I am formulating a "healthy" beverage based on brown rice and soy powder. The problem is that the minerals reduced tremendously (loss between 90-98%) after retort process. To my knowledge, minerals are stable at high temperature. Appreciate suggestions on how to overcome this problem.
Well Aishah. I also feel in the same way as minerals are heat stable. it could be easy to understand how you are measuring mineral contents? By ICO-OES or insoluble ash content and photometry.
Coming from a geological background, I feel the great urge to explain that you are talking about elements (such as Mg, Ca, Mn, P) here, rather than minerals (such as apatite, calcite, quartz). I know that nutritional advertorials confuse the two, but considering we're on a scientific forum here, perhaps we can use the correct terminology? Please?
Unfortunately, I cannot give any answer to the original question, as I do not know what a retort process is. So no luck there.
When you talk about liquids (beverage) the elements you mentioned should be existing in the ionic form or radical ions. These are not minerals according to my knowledge. If I am not wrong "retort" is a distillation process where heating a liquid and then condensing vapors to liquid again by cooling and it is mainly used for purifying the liquid or mixture of liquids from ionic species. So after retort principally you will get beverage devoid of all the ions (minerals??). If you elaborate your question you may get better and helpful answers. That's what I understood from your question. Good luck!
Thank you everyone for replying.
For your info, my question relates to the field of Food Science & Technology in which the mineral content comes from the ingredients (brown rice & soybean). For measuring the mineral, we use atomic absorption spectrometer that gives us the result in the form of element contained in the sample. The retort process is a heat treatment to kill all microorganisms in the food product, conducted at 121 degree Celsius for 20 minutes. Is the temperature and time used cause the loss of the elements?
To analyse the elements samples should be ashed (dry or wet) and subjected to AAS as Chlorides using the standards. Dry ashing is done using 550 Celcius while wet ashing using 250 - 300 Celcius. Therefore retorting or autoclaving cannot destroy the mentioned elements. I think when you get the samples for analysis always take homogenized samples and evaporation prior to ashing should be done in liquid samples. Also if you use a few drops of Sulphuric acid prior to ashing and make sulphated ash Sulphates of the mineral elements will be more stable and can analyse well.
Thank you so much Suraji.
You are probably right. The sample preparation technique used prior to AAS measurement may probably be the possible reason why the element content was reduced.
Dear Aishah
Hi. I think Suraji comments is correct. Retort temperature has no effect on the minerals and so the problem should be checked in prepartion method. If you evaporate the sample after retorting and the ashing, I am very possitive that you will get the right answer.
Dear Mahdi,
Thank you so much for your info. I have repeated the analysis and got a more logical result using advice from Suraji by adding 2 drops of sulphuric acid prior to ashing.
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