{"id":631,"date":"1984-04-22T09:43:30","date_gmt":"1984-04-22T14:43:30","guid":{"rendered":"https:\/\/secure.compusense.com\/?p=631"},"modified":"2018-02-22T09:49:03","modified_gmt":"2018-02-22T14:49:03","slug":"chicken-pepsin-as-a-rennet-substitute","status":"publish","type":"post","link":"https:\/\/secure.compusense.com\/research\/chicken-pepsin-as-a-rennet-substitute\/","title":{"rendered":"Chicken pepsin as a rennet substitute"},"content":{"rendered":"
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\"\"Semi-purified chicken pepsin was prepared from proventriculae at a yield of 33% of the original pepsin activity using a procedure based on the method described by Bohak (1970)<\/a>. Cheddar cheese was produced using the chicken pepsin preparation, and with calf rennet as a control, in two trials. The enzymes were standardized to the same milk-clotting strength on Berridge’s substrate at ca pH 6.3; the setting times were a little more than twice as long as calf rennet. While the composition and yield of cheese from the two<\/p>\n

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enzymes were not significantly different (P\u00a0<\u00a00.05), observed moisture was higher (1.9%) and moisture-adjusted yields lower (2%) with chicken pepsin. Cheeses were stored under refrigeration and analysed 3, 6, and 9 months after production. Sensory analysis of pepsin cheese demonstrated the development of bitterness between 3 and 6 months as compared to immediate bitterness found in a previous study. This change was paralleled by increases in acid soluble nitrogen and in stress relaxation, a textural parameter measured by the Instron apparatus. Scanning electron micrographs of the 9 month cheese revealed a breakdown in the matrix of the chicken pepsin cheese compared to the control. It would appear that this level of purity of chicken pepsin might be capable of producing acceptable Cheddar cheese for applications that do not require aging of more than 3 months and use heat to inactivate the enzyme, such as processed cheese spread. Further purification may improve the specificity of the enzyme and reduce delayed proteolysis but would increase its cost concomitantly.<\/p>\n<\/div>\n<\/div>\n

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\u00c0 partir d’une proc\u00e9dure bas\u00e9e sur la m\u00e9thode d\u00e9crite par Bohar (1970), on a extrait du proventricule de poulet une pepsine semi-purifi\u00e9e correspondant \u00e0 un rendement de 33% de l’activit\u00e9 de pepsine originale. La pepsine de poulet a \u00e9t\u00e9 utilis\u00e9e dans la production de fromage cheddar, avec la pr\u00e9sure de veau comme t\u00e9moin, dans deux essais. Les enzymes furent standardiz\u00e9es \u00e0 la m\u00eame force de coagulation du lait sur substrat de Berridge, au pH 6.3; les temps de coagulation furent un peu plus que deux fois plus longs que dans le cas de la pr\u00e9sure de veau. La composition et le rendement des fromages ne furent pas affect\u00e9s significativement (P \u2264 0.05) par le choix de l’enzyme, mais dans le cas de la pepsine de poulet, la teneur en humidit\u00e9 du fromage \u00e9tait plus \u00e9lev\u00e9e (1.9%), et les rendements corrig\u00e9s pour l’humidit\u00e9 furent plus faible (2%). Les fromages furent entrepos\u00e9s sous r\u00e9frig\u00e9ration et analys\u00e9s aux intervalles de 3, 6 et 9 mois. L’analyse sensorielle du fromage \u00e0 la pepsine a mis en \u00e9vidence le d\u00e9veloppement d’un go\u00fbt amer entre 3 et 6 mois, ceci diff\u00e8re d’une \u00e9tude ant\u00e9rieure dans laquelle l’amertume \u00e9tait \u00e9vidente d\u00e8s le d\u00e9but. Ce changement fut accompagn\u00e9 d’augmentation en azote soluble en milieu acide et en indice de relaxation de tension, un param\u00e8tre de la texture mesur\u00e9 \u00e0 l’aide de l’appareil Instron. Les micrographiques \u00e9lectroniques par balayage des fromages de 9 mois ont r\u00e9v\u00e9l\u00e9 une d\u00e9sagr\u00e9gation dans la matrice des fromages \u00e0 la pepsine par rapport au t\u00e9moin. Il semblerait que ce niveau de puret\u00e9 de la pepsine de poulet pourrait permettre la production de fromage cheddar acceptable pour des applications qui n’imposent pas une maturation exc\u00e9dant 3 mois et qui font appel \u00e0 la chaleur pour inactiver l’enzyme, comme dans le cas des fromages fondus. Une pepsine plus pure peut am\u00e9liorer la sp\u00e9cificit\u00e9 de l’enzyme et r\u00e9duire la prot\u00e9olyse tardive, mais le co\u00fbt en serait augment\u00e9 en cons\u00e9quence.<\/p>\n<\/div>\n<\/div>\n

Findlay, C. J., Stanley, D. W., & Emmons, D. B. (1984). Chicken pepsin as a rennet substitute. Canadian Institute of Food Science and Technology Journal-Journal de l\u2019Institut Canadien de Science et Technologie Alimentaires<\/em>, 17(2), 97-101. http:\/\/dx.doi.org\/10.1016\/S0315-5463(84)72363-7<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"

Semi-purified chicken pepsin was prepared from proventriculae at a yield of 33% of the original pepsin activity using a procedure based on the method described by Bohak (1970). Cheddar cheese was produced using the chicken pepsin preparation, and with calf rennet as a control, in two trials. The enzymes were standardized to the same milk-clotting strength on Berridge’s substrate at<\/p>\n

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