Cultured Dairy Foods

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Cultured Dairy Foods
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Cultured Dairy Products

• Bovine milk suitable for microbial fermentation
• contains 5 lactose, 3.3 protein, pH6.6-6.7,
  aw1.0

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Cultured Dairy Products

• Evolved on every continent
• Easy to produce, good shelf-lives, free of
  harmful substances, pleasant sensory appeal
• Yogurt like products
• Dahi (india), Jaban (Egypt, Lebanon), Jugar
  (turkey)
• Kefir and koumiss-made with lactose-fermenting
  yeasts in addition to lactic acid bacteria
• Contain alcohol

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Consumption of Cultured Dairy Products

• Most popular cultured dairy products in the US
• Yogurt gt50 of all cultured dairy products
  (mostly non-fat or low fat)
• Sour cream (and sour cream-based dips)
  increasing
• Cultured buttermilk decreasing
• US consumption much less than EU
• Catch on new trends

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Probiotics and Prebiotics

• Probiotics
• Live microbes which when administered in adequate
  amounts confer a health benefit on the host (WHO)
• Live and sufficient amount
• Health benefit beyond GI tract
• Suggested health benefits
• Reduce blood cholesterol
• Maintain intestinal health
• Alleviate intestinal bowel diseases
• Modulate immune system
• Reduce incidence of GI infections
• Reduce incidence of urinary and vaginal
  infections
• Alleviate lactose intolerance
• Anti-cancinogenic and anti-tumorogenic
• Reduce incidence and severity of diarrheal
  diseases

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Probiotics and Prebiotics

• Prebiotics
• Non-digestible food ingredients that beneficially
  affects the host by selectively stimulating the
  growth and/or activity of one or a limited number
  of bacteria in the colon, and then improves host
  health (Gilbson and Roberfroid, 1995)
• Polysaccharides or oligosaccharides (Fig 1)
• FOS (fructooligosaccharides)
• GOS (galactooligosaccharides)
• Resemble the oligosaccharides found in human milk
• May promote the growth of bifidobacteria in
  nursed infants

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Common probiotics

• As culture adjunct intend to promote health,
  instead of fermentation
• Lactobacillus acidophilus-80 yogurt in the US
• Bifidobacterium
• Both in yogurt and other cultured and
  non-cultured dairy products
• Some strains also involved in fermentation
• Yakult-Japanese product made using a human GI
  isolate of Lb. casei (strain Shirota)
• Cultura-a European bioyogurt made with a human
  isolate of Lb. casei F19
• Unfermented products as carriers of probiotics
• Sweet Acidophilus Milk
• Table 4.2

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Fermentation Principles

• Milk and LAB culture (Table 4.3)
• Cultured versus directly set
• Functions
• Lactose
• Precipitate casein (pH4.6)
• Flavor compounds
• Syneresis
• Separation of water from the coagulated milk
• Considered unfavorable to reduce,
• Increase milk solids
• heat well above pateurization temp to denature
  whey proteins
• Incorporate stabilizers
• Using strains produce exopolysaccharide
• Ropy strain-EPS released or dis-attached
• EPS remains attached to the cells surface

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Yogurt Cultures

• S. thermophilus and Lb. delbrueckii subsp.
  bulgaricus
• 11 ratio
• Synergistic growth
• S. thermophilus growth first, use free aa and
  small peptides in milk, lower pH etc, preferred
  environment for Lb. delbrueckii subsp. bulgaricus
• Lb. delbrueckii subsp. bulgaricus proteolysis
  helps S. thermophilus to grow
• Lb. delbrueckii subsp. bulgaricus produce more
  acid, S. thermophilus will decrease
• So the cultures are grown separately, harvested
  and mixed

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Frozen Yogurt and Other Yogurt Products

• Frozen yogurt
• No federal standard of identify
• Some states have their own definitions
• Marketing purpose
• Minnesota definition
• Frozen dairy products made from a mix containing
  safe and suitable ingredients including, but not
  limited to, milk products. All or a part of the
  milk products must be cultured with a
  characterizing live bacterial culture that
  contains the lactic acid producing bacteria
  Lactobacillus bulgaricus and Streptococcus
  thermophilus and may contain other lactic acid
  producing bacteria.
• Some stated require minimum acidity, ranging from
  0.3 to 0.5

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Cultured Buttermilk

• Buttermilk is the fluid remaining after cream is
  churned into butter
• Thin, watery liquid
• Rich in phospholipids
• Rarely consumed as a fluid drink, but good source
  of natural emulsifiers
• Typically spray dried and used as an ingredient
  in processed food products
• Cultured buttermilk
• Skim or low-fat milk fermented by suitable LAB
• Butter granules or flakes are occasionally added
  to provide butter flavor and mouth feel

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Cultured Buttermilk Manufacture

• Fig. 4-5
• Milk
• Heat
• Cool and inoculate mesophilic starter culture
• Cultures
• Acid producing flavor producing 51
• Acid producer homolactic L. lactis subsp. lactis
  or cremoris
• Flovor producer L. lactis diacetylactis,
  Leuconostoc mesenteroides subsp. cremoris, or
  Leuc. lactis (hetero)
• Citrate fermentation

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Sour Cream

• Same culture used for cultured buttermilk
• Use cream instead of milk
• Cream pasteurized but not extend as for
  buttermilk or yogurt
• Cream homogenized
• Starting material in the US 18-20 cream, or low
  fat version (10)
• Fig 4-7

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Kefir

• One of the most popular cultured dairy products
  in Middle East, Eastern Europe and Central Asia
• Kefir grain added as insoluble particles
• Retrieved after fermentation by filtration
• LAB and yeast
• Contain as much as 2 ethanol
• US has to be lower or non-ethanol producers
• Fig 4-8, Table 1