Bao Hua Kong

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

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.

Influence of Light on the Anthocyanins Stability and Antioxidant Activity of Black Currant (Ribes nigrum L.) Extract

Black currant (Ribes nigrum L.) possesses excellent antioxidant activity since it is rich in a great deal of phenolics, while its major phenolics, anthocyanins, are sensitive to light. This study investigated the anthocyanins stability and antioxidant activity of black currant extracts (BCE) stored under natural outdoor/indoor light and in the dark for 25 days. The anthocyanins content and antioxidant activity significantly decreased both in the presence and absence of light (P<0.05). The degradation of anthocyanins followed first-order kinetics, and the k values in light were higher than that in the dark, which revealed that the anthocyanins were more stable in the dark. Exposure of the BCE to light accelerated the degradation of anthocyanins and the loss of antioxidant activity, while BCE stored in darkness maintained relatively higher anthocyanins content and antioxidant activity. These results suggested that the BCE rich in anthocyanins should be protected from light during storage to maintain its antioxidant activity and bioactive compounds.

Antioxidant Activity of Seabuckthorn (Hippophae rhamnoides) Leaves Extracts on Pork Patties during Refrigerated Storage

This experiment was conducted to assess the antioxidant efficacy of Seabuckthorn (Hippophae rhamnoides) leaves extracts (SLE) in raw pork patties during chilled storage at 4 °C for 0-7 days. The pork patties were analyzed periodically for chemical characteristics, such as pH value, colour, thiobarbituric acid-reactive substances value (TBARS), peroxide value (POV) and protein carbonyls content. Compared with the control, SLE treatments significantly decreased the TBARs and POV values and carbonyls formation of pork patties in a dose-dependent manner (P < 0.05), which showed that the SLE significantly inhibited lipid and protein oxidation. The results of this study suggested that the antioxidant activities of seabuckthorn leaves extracts could have great effect on improving the quality characterizes of pork patties and prolong its shelf life.

Study on Antifungal Properties of Bacteriocin Produced by Lactobacillus and Application in Fruit Preservation

Strawberry is among the most perishable fruits and vulnerable to physical injuries and fungal invasion. To explore the effects of bacteriocin treatment on strawberry preservation, the inhibitory effect of bacteriocin produced by Lactobacillus on Botrytiscinerea was investigated. Meanwhile, the variation of weight-loss ratio, total soluble solids (TSS) and vitamin C content were determined after treatment of bacteriocin on field-grown strawberry. The results showed that spore germination of B. cinerea was significantly inhibited by bacteriocin at volume percentage of 20%, and bacteriocin inhibited increasing of weight-loss ratio, maintained more ascorbic acid, kept taste of strawberries. Therefore, bacteriocin is a kind of high efficiency natural preservatives and can be applied to the fruit preservation.

Quality Attributes of Four Major Retails Cuts from Songjiang Cattle

The quality characteristic of High Rib (HR), Striploin (SL), Brisket (BK) and Rump (RP) from Songjiang cattle was investigated. The water content, crude protein, intramuscular fat (IMF), color, shear force, pH, cooking loss and sensory evaluation of samples were analyzed. The results showed that, HR sample had the highest (P < 0.05) IMF and RP sample had the highest (P < 0.05) water content. Although crude protein contents among different of samples had significant difference (P < 0.05), its difference was not large as IMF and water content. Cooking loss and hardness value of HR were both lower than other cuts, whereas a* values was not the highest one (P < 0.05). Hardness and cooking loss were both lowest (P < 0.05) in SL, and highest in RP and BK, respectively. The results demonstrated that quality of HR and SL was better than other cuts, and IMF was the key factor that induced the beef quality difference.

Influence of Pre-Fried Time and Temperature on the Quality of Microwave Beef Kebabs

The influence of pre-fried time and temperature on the cooking yield, shear force, color and sensory quality of microwave beef kebabs were evaluated. The beef kebabs were fried for 20 s, 40 s, 60 s and 80 s at 170 ± 2 °C, 180 ± 2 °C or 190 ± 2 °C in the fryer. The results revealed that beef kebabs fried at 190 ± 2 °C for 60 s had significantly higher cooking yield, shear force, redness (a*), yellowness (b*), flavor, color and overall acceptability than the samples fried at 170 ± 2 °C and 180 ± 2 °C for 60 s. Lightness (L*), juiciness and tenderness of beef kebabs fried at 190 ± 2 °C for 60 s were lower than samples fried at 170 ± 2 °C and 180 ± 2 °C for 60 s. In addition, the cooking yield values fried at 190 ± 2 °C for different times was increased by 4.58%, 3.49%, 2.37% and 1.12% over that fried at 170 ± 2 °C. Beef kebabs fried at 190 ± 2 °C for 60 s promoted the color and cooking yield remarkably and had a beneficial effect on sensory characteristics during frying. The optimum frying parameters of kebabs were at 190 ± 2 °C of oil temperature for 60 s of frying time.

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

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

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

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 < 0.05). It revealed that G-NO-Hb was a potential substance to substitute for nitrite during meat curing.

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

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 Staphylococcus xylosus and Lactobacillus fermentum Inoculation on Raw Pork Batters and Optimization of the Fermentation Conditions

Nitrite is a key ingredient during meat curing but harmful to human health. Staphylococcus xylosus and Lactobacillus fermentum were inoculated to raw pork batters to replace for nitrite. Based on the pH value and redness (a*-value) of the batters, the fermentation conditions were optimized by single factor experiments. The results showed that with the inoculation level of 107 cfu/g, the fermentation temperature and time were chosen as 8 h and 30°C, respectively. The optimum ratio of S. xylosus to L. fermentum ratio was 2:1. 20 mg/kg nitrite was necessary for the color formation of the meat batters. It revealed that S. xylosus and L. fermentum fermentation could partially replace for nitrite in pork batters.