Xiao Gong

Ultra-performance convergence chromatography (UPC2) method for the analysis of biogenic amines in fermented foods

A rapid ultra-performance convergence chromatography (UPC(2)) method for the determination of eight biogenic amines (spermine, spermidine, putrescine, cadaverine, tryptamine, phenylethylamine, histamine and tyramine) in fermented foods was developed. The amines were pre-column derivatized with dansyl chloride and separated on UPC(2) system with a HSS C18 SB column (3.0 × 100 mm, 1.8 μm) using gradient elution with a binary system of CO2 and n-hexane:isopropanol:ammonium hydroxide (70:30:0.15, v/v/v), back pressure of 2,000 psi, flow rate of 2.0 ml/min and DAD detection at 254 nm. The result showed excellent linearity (r=0.9995-1.0000). Limits of detection (LOD) and limits of quantification (LOQ) were 21-67 ng/L and 72-224 ng/L, respectively. Relative standard deviations (RSD) for repeatability and reproducibility were 0.21-0.87% and 1.98-4.02%, respectively. Furthermore, this method was successfully applied to analysis of biogenic amines in Yulu and Sufu samples.

Simultaneous analysis of eight vitamin E isomers in Moringa oleifera Lam. leaves by ultra performance convergence chromatography

A new method for simultaneous determination of eight vitamin E isomers including α-, β-, γ-, and δ-tocopherol and α-, β-, γ-, and δ-tocotrienol by ultra-performance convergence chromatography (UPC(2)) equipped with a diode array detector was reported. They were separated on a BEH 2-EP column (3.0 mm × 100 mm, 1.7 μm) using gradient elution (95:5-80:20) with a mobile phase consisted of CO2 and methanol:isopropanol (1:1, v/v), back pressure of 1800 psi, flow rate of 1.5 ml/min and detection at 294 nm. The results showed good linearity (R(2)=0.9990-0.9998) and high resolution (1.48-7.67). Limits of detection (LOD) and quantification (LOQ) ranged from 23-49 ng/L and 70-150 ng/L, respectively. Relative standard deviations (RSD) for repeatability and reproducibility were 0.62-3.16% and 0.82-3.34%, respectively. Moreover, this method was successfully applied to analysis the vitamin E isomers in Moringa oleifera leaf samples.

Determination of biogenic amines in traditional Chinese fermented foods by reversed-phase high-performance liquid chromatography (RP-HPLC)

A survey of biogenic amine content of traditional Chinese fermented foods (douchi, sufu, fermented sausage, yulu, and shrimp paste) was carried out. Eight major biogenic amines including putrescine, cadaverine, histamine, phenylethylamine, tyramine, spermine, spermidine and tryptamine were separated by reversed-phase HPLC-DAD on Inertsil ODS-SP column after pre-column derivatisation with dansyl chloride. The results showed that spermine (1.65–3.96 mg 100 g−1), putrescine (0.20–10.89 mg 100 g−1), cadaverine (3.60–12.14 mg 100 g−1), and histamine (0.57–20.24 mg 100 g−1) were the most represented amines. All amines were detected in yulu, while sufu showed a much higher content of most amines. Shrimp paste showed the lowest level of total biogenic amines. Moreover, the composition and content of eight biogenic amines in the selected samples varied among different food types, origins and batches. Although the average content for each amine is within the range that may elicit direct adverse reactions, consumers should be aware of the potential synergistic effect among different amines and limit their consumption at each meal.

Comparison of Kjeldahl and the Elemental Analysis Methods for Determination of Nitrogen Content in Raw Natural Rubber

The nitrogen in raw natural rubber is mainly derived from crude protein of latex. In this study, the nitrogen content of six kinds of raw natural rubber was analyzed for evaluating Kjeldahl and elemental analysis methods. The nitrogen content ranged from 0.43% to 0.66% for Kjeldahl methods and from 0.45% to 0.75% for elemental analysis method. There was no significant difference between the two methods. The coefficient of variation was below 1%. The data of nitrogen content showed a simple linear correlation (r=0.9937) between the two methods. It was concluded that the elemental analysis method could replace Kjeldahl method in nitrogen analysis of raw natural rubber.

Determination of Microelements and Nutrition Ingredients of Jianghong Yulu

Ningli Qi , Xiao Gong 1, *,b , Xiaoli Yuan , Chunliang Yang 1, d Chinese Academy of Tropical Agricultural Sciences Center for Food Quality Supervision and Testing Ministry of Agriculture (Zhanjiang), Zhanjiang, China 2 Chinese Academy of Tropical Agricultural Sciences South Subtropical Crops Research Institute, Zhanjiang, China qiqi120518@163.com,42839221@qq.com, qiqi120518@163.com, yiyesuifeng@126.com

Analysis of Chemical Constituents in Jackfruit Peel by UPC2/Q-TOF-MS Method

A new method for the analysis chemical constituents in jackfruit peel by ultra performance convergence chromatography (UPC2) was developed for the first time. The extraction of jackfruit peel was carried out under classical heating with ultrasonic wave and extracted with ethyl ether. The analytes were separated on an ACQUITY UPC2 HSS C18 SB column with a gradient elution (80:20 to 99.8:0.2) of mobile phase consisting of CO2 and methanol. The result indicated that UPC2/Q-TOF-MS is a simple, rapid, reliable and effective method to analyze the biochemical compounds in jackfruit peel. A total of 65 compounds were identified, including acids, esters, alcohols, and pyrazine, etc.

Composition and Antioxidant Capacity of Flour and Hull Extracts from Different Tartary Buckwheat Cultivars

The content of rutin, quercetin, total phenol, total flavonoid, antioxidant properties in ethanol extract of flour and hull from 13 tartary buckwheat cultivars widely grown in China was investigated. HPLC showed that the content of rutin ranged from 7.33 to 440.43 in flour and from 5.18 to 168.7 mg/g DW in hull. Trace quercetin were detected in both flour and hull extracts of all cultivars and the values were determined as 0.74-275.90 and 0.77-15.65 mg/g DW, respectively. The contents of total phenol/flavonoid in the flour were significantly greater than that in hull, and their content varied between samples. The result showed that JQ, QW, and NP are potential candidates for developing of functional food.