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Liao H.,China Agricultural University | Liao H.,Key Laboratory of Fruits and Vegetables Processing | Liao H.,Research Center for Fruit and Vegetable Processing Engineering | Zhang L.,China Agricultural University | And 8 more authors.
International Journal of Food Microbiology | Year: 2010

Apple juice was pasteurized by high pressure carbon dioxide (HPCD) at 20 MPa with CO2 concentration of 4.5-5.3% and mild heat (MH) at atmospheric pressure. Microbial inactivation and stability of natural microorganisms in apple juice were investigated. The temperatures were 37, 42, 47, 52, 57 and 62 °C, treatment time was 30 min, and storage temperatures of pasteurized apple juice were 2 and 28 °C. The aerobic bacteria (AB) treated by MH at 62 °C and by HPCD at ≥ 52 °C were almost totally inactivated, the microbial counts were < 10 CFU/mL. The yeasts and moulds (Y&M) treated by MH at ≥ 57 °C and by HPCD at ≥ 42 °C were totally inactivated. HPCD increased the susceptibility of these natural microorganisms to temperature and enhanced their microbial inactivation. The AB in apple juice treated by HPCD at ≥ 52 °C and the Y&M treated by HPCD at ≥ 57 °C, the AB and the Y&M treated by MH at 62 °C showed a better stability during storage at 2 and 28 °C, but apple juice treated by HPCD at ≤ 47 °C was characterized with high microbial counts of the AB ≥ 2.75 × 103 CFU/ml. A viable but non-culturable (VBNC) state of the Y&M treated by MH at 57 °C and by HPCD at 42, 47 and 52 °C was observed during storage at 28 °C. Apparently the proper temperature of HPCD treatment of apple juice at 20 MPa and stored at 2 and 28 °C was greater than or equal to 52 °C, while for MH treatment the proper temperature increased to 62 °C in this study. © 2009 Elsevier B.V. All rights reserved. Source


Liu W.,China Agricultural University | Liu W.,Key Laboratory of Fruit and Vegetable Processing | Liu W.,Research Center for Fruit and Vegetable Processing Engineering | Zhou C.-L.,China Agricultural University | And 12 more authors.
Acta Scientiarum Polonorum, Technologia Alimentaria | Year: 2014

Background: 6-Gingerol is one of the most pharmacologically active and abundant components in ginger, which has a wide array of biochemical and pharmacologic activities. In recent years, the application of microwave-assi sted extraction (MAE) for obtaining bioactive compounds from plant materials has shown tremendous research interest and potential. In this study, an efficient microwave-assisted extraction (MAE) technique was developed to extract 6-gingerol from ginger. The extraction efficiency of MAE was also compared with conventional extraction techniques. Material and methods: Fresh gingers (Zingiber officinale Rosc.) were harvested at commercial maturity (originally from Shandong, laiwu, China). In single-factor experiments for the recovery of 6-gingerol, proper ranges of ratio of liquid to solid, ethanol proportion, microwave power, extraction time were determined. Based on the values obtained in single-factor experiments, a Box-Behnken design (BBD) was applied to determine the best combination of extraction variables on the yield of 6-gingerol. Results: The optimum extraction conditions were as follows: mi crowave power 528 W, ratio of liquid to solid 26 mL g-1, extraction time 31 s and ethanol proportion 78%. Furthermore, more 6-gingerol and total polyphenols contents were extracted by MAE than conventional methods including Maceration (MAC), Stirring Extraction (SE), Heat reflux extraction (HRE), Ultrasound-assisted extraction (UAE), as well as the antioxidant capacity. Conclusion: Microwave-assisted extraction showed obvious advantages in terms of high extraction efficiency and antioxidant activity of extract within shortest extraction time. Scanning electron microscopy (SEM) images of ginger powder materials after different extractions were obtained to provide visual evidence of the disruption effect. To our best knowledge, this is the first report about usage of MAE of 6-gingerol extraction from ginger, which could be referenced for the extraction of other active compounds from herbal plants. © by Wydawnictwo Uniwersytetu Przyrodniczego w Poznaniu. Source


Zhou C.-L.,China Agricultural University | Zhou C.-L.,Jiangxi Science and Technology Normal University | Zhou C.-L.,Key Laboratory of Fruit and Vegetable Processing | Zhou C.-L.,Research Center for Fruit and Vegetable Processing Engineering | And 16 more authors.
International Journal of Food Science and Technology | Year: 2014

Using hot water extraction, a large number of polysaccharides were obtained from Cucurbita maxima. A DEAE-Sepharose CL-6B chromatography column was used to isolate the major polysaccharides from C. maxima. Two fractions were obtained (LP2-1 and LP2-2). LP2-1 and LP2-2 consisted of neutral polysaccharides (MW: 1.02 × 104 and 4.32 × 108 g mol-1, respectively) comprised mainly of galactose units. Analyses by FT-IR spectrometry, partial acid hydrolysis, periodate oxidation, Smith degradation and GC-MS indicated that LP2-1 consisted of 85.3% (1→4) glycosidic linkages and 1.7% (1→3) or (1→6) glycosidic linkages. The LP2-1 backbone consisted of (1→4)-linked galactose units, which occasionally branched at O6 or O3. The branches were composed of (1→4)-linked galactose and terminated with galactose (13%). Two sulphated derivatives (SLP2-1 and SLP2-2) with variable degrees of sulphation (DS) were obtained by the sulphur trioxide-pyridine method, without degradation of the polysaccharide. DS of PL2-1 and PL2-2 was 0.19 and 0.20, respectively. © 2013 The Authors. International Journal of Food Science and Technology © 2013 Institute of Food Science and Technology. Source


Zhou C.-L.,Jiangxi Science and Technology Normal University | Zhou C.-L.,China Agricultural University | Zhou C.-L.,Key Laboratory of Fruit and Vegetable Processing | Zhou C.-L.,Research Center for Fruit and Vegetable Processing Engineering | And 21 more authors.
Innovative Food Science and Emerging Technologies | Year: 2014

Pumpkins were processed at high hydrostatic pressure (HHP) ranging from 350 to 550 MPa for 0.5 min to 30 min. Two different nonlinear mathematical models were compared to fit the inactivation kinetics. The second model consistently produced better fits to the inactivation data than the first model (Weibull model). According to the inactivation of microorganisms, pumpkin was subjected to 450 MPa/15 min and 550 MPa/10 min. The microbiological and physicochemical changes in pumpkin subjected to (HHP) and thermal-treated (854 °C/5 min) were compared during 4 °C storage. The total plate counts (TPC) treated with thermal processing, 450 MPa/15 min and 550 MPa/10 min were 5.12, 4.02 and 1.71 log10 CFU/g, respectively on the 60th day. The growth of microorganisms caused the increase in ΔE, decrease in hardness in other treatments. Treatment of 550 MPa for 10 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 pumpkin treated with 550 MPa/10 min decreased by 32.28% after 60 days. A greater retention of the original color, Vc and antioxidant capacity and increased total phenols were observed in 550 MPa/10 min-treated samples immediately after processing. During storage, color changed, Vc content, total phenols and the antioxidant activity were decreased. While the soluble solids content (SSC), sugars and pH value of pumpkin with HHP or thermal treatment did not show significant change immediately during 60-day storage. Based on these results, working at 550 MPa for 10 min ensures physicochemical and high standard of sanitation parameters in pumpkin. Industrial relevance Pumpkin (Cucurbita maxima Duch.) is one of the popular vegetables, and fresh-cut pumpkin 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 pumpkin and its storage time prediction through microbiological quality and physical-chemical characteristics analysis of these changes is necessary. The available data would provide technical support for commercial application of the HHP technique in fresh-cut pumpkin processing. © 2013 Elsevier Ltd. Source


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. Source

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