Improvement of reproducibility and sensitivity by reducing matrix effect in micellar electrokinetic chromatography for determination of amino acids in turtle jelly.

Matrix effect (ME) is commonly seen in electrophoretic separation, but this phenomenon lacks any systematic study. Our work aimed to find out the relationship between separation efficiency and current, and then figure out an effective, simple, and economic solution to overcome the negative impact of ME. This present study showed that small amount of NaCl (≤0.005 mg/mL) in the sample had no impact on the separation but enhanced the sensitivity. However, when concentration of NaCl increased above 0.005 mg/mL, it alleviated the separation efficiency, sensitivity, and migration time. Besides, increasing NaCl concentration resulted in increasing turning point. The study of relationship of current and NaCl concentration indicated that when the TP of a sample is higher than 62.36 µA, desalination is necessary. Since the reported desalination methods are either expensive or complicated, we developed a simple and economic method by simply adding 12 times (volume) of chloroform/methanol (2:1, v/v) into the sample. When applied this method to turtle jelly, the number of theoretical plate (N) of 20 amino acids got up to threefold enhancement.

Determination of the authenticity of plastron-derived functional foods based on amino acid profiles analysed by MEKC.

Plastron is a nutritive and superior functional food. Due to its limited supply yet enormous demands, some functional foods supposed to contain plastron may be forged with other substitutes. This paper reports a novel and simple method for determination of the authenticity of plastron-derived functional foods based on comparison of the amino acid (AA) profiles of plastron and its possible substitutes. By applying micellar electrokinetic chromatography (MEKC), 18 common AAs along with another 2 special AAs - hydroxyproline (Hyp) and hydroxylysine (Hyl) were detected in all plastron samples. Since chicken, egg, fish, milk, pork, nail and hair lacked of Hyp and Hyl, plastron could be easily distinguished. For those containing collagen, a statistical analysis technique - principal component analysis (PCA) was adopted and plastron was successfully distinguished. When applied the proposed method to authenticate turtle shell glue in the market, fake products were commonly found.

Phytochemical profiles, antioxidant activities of functional herb Abrus cantoniensis and Abrus mollis.

It has been claimed that consumptions of Abrus cantoniensis (AC) and Abrus mollis (AM) as folk beverages and soups are good to cleanse liver toxicants and prevent liver diseases. There is scant information on the phytochemical profiles and antioxidant activities of these two varieties. Five major phytochemicals in these two cultivars were qualitatively and quantitatively compared using UPLC-PDA. A high level of total phenolic content (TPC) and total flavonoid content (TFC) was found in AC and AM. AC, in general, showed some antioxidant activities comparable to that of BHT, and stronger radical scavenging activities and higher reducing power than that of AM (p<0.05). When principal component analysis (PCA) was applied, high correlation between TPC, TFC and their antioxidant activities was found. Hence, this study proved that, both AC and AM could serve as antioxidant-rich component in foods or beverages to promote health function.