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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.


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.


Hu W.,China Agricultural University | Hu W.,National Engineering Research Center for Fruit and Vegetable Processing | Hu W.,Research Center for Fruit and Vegetable Processing Engineering | Zhou L.,China Agricultural University | And 11 more authors.
Critical Reviews in Food Science and Nutrition | Year: 2013

High pressure carbon dioxide (HPCD) is an effective non-thermal processing technique for inactivating deleterious enzymes in liquid and solid food systems. This processing method avoids high temperatures and exerts a minimal impact on the nutritional and sensory properties of foods, but extends shelf life by inhibiting or killing microorganisms and enzymes. Indigenous enzymes in food such as polyphenol oxidase (PPO), pectin methylesterase (PME), and lypoxygenase (LOX) may cause undesirable chemical changes in food attributes, showing the loss in color, texture, and flavor. For more than two decades, HPCD has proved its effectiveness in inactivating these enzymes. The HPCD-induced inactivation of some microbial enzymes responsible for microbial metabolism is also included. This review presents a survey of the published knowledge regarding the use of HPCD for the inactivation of these enzymes, and analyzes the factors controlling the efficiency of HPCD and speculates on the underlying mechanism that leads to enzyme inactivation. © 2013 Copyright Taylor and Francis Group, LLC.


Huang W.,China Agricultural University | Huang W.,National Engineering Research Center for Fruit and Vegetable Processing | Huang W.,Key Laboratory of Fruit and Vegetable Processing | Bi X.,China Agricultural University | And 14 more authors.
Innovative Food Science and Emerging Technologies | Year: 2013

Effects of high hydrostatic pressure (HHP) at 300-500 MPa for 5-20 min and high temperature short time (HTST) at 110 C for 8.6 s on enzymes, phenolics, carotenoids and color of apricot nectars were investigated. Polyphenol oxidase (PPO) and peroxidase (POD) in apricot nectar were significantly activated (p < 0.05) and the activity of pectinmethylesterase (PME) was not changed by HHP treatments, but HTST induced a complete inactivation of these enzymes. Compared to the untreated apricot nectar, HTST resulted in a significant increase in total phenolics, and exhibited no effect on total carotenoids and individual carotenes except α-carotene. The effects of HHP treatments on total and individual phenolics, total carotenoids and individual carotenes and color were closely related to the pressure levels and treatment times. Mostly, HHP treatments increased total and individual phenolics in apricot nectars, which were significantly lower than those in HTST-treated apricot nectars. HHP treatments also showed no effect on total carotenoids and individual carotenes in apricot nectars except that the treatment at 500 MPa/20 min increased total carotenoids and β-carotene. Moreover, total color difference (2.21) in the HTST-treated apricot nectars with increased lightness and more intensity was higher than that (≤ 1.34) in the HHP-treated apricot nectars, indicating that the color of HPP-treated apricot nectars was closer to the untreated apricot nectar than after HTST. Compared with HHP treatment (500 MPa/20 min), HTST led to complete inactivation of enzymes, higher total phenolics, (-)-epicatechin, ferulic acid and p-coumaric acid and lighter and more intensity color, since HTST treatment gave better impact on the quality of apricot nectar. Industrial relevance Effects of high hydrostatic pressure (HHP) treatment and high temperature short time (HTST) treatment on enzymes, phenolics, carotenoids and color of apricot nectar were investigated. Our results show that micronutrients and phytochemicals of nectar were well preserved by both HHP and HTST. Compared with HHP treatment (500 MPa/20 min), HTST led to complete inactivation of enzymes, higher total phenolics, (-)-epicatechin, ferulic acid and p-coumaric acid, and lighter and more intensity color than those of HHP treatment, since HTST treatment gave better impact on the quality of apricot nectar. And polyphenol oxidase, peroxidase and pectinmethylesterase in apricot nectar were found to be highly resistant to high pressure inactivation, thus in order to maintain the quality of apricot nectar, high pressure processing should be accompanied by additional measures. © 2013 Elsevier Ltd. All rights reserved.


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.


Liu F.,China Agricultural University | Liu F.,National Engineering Research Center for Fruit and Vegetable Processing | Liu F.,Key Laboratory of Fruit and Vegetable Processing | Wang Y.,China Agricultural University | And 14 more authors.
Food and Bioprocess Technology | Year: 2013

The effects of high hydrostatic pressure (HHP) treatments at pressures of 300-600 MPa for 1-20 min and of high-temperature, short-time (HTST) treatment on the inactivation of natural microorganisms in blanched mango pulp (BMP) and unblanched mango pulp (UBMP) were investigated. No yeasts, molds, or aerobic bacteria were detected in BMP or UBMP after HHP treatments at 300 MPa/15 min, 400 MPa/5 min, 500 MPa/2.5 min, and 600 MPa/1 min and HTST treatment at 110 °C/8.6 s. Therefore, these conditions were selected to study the effects of HHP and HTST treatments on pectin methylesterase (PME) activity, water-soluble pectin (WSP) levels, and the rheological characteristics of UBMP and BMP. HHP treatment at a pressure of 600 MPa for 1 min significantly reduced PME activity in UBMP and significantly activated PME in BMP, whereas pressures of 300-500 MPa activated PME regardless of blanching. However, PME activity was reduced by 97 % in UBMP and was completely inactivated in BMP by HTST treatment. WSP levels were significantly decreased by HHP treatment but were increased by HTST treatment in UBMP and BMP. Both HHP and HTST treatments increased the viscosity, storage modulus, and loss modulus of UBMP and BMP. No significant changes in total sugar, total soluble solids, titratable acid, or pH were found after any treatment. © 2012 Springer Science+Business Media, LLC.


Wang Y.,China Agricultural University | Wang Y.,National Engineering Research Center for Fruit and Vegetable Processing | Wang Y.,Key Laboratory of Fruit and Vegetable Processing | Yi J.,China Agricultural University | And 11 more authors.
Food and Bioprocess Technology | Year: 2013

High hydrostatic pressure (HHP) processing was applied for inactivation of natural microorganisms, including total aerobic bacteria (TAB), and yeasts and molds (Y&M) in purple sweet potato nectar (PSPN). The pressurization rates were 60 and 120 MPa/min, the pressurization modes were stepwise and linear, the pressure-holding times were 2. 5-25 min, and the pressure levels were 400-600 MPa. In all the experimental conditions, the Y&M in PSPN were not detected, the maximum reduction of TAB was greater than 4 log cycles, and the inactivation of TAB was closely related to the HHP parameters. The fast pressurization rate and linear pressurization mode enhanced the inactivation effect of HHP on TAB. With increasing the pressure level and pressure-holding times, the inactivation of TAB was also enhanced. The mathematical models were fitted to the inactivation kinetic data of TAB and fitness of these models was investigated; the Weibull and Biphasic model successfully fitted all the inactivation curves. Pressurization rate and mode had a significant impact on the parameters of the models. © 2012 Springer Science+Business Media, LLC.


Li R.,China Agricultural University | Li R.,National Engineering Research Center for Fruit and Vegetable Processing | Wang Y.,China Agricultural University | Wang Y.,National Engineering Research Center for Fruit and Vegetable Processing | And 4 more authors.
Food and Bioprocess Technology | Year: 2015

The microbiological changes in N2-infused and N2-degassed banana smoothies subjected to high pressure processing (HPP) at 350–550 MPa for 2–10 min were compared. The counts of total aerobic bacteria (TAB) and yeasts and molds (Y & M) of N2-infused banana smoothies were lower when compared with N2-degassed samples/ones. The N2-infused samples were treated by HPP at 550 MPa for 10 min and subsequently stored at 4 °C for 15 days. The counts of Y & M were below the detection limit after HPP and during storage, but the TAB of the HPP-treated N2-infused samples increased to 2.11 log10 CFU/g after storage at 4 °C for 15 days. During storage, the polyphenol oxidase, pectin methyl esterase, particle size distribution, color, total soluble solids, and titratable acidity of HPP-treated N2-infused samples remained stable, whereas there was a significant decrease in the pH. The HPP-treated N2-infused banana smoothies exhibited stable microbiological and physicochemical qualities, even after 15-day storage at 4 °C. © 2014, Springer Science+Business Media New York.


Song J.,National Engineering Research Center for Fruit and Vegetable Processing | Zhao M.,National Engineering Research Center for Fruit and Vegetable Processing | Liu X.,National Engineering Research Center for Fruit and Vegetable Processing | Zhu Y.,National Engineering Research Center for Fruit and Vegetable Processing | And 2 more authors.
Food and Chemical Toxicology | Year: 2013

Acrylamide (AA) occurs in many cooked starchy foods and has caused widespread concern as a possible carcinogen. In the present study, we investigate the intervention of AA toxicity in MDA-MB-231 cells pretreated with cyanidin-3-glucoside (Cy-3-glu). Compared to the cells treated with AA, Cy-3-glu significantly inhibited AA-induced cytotoxicity, reduced reactive oxygen species (ROS) generation, recovered glutathione (GSH) depletion and decreased the activities of glutathione peroxidase (GPx) and glutathione S-transferase (GST). Moreover, the expression of GPx1, GSTP1 and gamma-glutamyl cysteine synthase (γ-GCS) were enhanced, and cytochrome P450 2E1 (CYP2E1) expression was inhibited by the pretreatment of Cy-3-glu. Cy-3-glu presents the protective role against oxidative stress induced by AA in MDA-MB-231 cells. © 2013 Elsevier Ltd.

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