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Lc_shi
26-02-2008, 11:08 AM
Hi dear sirs
How to prevent fresh fruit to dehydrate in cold room?
It's asked by one of my friends but I've no idea about that. Pls help me:)

thanks
LC

dsp
26-02-2008, 11:20 AM
Hi,
There is a product called Thermfresh that may help. They are here is Aust. but are overseas as well. They are an evaporator which has water jets in it to increase the humidity.
dsp

nike123
26-02-2008, 12:12 PM
Hi dear sirs
How to prevent fresh fruit to dehydrate in cold room?
It's asked by one of my friends but I've no idea about that. Pls help me:)

thanks
LC

By maintaining humidity in cold room at proper value with humidifier. Also, for preservation of fresh fruits from rapid decay, there must be control of atmosphere inside cold room (control of CO2 concentration).

Samarjit Sen
26-02-2008, 01:10 PM
Hello Lc,

For the storage of fresh fruits, temperature and humidity are very important. Each fruit has its own requirement and as depending on the fruit the temperature and the humidity is to be set.

The best way to maintain the humidity is by the Coil. Select a large surface coil with low Td. Generally a Humidity of 80 to 95% RH is required depending on the fruit. This way you will not only attain the required conditions, but also the size of the moisture contents would be so small, that it will not settle down on the fruit and cause chilling injury

The temperature may be any where between 0 to +4 oC.

I hope I have been able to answer your question.

mano
27-02-2008, 06:31 AM
TD / DT1 ; temperature difference controlled ;
water drain.

Humidity control : Added/ water

Co2 C.A.

nike123
27-02-2008, 09:59 AM
TD / DT1 ; temperature difference controlled ;
water drain.

Humidity control : Added/ water

Co2 C.A.

Hey pal, telegraph era is long time ago passed, now it is allowed to be little more eloquent in long distance communication.:D:D

Tesla
27-02-2008, 11:10 AM
Hi Lc Shi
Another parameter to consider is packaging - enough to alow product to breathe but restrict evaporation

Lc_shi
28-02-2008, 03:09 AM
i've learned that key points are:
1. temperature and humidity control
--- low TD large surface evaoprator + humodifier ?

2. co2 removal
---by ventilation? how to quantify the air volume?

3. packing --balance the breathe and evaporation
---How to do ?

thanks

LC

Samarjit Sen
28-02-2008, 08:47 AM
Hello Lc,

If you select the Evaporator properly and balance the system, no additional humidifiers shall be required for maintaining the Humidity. It is better to do without the humidifiers as they are liable to wet the boxes and damage the fruits.

As for the breathing, the fruits are packed in perforated boxes. They have these special packing boxes.

The most important aspect for fruit storage is Temperature and Humidity. If you want more details, you may contact U.C. Davis who are an authority in fruits. They have a Educational University and they share the information. I will try and get the website.

sunilbhat
28-02-2008, 11:02 AM
Hi LC

For presevation of fruits alone temp and RH maintaining won't be enough. First, one has to understand biology of various fruits. Some fruits are ethylene generator while some are ethylene sensitive. You have to manage ethylene levels. Ethylene is death senesense which destroys green leafy vegetables and many cut flowers.

You have to scrub ethylene many times to avoid decay in fruits/flowers stored. Ethylene generation is

less at lower temp.

Higher level of Co2 and Lower level Of O2 will keep fruit more fresh due to lowest rate of respiration.

The above is termed as Controlled atmosphere/Modified Atmosphere Rooms ( CA / MA Rooms)

Your querries will be answered by PM

Good Bye Sunil Bhat India

aansari
28-02-2008, 12:05 PM
Dear all:

The problem with humidifer that water should be fully vaporized and treated in order to prevent cross contamination, and this is not the case in most facilities. Also in order to have longer storage period and to avoid box collapsing, carton should ba waxed, this is costly

The use of PM valve is very imposrtant in a DX system to miantain constant DT which has a major impact of the RH. For secondary system, the use of FD is usiful. We developed what is called dry coil high humidity system that has 85-90% RH during the precooling process for grapes and strawberries.

Samarjit Sen
28-02-2008, 06:23 PM
For Food Preservation, Freezing, Pre Cooling etc, it is very important that one has to know more about the product. Refrigeration becomes a secondary feature.

However the question here is that how to avoid dehydration of the produces while storing them. CA & MA are special application and all fruits will not be required to be stored in such Cold Storages. For example apple storage is more effective when it is a CA Storage, whereas Grape Storage does not require CA.

aansari
28-02-2008, 06:48 PM
NO this is not right, CA and MA should be acompanied with refrigeration.

Josip
28-02-2008, 07:14 PM
Hi, aansari :)

welcome to RE forums...


NO this is not right, CA and MA should be acompanied with refrigeration.

....please, when approve or disapprove something it will be nice to explain that a little more....;)

Best regards, Josip :)

aansari
28-02-2008, 11:20 PM
Dear Josip

I am sorry for that. It is a vey well known fact that CA and MA dose not work unless there is a control in both T and RH. The edia on both technologies is to control the repiration, respiration is a function of temeprature so it must lowered based on several facts variaty among them.

I apologize agian for you.

Josip
29-02-2008, 12:53 AM
Hi, aansari :)


Dear Josib
I am sorry for that. It is a vey well known fact that CA and MA dose not work unless there is a control in both T and RH. The edia on both technology is to control the repiration, respiration is a function of temeprature so it must lowered based on several facts varite among them.
I apologize agian for you.

Thanks, I know a little about that, but here can be some other members not knowing what and why and for that reason we are trying to give a kind of full explanation or at least our opinion (what we are thinking about, usually right but sometimes wrong)

...... I believe you misinterpret post of Samarjit Sen...


For Food Preservation, Freezing, Pre Cooling etc, it is very important that one has to know more about the product. Refrigeration becomes a secondary feature.

However the question here is that how to avoid dehydration of the produces while storing them. CA & MA are special application and all fruits will not be required to be stored in such Cold Storages. For example apple storage is more effective when it is a CA Storage, whereas Grape Storage does not require CA.

Best regards, Josip :)

Samarjit Sen
29-02-2008, 03:49 AM
Hello aansari,

It appears that you have misinterprated my reply. I am fully aware that CA & MA has to be with refrigeration, and a person saying CA etc means the complete system. Josip has explained the situation .

jong0726
02-05-2008, 09:26 PM
i think it's finding a proper place like a cold room with the appropriate humidity. this will help.

jong0726
02-05-2008, 09:26 PM
just do not store them for too long.

Channa M
12-09-2008, 09:10 AM
i think it's finding a proper place like a cold room with the appropriate humidity. this will help.
What would be the Ideal Type of humidifier Warm Air Or Cold Air? Is there any justification in using a warm mist Humidifier (steam) in a cold room??

Josip
15-09-2008, 12:06 AM
Hi, Cnanna M :)


What would be the Ideal Type of humidifier Warm Air Or Cold Air? Is there any justification in using a warm mist Humidifier (steam) in a cold room??

please, try to search RE forums... there were some posts about types of humidifiers ....

.... typing word "humidifier" in search window .... found about 60 threads ..;)

Best regards, Josip :)

Channa M
15-09-2008, 04:11 AM
:)Hi josip Thanks very much
Channa

ice_cool
11-11-2008, 10:47 AM
add a humidity controller in the cold room.