Process for making a healthy snack food
The present invention is directed towards a method for making a healthy snack food having an appearance and taste similar to conventional fried snack products without the use of an oil-frying process. The method of the present invention includes the steps of providing food slices from a starch-based food or dough. The food slices can be blanched and a controlled amount of oil can be added to enhance final organoleptical properties. The food slices are then rapidly dehydrated to a much lower moisture content in a primary drying step that simulates conventional frying dehydration rates. A food snack, such as a corn or potato-based snack, produced by this method is a low-fat, ready-to-eat snack having the conventional texture and taste associated with fried snack products.
1. A method for preparing shelf-stable potato slices comprising the steps of:
a) lipophilically preconditioning a plurality of potato slices in oil, wherein said lipophilic preconditioning is of 60 to 120 seconds in duration and wherein said potato slices are brought to a temperature of 75° C. to 99° C. during said lipophilic preconditioning;
b) explosively dehydrating said potato slices to a moisture content of less than about 20% with a microwave, wherein said microwave includes a rotary microwave having a lining to provide a microwave field maximum to be coincident at the lining food contact surface to maximize the slice heating rate at that surface; and
c) further dehydrating said slices in a non-oil medium to a moisture content of less than 3%.
2. The method of claim 1 wherein the potato slices are subjected to an oil removal step after the thermal preconditioning of step a) and before the dehydrating of step b).
3. The method of claim 1 wherein the potato slices are subjected to a pre-drying step in a microwave pre-dryer prior to the dehydrating of step b) in the rotary microwave.
4. The method of claim 3 wherein said pre-drying creates an elastic slice that adopts a curl shape during the subsequent explosive dehydration.
5. The method of claim 3 wherein microwave pre-dryer comprises a linear belted oven on which the slices are spread.
6. The method of claim 3 wherein said pre-drying takes from 5 seconds to 90 seconds, optionally from 5 to 45 seconds, further optionally from 10 seconds to 20 seconds.
7. The method of claim 3 wherein at least one quarter of the water content, optionally from one quarter to one half, of the potato slices is removed during pre-drying.
8. The method of claim 1 wherein step b) simulates the dehydration profile with respect to moisture content and time of continuously fried potato chips and includes dehydrating from a moisture content of greater than 60% to a moisture content of less than 20% in less than 60 seconds.
9. The method of claim 1 wherein step b) comprises dehydrating to a moisture content of between 3% and 18%, optionally between 8% and 12%.
10. The method of claim 1 wherein step b) comprises microwave dehydrating said slices to a starch melting point range in less than 60 seconds and further microwave dehydrating said slices in a starch glass transition range in less than an additional 50 seconds, optionally dehydrating said slices to a starch melting point range in less than 40 seconds and further dehydrating said slices in a non-oil medium starch glass transition range in less than an additional 30 seconds.
11. The method of claim 1 wherein said non-oil medium at step c) comprises infrared radiation or hot air.
12. The method of claim 1 wherein the oil temperature of said lipophilic preconditioning of step a) is 85° C. to 95° C. and the duration of said lipophilic preconditioning is from 60 to 100 seconds.
13. The method of claim 1 wherein said explosive dehydration of step b) comprises a first dehydration rate and a second dehydration rate, optionally wherein said first dehydration rate is between 0.02 grams of moisture per gram of solid per second and 0.20 grams of moisture per gram of solid per second, further optionally between 0.06 grams of moisture per gram of solid per second and 0.18 grams of moisture per gram of solid per second, and/or wherein said second dehydration rate is between 0.004 grams of moisture per gram of solid per second and 0.08 grams of moisture per gram of solid per second, further optionally between 0.03 grams of moisture per gram of solid per second and 0.06 grams of moisture per gram of solid per second.
14. The method of claim 13 wherein said explosive dehydration of step b) further comprises a third dehydration rate of between 0.0005 grams of moisture per gram of solid per second and 0.03 grams of moisture per gram of solid per second, optionally between 0.002 grams of moisture per gram of solid per second and 0.02 grams of moisture per gram of solid per second.
15. The method of claim 1 wherein said lining comprises a microwave-transparent material.