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Add casein micelles stable in Ca; with produced LA and calf chymosin Ca sensitive micelles (gel) 6) Curd coagulation 7) Whey is drained; curd is compressed 8) Curd is cut into smaller pieces 9) Salted (further draw out whey via osmosis 10) Stored in cool room for 3-4 days (16°C; 16% RH) 11) Cured and ripened* for 60 days (2°C; 85% RH) *paraffin and vacuum packaging can be used to prevent mould by O2Curd: soft white substance formed after fermented & coagulating milk Matting: compressing curd pieces to form a rubbery slab Cheddaring: cutting matted curd into blocks, turning, and piling to further squeeze out whey Milling: cutting curd Pressing: compressing curds for curing Rennin/Chymosin: pure enzyme; commercial prep = rennet; from 4thstomach of cowAspects of cheese making resulting in preservation: moisture content and WA ↓, acidic conditions (enzyme/vinegar), LA bac microbial antagonism, antimicrobials, salt (limit AW; on certain MOs) Why is milk pasteurized before adding SC? to prevent competition between existing MOs in milk & the starter culture; pasteurization may affect the starter culture addedIn addition to SC, what is added to coagulate milk into curd? Rennet (a prep containing rennin & other compounds)How is whey removed from curd? LA bac produced LA from lactose to promote casein micelles to aggregate which promotes the removal of whey, also pressing matted curds helps Factors in cheese making: 1) Heat – cheese is cooked @ 38°C to accelerate LA production which promotes whey removal 2) Pressure – pressing curds to remove whey & matting 3) Salt – drawout whey, flavour, inhibit growth of proteolytic & lipolytic spoilage-causing MOs 4) Ripening – flavour Difference between cheeses: 1) Milk– (past or not); cow, goat, sheep 2) Method for curd formation (acid, enzyme or acid-heat coagulation) 3) SC 4) Time & temp of cooking 5) Washing & matting method 6) Pressure applied 7) Ripening 8) AcidityHard Cheeses: cheddarLA bac; swissLA AND propionic acid bac = CO2 holes, proline (sweet), propionic acid (nutty flav) *multiple starter used: heat tolerant Streptococcus thermophilus added as a SCSemi-soft Cheeses: blue veined cheese [COW: Blue cheese (US & Denmark), Stilton (England), Gorgonzola (Italy), SHEEP: Roquefort]mould ripened (Penicillium roquefortii); curd is needle-inoculated with mould (channels); distinct flavours due to action of lipase (forms free FA, aldehydes, ketones); sharp peppery odour & flavourSoft Cheeses: camembert & briemould ripened (Penicillium camembertii or Penicillium candimum); curds not pressed; sprayed w/ mist of mould spores; mould mycelia = “white velvet” surface; protease action = peptides (soft creamy text)Genetic engineering in cheeses: improves starter cultures (improced restistance to viruses, or improved enzyme activity), produces coagulating enzyme (rennet, chymosin, rennin) Recombinant chymosin: MOs engineered to produce chymosin or rennin; approved as food additive that may be used as food enzyme F&D Labelling Regulations Div 8: bacteria culture = 1+ species, mould culture = 1+ species, rennet = preparation containing