15 - Microbes in food and beverage production., microbes as cell factories, food spoilage

Which bacteria reduces pH of milk?

Lactobacilli / lactic acid bacteria

What does rennet do?

remove surface glycopeptides from soluble casein micelles in milk

What condition does rennet work best in?

Acidic

How is rennet (traditionally) obtained?

Extract from calve stomach

Treating casein:

Remove charge peptide side chain from kappa casein / allowing particle coagulation in presence of Ca

How is rennet obtain in modern times?

using recombinant calf chymosin from aspergillus niger

Ales:

top fermenter / yeast rise to surface

Lagers:

Bottom fermenter / yeast settle at bottom

2 component for ale/lager flavour development:

Ester / fusel alcohol

Production of citric acid

Produce from TCA cycle / induce under low Mn / Fe condition

What increases viscosity in gut?

High content of arabinoglucans