranoanthocyanin.

Anthocyanins are increasingly valued in the food industry for their functional properties and as food colorants. The broadness of their applications has, however, been limited by the lack of stability of these natural pigment extracts in a number of food systems. The potential application of pyranoanthocyanins, anthocyanin derivatives with better stability conferred by the added pyran ring, as a food ingredient was determined. Methylpyranoanthocyanin (MPA) was prepared from reaction of acetone and anthocyanin extracts from red grapes. Reaction products were sequentially purified with polyamide resin, TSK gel resin and semi-preparative HPLC to a purity level >98%. Cytoprotective influence tests of the purified MPA indicated its significant protective effect against H2O2 induced MRC-5 cell damage. Results of evaluations of possible acute toxicity effects on MPA-fed mice, including macro and microscopic assessments, support the conclusion of a non-toxic effect of MPA, and its potential safe use as a food additive.

Ultrasound-Assisted Extraction, Centrifugation and Ultrafiltration: Multistage Process for Polyphenol Recovery from Purple Sweet Potatoes.

This work provides an evaluation of an ultrasound-assisted, combined extraction, centrifugation and ultrafiltration process for the optimal recovery of polyphenols. A purple sweet potato (PSP) extract has been obtained using ultrasonic circulating extraction equipment at a power of 840 W, a frequency of 59 kHz and using water as solvent. Extract ultrafiltration, using polyethersulfone (PES), was carried out for the recovery of polyphenol, protein and anthocyanin. Pre-treatment, via the centrifugation of purple sweet potato extract at 2500 rpm over 6 min, led to better polyphenol recovery, with satisfactory protein removal (reused for future purposes), than PSP extract filtration without centrifugation. Results showed that anthocyanin was efficiently recovered (99%) from permeate. The exponential model fit well with the experimental ultrafiltration data and led to the calculation of the membrane’s fouling coefficient. The optimization of centrifugation conditions showed that, at a centrifugation speed of 4000 rpm (1195× g) and duration of 7.74 min, the optimized polyphenol recovery and fouling coefficient were 34.5% and 29.5 m−1, respectively. The removal of proteins in the centrifugation process means that most of the anthocyanin content (90%) remained after filtration. No significant differences in the intensities of the HPLC-DAD-ESI-MS2 peaks were found in the samples taken before and after centrifugation for the main anthocyanins; peonidin-3-feruloylsophoroside-5-glucoside, peonidin-3-caffeoyl-p-hydroxybenzoylsophoroside-5-glucoside, and peonidin-3-caffeoyl-feruloyl sophoroside-5-glucoside. This proves that centrifugation is an efficient method for protein removal without anthocyanin loss. This study considers this process an ultrasound-assisted extraction-centrifugation-ultrafiltration for purple sweet potato valorization in “green” technology.

Green ultrasound-assisted extraction of anthocyanin and phenolic compounds from purple sweet potato using response surface methodology**

Abstract Response surface methodology was used to optimize experimental conditions for ultrasound-assisted extraction of valuable components (anthocyanins and phenolics) from purple sweet potatoes using water as a solvent. The Box-Behnken design was used for optimizing extraction responses of anthocyanin extraction yield, phenolic extraction yield, and specific energy consumption. Conditions to obtain maximal anthocyanin extraction yield, maximal phenolic extraction yield, and minimal specific energy consumption were different; an overall desirability function was used to search for overall optimal conditions: extraction temperature of 68ºC, ultrasonic treatment time of 52 min, and a liquid/solid ratio of 20. The optimized anthocyanin extraction yield, phenolic extraction yield, and specific energy consumption were 4.91 mg 100 g−1 fresh weight, 3.24 mg g−1 fresh weight, and 2.07 kWh g−1, respectively, with a desirability of 0.99. This study indicates that ultrasound-assisted extraction should contribute to a green process for valorization of purple sweet potatoes.

The use of solvent-soaking treatment to enhance the anisotropic mechanical properties of electrospun nanofiber membranes for water filtration

Cellulose acetate derived from bamboo cellulose (B-CA) was prepared via a typical acetylation process and used to fabricate the aligned electrospun nanofibrous membranes (ENMs). A solvent post-treatment by soaking the B-CA ENMs in a mixture solution with different ethanol/acetone volume ratios was also performed to improve the mechanical properties of the membranes. In this study, we showed that this approach can enhance the bonding in the fiber membranes by solvent-induced fusion of inter-fiber junction points and change the degree of molecular orientation of the polymer, which are both considered to have important influences on the mechanical properties of ENMs. The treated membranes exhibited a significant enhancement in mechanical strength while retaining high hydraulic permeability. Increased performances will improve the prospects of ENMs as an emerging material in the filtration space for handling and scale-up manufacturing.

Enzyme-assisted extraction of polyphenol from edible lotus (Nelumbo nucifera) rhizome knot: Ultra-filtration performance and HPLC-MS2 profile

Rhizome knot is always wasted as useless and inedible part of lotus root, despite its abundance of polyphenols. In this work, enzyme-assisted extraction followed by ultra-filtration was investigated to recover polyphenols from rhizome knot. Cellulase and pectinase treatment enhanced the polyphenols extraction. The 100 kDa membrane resulted in better filtration yield than 50 kDa membrane, 3.84% and 3.37%, respectively. With 100 kDa membrane, the highest filtration yield (4.08%) was achieved with a rotational speed of 600 rpm, TMP of 0.3 MPa and pH of 5. Satisfied permeate turbidity (<3 NTU) and polyphenol transmission (>90%) were obtained under these conditions. The main polyphenols identified in both rhizome knot extract and permeate were: chlorogenic acid, B-type procyanidin dimer·H2O, (+)-Catechin, B-type procyanidin dimer, (-)-Epicatechin, propyl gallate·H2O, caffeic acid, (-)-Epicatechin-3-gallate, and rutin. Membrane fouling led to the most important resistance (58% of total resistance). Scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM) evidenced that protein accumulation was the main fouling cause.

Recovery of Oil with Unsaturated Fatty Acids and Polyphenols from Chaenomelessinensis (Thouin) Koehne: Process Optimization of Pilot-Scale Subcritical Fluid Assisted Extraction

The potential effects of three modern extraction technologies (cold-pressing, microwaves and subcritical fluids) on the recovery of oil from Chaenomelessinensis (Thouin) Koehne seeds have been evaluated and compared to those of conventional chemical extraction methods (Soxhlet extraction). This oil contains unsaturated fatty acids and polyphenols. Subcritical fluid extraction (SbFE) provided the highest yield—25.79 g oil/100 g dry seeds—of the three methods. Moreover, the fatty acid composition in the oil samples was analysed using gas chromatography–mass spectrometry. This analysis showed that the percentages of monounsaturated (46.61%), and polyunsaturated fatty acids (42.14%), after applying SbFE were higher than those obtained by Soxhlet, cold-pressing or microwave-assisted extraction. In addition, the oil obtained under optimized SbFE conditions (35 min extraction at 35 °C with four extraction cycles), showed significant polyphenol (527.36 mg GAE/kg oil), and flavonoid (15.32 mg RE/kg oil), content, had a good appearance and was of high quality.

Effect of the A-Type Linkage on the Pharmacokinetics and Intestinal Metabolism of Litchi Pericarp Oligomeric Procyanidins

The bioavailability of A-type procyanidins in vivo has been rarely investigated; as such, this study discusses the effect of A-type linkage and degree of polymerization on the metabolism of procyanidins extracted from litchi pericarp (LPOPC). Sprague-Dawley rats were gavaged with (-)-epicatechin (EC) and LPOPC and sacrificed at different time points after ingestion. A-type linkage procyanidin oligomers inhibited the absorption of EC. Analysis of urinary contents from rats administered with EC, A-type procyanidin dimer (A-2), and A-type procyanidin trimer (A-3) showed distinct native and metabolite profiles for each rat. Rats fed with A-2 and A-3 presented significantly higher levels of shikimic acid and less amount of m(p)-coumaric acid metabolites in vivo and provide insight into the quantitative structure-activity relationship of procyanidin oligomers during metabolism, indicating that procyanidins with A-type linkage could induce an altered metabolic pathway of oligomers in the gastrointestinal system.

Heat stability improvement of whey protein isolate via glycation with maltodextrin without control of the relative humidity

The reduction of protein aggregation and their improved heat stability in solutions are often achieved through glycation. While a controlled relative humidity (RH) is standard practice in the glycation process, its requirement and associated cost, as a condition of the treatment, has not been demonstrated. The improved heat stability of whey protein isolate (WPI) at pH 3–7 and 0–150 mM NaCl after glycation with maltodextrin (MD) using the Maillard reaction in the dry state without the need to control the RH is reported in this study. Dispersions of glycated WPI remained transparent after heating at 88 °C for 2 min at pH values that are close to whey protein pI values, including pH 5.0. Transparent dispersions were enabled as indicated by circular dichroism of the WPI–MD conjugates heated in aqueous solutions that underwent secondary structure changes and by AFM images that indicated globular aggregates smaller than 40 nm.

Evaluation of gliadins-diglycosylated cyanidins interaction from litchi pericarp through ultraviolet and fluorescence measurements

ABSTRACT The low stability of anthocyanins limits their use in industry, which can be surpassed by gliadins linkage. This work was aimed to study the anthocyanins-gliadins bonding properties. HPLC-DAD-ESI-MS2 analysis indicated that the main litchi pericarp anthocyanin (LPA) was cyanidin-3-glucoside-5-rhamnoside (C3G5R). Ultraviolet and fluorescence data revealed the presence of anthocyanin-protein complexes, with strong binding affinity by a combination of hydrogen bonds and van der Waals forces. The combination of C3G5R and gliadins changed its secondary structure. The scavenging effect of the anthocyanin-protein complex over 2,2-diphenyl-1-picrylhydrazyl was comparable to LPA alone. These results may broaden gluten usage to stabilize anthocyanins and so their use in the food, pharmaceutic, and cosmetic industries due to their potential use as colorants and antioxidants.