• Korean Journal of Food Science and Technology
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• v.27 no.6
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• pp.845-851
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• 1995

To improve the utilization of pear in its processing, the cloudy and clear juice concentrates were prepared and their rheological properties were investigated in the range of temperatures($5{\sim}60^{\circ}C$) and concentrations($15{\sim}60^{\circ}Brix$). Pear juice concentrates showed flow behavior close to Newtonian fluids. Their flow behavior was also explained by applying Power law model and Herschel-Bulkley model. Flow behavior index did not have good correlation with concentration, but decreased with the increase of temperature, showing pseudoplastic properties. Consistency index increased with the increase of concentration and with the decrease of temperature. The effect of temperature and concentration on the apparent viscosity at 1500 1/s shear rate was examined by applying Arrhenius equation. The activation energy for flow of the cloudy and clear pear juice concentrates increased from $1.5140{\times}10^4\;to\;3.4141{\times}10^4\;J/kg{\cdot}mol$, and from $1.4762{\times}10^4\;to\;3.4963{\times}10^4\;J/kg{\cdot}mol$ with the increase of concentration, respectively. The influence of temperature on the apparent viscosity was more pronounced at higher concentration. And the concentration-dependent constant A decreased from $0.0789\;to\;0.0484^{\circ}Brix^{-1}$, and from $0.0786\;to\;0.0476^{\circ}Brix^1$ with the increase of temperature, respectively.

• The Korean Journal of Mycology
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• v.38 no.2
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• pp.189-191
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• 2010

Mixed juice of pear and strawberry was fermented by commercial Saccharomyces cerevisiae C-2 at $25^{\circ}C$ for 7 days and obtained the pear-strawberry fermentative concentrates (PSFC). The PSFC showed high ACE inhibitory activity of 70.8%. The PSFC drink was prepared by using PSFC and by-materials including amylopeptide, and determined changes of quality and ACE inhibitory activity during storage of $20^{\circ}C$ and $40^{\circ}C$. PSFC drink was very stable at storage of $20^{\circ}C$ for 8 weeks without any quality and ACE inhibitory activity.

• Journal of Food Hygiene and Safety
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• v.24 no.1
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• pp.56-62
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• 2009

Patulin, a mycotoxin mainly produced by Penicillium and Aspergillus, is found in various foods. In the present, a maximum acceptable level for patulin is established at $50{\mu}g/kg(ppb)$ in apple juices and apple concentrates in Korea. But patulin may be detected in foods produced with other fruits. In the present study, patulin contamination was analyzed in 520 samples of fruit juices and beverages, and 50 samples of fruit juice concentrates. High performance liquid chromatography(HPLC) was applied to quantitatively analyze patulin levels in samples and liquid chromatography-mass spectrometry(LC/MS/MS) was used to remove false positive results. The results showed that three samples of 520 fruit juices and beverages and five samples of 50 fruit juice concentrates were contaminated by patulin, $9.8-18.0{\mu}g/kg$ and $4.7-18.2{\mu}g/kg$ respectively. Contaminated samples were produced with apple, orange or pear. This indicates that it is necessary to extend the regulatory range of patulin. In the other hands, the present study confirmed the effectiveness of LC/MS/MS analytical method to remove false positive results.