Comes the kitchen revolution: electronics in an apron

Thelma Pressman gets paid to cook all day. She runs a microwave oven cooking school in Encino, Calif., and while she teaches she also tests the latest in electronic kitchen appliances from Sanyo Electric Company. ''I've been liberated'' by electronic appliances, she exclaims.

Having Ms. Pressman's new-product-testing job is probably the closest anyone can get to experiencing the kitchen of the future. She has watched the evolution of kitchen appliances over the years and defiantly says: The world is ''ready to get rid of stupid appliances and start using smart ones. . . . You work all day with computers in offices but you come home to a kitchen that's archaic.''

The appliance industry has set about creating ''smart'' appliances by using the microprocessor. This computer on a chip makes it possible to program your dishwasher to kick on at 1 in the morning - when electricity is cheaper and the noise won't disturb the household. Because of the microprocessor, your microwave oven can audibly announce that in 10 more minutes your dinner will be cooked.

''There is a definite trend toward electronics in appliances,'' says Robert Pendergast, vice-president of RobertShaw Controls Company, a manufacturer of solid-state controls for the appliance industry.

But Charles Ryan, a follower of the appliance industry and vice-president of Merrill Lynch, Pierce, Fenner & Smith, hedges this trend with the comment: ''It has been a slow, gradual, progress from electromechanical controls to microprocessors.''

There are plenty of reasons behind the industry move toward high-tech appliances. But factors such as cost, the recession, and consumer fears of these new products have been slowing that move somewhat, Mr. Ryan says.

The industry believes the microprocessor will eventually storm the appliance market. Here's why:

* No moving parts: Solid-state appliances work on electrical charges, so no mechanical parts rub together and wear out. With no moving parts in appliance controls, the appliance can last longer.

* Accuracy: Mechanical timers and temperature controls are inexact. With solid-state devices, consumers can set time and temperature down to the last second and degree. And with the memory capacity of a microprocessor, appliances can know when to turn on, turn down, or turn off at a programmed time.

* Energy efficiency: Electronic controls allow appliances to sense exactly how much water, heat, electricity, etc., is needed to do the job. Dryers shut off when the humidity is low enough; dishwashers operate with the lowest possible hot-water use. The Whirlpool washing machine even reuses wash water left over from previous cycles. With its time-delay feature, the Westinghouse air conditioner can cool your house by the time you get home from work, and shut off shortly after you go to sleep.

* Self-diagnosis: With the microprocessor, appliances can constantly monitor themselves for safety problems and malfunctions - and then alert the consumer if something goes wrong. Thus, servicing appliances becomes more than trial and error. Whirlpool's top-of-the-line refrigerator has a display panel that tells the consumer whether the door has been left open, whether the temperature is too warm, and whether the condensor should be checked. If something else is wrong, the alarm signal will light up. When all systems are go, the display shows an OK sign. General Electric envisions a system in which the consumer phones a service center whose computer listens to an appliance run through its self-diagnosis. Variations in tones made by the check system would pinpoint the problems.

* Easy cleaning: All there is to clean on an electronic control panel is a smooth surface that is touch-sensitive - no crevices, cracks, and dials to maneuver around. Frasar Systems Inc. in Burbank, Calif., offers the smooth idea with its inductive cooking range. The cooking surface is completely smooth and does not get dangerously hot, so it's safe for children. Coils beneath the stove's surface create an alternating magnetic field which produces an eddy current in the bottom of the metal pot. Iron and high carbon steel pots resist this current and this resistance creates heat - in the pot, not on the stove's surface. Because of the relatively cool surface of this type of range, spilled food won't bake on to the surface.

Despite these marketable advantages, retailers are just beginning to see a flow of solid-state appliances. ''High-tech has a 20 to 30 percent premium cost over conventional electromechanical controls,'' asserts Merrill Lynch's Ryan, who also says cost is preventing many companies from going full force into solid state.

Harold Schafer, president of White Westinghouse, says he recently toured Pittsburgh's appliance retailers, looking for competitive models of its solid-state dishwasher. ''I was stunned. We couldn't find a single one in Pittsburgh,'' he says. ''Dealers weren't displaying (solid-state) models because many consumers couldn't afford them.'' The suggested retail price for the Westinghouse dishwasher is $799.

Though solid-state manufacturing costs are still high, they have been gradually decreasing due to a downward trend in chip prices. Analysts say costs will drop further when the industry begins to mass-produce microprocessor controls.

Peter Sogmefest, vice-president and business director of Motorola Inc., a worldwide supplier of appliance controls, says, ''In our case, our average selling price (of microprocessor controls) by 1983 will be half our average selling price of 1980.''

Since 1980, the appliance industry has been in a slump. In February, factory shipments dropped 14 percent from the same month last year. High interest rates, a slowdown in housing starts, and the long life of appliances (12 to 15 years) have contributed to the problem.

Ironically, the only appliance to have really taken off has been the microwave oven - the most ''high-tech'' of the appliances. Last year, total retail sales of microwaves reached 4,323,000 units - almost double the amount sold in 1978. And according to the US Department of Commerce, the microwave has still penetrated only 25 percent of the market.

Sales of other appliances haven't fared as well. ''Business is tough, it's obvious, but everyone is looking forward to pent-up demand,'' says James Barry, editor of Dealerscope, an industry magazine. ''The last boom in sales was 12 to 15 years ago. Appliance replacement, combined with demographic trends, should make for a good market when the economy turns around.''

But before that demand explodes, the appliance industry has a job to do. ''We've got to correct that misnomer of fear the public has about high-tech appliances,'' says Mr. Schafer. ''We've got to educate our retail sales people, so they can explain to customers how to work these appliances.''

Industry experts see all kinds of new developments coming to appliances in the next 10 years. ''Today, even with solid-state controls, consumers make a lot of decisions just to do a load of wash,'' says Motorola's Mr. Sogmefest. ''But soon, if you just tell the machine what fabric you want washed, it will make all the decisions for you.'' Texas Intruments suggests that future washers may have electronic soil sensors which automatically add or delete wash and rinse cycles or dispense the amount of detergent needed. The consumer just ''tanks up'' once a month.

Sogmefest also believes that ''within 10 years, you will be talking to many appliances and they will talk back.'' Voice synthesis is already being used as prompters in some appliances.

High-tech ''can't take away the tubs, transmissions, drives, and gears needed to run appliances,'' says Ryan, but it can still make improvements in solid-state controls.

''High-tech will move from the large appliances to the smaller ones,'' says Thelma Pressman. Already, SCM Corporation has a toaster with an adjustable throat for bread thickness. It stays cool on the outside. It senses heat and humidty - producing ''perfect toast.''