Lactose has limited solubility and crystallization is a problem in ice cream, sweetened condensed milk dulce de leche, and other dairy products. The lactose crystals impart an objectionable sharp and gritty mouth feel termed sandiness. LactoDigest Yeast Lactase ·    Selectively and efficiently breaks down lactose to galactose and glucose. ·    Lactose hydrolysis increases sweetness and depresses the freezing point. ·    Lactose hydrolysis prevents lactose crystallization. ·    Is stable and efficient over pH range common to milk and dairy (pH 5.25-6.75). ·    Highly purified  ·    Provide excellent color and flavor stability.   LACTOSE or milk sugar  is a disaccharide with relatively low sweetness intensity found in mammalian milk. It has a low solubility and it cannot be absorbed directly from the human intestine. Its constituents — glucose and galactose — are 3-4 times more soluble and are easily absorbed from the intestine. Only these monosaccharides are utilized as energy or building bricks in the body. The hydrolysis necessary for the utilization of lactose is affected by the enzyme lactase, which is normally present in the small intestine. The problem of lactose intolerance With most individuals the lactase activity level reaches its maximum value at the moment of birth when lactase activity is most needed to utilize the lactose calories (mother’s milk contains about seven percent lactose which supplies the majority of the calories during the first year of life).Problems with the lactase activity level occur in the following groups:  Due to a very rare congenital disease, babies may lack lactase activity from the very moment of birth. The results are severe gastro-intestinal disorders, which can be fatal if other foods are not offered immediately. With a second group, premature birth results in insufficient lactase activity. Lactase activity is mostly fully restored within one or two months.  A decline in lactase activity has also been demonstrated in people that normally are lactose tolerant but lose this capacity later in life. This seems to occur mostly at about the age of 40 to 50 years old. It is speculated that this reduction of lactase activity represents an important factor in the decalcification process of the skeleton.  With all people, lactase activity, present during the weaning period, gradually declines between the second and fifth year of age. Only in populations that have been drinking milk as a part of their staple diet for many generations is lactase activity still present after the weaning period. These populations include Caucasian people and a number of cattle breeding tribes in Africa. A genetic selection process is considered to be the cause for this phenomenon. Table 1 lists the tendency to lactose indigestion worldwide.When lactose is not hydrolyzed, it will not be absorbed and will reach the latter part of the small intestine and the colon. The micro-organisms present will grow on this lactose abundantly. The results are a change in the intestinal micro flora very often accompanied by excessive production of gas and acid, and withdrawal of water from the body into the colon, eventually resulting in intestinal disorders such as cramps and diarrhea. Population Tendency to Lactose Intolerance Area Tendency % Area Tendency % Western Europe   Americas   Austria 15-20 North America (whites) 15 Balkans 55 North America (Hispanics) 53 Finland 17 North America (blacks) 80 France (north) 17 South America 65-75 France (south) <70     Germany 15 Africa 70-90 Great Britain 5-15 Bedouins 25 Italy 20-70 Taureg 13 Scandinavia 3-5     Asia       India (north) 30 Central Asia 80 India (south) 70 East Asia 90-100   Unmetabolized Lactose The result of unmetabolized lactose is that for the majority of mankind the body cannot utilize the energy presented by lactose. (Depending on the fat content lactose represents 30-60 percent of the calories in milk). However, when the lactose is hydrolyzed before consumption, lactase deficient persons can use this energy. This is particularly important in all cases where the energy requirements are inadequately or marginally met, for instance in food-aid programs.It is a generally known fact that in these cases the proteins consumed are not converted into body proteins, but are burnt up. In other words: protein is only utilized as protein when the energy requirements have been met. Therefore with lactase-deficient persons the energy supply is increased by the presence of hydrolyzed instead of ordinary lactose in their diet, thus improving the protein utilization. Consequently with children suffering from malnutrition, and weakened patients, the positive results of the extra energy supply and the improved protein utilization soon become noticeable.Milk also supplies an important part of the necessary minerals, especially calcium. Lactose, as well as some other sugars, being carriers for minerals through ligand-formation, is able to facilitate the absorption of minerals. If the lactose is not absorbed and therefore transported to the colon, which occurs with unmetabolized lactose, losses of calcium and other minerals will be the result.Hydrolysis of lactose (figure 1) also influences calcium-absorption positively.When not only unmetabolized lactose but also intolerance symptoms occur, the appetite will be inhibited, so that even less food is consumed. If, on top of that, diarrhea occurs, this also causes the direct loss of a quantity of food already consumed but not yet absorbed; valuable proteins, vitamins, minerals and calories of milk are only partly utilized.Of course, it would be possible to remove milk products altogether from the diet. However, milk being a natural, essential and generally accepted food, it would be extremely difficult to find a substitute, which is as well balanced.One can also consider removing the lactose from the milk by a physical process. The objection is that, together with the lactose, vitamins and minerals are also lost. The best solution therefore is to pre-digest the lactose enzymatically, resulting in dietary milk in which all the nutrients have been retained. Natural sources of lactase Lactase (6-D-galactoside galacto-hydrolase), the lactose splitting enzyme, is found in the intestine of young mammals, in plants, fungi, yeasts and bacteria.The pH optimum of lactases is the predominant factor determining a particular potential area of application. Yeast and bacterial lactase possess a neutral pH optimum, which makes them directly applicable for the treatment of milk, sweet whey permeate and lactose solutions. The pH of other substrates has first to be corrected to the proper range. Lactases from fungi, with their low pH optima, are only suitable for acid wheys and whey permeates. Commercial neutral lactase The dairy yeast Kluyveromyces lactis was described by Beyerinck in 1889. It is a well known dairy organism used in the production of certain fermented milk products like kumiss and kurung. It has also been frequently used as protein supplements for food and feeding purposes. Efforts to use the enzymatic hydrolysis of lactose to improve milk products and milk processing have been strongly stimulated by the commercial development of Kluyveromyces lactis lactase preparations. Because of this, the applications described in the literature mainly concern 25 years of practical and commercial experience with this lactase.K. lactis neutral lactase preparations are available under the brand name LactoDigest™ from Novact Corporation. In the food industry, conditions for the use of enzymes, such as pH and temperature, are generally set by the substrate itself. In industrial practice, the lowest limit for pH is that of acid whey (pH 4-0-4.4) and the highest that of milk (pH 6.7- 6.8).Being isolated from a dairy organism, it is not surprising that the optimum conditions of Kluyveromyces lactis lactase activity are found near the natural pH and temperature of fresh milk. Figures 3 and 4 show the pH activity and temperature activity curves for this lactase. Enzyme activity is slowed by very low temperatures, but this enzyme still exhibits noticeable activity at temperatures around 4°C. Optimal activity occurs at 30-40°C but these temperatures present special problems due to microbial contamination, and so a short hydrolysis period of three to four hours is advisable if these temperatures are employed. increased because more micro-organisms can grow on glucose than on lactose. It is therefore very important that the milk is handled after pasteurization as aseptically as possible, i.e. clean all piping and the hydrolysis tank, preferably by CIP .Often a longer period of 15-24 hours at low temperatures of 4-8°C is chosen to avoid the problems of microbial spoilage. Other important practical limitations in the enzymatic processes in the food industry are end-product inhibition and the equilibrium situation of enzymatic reactions. Conclusion The rapidly increasing demand for "low lactose" dairy products is a major opportunity to open up a new market segment and make dairy products acceptable to people previously unable to consume them. These consumers can now benefit from the nutritional value of dairy products. Novact’s LactoDigest™ can convert the lactose content of milk to its component sugars and provide milk acceptable to "lactose intolerant" consumers. Dairy products made from "low lactose" milk can also be consumed without alimentary tract problems. Products of dairy origin thus become readily available to consumers who previously had to avoid them.  Have a question related to the Lactase Enzyme? Mail it to us and and one of our experts will answer