Effects Of Superfine Grinding Research Articles

Effect of Superfine Grinding on the Phytochemicals and Antioxidant Activities of Mulberry Leaves

In this study, two species of mulberry leaves were used as materials and four different size powders (about 20-115 µm, 15-20 µm, 10-15 µm and <10 µm) were prepared. The effects of superfine grinding (SG) on the extraction of active components from mulberry leaves (MLs) and their antioxidant activities were investigated. The results indicated that the contents of the active component such as polyphenol, polysaccharides, alkaloids were increased markedly with the decreasing in the particle size, but there was a bit difference in flavonoids. Additionally, the antioxidants properties of MLs treated on 1,1-diphel-2-picrylhydraxyl (DPPH) radical scavenging activity and ferric reducing antioxidant power (FRAP) were also increased, but the scavenging activity in hydroxyl radical scavenging assay (HAS) decreased in the size of D10. These results indicated that SG could improve the extraction efficiency of active components from MLs and make its antioxidant activity enhance, implying that SG can be an effective way to improve the quality and functionality of MLs in foodstuff and pharmacological field.

Effect of superfine grinding on physicochemical and antioxidant properties of pomegranate peel

SummaryPomegranate peel powders were prepared by superfine grinding, whose effects were investigated on the composition, functional and antioxidant properties of the pomegranate peel products. Fluidised bed jet milling technology was used to process superfine pomegranate peel powder. The physical–chemical properties of coarse powder A (D50 = 413.4 μm) and B (D50 = 197.1 μm), fine powder C (D50 = 142.6 μm) and D (D50 = 41.2 μm), superfine powder E (D50 = 7.68 μm) and raw material powder (RMP) (D50 = 352.2 μm) were investigated in this study. SEM images revealed the shape and surface morphology of six pomegranate peel powders. The physical determinations showed that the smaller the powder particle size was, the greater the surface area (from 0.214 to 1.597 m2 g−1) and bulk density (from 0.653 to 0.751 g mL−1) were, the smaller the angles of repose (from 51.69° to 38.74°) and slide (from 48.32° to 34.18°) were. The water holding capacity (WHC), water‐solubility index (WSI), polyphenols and flavonoids release were significantly improved as the size of pomegranate peel particle decreased. The results of FTIR and UV indicated that grinding process would not influence chemical composition of pomegranate peel. Vitamin C (VC) and butylated hydroxytoluene (BHT) were used in DPPH scavenging activity determination, and DPPH scavenging activity was A &lt; RMP &lt; BHT &lt; B &lt; C &lt; D &lt; E &lt; VC.

Effect of superfine grinding on the structural and physicochemical properties of whey protein and applications for microparticulated proteins

Effects of superfine grinding on structural and physicochemical properties of whey protein concentrate (WPC) and applications for microparticulated whey protein (MWP) were investigated. WPC and MWP particle sizes significantly (p<0.05) decreased after superfine grinding from 62 and 15 µm to 15 and 9 µm, respectively, compared with controls. A basis for exploration of WPC applications as a fat replacer because of WPC and MWP particle size reductions due to superfine grinding is established. The effect of superfine grinding on molecular configuration, thermal stability, and physicochemical properties of WPC were also investigated. Amounts of free sulfhydryl groups decreased significantly (p<0.05) from 18.16 to 14.49 µmol/L, and thermodynamic properties, including transition temperature, were changed after superfine grinding. The whey protein solubility, protein surface hydrophobicity, oil binding capacity, foaming capacity, and foaming stability of WPC were all improved after superfine grinding.

Effect of superfine grinding on the physicochemical properties and antioxidant activity of red grape pomace powders

The objectives of this study were to determine the physicochemical properties and antioxidant activity of red grape pomace powders (GPPs) from winemaking residue with particle sizes of >300, 250–125, 125–70, 70–38, and <18.83μm. Superfine grinding treatment could decrease bulk density (from 0.40 to 0.21kg/m3), tapped density (from 0.51 to 0.31kg/m3), and fluidity (repose angle from 33.87 to 56.34° and slid angle from 36.76 to 71.97°, respectively) of GPPs, but improve the solubility (from 9.38 to 48.86%). The extract of GPP with a particle size of <18.83μm showed that highest total polyphenolic content (757.36mg GAE/100g) and flavanol content (19.46mg CE/100g) accompanied with the best antioxidant activity through all antioxidant assays (p<0.05). SEM images revealed the shape and surface morphology of GPPs with different sizes. FTIR analysis showed that the superfine grinding did not damage the main structure of phenols as the powder particle size decreased. The results indicated that after superfine grinding treatment, GPPs could serve as a potential resource of natural ingredients for food and nutraceutical application.

Effects of superfine grinding and microparticulation on the surface hydrophobicity of whey protein concentrate and its relation to emulsions stability

In this study, superfine grinding and microparticulation were employed to increase the hydrophobicity of whey protein concentrate (WPC), which was investigated using 8-anilino-1-naphthalene sulfonic acid. WPC-stabilized emulsions containing 40% and 80% (w/w) oil showed smaller average droplet size when superfine grinding-treated WPC (sWPC) and microparticulated protein (MPP) were used than when WPC was used. The micro-rheology of the emulsions was measured upon diffusing wave spectroscopy; results showed that MPP can form stable emulsions. Moreover, the solid liquid balance of the emulsions significantly decreased from 0.87 to 0.38, with changing states from liquid to solid. The Turbiscan Stability Indexes of sWPC and MPP significantly reduced from 15.23 to 13.58 and 1.17, respectively. The operations of superfine grinding and microparticulation rendered WPC into an ingredient with excellent emulsifying properties. Thus, this ingredient can be utilized in both reduced-fat and high-fat food applications.

Effects of superfine grinding on the quality characteristics of whole-wheat flour and its raw noodle product

Four particle size distributions of whole-wheat flour (WWF) with mean particle sizes (MZ) of 125-μm, 96-μm, 72-μm, and 43-μm were obtained by superfine grinding. Starch damage and Farinograph water absorption were significantly affected by the reduction of particle size, while dough development time, stability, tolerance index and time to breakdown of WWF were little changed. The peak viscosity, trough, and final viscosity of WWF significantly decreased as particle size reduced. Although finer WWFs produced by superfine grinding caused more discoloration of whole-wheat noodle (WWN) after 24 h storage, they still showed brighter noodle appearance (higher L∗) than coarser WWFs. A significant increase in the cooking yield of WWN was noticed from the 125-μm WWF group to the 43-μm group, perhaps due to increasing damaged starch, while the 72-μm group exhibited the smallest cooking loss of WWN. Additionally, the hardness, cohesiveness, and resilience values of texture profile analysis (TPA) of cooked WWN significantly increased from the 125-μm group to the 72-μm group, and scanning electron microscope (SEM) analysis showed that the 72-μm group revealed the largest coverage of starch granules and degree of protein network connectivity among the WWF groups. The results demonstrated that the superfine grinding technique could improve the quality of WWN by significantly reducing the particle size of WWFs.

Effect of superfine grinding on antidiabetic activity of bitter melon powder.

The antidiabetic activities of bitter melon powders produced with lyophilization/superfine grinding and hot air drying/normal grinding were investigated in vivo for selecting a suitable bitter melon processing procedure. After a five-week treatment, bitter melon lyophilized superfine grinding powder (BLSP) had a higher antidiabetic activity with reducing fasting blood glucose levels from 21.40 to 12.54 mmol/L, the serum insulin levels from 40.93 to 30.74 mIU/L, and restoring activities of SOD compared with those in the bitter melon hot air drying powder (BAP) treated group. Furthermore, BLSP protected pancreatic tissues including islet beta cells and reduced the loss of islet cells. Combined with the difference of compositions in BLSP and BAP, it could be concluded that superfine grinding and lyophilization processes were beneficial for presenting the antidiabetic activity, which will provide a reference for direct utilization of bitter melon as a suitable functional food to relieve symptoms of diabetes.

Effect of superfine grinding on quality and antioxidant property of fine green tea powders

Six Green tea powders (GTPs) were prepared from green tea with superfine grinding process. Their main quality components were determined by chemical methods and the scavenging effects of GTPs on ·OH and O2.−in vitro were evaluated by using deoxyribose assay and xanthine oxidase method, respectively. The results indicated that tea polyphenols and catechins contents decreased, while the contents of water-soluble carbohydrates in GTPs increased markedly, and no significant difference in amino acids and caffein with the decrease in particle size during superfine grinding, which benefited to reduce bitterness and preserve briskness of GTPs. Meanwhile, superfine grinding increased extraction of TPS markedly, which could lead to more potent scavenging capacity of GTPEs on ·OH. Based on the above analysis, it suggested that superfine grinding time should be controlled within 30–50 min, with ideal parameters of GTP: X: 4.93–4.75%, d50: 20.3–13.5 μm, ρbulk: 0.323–0.297 kg/m3, ρtapped: 0.666–0.614 kg/m3. Under this condition, we could prepare GTP with green and bright color, narrower and more uniform particle size distribution, as well as possessing more food processing property.

Effect of superfine grinding on properties of ginger powder

The superfine grinding could produce a narrow and uniform particle size distribution in dry ginger. The physical–chemical properties of five types of ginger powders with particles size of 300, 149, 74, 37 and 8.34 μm were investigated. The size was smaller for ginger powders, greater for the surface area (from 0.331 to 1.320 m 2/g) and bulk density (from 0.3069 to 0.3426 g/ml) and smaller for the angle of repose (from 51.50° to 46.33°) and slide (from 45.80° to 39.50°). The values of water absorption index (WAI), water solubility index (WSI) and protein content significantly increased with decreasing the size of ginger particles ( p < 0.05). Interestingly, the values of WAI, WSI and protein content of ginger powder with a particle size of 8.34 μm during soaking reached 0.52 g/g, 33.70% and 84.93% for 60 min, respectively. SEM observations revealed the shape and surface morphology of five types of ginger powders.