Pei Jun Li

Bio: Pei Jun Li is an academic researcher from Northeast Agricultural University. The author has contributed to research in topics: Nitrite & Maillard reaction. The author has an hindex of 1, co-authored 7 publications receiving 37 citations.

Low Field-NMR in Measuring Water Mobility and Distribution in Beef Granules during Drying Process

Abstract: Low field-nuclear magnetic resonance (LF-NMR) was employed in this study to evaluate water mobility and distribution in beef granules during drying process due to its fast and nondestructive detection. Beef granules were dried in a blast drying oven at different temperatures (40, 50 and 60 °C) to a final moisture content around 21% after cooking. Results showed that it took about 150, 90 and 60 min for the samples dried at 40, 50 and 60 °C to get to the drying destination, respectively. The immobilized water was transformed into bound water with lower association degree and free water during drying at different conditions. Drying also resulted in a proportion increase of bound water; what’s more, the proportion of bound water is the largest when drying at 50 °C compared to 40 and 60 °C. After the drying destination was reached, the transverse relaxation time for bound water and immobilized water appeared significant change. It revealed that LF-NMR was an effective tool to assess water mobility and distribution during food drying process.

Application of Glycosylated Nitrosohemoglobin in Meat Batters: Color Formation and Antimicrobial Activity

Abstract: Sodium nitrite is an important food additive in meat industry. However, because of its carcinogenicity, the studies about nitrite substitutes have been focused on for many years. In this study, glycosylated nitrosohemoglobin (G-NO-Hb) synthesized by porcine blood, nitrite and sugar through maillard reaction was applied in chilled meat batters to replace for nitrite. Color difference, total aerobic plate count (APC) and total volatile basic nitrogen (TVB-N) were determined in order to evaluate the quality of meat batters. The identified results by UV-Vis spectra analysis showed that the produced pigment products by porcine blood, nitrite and sugar through maillard reaction was NO-Hb because they had special absorption peaks at 420, 542 and 578 nm. The a*-values of batters treated with G-NO-Hb showed a significant increase (P 0.05), which indicated that the addition of G-NO-Hb had a positive effect on the red color formation of pork batters. Also, both TVB-N values and APC of samples treated with G-NO-Hb were significantly lower than the control samples (P

Changes in Structural Properties of Porcine Myofibrillar Protein Induced by Frozen Storage

Abstract: Changes in structure property of myofibrillar protein from porcine longissimus dorsi were monitored during 12 months of storage at –5, –18, –26, –35 and –70 °C. With the extended frozen time at the same temperature, Ca2+-ATPase activity, K+-ATPase activity, total sulfhydryl content reactive sulfhydryl content decreased (P

Preparation of Glycosylated Nitrosohemoglobin by Maillard Reaction and its Stability under Fluorescent Light at 20°C

Abstract: One of the roles nitrite played in meat curing is to produce the characteristic pink color, but the use is limited due to its potential carcinogenicity. In this study, porcine blood was used for synthesizing glycosylated nitrosyl-hemoglobin (G-NO-Hb) through maillard reaction and the preparation conditions were optimized. Also, the stability of G-NO-Hb was assessed by UV-Vis spectra. The results showed that: the optimum ratio of blood cells to water was 1: 2, nitrite of 2 mg/kg reaction mixture was chosen. The synthesized G-NO-Hb solution was rather stable under light radiation at 20°C for 20d. It revealed that G-NO-Hb was a potential stable pigment used for meat curing as a nitrite substitute.

Effect of Different Starching Recipes on Quality of Fried Shredded Meat in Chinese Cuisine

Abstract: Starching is a common technique that used to improve the quality of shredded meat dishes in Chinese cuisine. However, there is little information available for the use of starching shredded meat as a kind of commercial products. In our study, effect of different levels of the main components for meat starching, water, starch, and salt on the quality of fried shredded meat was investigated, using cooking yield, moisture content, textural and sensory properties as the evaluation parameters. Results showed that the optimal recipe for shredded meat starching was a mixed ingredients of 6% starch, 10% water and 1.5% salt. It could help to provide theoretical basis for developing convenience shredded meat products with high and uniform quality in Chinese cuisine.Starching is a common technique that used to

Suitability of LF-NMR to analysis water state and predict dielectric properties of Chinese yam during microwave vacuum drying

Abstract: The feasibility of low-field nuclear magnetic resonance (LF-NMR) was investigated to predict the dielectric properties of Chinese yam slices. Changes in relaxation behaviors and dielectric properties (at 915 and 2450 MHz) of samples during microwave vacuum drying as well as their relationship were studied. Results showed that the total moisture content decreases gradually over drying time, and the free water was removed first, followed by the immobile water and bound water. Correspondingly, the dielectric constant (e′) gradually decreased till to reach a relative and stable low value; while the loss factor (e″) changed slightly first, then decreased gradually and also reached a low value finally. Univariate linear models showed that the signal intensity of free water peak (A23) and the transverse relaxation time of immobile water (T22) had good correlation with dielectric properties. Furthermore, partial least squares regression (PLSR) models with four NMR parameters as variables gave better results with R2P of 0.946, 0.936, 0.962 and 0.921 for e′ and e″ at 915 MHz and e′ and e″ at 2450 MHz, respectively. The overall results revealed that LF-NMR is suitable for predicting the dielectric properties as a rapid and noninvasive method.