(1) The hardness of potato chips decreases with the increase of peeling time,
(2) There is no significant relationship with peeling time.
(3) As the blanching time increases, the degree of discoloration decreases and the degree of enzyme inactivation increases.
(4) As the blanching time increases, the degree of browning of potato slices decreases, and it stabilizes after blanching for 60 seconds.
Taking into account the effects of potato chip blanching time on hardness, vc content, enzyme inactivation, potato browning and fuel cost, the best blanching time for potato chips with a thickness of 0.5m in water at 100°C is 60s. The blanching time can inactivate enzymes, reduce browning value, maintain a certain degree of hardness, and facilitate subsequent processing operations.
Materials and Methods
Test potatoes purchased at the local market
Main equipment: Kang Bavaria refrigerator, handheld hardness tester, ultraviolet spectrophotometer, constant temperature water bath
Process flow of frozen potatoes
Potatoes – Clean – Peel – Slice – Branch – Cool – Dehydrate – Transfer to the plate – Pre-frozen – Freeze – Pack – Freeze
Testing and evaluation
Hardness measurement: use a handheld hardness tester to test
The level of the teat enzyme activity of the teat: Cut the scalded potato with a knife, and then put it in the guaiacol solution.
Take it out after a while, and drop a few drops of 0.3% hydrogen peroxide solution on the cut surface. Discoloration observed after a few minutes
. If the whitening is not sufficient, the undegraded enzyme will react with it and become reddish brown. If the color does not change, the enzyme is
VC determination: determined by iodometric method.
Determination of submergence: Mix the sample with distilled water in a ratio of 1:10, homogenize for 2 minutes at low temperature,
Then extract the supernatant in a centrifugal device for 15 minutes (4000 r.min-1). Use a UV spectrophotometer with a wavelength of 416nm
Measure absorbance. That is the browning value.
- Experimental design
After washing and peeling, cut the potatoes into potato slices with a thickness of 0.5 cm. Then put the potato chips in cold water
In order to protect its original color, waiting to turn white. Put the slices into 100℃ boiling water, respectively, 0s, 20s, 40s, 60s, 80s, 100s
And 120s. Then use ice water to quickly cool the cooked potato slices to 0~5°C, check each index, and mark the blanching time
It is 0s as a blank control. The whitening time depends on hardness, VC content, enzyme inactivation
Degree and degree of browning.
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