The right impact on taste and teture YOGHURT
Introduction This application brochure is prepared to provide you with an overview of the culture characteristics and manufacturing technology to produce your desired yoghurt. Our aim is to support you in selecting and applying the right ingredients and technology, as the CSK s cultures have a substantial impact on taste, teture and perception of your final product. With a track record of more than 100 years in the dairy industry, CSK is acknowledged as a reliable partner with great proficiency and many years of eperience in dairy manufacturing. We take our customers process and products as a starting point and provide well-considered choices and tailor-made solutions on the basis of partnership. Customers can not only rely on CSK for good ingredients, but also for support in the development and improvement of new or eisting yoghurt products. Ceska -star yoghurt cultures The range of Ceska -star yoghurt cultures are highly concentrated cultures, which are developed to provide various flavour, viscosity and teture profiles. The possible organoleptic profiles vary from etra mild flavour to a more traditional distinct flavour with varying viscosity characteristics. CSK has a complete portfolio of yoghurt cultures to effectively meet all market demands. The following DVI culture ranges have been developed, which contain a combination of strains, in the form of deep frozen pellets and are available in gable-top cartons: Y-range of cultures, which contains a miture of Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus; A-range of cultures, which contains Lactobacillus acidophilus; B-range of cultures, which contains Bifidobacterium lactis. Table 1. Overview of the different strains in Ceska -star yoghurt range Ceska -star cultures St. thermophilus Y 200, Y 700, Y 800, Y 900 Y 103, Y 104, Y 106, Y 107 Y 111, Y 118, Y 126, Y 128, Y 501 Y 318 Y 508, Y 510, Y 518 B 100 Strains Lb. delbrueckiisubsp.bulgaricus B 190 B 191, B 194 B 192, B 193 A 900 A 909, A 922 A 940 Properties Ceska -star yoghurt cultures Lb. acidophilus Bifidobacteria Ceska -star yoghurt cultures can be used for the production of different types of yoghurt products, such as set, stirred, or drinking yoghurt. In each of these segments there is a demand for traditional, semi-mild and mild varieties. The desired viscosities and structures vary significantly among regions and markets. In the tables below the different Ceska -star yoghurt cultures are classified according to their contribution to flavour, viscosity and post-acidification in yoghurt. The traditional flavour segment The traditional flavour segment is characterised by a high flavour intensity, high levels of acetaldehyde and low ph: < 4,0 after 28 days of shelf life. The presence of acetaldehyde is associated with a typical yoghurt flavour. This flavour profile can be applied in set, stirred and drinking yoghurt types. Most typically in high dry matter and high fat content yoghurt, like Greek, Turkish and Bulgarian yoghurt. Table 2. Ceska -star range for yoghurt with traditional flavour profile Y 200 St/Lb high high high Y 700 St/Lb high low high Y 800 St/Lb high low high Y 900 St/Lb high medium high * St = Streptococcus thermophilus; La = Lactobacillus acidophilus; Bl = Bifidobacterium lactis; Lb = Lactobacillus delbrueckii subsp. bulgaricus 02
The semi-mild segment The semi-mild flavour segment is characterised by a milder flavour profile compared to the traditional flavour segment. The final ph after 28 days of shelf life is 4,0 < ph < 4,25. Table 3. Ceska -star range for yoghurt with semi-mild flavour profile Code Species* Postacidification Viscosity Flavour Y 103 St/Lb low medium medium medium Y 104 St/Lb low medium medium high medium Y 106 St/Lb medium high medium high Y 107 St/Lb low medium high medium Y 111 St/Lb low medium medium high medium Y 118 St/Lb low medium high medium Y 126 St/Lb medium very high medium high Y 128 St/Lb low medium medium high medium Y 501 St/Lb low medium low medium The mild segment This mild flavour segment is an emerging segment within the yoghurt market. Therefore, CSK has developed a range with different viscosities and structures with a very low postacidification (ph > 4,3 after 28 days of shelf life.) The segment with Bifidobacterium lactis and/or Lactobacillus acidophilus CSK can blend different cultures with strains, like Bifidobacterium lactis and/or Lactobacillus acidophilus. Mild products can also be produced in this way. Table 5. Ceska -star range with Bifido bacteria and/or Lactobacillus acidophilus B 100 Bl - - - B 190 St/La/Bl very low high low B 191 St/La/Bl low high low B 192 St/La/Bl/Lb low high medium B 193 St/La/Bl/Lb very low high low B 194 St/La/Bl very low very high low Table 6. Ceska -star range containing Lactobacillus acidophilus A 900 La - - - A 909 St/Lb/La medium high medium medium high A 922 St/Lb/la medium high high medium high A 940 St/La medium medium medium Table 4. Ceska -star range for yoghurt with mild flavour profile Y 318 St/Lb low high low medium Y 508 St/Lb low high low Y 510 St/Lb low high low Y 518 St/Lb low high low The Ceska -star yoghurt cultures can be classified with respect to their flavour intensity/post-acidification and viscosity contribution as specified in figure 1. Figure 1. Performance of Ceska - star yoghurt range Y508 Viscosity Post-acidifi cation aroma intensity 03
Classification and production of yoghurt products Liquid milk Concentrated milk Dairy powders Many different types of yoghurt are produced, which are classified into different categories based on following characteristics: physical characteristics (set, stirred or drinking yoghurt); flavour (natural, fruit or flavoured); fat content (full, semi- or low-fat). The manufacturing stages of milk for producing the mentioned yoghurt products have many similarities. In figure 2 the flow diagram of the different production stages is shown. Production set yoghurt For set yoghurt the acidification and coagulation of the processed milk takes place in the consumer packaging. The coagulum is not broken until it is consumed and therefore the gel firmness is an essential aspect for set yoghurt. For the production of set yoghurt (natural, fruit or flavoured) the manufacturing scheme is shown in figure 3. The processed milk base is cooled to 40-45 C, short set, or 35-37 C, long set. The milk is inoculated with starter culture and optional fruit, sugar, flavour or colouring agents are added. The processed milk is filled into retail packaging and incubated to the required ph. At 42 C the acidification Reception and storage Standardization, fortification and addition of other ingredients Homogenization Heat treatment Cooling Production of different types of yoghurt Figure 2. Overview of different production stages of milk time to reach ph 4.5-4.7 will usually be 4-6 hours. Lower fermentation temperatures gives longer fermentation time and higher viscosity. There are two possible routes for handling set yoghurt after fermentation stage. The first route is that the packaging is removed from the incubator, passed through a blast chiller to cool the yoghurt in a few minutes and then stored at 2 C until dispatch. The second route is that the product is cooled slowly in the refrigerated storage room at 6 C. When the second method is applied, the yoghurt is removed from the incubation cabinets at a higher ph to compensate for slower cooling and realise the desired final ph. Addition of starter culture Processed milk Set yoghurt Stirred yoghurt Fruit/Natural/Flavored Fruit Natural Flavored Add fruit to retail container Mi flavor and coloring matter Incubate in bulk tanks Pack processed milk in retail container Cool to 20-25 C (68-77 F) Incubate in retail container Fruit Set yoghurt Natural Flavored Mi fruit Mi flavor and coloring matter Chilling and/or cooling Packaging Cold storage and dispatch Figure 3. Production stages for set and stirred yoghurt 04
Production stirred yoghurt Stirred yoghurt is produced in insulated tanks and the manufacturing stages as shown in figure 3. The incubation temperatures are similar to set yoghurt. At 42 C the acidification till ph 4.4-4.5 is normally between 4-6 hours. At the required ph, the teture is broken by gently stirring prior to being pumped to a cooler. The process of cooling may be carried out by using one-or two-phase cooling, which gives better viscosity of the final product. Partially cooling to 20-25 C in a plate or tubular heat echanger results in a low shear force on the yoghurt and a low pressure drop in the processing line. The pre-cooled yoghurt should be packed within 1 hour in order to maintain the desired quality of the product. The packed yoghurt is palletised and usually passed through a blast chiller to cool the yoghurt to 10 C. Subsequently it is transported to cold storage at 2 4 C. Sometimes cooling of the packed yoghurt starts during cold storage.the viscosity of the product recovers in the cold store within 48 hours. The yoghurt should be handled with care to ensure optimal recovery of teture during cooling. Functionality of yoghurt starter cultures Yoghurt starter culture consists of a blend of Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus species: Lactobacillus delbrueckii subsp. bulgaricus: Gram + bacillus responsible for acid production as well as for the production of the typical yoghurt aroma ( acetaldehyde); Streptococcus thermophilus: Gram + coccus, which grows fast in milk. It produces lactic acid and small quantities of formic acid, which promotes the outgrowth of Lactobacillus delbrueckii subsp. bulgaricus. On the other hand Lactobacillus delbrueckii subsp. bulgaricus species produce amino acids to stimulate the growth of the cocci. Production drinking yoghurt Drinking yoghurt can be categorised as stirred yoghurt with low viscosity. Therefore, cultures are used which give low viscosity. The fermentation should proceed until the ph reaches 4.4-4.2 in order to obtain the best stability. After fermentation, the coagulum of drinking yoghurt is broken down. This treatment is carried out to assure a homogenous product with no gel lumps. Various methods can be applied to break the coagulum after the acidification: agitation at high speed; pumping from tank to cooler with a centrifugal pump; homogenisation. To keep the viscosity of drinking yoghurt low, the product is cooled till < 20 C. Ad the same time different kind of flavours can be added. After the addition of these ingredients the yoghurt mi is agitated slowly before further treatment and packaging. Production of long shelf life yoghurt drinks Long shelf life yoghurt drinks are also fermented with a culture which give al low viscosity. In contradictory to fresh products stabilisers and sugar are added after the fermentation. The most applicable stabiliser is pectin. To reach a longer shelf life the yoghurt is thermised and eventually also ascepticly homogenised. Figure 4. Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus Interaction between the two species influence the yoghurt quality. In figure 5 the interaction between them is shown. Formic acid Carbonic acid <4 mg O 2 /kg fast Streptococcus thermophilus Amino acids and small peptides from casein Lactobacillus delbrueckii subsp. bulgaricus Figure 5. Symbiosis between Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus Fermentation process During the incubation period, colloidal calcium dissociates from the casein micelle to the aqueous phase as the ph drops. Gradually micellar disintegration occurs below ph 5.2. The casein aggregate to form structures with empty spaces between them. It is critical that the milk gel should not be disturbed when such interactions between the micelles takes place at ph 4.8-5.2. These particles are larger in size compared to the native micelles. Finally, 05
rearrangement and aggregation of casein particles occurs at around ph 4.5 leading to the formation of the protein matri of yoghurt consisting of micellar chains and clusters. Other metabolites produced by the starter culture during the same period include eopolysaccharides (EPS), folic acid and certain vitamins. Post-acidification Cooling of the product below 7 C reduces the metabolic activity of the starter culture. However, even at low temperature, acid development can occur during shelf life. In table 7 the acidification time of the Ceska -star yoghurt cultures are shown in relation to the level of post-acidification and ph after 28 days of shelf life Product description Deep frozen dairy cultures are suitable for direct inoculation of the milk (DVI). The Ceska -star pellets are highly concentrated frozen cultures in pellet form. This offers our customer a number of advantages: no risk of bacteriophage contamination with bulk starter production; easy application; high fleibility. Defined strains or mied strains can be delivered separately or mied, specially formulated for the specific application. DVI cultures are available in gable-top packs. The contents of the pack depends on the type of culture and application. Dosage The recommended dosage is epressed in units. The number of units per pack is indicated on the packaging. The recommended dosage is 1 unit per 10 litres of milk. Dosage depends on the application, the process conditions and the desired result. Table 7. Acidification time in relation to level of post-acidification and ph after 28 days of shelf life Ceska - star cultures Acidification time* Postacidification ph after 28days at 7 C Y 200 4,5-5,0 h high 0,50 Y 700 4,0-4,5 h high 0,50 Y 800 4,5-5,0 h high 0,50 Y 900 4,5-5,0 h high 0,50 Y 103 5,0-5,5 h low medium 0,35 Y 104 4,5-5,0 h low medium 0,35 Y 106 4,5-5,0 h medium 0,40 Y 107 4,5-5,0 h low medium 0,30 Y 111 4,5-5,0 h low medium 0,35 Y 118 4,5-5,0 h low medium 0,30 Y 126 4,5-5,0 h medium 0,40 Y 128 4,5-5,0 h low medium 0,35 Y 501 6,5-7,5h low 0,25 Y 318 6,5-7,5 h low 0,20 Y 508 5,0-5,5 h low 0,25 Y 510 4,5-5,0 h low 0,25 Y 518 5,0-5,5 h low 0,25 B 190 8,0-10,0 h very low 0,20 B 191 5,0-6,0 h low 0,25 B 192 5,0-6,0 h low 0,25 B 193 8,0-10,0 h very low 0,20 B 194 8,0-10,0 h very low 0,20 A 909 5,0-6,0 h medium high 0,25 A 922 5,0-6,0 h medium high 0,35 A 940 4,0-4,5 h medium 0,30 * stirred yoghurt; pasteurised at 100 C for 30 min.; protein content 4,2%; fat content 1,0%; inoculation with 0,02% DVI; incubation at 42 C Consultancy Our consultants can provide you with further advice on the use of Ceska -star cultures for application in yoghurt products. They are pleased to cooperate with you to optimise your process, improve your product or to develop new products. 06
Ceska -star yoghurt culture range The functionality and composition of the Ceska -star yoghurt cultures are listed in the tables below. For selecting the right culture, please consult our technical eperts for customer specific advice. Application: stirred-type, set-type and Greek style yoghurt Ceska - star cultures Post-acidification Viscosity Aroma Packaging Contents Cultures for a traditional flavour profile Y 200 high high high gable top 125 units Y 700 high low high gable top 125 units Y 800 high low high gable top 125 units Y 900 high medium high gable top 125 units Cultures for a semi mild flavour profile Y 103 low medium medium medium gable top 250 units Y 104 low medium medium high medium gable top 75-250 units Y 106 medium high medium high gable top 125 units Y 107 low medium high medium gable top 250 units Y 111 low medium medium high medium gable top 250 units Y 118 low medium high medium gable top 125-250 units Y 126 medium very high medium high gable top 125 units Y 128 low medium medium high medium gable top 250 units Y 501 low medium low medium gable top 125 units Cultures for a mild flavour profile Y 318 low high low medium gable top 250 units Y 508 low high low gable top 250 units Y 510 low high low gable top 250 units Y 518 low high low gable top 250 units Application: yoghurt-like products containing Bifidobacterium and/or Lactobacillus acidophilus Thermophilic cultures for DVI application; St = Streptococcus thermophilus; La = Lactobacillus acidophilus; Lb = Lactobacillus delbrueckii subsp. bulgaricus; Bl = Bifidobacterium lactis. Ceska - star cultures Species Post-acidification Viscosity Aroma Packaging Contents B 100 Bl - - - gable top 300 units B 190 St/La/Bl very low high low gable top 200, 500 units B 191 St/La/BI low high low gable top 500 units B 192 St/Lb/La/BI low high medium gable top 500 units B 193 St/La/Bi/Lb very low high low gable top 250 units B 194 St/La/Bl very low very high low gable top 250 units A 900 La - - - gable top 500 units A 909 St/Lb/La medium high medium medium high gable top 250 units A 922 St/Lb/La medium high high medium high gable top 800, 1200 units A 940 St/La medium medium medium gable top 250 units This publication is solely intended for information purposes. CSK food enrichment cannot be held liable for the contents. This specifically applies in cases where its products are used in violation with prevailing legislation and rules and/or licenses. 07