Active yeasts

21.02 - Yeasts (active or inactive); other single-celI micro-or anisms, dead (but not including vaccines of heading 30.02); prepared baking pow ers. 2 102.10 - Active yeasts - Inactive yeasts; other single-cell micro-organisms, dead 2 102.30 - Prepared baking powders 2102.20 (A) YEASTS The yeasts of this heading may be in the active or inactive state. Active yeasts enerally provoke fermentation. The consist essentially of certain micro-organisms $almost exclusively of the genus Sacc mmyees), which multiply durin alcoholic fermentation. Yeasts may also be produced by partial or total prevention o fermentation, according to the aeration process. X T The active yeasts include : (1) Brewery yeast. This forms in beer fermentation vats. It is resented as a yellowish-brown paste or solid generally with the bitter flavour of hops and e odour of beer. tR (2) Distillery yeast. This is produced during the fermentation, of, e-g., grain, potatoes or h i t , in distilleries. It is a firm cream-coloured paste varying in odour according to the product used in the distillation. (3) Bakers' east, produced by the propagation under special conditions of specially cultured strains o yeast in a carbohydrate medium such as molasses. It is general1 marketed in the form of pressed yellowish-gre cakes ( ressed yeast) which sometimes ave an alcoholic odour. It is, however, also mar eted in . t Re dried form (usually in grains) or as liquid yeast. P i E (4) Culture east, a ure strain of yeast prepared under laborato conditions. It may be suspende in distil ed water or in gelatin or agar-agar. It is usual y marketed in measured quantities put up in sealed containers to protect it from contamination. B I? (5) Seed yeast, produced from culture yeast by successive fermentation processes, is used to " seed" commercial yeast. It is usually marketed in the form of a moist pressed and plastic mass or in the form of a liquid suspension. Inactive yeasts, obtained by dryin , are enerally brewery, distillery or bakers' yeasts which have become insufficiently active fgor &er use m those mdustries. They an used for human consumption (source of w t m n B) or for feedin animals. It should, however, be noted that, owing to then growing importance, these drie yeasts are to an increasing extent being produced directly from specially prepared active yeasts. The heading also covers other types of dried yeasts e.g.,. Candida lipolytica or tropicalis, Candida maltosa) developed from the easts not be ongin to Saccharomyces. They are obtained by drying the yeasts which have een cultivated on su strates containing h drocarbons (such as gas-oils or n-paraffins or carbohydrates. These dried yeasts are p m c u arly rich in rotein and are used in animal eeding. They are commonly known as petroproteins or yeast gioproteins. g % p (B) OTJXER SINGLE-CELL MICRO-ORGANISMS, DEAD This cate ory covers single-cell micro-organisms such as bacteria and unicellular algae, which are not a7ive. Inter olia, covered here are those which have been obtained by cultivation on substrates containing hydrocarbons or carbon dioxide. These products are particularly rich in protein and are generally used in animal feeding. Certain roducts of this grou may be put up as food supplements for human consumption or animal eeding (e.g., in pow er or tablet form) and may contain small uantities of excipients, e.g., stabilisin agents and anti-oxidants. Such products remain classi led here provided that the addition o such ingredients does not alter their character as micro-organisms. ! H B (C) PREPARED BAKING POWDERS The " prepared baking owders " classified in this heading consist of mixtures of chemical products e.g., sodium icarbonate, tartaric acid, ammonium carbonate, phosphates), with or without a ded starch. Under suitable conditions they evolve carbon dioxide and are therefore used in baking for leavening dough. They are usually sold in retail packings (sachets, tins,etc.) under various names (baking powder, Alsatian leaven, etc.). The heading excludes, inter alia : a (a) Self-raising cereal flour, e-g., flour to which baking powder has been added (heading 11.01 or 11.02). (b) AutoIysed yeast (heading 21.06). (c) Cultures of micro-organisms (other than yeasts) and vaccines (heading 30.02). (d) Medicaments of heading 30.03, or 30.04. (e) Enzymes (amylases, pepsin, rennet, etc.) (heading 35.07).