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Fermented Sausages “Scientists as Teachers, Teachers as Scientists” Fellowship Erin Graham and Guy Amoroso W.B. Saul High School of Agricultural Sciences. Two Major Types. Semi-dry Quickly fermented Cervelats, metwursts Bolognas (U.S.) Dry Slow fermentation Salami, pepperoni
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Fermented Sausages“Scientists as Teachers, Teachers as Scientists” FellowshipErin Graham and Guy AmorosoW.B. Saul High School of Agricultural Sciences
Two Major Types • Semi-dry • Quickly fermented • Cervelats, metwursts • Bolognas (U.S.) • Dry • Slow fermentation • Salami, pepperoni • Both types include soft and hard
Semi-dry characteristics • Tangy flavor • Water >35% • pH 4.8 - 5.4 • Spreadable or able to be sliced • Often smoked at lower temperatures • Usually contain beef
Dry Characteristics • Longer curing time (up to 90 days) • pH 5 – 5.5 • Water content < 35% • When in larger casings (>4.5 cm) called salami • Pork or beef • Fermentation AND biochemical changes over the long curing add to sensory qualities
Fermented sausage preparation • Raw meat in casings is allowed to sit without refrigeration • Bacteria perform lactic acid fermentation using sugars in the meat • Sugar is added to speed acidification • Acidification of the meat adds to sensory qualities • Gives tangy taste • Nonpathogenic microorganisms in the meat prevent pathogenic organisms from growing
Organisms that Ferment • Lactic Acid Bacteria (LAB) • Gram-positive, catalase-positive cocci (GCC) • Molds • Yeast Lactobacillus sp. Penicillium chrysogenum Pediococcus sp. Yeast
Lactic Acid Fermentation • One molecule of sugar is converted to lactic acid • Sugar is first split into 2 molecules pyruvate in glycolysis • Fermentation proceeds in the absence of oxygen What process happens if oxygen is present?
Starter Cultures • Mixture of bacteria added to immediately start fermentation • Quicker than waiting for “house flora” to develop • Used in quick fermenting (semi-dry) products • Used by large manufacturers • Often considered inferior to “spontaneous fermentation” • Improves safety and quality of product
Methods • Mix the contents for each beaker and pack into the paper cups • Label each cup • Measure pH of each mixture • Incubate cups at 37o C for two days • Examine the contents of each cup- color, texture, and pH