Key Laboratory of Fruit and Vegetable Processing

Beijing, China

Key Laboratory of Fruit and Vegetable Processing

Beijing, China

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Chen D.,National Engineering Research Center for Fruit | Xi H.,National Engineering Research Center for Fruit | Guo X.,National Engineering Research Center for Fruit | Qin Z.,National Engineering Research Center for Fruit | And 4 more authors.
Innovative Food Science and Emerging Technologies | Year: 2013

Inactivation of microorganisms and its kinetic model of high hydrostatic pressure (HHP) processing of cloudy pomegranate juice at different pressures (300 and 400 MPa) and different treatment times (2.5, 5, 10, 15, 20, and 25 min) were studied. Besides, HHP (400 MPa/5 min) and high temperature short time (HTST) (110 C/8.6 s) treatment were comparatively evaluated by examining their impacts on microorganisms, pH, total soluble solids (TSS), titratable acidity (TA), color, total phenols, anthocyanins, antioxidant capacity and shelf-life characteristics of 90 days at 4 C. The inactivation effect of microorganisms by HHP fitted Weibull model well and HHP at 400 MPa/5 min inactivated microorganisms effectively. The microbial safety was ensured in HHP-treated and HTST-treated sample. A greater retention of the original color, anthocyanins and antioxidant capacity and increased total phenols were observed in HHP-treated samples immediately after processing. During storage, color changed and anthocyanins content, total phenols and the antioxidant activity decreased, where the changes depended on the applied treatments. The pH, TSS and TA did not show significant change immediately after HHP or HTST treatment and during storage. Industrial Relevance Cloudy pomegranate juice is one of the most popular fruit juice and requires strict processing and storage conditions to keep the safety and quality. Our research presents a fair comparison between HHP and HTST treatment. The available data shows the different impacts on cloudy pomegranate juice of HHP and HTST treatment and the changes of quality during storage. This study would provide technical support for commercial application, evaluation and the criteria establishment for commercial production of HHP and HTST treatment in juice industry, and also provide a non-thermal treatment to meet the growing demand from consumers for healthier food products. © Crown Copyright © 2013 Published by Elsevier Ltd. All rights reserved.


Liu F.,China Agricultural University | Liu F.,Key Laboratory of Fruit and Vegetable Processing | Liu F.,Engineering Research Center for Fruit and Vegetable Processing | Cao X.,China Agricultural University | And 6 more authors.
Powder Technology | Year: 2010

Changes of tomato powder qualities at different storage temperatures (0, 25, and 37°C) for 5months were evaluated in this study. Color parameters (L*, a*, b*), glass transition temperature (Tg) and pH decreased significantly, while 5-Hydroxymethylfurfural (HMF), browning degree (BD) and titratable acid (TA) increased significantly (P<0.05) at 25and 37°C after 5months. The increased HMF and BD followed a combined kinetics model well. There were insignificant changes for these indicators at 0°C during storage (P>0.05). Sucrose, fructose and total sugar (TS) exhibited significant reduction (P<0.05) only at 37°C. Free amino acids (FAAs), l-ascorbic acid and solubility of tomato powder underwent significant reduction and total color change δE significantly increased after 5months regardless of storage temperatures (P<0.05), while lycopene and total soluble solid (TSS) showed no significant changes (P>0.05). SEM micrographs indicated that tomato powder tended to aggregate with increasing the storage temperature or time, which conformed to decreased Tg. There were good correlations between HMF and total free amino acids (TFAA), TS, l-ascorbic acid, BD, L*, a*, b* when stored at 25and 37°C. © 2010 Elsevier B.V.


Bi X.,China Agricultural University | Bi X.,National Engineering Research Center for Fruit and Vegetable Processing | Bi X.,Key Laboratory of Fruit and Vegetable Processing | Wu J.,China Agricultural University | And 11 more authors.
Innovative Food Science and Emerging Technologies | Year: 2011

The effects of high pressure carbon dioxide (HPCD) treatment on natural microorganisms, indigenous enzyme activity, damage to cell membranes and hardness in fresh-cut carrot slices were investigated. 1.86 log10 cycle reduction for aerobic bacteria (AB) and 1.25 for yeasts and molds (Y&M) were achieved at 5 MPa and 20 °C for 20 min. The residual activity (RA) of peroxidase (POD), polyphenol oxidase (PPO), and pectinmethylesterase (PME) exhibited initially increase and secondly decrease with treatment time and their minimum activity was 75.8%, 90.9% and 52.8% at 5 MPa and 20 C for 15 min, respectively. Membrane damage was evaluated by relative electrolyte leakage (REL) and malondialdehyde (MDA) content. HPCD caused a significant increase of REL in carrot slices and the REL of carrot slices treated at 5 MPa and 20 °C for 15 min was 5.7 times as much as that of the untreated, however, HPCD showed no effect on MDA content. The hardness was well retained after HPCD treatment and the largest loss was 7.9% at 5 MPa and 20 °C for 15 min. Industrial relevance: Fresh-cut carrot slices are one of the most widely used products in prepared salads, and it required strict treatment conditions to protect its quality, especially to prevent microbial spoilage and enzymatic discoloration. HPCD is one promising novel non-thermal technique without compromising the flavor, taste and nutrition aspect of food. This study analyzed the effectiveness of HPCD as a method of preserving fresh-cut carrot slices, including inactivating natural microorganisms and enzymes which are crucial to quality control. Available data provided in this study will benefit the fresh-cut fruits and vegetables industry. © 2011 Published by Elsevier Ltd. All rights reserved.


Cao X.,China Agricultural University | Cao X.,National Engineering Research Center for Fruit and Vegetable Processing | Cao X.,Key Laboratory of Fruit and Vegetable Processing | Bi X.,China Agricultural University | And 14 more authors.
Innovative Food Science and Emerging Technologies | Year: 2012

Changes of quality of cloudy and clear strawberry juices processed by high hydrostatic pressure (HHP) at 600 MPa/4 min during 6-month storage at 4 and 25°C were investigated. After 6 months of storage at 4°C, ascorbic acid, anthocyanins and total phenols decreased by 39.41%, 29.76% and 16.22% in cloudy juices, and by 48.91%, 7.02% and 13.82% in clear juices, but the antioxidant capacity in both juices decreased by less than 10%. The decrease of these indices at 25°C for 6 months almost doubled. The lightness (L*) and redness (a*) in both juices at 25°C were significantly lower than at 4°C, while total difference color (ΔE) and browning degree (BD) were significantly higher. 66.93% and 70.75% decreases of viscosity and 47.60% and 79.98% of cloud in cloudy juices were observed after 6 months of storage at 4 and 25°C, respectively. The loss of ascorbic acid, anthocyanins, total phenols and antioxidant capacity fits well to a first-order equation. Total anthocyanin content was selected as a biomarker to predict the shelf life due to their influence on the consumer acceptance and higher sensitivity to the storage temperature. Industrial relevance: Strawberry juice is one of the popular fruit juices, and it requires strict processing treatment and storage conditions to protect its quality. HHP is one promising novel non-thermal technique and is likely to replace thermal processes. A better knowledge of effects of storage temperature on the quality of HHP-treated strawberry juice and its shelf life prediction through kinetics analysis of these changes is necessary. This study would provide technical support for commercial application of the HHP technique in strawberry juice processing. © 2012 Elsevier Ltd.


Zhao F.,China Agricultural University | Zhao F.,Chinese National Engineering Research Center for Fruit and Vegetable Processing | Zhao F.,Key Laboratory of Fruit and Vegetable Processing | Bi X.,China Agricultural University | And 8 more authors.
PLoS ONE | Year: 2013

The viable but nonculturable (VBNC) state is a survival strategy adopted by many pathogens when exposed to harsh environmental stresses. In this study, we investigated for the first time that whether high pressure CO2 (HPCD), one of the nonthermal pasteurization techniques, can induce Escherichia coli O157:H7 into the VBNC state. By measuring plate counts, viable cell counts and total cell counts, E. coli O157:H7 in 0.85% NaCl solution (pH 7.0) was able to enter the VBNC state by HPCD treatment at 5 MPa and four temperatures (25°C, 31°C, 34°C and 37°C). Meanwhile, with the improvement of treatment temperature, the time required for E. coli O157:H7 to enter VBNC state would shorten. Enzymatic activities in these VBNC cells were lower than those in the exponential-phase cells by using API ZYM kit, which were also reduced with increasing the treatment temperature, but the mechanical resistance of the VBNC cells to sonication was enhanced. These results further confirmed VBNC state was a self-protection mechanism for some bacteria, which minimized cellular energetic requirements and increased the cell resistance. When incubated in tryptic soy broth at 37°C, the VBNC cells induced by HPCD treatment at 25°C, 31°C and 34°C achieved resuscitation, but their resuscitation capabilities decreased with increasing the treatment temperature. Furthermore, electron microscopy revealed changes in the morphology and interior structure of the VBNC cells and the resuscitated cells. These results demonstrated that HPCD could induce E. coli O157:H7 into the VBNC state. Therefore, it is necessary to detect if there exist VBNC microorganisms in HPCD-treated products by molecular-based methods for food safety. © 2013 Zhao et al.


Bi X.,National Engineering Research Center for Fruit and Vegetable Processing | Liu F.,National Engineering Research Center for Fruit and Vegetable Processing | Rao L.,National Engineering Research Center for Fruit and Vegetable Processing | Li J.,National Engineering Research Center for Fruit and Vegetable Processing | And 4 more authors.
Innovative Food Science and Emerging Technologies | Year: 2013

Effects of electric field strength (0-35 kV/cm) and pulse rise time (PRT) of 2 μs and 0.2 μs during pulsed electric fields (PEF) on enzymatic activity, vitamin C, total phenols, antioxidant capacities, color and rheological characteristics of fresh apple juice were investigated. With increasing the electric field strength and PRT, the residual activity (RA) of polyphenoloxidase (PPO) and peroxidase (POD) decreased, almost complete inactivation of both enzymes was achieved at 35 kV/cm and 2 μs-PRT. The content of vitamin C in apple juice decreased significantly (p < 0.05) during PEF treatment, the largest loss was 36.6% at 30 kV/cm and 2 μs-PRT. The content of total phenols was not affected by PEF with 2 μs-PRT but decreased significantly (p < 0.05) by PEF with 0.2 μs-PRT. The antioxidant capacity of apple juice was evaluated by DPPH radical scavenging activity, ferric reducing antioxidant power (FRAP) and oxygen radical absorbance capacity (ORAC). The DPPH value was not affected by PEF, whereas FRAP and ORAC values increased with increasing the electric field strength and decreasing the PRT. PEF-treated apple juice had a significantly higher (p < 0.05) lightness (L) and yellowness (b) than the controlled sample. The apparent viscosity and consistency index (K) of apple juice decreased while the flow behavior index (n) increased with increasing the electric field strength, and apple juice treated at 2 μs-PRT had significantly higher apparent viscosity than treated at 0.2 μs-PRT. Industrial relevance: Apple juice is one of the most popular fruit juices, and it required strict treatment conditions to protect its quality, especially to prevent enzymatic discoloration. PEF is one promising novel non-thermal technique without compromising the flavor, taste and nutrition aspect of food. This study analyzed the effectiveness of PEF as a method of preserving qualities of apple juice, including inactivating enzymes which are crucial to quality control. Available data provided in this study will benefit the fruit juice industry. © 2012 Elsevier Ltd.


Dong P.,National Engineering Research Center for Fruit and Vegetable Processing | Kong M.,National Engineering Research Center for Fruit and Vegetable Processing | Yao J.,National Engineering Research Center for Fruit and Vegetable Processing | Zhang Y.,National Engineering Research Center for Fruit and Vegetable Processing | And 4 more authors.
Innovative Food Science and Emerging Technologies | Year: 2013

Lotus root (Nelumbo nucifera Gaertn), an aquatic vegetable in China, is widely consumed due to its unique sensory and nutritional properties. However, fresh lotus root tends to deteriorate during storage. The aim of the study was to evaluate the effect of high hydrostatic pressure (HHP) on microbiological quality and physicochemical properties of lotus root. Lotus root was processed at HHP ranging from 300 to 600 MPa for 2.5 min to 25 min. The inactivation curves of natural microorganisms in lotus root by HHP were well fitted with the Weibull model. According to the inactivation of microorganisms, lotus root was subjected to 400 MPa for 10 min, 500 MPa for 5 min and 600 MPa for 2.5 min. The changes of microbiological quality and physicochemical properties (color, texture, pH and yield) were analyzed during three months of storage at 4 C. The results showed that lotus root processed by 600 MPa exhibited a better microbiological stability than those of other treatments. The total plate counts (TPC) in lotus root treated with thermal processing, 400 and 500 MPa were 5.20, 5.12 and 4.36 log10 CFU/g, respectively on 45th day. The growth of microorganisms caused the increase in â-E, decrease in hardness and pH in other treatments. Treatments of 600 MPa for 2.5 min had little effect on color during storage. There were no significant changes in the L*, a* and b* values (p > 0.05). The hardness of lotus root treated with 600 MPa decreased by 34.22% after 90 days. The pH value of lotus root with 600-MPa treatment remained statistically constant during 90-day storage. After 90 days, lotus root processed by 600 MPa retained 88.04% of its weight. These results indicated that HHP at 600 MPa for 2.5 min was an efficient non-thermal alternative for extended shelf-life of lotus root. Industrial Relevance As an interesting alternative to traditional processing method, high hydrostatic pressure processing has the potential to produce high quality foods. This research provides information of storage stability of lotus root after HHP and thermal processing. The available data are provided for the evaluation and application of HHP in lotus root, and criteria for commercial production of high quality lotus root with safety requirements could be established.


Zhang Y.-Y.,China Agricultural University | Song Y.,China Agricultural University | Hu X.-S.,China Agricultural University | Liao X.-J.,China Agricultural University | And 2 more authors.
Food Research International | Year: 2012

5-Hydroxymethylfurfural (HMF) and furfural (F) could be formed in sugar-rich foods during baking. The effects of batter formula and baking conditions on the formation of HMF and F and the kinetics of HMF formation during baking were studied in 15 sponge cake models. A fixed amount of sucrose (40%) was included as minimum in sponge cake models to improve the batter consistency and texture of sponge cakes. The results showed that increase of the sugar and citric acid amount in the batter formula increased HMF and F formation during baking at 205°C for 11min. With increasing of the baking temperature and time, the concentrations of HMF and F were also increased in the sponge cake models, and the maximum concentrations of HMF and F attained were 4100±11mgkg -1 and 59±1mgkg -1, respectively. Formation of HMF in the sponge cake models (Models 11-15) followed a first-order kinetics. By applying the Arrhenius equation, the activation energy (E a) of sponge cake models was found to a span range between 15.4kJmol -1 and 25.8kJmol -1. The results showed that sugar type, pH and baking temperature and time strongly affected HMF and F formation in sponge cake models. © 2012 Elsevier Ltd.


Sun J.,China Agricultural University | Sun J.,Key Laboratory of Fruit and Vegetable Processing | Sun J.,Engineering Research Center for Fruit and Vegetable Processing | Sun J.,Jinan University | And 10 more authors.
Food Chemistry | Year: 2011

The effects of three electrode materials - stainless steel (SS), pure titanium (PT), and titanium-based alloy (TA) - on the PEF-induced degradation, spectral characteristics, visual colour, and antioxidant capacity of cyanidin-3-glucoside (Cy-3-glc) and cyanidin-3-sophoroside (Cy-3-soph) were studied. Cy-3-glc and Cy-3-soph were degraded by PEF; SS retained Cy-3-glc and Cy-3-soph the most, while PT and TA led to greater degradation. Cy-3-glc was more susceptible to PEF than Cy-3-soph. The intensity of UV-Vis spectra absorbance at 520 nm decreased, but it increased at 280 and 325 nm after PEF when using the three electrodes. Their lightness (L*) exhibited no changes with SS, but showed a significant reduction with PA and TA. Redness (a*) significantly decreased with all three electrodes; the yellowness (b*) of Cy-3-glc with PA and TA, and of Cy-3-soph with SS, were also significantly reduced. The antioxidant capacity of Cy-3-glc and Cy-3-soph with SS, in contrast to PT and TA, was enhanced after PEF. © 2011 Elsevier Ltd. All rights reserved.


Li R.,China Agricultural University | Li R.,Key Laboratory of Fruit and Vegetable Processing | Wang Y.,China Agricultural University | Wang Y.,Key Laboratory of Fruit and Vegetable Processing | And 4 more authors.
Innovative Food Science and Emerging Technologies | Year: 2014

Effects of high pressure CO2 (HPCD) on the activity, dissociation and aggregation, as well as secondary and tertiary structures of a thaumatin-like protein (TLP) with polyphenol oxidase (PPO) activity from apples (Malus domestica, Fuji) were investigated. The PPO activity of TLP subjected to HPCD was initially increased and then decreased after increasing pressure, temperature, time and cycles. The secondary structure was changed by HPCD. The λmax of fluorescence spectra was red-shifted with intensity increasing or decreasing, depending on the treatment parameters. HPCD induced dissociation and aggregation of the native TLP aggregates. More intense HPCD treatment caused the dissociation of larger aggregates and further aggregation in the smaller aggregates. Activation of TLP may be attributed to the dissociation of its aggregates and the structural changes at the catalytic centre; inactivation was due to the aggregation of TLP and collapse of the catalytic centre. Industrial relevance High pressure carbon dioxide (HPCD) is one merging non-thermal technique for inactivating microorganisms and enzymes in food products. Polyphenol oxidase (PPO) can cause quality deterioration in many food products. This study analyzed the effects of HPCD on the activity, dissociation, aggregation, and the secondary and tertiary structure of a thaumatin-like protein (TLP) with a high PPO activity. Available data provided in this study will benefit the food industry.

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