Year: 1977
Type: article
Abstract: The secretion of pregastric esterase and other oral lipases has been detected in 13 species.Research on secretion by the human, calf, kid goat, lamb, and rat of pregastric esterase has been significant.Secretion by calves is little affected by age or diet but is greater when calves are nipple fed than when pail fed.Whole milk sham-fed to calves exhibits immediate, sharp decreases in pH and rennet coagulation time resulting from liberation of free fatty acids by pregastric esterase.Bacterial counts in sham-fed products are higher than in control (nonfed)products, but during subsequent incubation bacterial numbers increase less rapidly in sham-fed proudcts.Calf pregastric esterase is a major fat digestive enzyme in young calves but gradually becomes subsidiary to pancreatic lipase as secretion of the latter develops with age.Calf, kid goat, and lamb pregastric esterase exhibits optimum activity on milk fat but is capable of splitting other dietary fats.Data on oral and "gastric" lipases in calves, humans, and rats suggests that gastric lipase is oral lipase.Data on pH and temperature optima as well as activation and inhibition of oral tipases is contradictory but appears to vary considerably between species.Calf pregastric esterase exhibits a unique specificity for fatty acids 4:0 to 10:0 and preferentially hydrolyzes the primary ester position of glycerin.Preparations of calf, kid goat, and lamb pregastric esterase are used commercially to impart typical flavors to Italian-type and Feta cheeses and to accelerate flavor development in other Received April 28, 1976.cheeses and cheese-like products.Butterfat modified by pregastric esterase is utilized to impart dairy flavor character to a wide range of processed foods.Treatment with pregastric esterase of calf scours and human malabsorption of syndrome also has been reported.330 NELSON El" AL.Farnham (25) was the first to identify the oral tissues in the calf which secrete PGE.A succession of publications by Wise et al. (129 to 133) and other investigators (20, 63, 90 to 93, 102 to 110, 119, 134, 135) reported on PGE secretion in calves, including relationships to age, diet, feeding method, and digestion of milk fat.This research established that PGE is the major enzyme responsible for digestion of milk fat in young calves.Ramsey (111) reviewed physiological research on PGE through 1967.Grosskopf (38) independently discovered PGE in calves, kid goats, and lambs and did extensive research on enzyme characteristics.The role of PGE in the digestion of fats from various sources by the calf has been reported by Siewert and Otterby (123 to 126), Hamilton and Raven (39, 40), and Gooden (36, 37).Hamosh et al. (41,42) has characterized lingual lipase in rats and pharyngeal lipase in humans.Numerous workers have described the specificity of PGE for short-chain fatty acids (FA 1 ).Although reports have been published, comprehensive information on PGE characteristics is lacking.Brockerhoff and Jensen (13) briefly reviewed both PGE and oral lipases.Farnham (25, 27) pioneered the commercial application of PGE.Harper et al. (43 to 48, 65, 66) published extensively on characteristics of calf, kid goat, and lamb PGE and their role in Italian-type cheese.Pregastric esterase plays a major role in controlled flavor production in foods.The two primary applications are in cheese and cheeselike products and modification of milk fat (butterfat).Anti (8) and Nelson (84) described the commercial application of PGE modified milk and butter fats.Arnold et al. (10) comprehensively reviewed commercial applications of lipolytic enzymes, including PGE, to flavor development in dairy and other food products.Two pharmaceutical applications, the treatment of "scours" or diarrhea in calves (17,28,77,78) and the treatment of malabsorption syndrome in humans (80), have been reported.This review assesses the occurrence, characteristics, physiological significance, and commercial applications of PGE and other oral lipases. SECRETORY SITES1 This manuscript utilizes the abbreviations FA and FFA for fatty acid(s) and free fatty acid(s).Individual fatty acids are denoted numerically by carbon chain length and number of unsaturated bonds; e.g.4:0 is butyric acid.Abbreviations MG, DG, and TG denote mono-, di-and tri-glycerides. Tissue and Saliva AssaysFarnham (25) was the first to identify the oral tissues from which PGE is secreted in calves, kid goats, and lambs.He described them as "that part of the pharyngeal region of mammals bounded in front by (a) the base of Journal of Dairy Science Vol.60, No. 3
Source: Journal of Dairy Science
Authors: J.H. Nelson, R.G. Jensen, R.E. Pitas
Institution: University of Connecticut
Language: English
Subfield: Biotechnology
Domain: Life Sciences
SDG: Zero hunger
Open Access status: hybrid
Estimated APC paid: $3,500
OpenAlex ID: W1973606846