Is your manufacturing line on a tight schedule? Can’t wait for a fermentation to complete? Need better control of pH development or some kick in flavor? Acidulants might be the answer.

“Acidulants serve a wide range of functions in food systems,” says Jan Payne, senior market development specialist, PURAC America, Lincolnshire, Ill. “Food-grade acids are added for flavor, microbial prevention and their ability to reduce processing time, which in the dairy industry translates to improved efficiencies.

“Acidulants help dairy processors achieve a desired pH quickly, but they must be handled carefully,” says Payne. “If you add too much, there is no going back. This is why it is important to work closely with your supplier to determine the best acid to use and at what levels. In addition, it is critical to identify an effective means of dosing or metering the acid into the milk system.”

This is because acid curdles milk protein upon contact. When manufacturing direct-set sour cream or cream cheese, the acid is often diluted and added slowly, with constant agitation, in order to develop a smooth texture. The term direct-set describes the fact that an acidulant is used to lower the pH of the system, as opposed to a microbial culture, which lowers pH through fermentation.

“Lactic acid is the most frequently used acidulant in dairy products because it naturally occurs there,” says Payne. “Dairy manufacturers understand that the traditional cultures used in dairy processes produce lactic acid, so it only makes sense that lactic acid is the choice for any direct acidification from a flavor perspective.” Applications include buttermilk, dairy drinks, and cottage, mozzarella, feta and ricotta cheeses. It is the acidulant of choice in making sour cream, as it has a smooth acid taste that complements the sour cream flavor without the overpowering tartness of other acids.

“A large percentage of buttermilk production today goes to baking applications rather than direct consumption,” adds Payne. “It makes sense for a manufacturer to free up that valuable tank space quickly by directly acidifying the milk and packaging immediately.”

So many acids, so many options

Other acids are useful in different dairy applications. For example, phosphoric, citric and hydrochloric acids all have application in direct-set cottage cheese. Citric acid is also used as an acidifying agent and flavor modifier in cultured milk, butter and some natural cheeses.

“We are the only producer of all-natural Glucon® GDL, glucono-delta-lactone in the United States,” says Payne. “GDL is a slow-release acidulant that has minimal effect on organoleptic properties. In dairy applications GDL acts as a controlled coagulator without adding undesirable sourness.”

GDL is the neutral ester of gluconic acid. It hydrolyzes in aqueous solutions to form gluconic acid. It is often used in the manufacture of direct-set cottage cheese, as well as for pre-acidifying milk for cheesemaking. In direct-set cottage cheese, the process begins when cold milk is mixed with an acidulant to obtain a pH up to 5.0. After heating the acidified milk to 90˚F, GDL and rennet is added, which causes the curd to coagulate in about one-fourth the time necessary with culture acidification.

“The advantages of using GDL include constant end-product quality, higher yields, faster coagulation, no post-acidification and longer shelflife,” says Payne. “Acidification with GDL creates the same slow pH reduction as one would achieve through microbial acidification, just without any possible microbiological problems.

“Because GDL is a slow release system, it is sometimes difficult to determine the correct amount needed to arrive at a particular pH,” says Payne. “In this situation, one can quickly ascertain the amount of strong acid needed, then calculate the amount of GDL required to achieve the same endpoint.”

Acetic acid, the major component of vinegar, is used in the manufacture of pasta-filata style mozzarella cheese. Its primary function is to control pH, which subsequently causes the milk to coagulate and the curd to form. It also contributes a sour flavor that is associated with traditional mozzarella. “For a milkier, dairy flavor, lactic acid can be used with or instead of acetic acid in pasta-filata type cheeses,” says Payne.

The whey drained from such mozzarella is packed full of protein and has traditionally been used to make ricotta cheese. The residual protein in the whey is not readily coagulated by starter cultures, but will coagulate under the influence of an acidulant like lactic or acetic acid.

Acidulants provide a type of process control that is not attainable with live and active cultures.

PURAC America, Inc
847/634-6330
www.purac.com