“The ice creams produced with the new methods are simply better than any ice creams have ever been,” Professor Goff said. “Quite definitely better in texture, and much better tasting.”

A tasting by the staff of the Dining section found the Breyers Light Double Churned chocolate ice cream bar with the ice-structuring protein very creamy, even dense. It was the favorite of five ice cream bars tasted. The Häagen-Dazs Light and the Breyers Light chocolate ice cream, using low-temperature extrusion, were also very creamy and did not seem to be low-fat. But tasters found that the new ice creams still lagged behind full-fat versions in flavor.

“The quest has always been for the taste and texture of full-fat ice cream,” said Tyler Johnston of Edy’s. “Since the 1980’s it’s been about adding ingredients,” he said, referring to the gels and gums that commercial producers churn into reduced-fat ice cream to improve and stabilize its texture. “Now we have a complicated process, but the recipe can be simplified,” he added, referring to the industrial freezers that reduce the ice cream from minus 5 to minus 25 degrees Celsius for low-temperature extrusion.

The public seems persuaded. Shelf space for Dreyer’s/Edy’s Slow Churned, Breyers Light Double Churned and Häagen-Dazs Light has consistently expanded since they appeared. The category to which they belong, reduced fat, is the only part of the ice cream market that has been increasing in sales. As defined by the F.D.A., light or reduced-fat products can contain up to half the fat grams and two-thirds the calories of the original. (For a product like Häagen-Dazs dulce de leche ice cream, this means a reduction from 18 fat grams to 7 in the Light line; a low-fat product can have no more than three fat grams per serving.)

While full-fat ice cream still makes up more than 65 percent of the total market, the International Dairy Foods Association says that sales in the category have been flat for three years and that sales of low-fat and nonfat ice cream have gone down in the same period.

Professor Goff said that outside the United States the significance of the new technologies would be noted not on the palate but on the pallet. “American companies are getting ready to export ice cream to China, India, the Philippines,” he said. “These are places that have very real cold-chain issues,” he said, referring to the challenge of keeping ice cream consistently frozen throughout the shipping process.

Products produced with the new technologies are less affected by partial thawing than traditional ice creams, which become dry, sticky and hard in fluctuating temperatures. (This is why letting a container of ice cream thaw on the counter before scooping it is a bad idea.)