Patent GB-1532783-A (GB)
Title: Edible thermoplastic moulding compositions containing starch and protein salts
IPC: A23L1/00
Filed: 1975-11-21
Abstract: 1532783 Edible packaging material SUMITOMO BAKELITE CO Ltd 21 Nov 1975 [22 Nov 1974 (4) 23 Dec 1974 28 Dec 1974 27 March 1975 (2) 16 April 1975 17 April 1975 22 July 1975] 48069/75 Heading A2B [Also in Division C3] An edible moulding composition for packaging human or animal food comprises water, a starch an alkali metal or alkaline earth metal of a protein, an edible hydrophilic organic plasticiser of molecular weight of not more than 1,000 and an edible lubricant wherein the weight ratio of starch to said protein salt is preferably 90:10 to 10:90. The starch may be selected from at least one of potato starch, cereal starch, pulse starch, edible root starch, high-amylose starch, high-amylopectin starch, or a corresponding 2-starch which may contain, preferably up to 10% by weight, of a modified starch selected from carboxymethyl starch, 2-hydroxyethyl starch, 3-hydroxypropyl starch, methyl starch, ethyl starch or starch phosphate. The protein salt is preferably a sodium, calcium or potassium salt of an animal protein, plant protein, or protein obtained from a microorganism (beer yeast, baker's yeast, tortula yeast, waste molasses yeast, single cell protein), edible plasticiser is preferably glycerol, ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, sorbital, sorbitan, mannital, maltital, hydrogenated starch syrup, sucrose and the lubricant is preferably mono, di or triesters of the above plasticisers with a fatty acid of at least 10 carbon atoms, a phosphoric acid derivative thereof, or lecithin and the compositions may also contain edible proteincoagulating agents (chloride, carbonate or phosphate of sodium, potassium or calcium, lactic acid, malic acid, citric acid, tartaric acid, acetic acid, butyric acid, maleic acid, fumaric acid, succinic acid, and the sodium, potassium or calcium salt thereof). The protein salt may be prepared in situ from the protein and an alkaline solution. The moulding composition is preferably in the form of powder, or granules, and may be subjected to compression-, transfer-, extrusion-, blow-, inflation- or injection moulding, vacuum-forming, pressure-forming or heat-sealing to yield a biodegradable article, preferably in the form of a sheet, film, tube or bottle. The watersolubility of the article may be decreased by subjection to ultra-violet radiation. In the Examples, the components used are carbohydrates, corn starch, potato starch, tapioca starch, wheat starch, dextrin, gum arabic, mannan, pectin, pullulan, 2-hydroxyethyl starch, carboxymethyl starch, starch phosphate, ethyl ether of corn starch, sodium alginate; proteins, sodium salt of casein, potassium salt of casein, sodium salt of gelatin, alkali metal salts of soybean casein, wheat gluten, corn zein or yeast, casein or gelatin/ sodium hydroxide or calcium hydroxide solution, casein/sodium carbonate solution, dried yeast, beer yeast, sodium salt of yeast; plasticisers, glycerol, ethylene glycol, sorbital, maltital, mannital, hydrogenated starch syrup, propylene glycol, sorbitan, lubricants, lecithin, sucrose monostearate, glycerol monolaurate, sorbitol distearate, maltital monostearate, glycerol monostearate, sucrose distearate, glycerol trilaurate, mannital monolaurate, sodium cellulose glycollate: protein-coagulating agents, sodium chloride, potassium chloride, potassium phosphate, potassium carbonate, sodium phosphate, sodium carbonate, calcium hydroxide, calcium chloride, lactic acid, malic acid, citric acid, tartaric acid, acetic acid, butyric acid. The compositions are formed into films, and the films-subjected to ultraviolet radiation.