Colour improvement of common carp (Cyprinus carpio) fillets by hydrogen peroxide for surimi production

The preferred colour for surimi is white, but surimi prepared from light fillets of common carp (Cyprinus carpio) is slightly pink. Hydrogen peroxide (H₂O₂; 1–3% v/v) with and without sodium tri‐polyphosphate (STP; 1–2% w/v) was added to a sodium carbonate bath (pH 7.0–11.5) resulting in a final pH range of 4.4–10.1 which was injected into carp fillets. After soaking and tumbling for 30 min at 4–10 °C, the fillets were evaluated for colour and water holding capacity (WHC). Fillets tumbled with treatment solution with different pH levels (7.0–11.5), but with no H₂O₂ or STP added, had improved colour with significantly (P < 0.05) higher L* compared with untreated fillets as the control. However, the colour improvement [(L* and colour deviation (ΔE)] was not significantly different (P > 0.05) within the pH levels (7.0–11.5) trialled. With increasing H₂O₂ levels (1–3%), fillets became lighter and ΔE increased significantly (P < 0.05), especially with a 3% H₂O₂ treatment at pH of 10.5 (adjusted pH before H₂O₂ addition, actual pH after H₂O₂ addition was 8.2). The whiteness (L*?3b*) of kamaboko produced from treated (3% H₂O₂, pH 10.5) common carp light fillets was not significantly different to that of kamaboko from Alaska pollock and threadfin bream. Treatments combining H₂O₂ (3%) with STP (1–2%) significantly reduced the L* value obtained in comparison with fillets treated with only H₂O₂ (3%). Similarly, fillets treated with STP (1%) alone, resulting in lower L* values, irrespective of treatment pH (7.0–11.5). WHC, an indicator of the quality of the fillet texture, increased from 816 g/kg at pH 7.0 without STP to 841 g/kg at pH 11.5 with 1% STP. Treatment with H₂O₂ (without STP) decreased the WHC of the fillets.     

Formulation and corneal permeation of ketorolac tromethamine-loaded chitosan nanoparticles

Abstract

The aim of this work was to formulate chitosan (CS)-based nanoparticles (NPs) loaded with ketorolac tromethamine (KT) intended for topical ocular delivery. NPs were prepared using ionic gelation method incorporating tri-polyphosphate (TPP) as cross-linker. Following the preparation, the composition of the system was optimized in terms of their particle size, zeta potential, entrapment efficiency (EE) and morphology, as well as performing structural characterization studies using Fourier transform infrared spectroscopy (FT-IR) and differential scanning calorimetry (DSC). The data suggested that the size of the NPs was affected by CS/TPP ratio where the diameter of the NPs ranged from 108.0?±?2.4?nm to 257.2?±?18.6?nm. A correlation between drug EE and the corresponding drug concentration added to the formulation was observed, where the EE of the NPs increased with increasing drug concentration, for up to 10?mg/mL. FT-IR and DSC revealed that KT was dispersed within the NPs where the phosphate groups of TPP were associated with the ammonium groups of CS. The in vitro release profile of KT from CS NPs showed significant differences (p?<?0.05) compared to KT solution. Furthermore, mucoadhesion studies revealed adhesive properties of the formulated NPs. The KT-loaded NPs were found to be stable when stored at different storage conditions for a period of 3 months. The ex vivo corneal permeation studies performed on excised porcine eye balls confirmed the ability of NPs in retaining the drug on the eye surface for a relatively longer time. These results demonstrate the potential of CS-based NPs for the ocular delivery of KT.     

三聚磷酸钠钙螯合值测定方法

分别采用铬黑T指示剂络合滴定法、草酸钙沉淀滴定法、自指示沉淀滴定法3种方法测量了三聚磷酸钠的钙螯合能力.结果表明,由于三聚磷酸钠能与钙离子形成沉淀,影响络合滴定的终点,所以络合滴定法的测量误差较大,最大偏差达到26.5 mg·g-1;而沉淀滴定法中草酸钙沉淀滴定法最大偏差为1.6 mg·g-1,自指示沉淀滴定法最大偏差为1.8 mg·g-1.     

运用铝土矿选矿尾矿制备三聚磷酸铝防腐颜料(英文)

将铝土矿选矿尾矿与磷酸以P与Al摩尔比等于3的比例混合,制备了三聚磷酸铝,并用氧化锌对所制备的三聚磷酸铝进行改性处理,得到三聚磷酸铝防腐颜料。改性的三聚磷酸铝的酸度、白度及粒度均得到了改善。运用电化学阻抗方法测试了所制备的三聚磷酸铝防腐颜料的防腐性能。结果表明:含有改性三聚磷酸铝防腐颜料的涂层在电解质中浸泡40d后的阻抗为7×107Ω,含商品三聚磷酸铝防腐颜料APW?2的涂层浸泡40d后的阻抗为5.7×107Ω,这表明所制备的三聚磷酸铝防腐颜料具有优于或相当于商品防腐颜料的防腐性能。