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Effect of juice extractor settings on juice cloud stability
R G Cameron1, R A Baker, B S Buslig
1Citrus and Subtropical Products Laboratory, SAA, ARS, U.S. Department of Agriculture, P.O. Box 1909, Winter Haven, Florida 33883, USA. rcameron@asrr.arsusda.gov
Journal of Agricultural and Food Chemistry
|December 20, 1999
Summary
Orange juice cloud stability varies with extraction method, with soft-extracted juice being most stable. Pectinmethylesterase (PME) activity at pH 4.5 predicts stability, but not at pH 7.5.
Area of Science:
- Food Science
- Biochemistry
Background:
- Juice cloud stability is crucial for consumer acceptance.
- Extraction methods can influence juice properties.
- Pectinmethylesterase (PME) activity is a key enzyme affecting juice quality.
Purpose of the Study:
- To investigate the impact of different orange juice extraction settings on juice cloud stability.
- To determine the role of protein extracts and PME activity in juice cloud stability.
- To evaluate the reliability of PME activity measurements at different pH levels for predicting juice stability.
Main Methods:
- Valencia oranges were juiced using three distinct extractor settings: soft, medium, and hard.
- Protein extracts were isolated from each juice type and added to pasteurized juice.
- Pectinmethylesterase (PME) activity was measured at pH 4.5 and pH 7.5.
Main Results:
- Soft-extracted orange juice exhibited the highest cloud stability, while hard-extracted juice showed the least.
- Protein extracts from different extraction methods differentially affected pasteurized juice cloud stability.
- PME activity measured at pH 4.5 correlated with observed juice cloud stability.
- PME activity measurements at pH 7.5 yielded inconsistent and unreliable results for predicting stability.
Conclusions:
- Orange juice extraction intensity significantly impacts juice cloud stability.
- PME activity at pH 4.5 is a reliable indicator for predicting juice cloud stability.
- PME activity estimation at pH 7.5 is not a reliable method for assessing juice cloud stability.
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