Benders'dictionary of nutrition and food technology

390Pronutro TM Protein-rich baby food (22% protein) developed inSouth Africa; made from maize, skim-milk powder, groundnutflour, soya flour and fish protein concentrate with addedvitamins.proof spirit An old method of describing the alcohol content ofspirits; originally defined as a solution of alcohol of such strengththat it will ignite when mixed with gunpowder. Proof spirit contains57.07% alcohol by volume or 49.24% by weight in GreatBritain. In the USA it contains 50% alcohol by volume. Pure(absolute) alcohol is 175.25 ° proof UK or 200 ° proof USA.Spirits were described as under or over proof; a drink 30 ° overproof contains as much alcohol as 130 volumes of proof spirit;30 ° under proof means that 100 volumes contains as muchalcohol as 70 volumes of proof spirit. Nowadays alcohol contentis usually measured as per cent alcohol by volume.pro-opiomelanocortin (POMC) Peptide hormone precursor thatis normally modified by carboxypeptidase e. POMC neuronsin the central nervous system mediate feeding behaviour andinsulin levels, and peptides derived from POMC are ligands forthe hypothalamic melanocortin receptor, which inhibits feedingbehaviour. See also agouti mouse; fat mouse.propanetheline See atropine.propellant Gas used to expel a product from a container.propionates Salts of propionic acid, CH 3 CH 2 COOH, a normalmetabolic intermediate.The free acid and salts are used as mouldinhibitors, e.g. on cheese surfaces; to inhibit rope in bread andbaked goods (E-280–283).propolis Waxy substance produced by bees, used to seal the hive;has antioxidant and antibacterial activities, and sold as a nutritionalsupplement, with little evidence of efficacy.propyl gallate An antioxidant,E-310.Prosparol TM An emulsion containing 50% vegetable fat, 1.7 MJ(405 kcal)/100 g; used as a concentrated source of energy.prostaglandins Locally acting hormones (paracrine agents)synthesised from long-chain polyunsaturated fatty acids; seeeicosanoids.prosthetic group Non-protein part of an enzyme molecule, unlikea coenzyme, covalently bound to the protein; either an organiccompound or a metal ion. Essential for catalytic activity. Theenzyme protein without its prosthetic group is the apo-enzymeand is catalytically inactive.With the prosthetic group, it is knownas the holo-enzyme.See also coenzyme; enzyme activation assays.protamines Small water-soluble proteins found especially insperm, rich in basic amino acids, especially arginine, and not