Technique improves yogurt’s consistency

Tearing off the foil lid from a cup of yogurt sometimes reveals more than you want to eat — a pool of murky liquid floating above the fruitful treat. New manufacturing techniques developed by CALS food scientist John Lucey could keep this watery substance — called surface whey — beneath the surface without adding extra ingredients.

The whey separates from the yogurt’s gel structure during the standard manufacturing process. Although it doesn’t affect quality, consumers often take it as a sign that they should throw away the yogurt. To stop separation, most yogurt makers add stabilizers, such as pectin. But, as Lucey notes, doing so increases cost and reduces consumers’ perception of yogurt as a heath food. He found that simply lowering the incubation temperature creates fewer defects without affecting production time.

Lucey and graduate student Wonjae Lee now are developing tests that allow yogurt makers to determine how their manufacturing and fermentation processes affect the formation of surface whey.