Their appeal is growing in today’s modern processing world, as they are recognized as clean label ingredients. In some applications, use allows for the removal or reduction of label unfriendly ingredients. It is no wonder suppliers are investing in research to allow for culture and enzyme selection based on performance capabilities.
The American Heart Association and the Dietary Guidelines for Americans both urge consumers to reduce their intake of added sugars, which are refined sugars directly added to foods. When quantifying added sugars in dairy foods, lactose, also known as milk sugar because it is an inherent component of milk, is not included.
Though lactose is sugar, it is not very sweet. Compared to sucrose with a sweetness index of 100, lactose is a mere 16. Scientists have learned that when lactose, a disaccharide, is broken down by lactase enzyme into its constituent monosaccharides, glucose and galactose, its sweetness is increased approximately three-fold. Through controlled use of lactase, added sugars in such sweetened dairy foods as flavored milk, ice cream and yogurt, may be reduced.
“Lactase can be used to unleash the natural sweetness of dairy,” said Merel Roes, global marketing manager of dairy and confectionery enzymes for DSM Food Specialties B.V., The Netherlands. “Simultaneously, lactase allows for the production of a lactose-free product, which brings additional value by appealing to those consumers avoiding lactose.”
Mirjana Curic-Bawden, senior scientist, application manager-fermented milk and probiotics, cultures and enzymes for Chr. Hansen, Milwaukee, said, “It is important to emphasize that sweetness obtained from lactose is not enough to fully replace added sugars or sweeteners, but it allows for a reduction of added sugar.”
For example, if lactase is used in combination with a yogurt culture with mild flavor and low acidity, adding around 5% to 6% sugar to the formula delivers sufficient sweetness, as compared to non-lactase-treated milk, where the formula would call for about 7% to 7.5% added sugar.
Of course, nothing is as simple as it sounds.
“The shelf life of lactose-free products can be limited because of taste deterioration,” Ms. Roes said. “We have done extensive research on off-flavor development when lactase is used in dairy products and found that arylsulfatase, a common impurity in lactase preparations, causes this off-flavor once a dairy product is treated with an enzyme preparation. Our scientific knowledge has enabled us to develop a lactase ingredient free of arylsulfatase.”
Another sugar-reduction technology uses invertase enzyme and works much the same as lactase.
“Invertase breaks down sucrose into its constituent monosaccharides: glucose and fructose,” Ms. Roes said. “This is called invert sugar. Depending on the finished product, sucrose may be completely or partially broken down by invertase. Determining how much sucrose to break down is related to the desired sweetness intensity, including whether the sweetness perception should be immediately intense and short lived or less intense but linger. The presence of other ingredients in the formula, such as fruit, may mask or enhance the sweetness.”
DSM developed a chocolate milk prototype using both lactase and invertase.
“The lactase enzyme releases the natural sweetness of the lactose in the milk without increasing the calories of the milk base,” Ms. Roes said. “A chocolate syrup produced with invert sugar made by invertase can lead to a further reduction of added sugar and calories.”
The exact sugar reduction amount will depend on the individual formulation, amount of chocolate and other ingredients such as stabilizers.
“The application of these enzymes is flexible with respect to process requirements and necessitate very little, if any, capital improvements at the manufacturer in order to achieve the benefits,” Ms. Roes said.
The most common approach to adding lactase is to do so as a batch treatment of the raw, cold milk prior to the main heat treatment. During heat treatment, the enzyme is denatured and therefore qualifies as a processing aid and generally does not need to be labelled on the retail product.
Lactose reduction also may be achieved by adding lactase enzyme to the heat-treated product. With fermented dairy products, the lactase may be added with the culture inoculation. With this approach, the lactase remains active throughout the shelf life of the product and must be declared on the ingredient statement. Though this approach is less labor intensive than the batch process, one must consider the product and its time in distribution, as there’s a chance some of the lactose will remain intact. This may impact product sweetness as well as compliancy if a lactose-free claim is being made. Further, if this approach is used with milk intended for aseptic packaging, it is necessary to use a lactase preparation that has been sterilized and comes in a format for aseptic dosing.
Culturing safety
Controlling contamination of fermented dairy products by yeast and mold is one of the most significant challenges facing dairy manufacturers. Adding chemical protectants is not typically an option, as processors don’t want to add ingredients that compromise the product’s naturalness and clean-label positioning.
DuPont Nutrition & Health, Kansas City, offers a range of protective dairy cultures that function as a weapon against spoilage, helping processors ensure production of longer-lasting, fresher-tasting fermented dairy products. It controls a range of difficult fungal contaminants, in particular spoilage yeast, a constant challenge in cold-chain logistics.
The range includes a number of ingredients that are unique blends of selected and patented strains of Propionibacterium and Lactobacillus, which creates a broad inhibition spectrum against yeast and mold. The Lactobacillus strain varies by application, with L. paracasei and L. rhamnosus especially effective in yogurt and sour cream. A blend of L. plantarum and L. paracasei is designed for use in very mild-flavored dairy products, while L. plantarum works alone in cheese.
“Use of any of these cultures requires no change to the manufacturing process. The protectant cultures can simply be added to the milk together with the starter culture,” said Jeff Lambeseder, regional product manager of bioprotection with DuPont. “The manufacturer can choose to label the ingredient simply as ‘cultures; or they may call out the specific organisms.”
Cultures for authenticity
In an effort to assist formulators with adding authenticity to their Greek yogurt innovations, Chr. Hansen has introduced an authentic Greek yogurt culture series sourced from a strain collection at the Agricultural University of Athens. The university visited small producers and families around the Aegean Sea to sample their homemade recipes. This culture was isolated from an artisanal Greek yogurt from Crete some 20 years ago.
“The new cultures make it easy for Greek yogurt producers to obtain optimal taste and texture,” Ms. Curic-Bawden said. “They also perform extraordinarily well in low-fat milk. The cultures are designed to produce excellent Greek-type yogurt using either separation technology or milk protein fortification to reach the high protein level.”
The new cultures are available with or without the company’s well-documented probiotic Bifidobacterium animalis ssp. Lactis known as BB-12.
“The cultures are designed to help solve a number of issues for producers,” Ms. Curic-Bawden said. “They deliver a smooth texture and fresh and balanced flavor in fortified yogurt and allow strained yogurt to maintain a low post acidification in the production process, ensuring a tasty mild flavor.”
DuPont offers a five-species yogurt culture blend specifically for Greek yogurt. As a one-step culture solution, it reduces formulation errors during production by ensuring consistency of culture delivery and eliminating plant mixing and measuring of starters.
The balanced blend is designed to deliver a mild dairy flavor over the shelf life of the yogurt, Mr. Lambeseder said.
As scientists identify new functions of cultures and enzymes, uses for these clean label ingredients will grow in dairy applications. This will allow for the innovative development of new products, as well as improved nutrition and composition profiles of current products.
