Variability in the substitution pattern of hydroxypropyl cellulose affects its physico-chemical properties.

Hydroxypropyl cellulose (HPC) is a water-soluble polymer with many applications in food, pharmaceutical, medical, or paints industries. Past studies have reported that differences in functionality can occur between products of similar pharmaceutical grades. Understanding the origin of these differences is a major challenge for the industry. In this work, the structure and physico-chemical properties of several HPC samples of the same commercial grade were studied. Structural analysis by NMR and enzymatic hydrolysis were performed to study molar substitution and distribution of substituents along the polymer chain respectively. Water-polymer interactions, surface properties as well as rheological and thermal behavior were characterized to tentatively correlate them with the structure, and gain new insights into the structure-function relationship of this polymer. The differences in structure revealed between the samples affect their properties. The unexpected behavior of one sample was attributed to a more heterogeneous substitution pattern, with the coexistence of highly and weakly substituted regions along the same polymer chain. The more block-like distribution of substituents has a great effect on the clouding behavior and surface tension reduction ability of the polymer.

Impact of Crude Oil Quality on the Refining Conditions and Composition of Nutraceuticals in Refined Palm Oil.

Palm oil is the major vegetable oil used worldwide due to its unique properties. The effect of crude palm oil acidity on the final free fatty acids (FFA) content, neutral oil loss (NOL), and nutraceutical compounds, such as carotenes, total tocols (tocopherols and tocotrienols), squalene, and phytosterols was investigated. A central composite design was employed to study the influence of the refining conditions: temperature (200 to 260 °C), steam percentage (0.5% to 3.5%), and initial FFA content (2.2% to 6.0%) on the quality of the refined product. The results revealed that initial palm oil acidity is a statistically important parameter to obtain commercially acceptable values for final FFA content. The increase of temperature presented the most important effect on the reduction of all nutraceutical compounds. The highest tocopherols (88%), phytosterols (98%), and squalene retention (84%) was obtained when applying the mildest temperature (200 °C). From the experimental results, 3 equations were generated enabling the prediction of the free fatty acids content, the tocols content, and the losses of neutral oil. Therefore, this work contributes to the understanding and optimization of the process for the production of palm oil with high nutraceutical quality and low free fatty acid contents.

Development of an enzyme-linked immunosorbent assay for bisphenol a using chicken immunoglobulins.

Bisphenol A was coupled, after derivatization into a suitable hapten, to bovine serum albumin and ovalbumin in order to produce immunizing and coating antigens. The immunizing antigens were injected into chickens, which allowed the isolation of specific bisphenol A immunoglobulins from the egg yolk. These antibodies were used in an indirect competitive enzyme-linked immunosorbent assay for the determination of bisphenol A in aqueous solutions. Various parameters, influencing the assay sensitivity, were evaluated. The applicability of the assay for the determination of bisphenol A in milk was also studied. The assay was not as sensitive as other analytical techniques used in bisphenol A analysis, since typical I(50) levels of 2.5 microM were reached in aqueous solutions. This study nevertheless illustrates the usefulness and the potency of chicken antibodies in the analysis of migration residues from packaging materials using immunochemical techniques. In addition, the assay showed to be quite specific for bisphenol A as well. Only for bisphenol A analogues, cross reactivities of about 40% were reached, enabling the use of the antibodies for the screening of bisphenol A and alike compounds.