Yogurt (also spelled yogourt or yoghurt) is a semi-solid fermented milk product that originated centuries ago and has evolved from many traditional Eastern European (e.g., Turkish and Bulgarian) products. The word is from the Turkish Yogen, meaning thick. It's popularity has grown and is now consumed in most parts of the world. Although the consistency, flavour and aroma may vary from one region to another, the basic ingredients and manufacturing are essentially consistent:
Arla Foods, the Swedish dairy group, has launched two new flavour variants for its drinking yoghurt brand, Yoggi Yalla, one of its best-selling dairy products.
Yoggi Yalla was launched in 2001 in Sweden and has already garnered 73 per cent of the national market for drinking yoghurt, a sector which is growing quickly there.
"We know that consumers want new and interesting flavour combinations," said Madeleine Gössner, product manager from the marketing department of Arla's Swedish division. "This is precisely what the two new Yoggi Yalla products offer."
The two new varieties, raspberry-pomegranate-guarana and mango-kombucha, will help secure this position. Mango-kombucha combines the sweet taste of mango with the slightly bitter taste of kombucha, a type of tea which originally comes from China and Russia. Raspberry-pomegranate-guarana is in the same bitter-sweet category, with the guarana giving an added energy boost.
The latest addition to the drinking yoghurt range is just one of a number of developments at Arla in recent weeks. For example, the dairy company recently announced that it was to take on the organic milk market with a new publicity campaign which aims to increase sales of the product in the Danish market - a country where much of the organic milk output is sold simply as 'normal' milk.
The company has also announced that the new production line for its Gaio tagatose artificial sweetener will be tested this month with a view to delivering the first shipments of the sweetener in April. The sweetener is produced by Arla and its partner Nordzucker under licence from US group Spherix - which is taking legal action against the company for failing to begin production earlier.
Arla was granted the licence for tagatose production in 1996, and last year Spherix instituted arbitration proceedings against the company because of the delay in production. The US group has said it will seek damages from Arla if it believes that revenues have been lost as a result of the delay.
IngredientsAlthough milk of various animals has been used for yogurt production in various parts of the world, most of the industrialized yogurt production uses cow's milk. Whole milk, partially skimmed milk, skim milk or cream may be used. In order to ensure the development of the yogurt culture the following criteria for the raw milk must be met:
low bacteria count
free from antibiotics, sanitizing chemicals, mastitis milk, colostrum, and rancid milk
no contamination by bacteriophagesOther yogurt ingredients may include some or all of the following:Other Dairy Products: concentrated skim milk, nonfat dry milk, whey, lactose. These products are often used to increase the nonfat solids contentSweeteners: glucose or sucrose, high-intensity sweeteners (e.g. aspartame)Stabilizers: gelatin, carboxymethyl cellulose, locust bean gum, guar, alginates, carrageenans, whey protein concentrateFlavoursFruit Preparations: including natural and artificial flavouring, colour
Starter CultureThe starter culture for most yogurt production in North America is a symbiotic blend of Streptococcus thermophilus (ST) and Lactobacillus delbrueckii subsp. bulgaricus (LB). Although they can grow independently, the rate of acid production is much higher when used together than either of the two organisms grown individually. ST grows faster and produces both acid and carbon dioxide. The formate and carbon dioxide produced stimulates LB growth. On the other hand, the proteolytic activity of LB produces stimulatory peptides and amino acids for use by ST. These microorganisms are ultimately responsible for the formation of typical yogurt flavour and texture. The yogurt mixture coagulates during fermentation due to the drop in pH. The streptococci are responsible for the initial pH drop of the yogurt mix to approximately 5.0. The lactobacilli are responsible for a further decrease to pH 4.5. The following fermentation products contribute to flavour:
lactic acid
acetaldehyde
acetic acid
diacetyl
Manufacturing MethodThe milk is clarified and separated into cream and skim milk, then standardized with other dairy ingredients to achieve the desired fat and milk solids-not-fat content. The various ingredients are then blended together in a mix tank equipped with a powder funnel and an agitation system. The mixture is then pasteurized using a continuous plate heat exchanger for 30 min at 85° C or 10 min at 95° C. These heat treatments, which are much more severe than fluid milk pasteurization, are necessary to achieve the following:
produce a relatively sterile and conducive environment for the starter culture
denature and coagulate whey proteins to enhance the viscosity and textureThe mix is then homogenized using high pressures of 2000-2500 psi. Besides thoroughly mixing the stabilizers and other ingredients, homogenization also prevents creaming and wheying off during incubation and storage. Stability, consistency and body are enhanced by homogenization. Once the homogenized mix has cooled to an optimum growth temperature, the yogurt starter culture is added.
A ratio of 1:1, ST to LB, inoculation is added to the jacketed fermentation tank. A temperature of 43° C is maintained for 2-2.5 h under quiescent (no agitation) conditions. This temperature is a compromise between the optimums for the two micoorganisms (ST 39° C; LB 45° C). The titratable acidity is carefully monitored until the TA is 0.85 to 0.90% (pH 4.5). At this time the jacket is replaced with cool water and agitation begins, both of which stop the fermentation. The coagulated product is cooled to 5-22° C, depending on the product. Fruit and flavour may be incorporated at this time, then packaged. The product is now cooled and stored at refrigeration temperatures (5° C) to slow down the physical, chemical and microbiological degradation.
Yogurt ProductsThere are two types of plain yogurt:
Stirred style yogurt
Set style yogurt - The above description is essentially the manufacturing procedures for stirred style. In set style, the yogurt is packaged immediately after inoculation with the starter and is incubated in the packages.
Other yogurt products include:
Sweetened stirred style yogurt with fruit preparation
Fruit-on-the-bottom set style: - fruit mixture is layered at the bottom followed by inoculated yogurt, incubation occurs in the sealed cups
Soft-serve and Hard Pack frozen yogurt (see Frozen desserts section)
Probiotic yogourts: it has become quite common to add probiotic bacterial strains to yogourt (those with proven health-promoting benefits, in addition to ST and LB. These could include Lactobacillus acidophilus, Lactobacillus johnsoni, Lactobacilus casei, or Bifidobacterium spp. When probiotics are added, it has also become common to add ingredients known as prebiotics, such as inulin, which will, after digestion, aid in the growth of the probiotics in the colon. Inulin, for example, is a polymer of fructose (fructo-oligosaccharide) that is indigestible in the small intestine because we do not have sufficient enzymes to cleave the fructose bonds. However, in the colon, bacterial enzymes can easily release free fructose, which has been shown to positively affect the growth of the probiotic organisms.
Yogurt Beverages
Drinking yogurt is essentially stirred yogurt that has a sufficiently low total solids content to achieve a liquid or pourable consistency and which has undergone homogenization to further reduce the viscosity. Sweeteners, flavouring and colouring are invariably added. Heat treatment may be applied to extend the storage life. HTST pasteurization with aseptic processing will give a shelf life of several weeks at 2-4°C, while UHT processes with aseptic packaging will give a shelf life of several weeks at room temperature.
Other Fermented Milk Beverages
Cultured Buttermilk
This product was originally the fermented byproduct of butter manufacture, but today it is more common to produce cultured buttermilks from skim or whole milk. The culture most frequently used in Loctococcus lactis, perhaps also subsp. cremoris or diacetylactis. Milk is usually heated to 95°C and cooled to 20-25°C before the addition of the starter culture. Starter is added at 1-2% and the fermentation is allowed to proceed for 16-20 hours, to an acidity of 0.9% lactic acid. This product is frequently used as an ingredient in the baking industry, in addition to being packaged for sale in the retail trade.
Acidophilus milk
Acidophilus milk is a traditional milk fermented with Lactobacillus acidophilus (LA), which has been thought to have therapeutic benefits in the gastrointestinal tract. Skim or whole milk may be used. The milk is heated to high temperature, e.g., 95°C for 1 hour, to reduce the microbial load and favour the slow growing LA culture. Milk is inoculated at a level of 2-5% and incubated at 37°C until coagulated. Some acidophilus milk has an acidity as high as 1% lactic acid, but for therapeutic purposes 0.6-0.7% is more common.
Another variation has been the introduction of a sweet acidophilus milk, one in which the LA culture has been added but there has been no incubation. It is thought that the culture will reach the GI tract where its therapeutic effects will be realized, but the milk has no fermented qualities, thus delivering the benefits without the high acidity and flavour, considered undesirable by some people.
Sour Cream
Cultured cream usually has a fat content between 12-30%, depending on the required properties. The starter is similar to that used for cultured buttermilk. The cream after standardization is usually heated to 75-80°C and is homogenized at >13 MPa to improve the texture. Inoculation and fermentation conditions are also similar to those for cultured buttermilk, but the fermentation is stopped at an acidity of 0.6%.
Others
There are a great many other fermented dairy products, including kefir, koumiss, beverages based on bulgaricus or bifidus strains, labneh, and a host of others. Many of these have developed in regional areas and, depending on the starter organisms used, have various flavours, textures, and components from the fermentation process, such as gas or ethanol.
low bacteria count
free from antibiotics, sanitizing chemicals, mastitis milk, colostrum, and rancid milk
no contamination by bacteriophagesOther yogurt ingredients may include some or all of the following:Other Dairy Products: concentrated skim milk, nonfat dry milk, whey, lactose. These products are often used to increase the nonfat solids contentSweeteners: glucose or sucrose, high-intensity sweeteners (e.g. aspartame)Stabilizers: gelatin, carboxymethyl cellulose, locust bean gum, guar, alginates, carrageenans, whey protein concentrateFlavoursFruit Preparations: including natural and artificial flavouring, colour
Starter CultureThe starter culture for most yogurt production in North America is a symbiotic blend of Streptococcus thermophilus (ST) and Lactobacillus delbrueckii subsp. bulgaricus (LB). Although they can grow independently, the rate of acid production is much higher when used together than either of the two organisms grown individually. ST grows faster and produces both acid and carbon dioxide. The formate and carbon dioxide produced stimulates LB growth. On the other hand, the proteolytic activity of LB produces stimulatory peptides and amino acids for use by ST. These microorganisms are ultimately responsible for the formation of typical yogurt flavour and texture. The yogurt mixture coagulates during fermentation due to the drop in pH. The streptococci are responsible for the initial pH drop of the yogurt mix to approximately 5.0. The lactobacilli are responsible for a further decrease to pH 4.5. The following fermentation products contribute to flavour:
lactic acid
acetaldehyde
acetic acid
diacetyl
Manufacturing MethodThe milk is clarified and separated into cream and skim milk, then standardized with other dairy ingredients to achieve the desired fat and milk solids-not-fat content. The various ingredients are then blended together in a mix tank equipped with a powder funnel and an agitation system. The mixture is then pasteurized using a continuous plate heat exchanger for 30 min at 85° C or 10 min at 95° C. These heat treatments, which are much more severe than fluid milk pasteurization, are necessary to achieve the following:
produce a relatively sterile and conducive environment for the starter culture
denature and coagulate whey proteins to enhance the viscosity and textureThe mix is then homogenized using high pressures of 2000-2500 psi. Besides thoroughly mixing the stabilizers and other ingredients, homogenization also prevents creaming and wheying off during incubation and storage. Stability, consistency and body are enhanced by homogenization. Once the homogenized mix has cooled to an optimum growth temperature, the yogurt starter culture is added.
A ratio of 1:1, ST to LB, inoculation is added to the jacketed fermentation tank. A temperature of 43° C is maintained for 2-2.5 h under quiescent (no agitation) conditions. This temperature is a compromise between the optimums for the two micoorganisms (ST 39° C; LB 45° C). The titratable acidity is carefully monitored until the TA is 0.85 to 0.90% (pH 4.5). At this time the jacket is replaced with cool water and agitation begins, both of which stop the fermentation. The coagulated product is cooled to 5-22° C, depending on the product. Fruit and flavour may be incorporated at this time, then packaged. The product is now cooled and stored at refrigeration temperatures (5° C) to slow down the physical, chemical and microbiological degradation.
Yogurt ProductsThere are two types of plain yogurt:
Stirred style yogurt
Set style yogurt - The above description is essentially the manufacturing procedures for stirred style. In set style, the yogurt is packaged immediately after inoculation with the starter and is incubated in the packages.
Other yogurt products include:
Sweetened stirred style yogurt with fruit preparation
Fruit-on-the-bottom set style: - fruit mixture is layered at the bottom followed by inoculated yogurt, incubation occurs in the sealed cups
Soft-serve and Hard Pack frozen yogurt (see Frozen desserts section)
Probiotic yogourts: it has become quite common to add probiotic bacterial strains to yogourt (those with proven health-promoting benefits, in addition to ST and LB. These could include Lactobacillus acidophilus, Lactobacillus johnsoni, Lactobacilus casei, or Bifidobacterium spp. When probiotics are added, it has also become common to add ingredients known as prebiotics, such as inulin, which will, after digestion, aid in the growth of the probiotics in the colon. Inulin, for example, is a polymer of fructose (fructo-oligosaccharide) that is indigestible in the small intestine because we do not have sufficient enzymes to cleave the fructose bonds. However, in the colon, bacterial enzymes can easily release free fructose, which has been shown to positively affect the growth of the probiotic organisms.
Yogurt Beverages
Drinking yogurt is essentially stirred yogurt that has a sufficiently low total solids content to achieve a liquid or pourable consistency and which has undergone homogenization to further reduce the viscosity. Sweeteners, flavouring and colouring are invariably added. Heat treatment may be applied to extend the storage life. HTST pasteurization with aseptic processing will give a shelf life of several weeks at 2-4°C, while UHT processes with aseptic packaging will give a shelf life of several weeks at room temperature.
Other Fermented Milk Beverages
Cultured Buttermilk
This product was originally the fermented byproduct of butter manufacture, but today it is more common to produce cultured buttermilks from skim or whole milk. The culture most frequently used in Loctococcus lactis, perhaps also subsp. cremoris or diacetylactis. Milk is usually heated to 95°C and cooled to 20-25°C before the addition of the starter culture. Starter is added at 1-2% and the fermentation is allowed to proceed for 16-20 hours, to an acidity of 0.9% lactic acid. This product is frequently used as an ingredient in the baking industry, in addition to being packaged for sale in the retail trade.
Acidophilus milk
Acidophilus milk is a traditional milk fermented with Lactobacillus acidophilus (LA), which has been thought to have therapeutic benefits in the gastrointestinal tract. Skim or whole milk may be used. The milk is heated to high temperature, e.g., 95°C for 1 hour, to reduce the microbial load and favour the slow growing LA culture. Milk is inoculated at a level of 2-5% and incubated at 37°C until coagulated. Some acidophilus milk has an acidity as high as 1% lactic acid, but for therapeutic purposes 0.6-0.7% is more common.
Another variation has been the introduction of a sweet acidophilus milk, one in which the LA culture has been added but there has been no incubation. It is thought that the culture will reach the GI tract where its therapeutic effects will be realized, but the milk has no fermented qualities, thus delivering the benefits without the high acidity and flavour, considered undesirable by some people.
Sour Cream
Cultured cream usually has a fat content between 12-30%, depending on the required properties. The starter is similar to that used for cultured buttermilk. The cream after standardization is usually heated to 75-80°C and is homogenized at >13 MPa to improve the texture. Inoculation and fermentation conditions are also similar to those for cultured buttermilk, but the fermentation is stopped at an acidity of 0.6%.
Others
There are a great many other fermented dairy products, including kefir, koumiss, beverages based on bulgaricus or bifidus strains, labneh, and a host of others. Many of these have developed in regional areas and, depending on the starter organisms used, have various flavours, textures, and components from the fermentation process, such as gas or ethanol.
Sales of drinking yoghurt are showing signs of a struggle as growth slowed down in Europe at the end of last year, according to a new market report.
Out of the 29 packaged food categories tracked by US-based research firm Sanford C. Bernstein, it said 22 saw positive sales growth.
However, the slowest growing category was drinking yoghurt, which was down nine per cent, followed by gum which dropped seven per cent, according to the report called “European Food: Sales growth and share gains” for December 2008.
The figures add weight to analysts’ predictions that despite rapid growth in sales volumes and value over recent years, manufacturers of yoghurt drinks are set to face some difficulties.
Meanwhile the strongest category was sauces which increased 12.9 per cent, followed by margarine which was up 10.5 per cent and salty snacks increased 7.5 per cent.
The monthly report from Bernstein covers France, Germany, Italy, Spain and UK – the top five markets in Europe which make up an estimated 70-75 per cent of all European sales.
The figures are based on sales growth and share trends in the region for the top categories of four major companies - Cadbury, Danone, Nestlé and Unilever – covering four weeks up to January 4th.
The report said that Danone, a major player in the drinking yoghurt category, “saw a marked deterioration in growth in the period to -2.1 per cent from 3.9 per cent in the last period”.
Growth was particularly weak in bottled water (-9.8 per cent) and drinking yoghurt (-8 per cent).
But the report said Danone’s this was attributable to weak growth in its categories as the company actually gained market share in drinking yoghurt, yoghurt and baby formula.
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Market view
In 2008, 310 new drinking yoghurt or liquid culture milk-based beverage products were launched in Europe, according to figures from analyst Mintel in November.
It said that in the UK for example, sales surged between 2002 and 2005 when yoghurt drink value climbed by £183m to £268m, but the retail value was estimated to have fallen to £245m in 2007.
Mintel added that 90 per cent of yoghurt drinks in the UK fell under the active health banner, which is confusing for consumers and a major factor setting back further development. However, it said there was still strong potential.
Confectionery and sauces
The Bernstein report said confectionery was mixed with good growth in chocolate (up 4.9 per cent), but negative growth in sugar (-0.3 per cent) and gum (-7 per cent).
Cadbury’s performance echoed this with positive chocolate growing 2.6 per cent) and sugar confectionery up one per cent, but gum was down 6.2 per cent.
Meanwhile Nestlé’s growth decelerated to -1.8 per cent, while the strongest growth came from sauces, which was up 7.2 per cent.
Unilever’s growth was “flat” but growth was strong in bouillon (up12.3 per cent) and mayonnaise (up 11.4 per cent).
Overall it said that packaged food in Western Europe was growing by about two to four per cent.
However, there was a mild deceleration to 2.4 per cent from 3.1 per cent
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