Food Engineering/Manufacturing/Green color retention & sauce concentration
Expert: J. Peter Clark - 7/31/2013
Question Hi I would like to get to suggestions on how to preserve green color of vegetable such as sweet basil as a composite in ready meal products which the basil must gone through the process of pasteurization, freezing, and then heating by microwave.
Second question is how to concentrate the soup that contains coconut milk and prevent phase separation of coconut oil.
Thank you so much in advance for your time and your answers.
Answer The green color of basil and other vegetables is from chlorophyll,which is vulnerable to heat and pH changes. One possible solution might be to use dried or freeze dried basil in which the color might be fixed. Another might be to blanch and quickly chill the basil then add it just before freezing, if possible. It will still darken, probably, upon heating in a microwave. I think treatment with sodium bicarbonate can fix some green colors by raising pH. One would soak the leaves in a baking soda solution before drying. It might be worth testing at least.
As to the concentrated coconut milk, you might try homogenizing or adding an emulsifier, such as mono- or di-glycerides. If you are concentrating by evaporation, the heating promotes separation of the oil. Concentration at a lower temperature might help, by using vacuum, for instance.You also might consider other ways of thickening, perhaps by adding starch.
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Very quick response. I really appreciate it. Love J. Peter Clark! and love the founder of this webpage/group.
How various processed foods are made; ways to improve manufacturing; how to make a new food product.
Employment history: Research Engineer, U.S.Agricultural Research Service, Associate Professor Chemical Engineering, Virginia Tech, Director of Research, Continental Baking Company, President, Epstein Process Engineering, Inc., Vice Presdent Technology, Fluor Daniel, Inc., Consultant to the Process Industries
Organizations: American Institute of Chemical Engineers (Fellow) Institute of Food Technologists, American Association of Cereal Chemists, American Association of Candy Technologists, American Society of Agricultural Engineers,
Publications: Several Encyclopedias (Kirk and Othmer, Chemical Technology; Food Science, Food Technology and Nutrition; Wiley Encyclopedia of Food Science and Technology; Encyclopedia of Life Support Systems); five books, two book chapters; numerous journals.
Education: BSChE Notre Dame PhD University of California, Berkeley
Awards: AIChE Food, Pharmaceutical and Bioengineering Division Award 1998
Clients: Major food processing and pharamaceutical companies.