Modern consumers are demanding modern dairy products. They are looking for innovative, exciting products to match their lifestyle with characteristics that meet their priorities for health and wellness, convenience, indulgence or value. This new perspective is creating a global transformation within the dairy industry, presenting fresh opportunities, but also fresh challenges to meet specific market demands.
Dairies have started to invest in new opportunities in the production of fermented fresh dairy products in addition to their core processes. Dairies building yogurt production lines require a stable base and, regardless of size or location, must consider five key performance criteria: operational efficiency, production capacity, food safety, production time and utility consumption, to ensure they remain competitive and free to spend resources on new innovations into the future. These areas require the right equipment, the right know-how and the right support from suppliers of fermented fresh dairy production equipment. The ongoing changes within the industry also requires a partner that understands, has innovation infrastructure, keeps pace with, and even leads the way with breakthrough technology and plant designs to meet new demands without compromising the core of the business.
Quality Milk is a versatile fermentation medium containing all the growth factors necessary for lactic acid bacteria. However, if the quality parameters of the final product are to be controlled:
To produce high-quality yogurt, it is often necessary to increase the solid non-fat (SNF) content. This can be carried out by the addition of milk powder or by concentration. Careful control of re-combination conditions are necessary to ensure full hydration.
For many products, the curd properties are improved by increasing the protein content of the milk. The most common methods of increasing the total solids content are evaporation and membrane filtration. The choice of method will usually be determined by factors such as local regulations, energy prices and other running costs, investment costs, capacities, and product range.
The degree of evaporation depends on the composition of the raw milk and the desired composition of the final product. For production of yogurt, the raw milk SNF is normally concentrated to 9.5-12%. Evaporation can take place either in a separate evaporator (external evaporation) or in-line as part of the yogurt processing line (internal evaporation). External evaporators are more expensive than the in-line solution, but the running costs may be lower. Therefore, external evaporators are used only when the amount of water to be evaporated is large, or when the evaporators are to be used for other products as well. Internal evaporation has some capacity limits and will normally only be used for a maximum of 1,500 l/h of evaporated water. The advantages of using an internal evaporator include: no extra buffer tanks for the concentrated milk, no extra CIP cleaning of equipment, minimal space requirement, less product waste, and fewer operating steps.
The viscosity of the final product is highly dependent on the fat content and the size of the fat globules. To obtain yogurt with a uniform and well-defined fat content, the fat content of the milk must be adjusted to the required level, and all production parameters must be kept constant. Fat standardization will usually take place before the yogurt milk is processed but can also be performed in-line.
Heat treatment for yogurt products improves viscosity. Optimum improvement of stability and viscosity is typically achieved by subjecting the milk to a heat treatment of 90°C for a minimum of 10 minutes. However, a pasteurization temperature of 90°C is not always satisfactory in terms of bacteriological composition. To destroy bacteria spores and enzymes, additional pasteurization at 120-130°C with a holding time of 4-20 seconds is necessary. Heat treatment causes changes in the milk proteins so that the whey proteins are denatured and form complexes with the caseins. The whey proteins function as natural stabilizers. Furthermore, heat treatment de-activates most of the substances which inhibit bacterial growth in the milk, it reduces the content of dissolved oxygen, and it improves the milk as a growth medium of lactic acid bacteria.
Since the starter culture bacteria are anaerobic bacteria, de-aeration of milk will improve the growth conditions. De-aeration will also improve the working conditions for the homogenizers. If an internal evaporator is used, it can also function as a de-aerator.
When milk is homogenized, some of the milk proteins create new fat globule membranes. This steps makes many small uniform fat globules from big ones. The more efficient homogenization, the greater the improvement in the stability and viscosity of the curd structure. Efficient homogenization is a combination of temperature and pressure. The fat content of the milk is the main basis upon which the homogenization pressure is chosen; typically, it will be between 250 and 400 bar, with the highest pressure being applied to the products with the lowest fat content. Other parameters in the choice of homogenization pressure are the amount of protein in the milk and the protein-fat ratio. Finally, the type and number of homogenizer heads play an important role in the choice of the correct homogenization pressure.
The pH value of milk can be lowered either by the addition of acid or by bacteriological fermentation of the lactose - the basic component from which curd is formed when the pH is lowered is the milk protein and especially the casein. Milk has a pH value of 6.6. At a pH of approx. 5.2, curd formation begins. With a further reduction of the pH value, the maximum curd firmness is obtained around pH 4.6.
When the yogurt milk has been filled into the final packages, these must be incubated at the fermentation temperature in an incubation chamber/room. It is very important that the packages are not handled in any way during fermentation as any vibration will disturb the curd formation. The temperature in the incubation chamber/room must be kept constant and the circulation of air must be properly controlled.
The choice between a chamber system and a room system depends primarily on the type and volumes of products to be produced. In the chamber system, each individual pallet may be subjected to its own individual heat treatment, and there is no need to move the products before they have been cooled. Incubation rooms, however, have certain limitations regarding the individual treatment of pallets. These must be transferred from the incubation room to the blast cooling area, and such transfers must be carried out without any vibration or shaking taking place since this will destroy the stability of the products. Cooling of the products also involves special care, the products must be cooled as quickly as possible to stop fermentation, but whey separation in the packages must also be avoided and this requires slow, controlled cooling.
The yogurt consumers are looking for more value addition in day to day yogurt consumption. The ultra-filtered ( UF ) treated milk which separates out the proteins from the rest, is used to make this high protein yogurt. High protein yogurt has high amount of amino acids. And amino acids are building blocks of the muscles. The need of high-quality nutrition and wholesome calories is supplemented by high protein yogurt. Natural milk protein and less sugar yogurts are the guilt-free indulgence that today’s consumer looks for.
Dairy snacks are basically the “grab and go dairy” category. These dairy snacks are basically single portion, which can be consumed during instant hunger cravings. This dairy snack is possible to have in sugar free and protein rich recipes. The fancy size and shapes packages add to this attractive dairy snack acceptance among consumers of all ages.
The high protein trend dairy snack are gaining popularity off the back of the rapid rise in urbanization and faster pace of working lives in cities, and the unprecedented rise in single-person households, all of which help to contribute to a demand for healthier snack replacement, where dairy shows up as the number one choice.
Working with suppliers such as SPX FLOW, dairies can benefit from the extensive knowledge they offer, not only of technologies but also areas such as utilities, ingredients, recipes, trialing, training the staff and optimizing solutions. Choosing a manufacturer that supplies all components of the system and has in-depth knowledge and experience of the dairy market, equates to additional peace of mind, reduced risk and a partner that will you meet your goals today and into the future. Small scale plants with SPX FLOW are available in a range of 150-250kg/hr final product throughput.
SPX FLOW has an innovation Center at ENIL in Mamirolle, France, which houses a small-scale plant for fresh dairy processing. Companies from all over the world visit to test new recipes or make trials of new products under strict confidentiality and, for those considering a small-scale solution, they can trial the actual solution before committing to purchasing one for themselves.
For both existing dairies and new entrepreneurs, a small-scale multipurpose plant offers an excellent return on investment for the launch of novel products into the marketplace. For larger dairies that carry out frequent research and development within their own premises, small-scale plants also offer an ideal solution without the need to turn to an external facility. Ultimately, small-scale plants are a low-risk option, provide ample flexibility to research different products and markets, can produce beta products to test the market and, after necessary feedback, iterations and value additions can continue to full production of niche products.