Hydrolysis Of Milk Fat Research Articles

Valorization of Chicken Viscera as Natural Raw Material Source: Application to Hydrolysis of Fatty Esters for Sewage Treatment.

"Chicken viscera" constitutes very abundant domestic wastes interestingly investigated in the present paper. The efficiency of this crude slaughter co-product of high protein component, as biocatalyst, for the hydrolysis of fatty acid esters was reported and that, without any pre-treatment. The crude chicken intestine powder (CIP) has shown a high reactivity for the hydrolysis of fatty esters. Two biocatalyst preparations were independently explored for the bioresolution of sec-phenyl alkyl carbinol esters: the CIP preparation and the crude chicken intestine acetone powder CIAP preparation. The last one has shown good catalytic activity during the bio-hydrolysis in biphasic medium. Furthermore, the direct hydrolysis of milk fat using CIAP (500mg) reveals the elimination of fats present in 50ml of treated milk. These results open up very interesting prospects for the use of this biowaste for the treatment of milk fat.

The effect of probiotic crops and lipolytic enzymes on the properties of dairy products in the cheese biotechnology under development

This article aims to evaluate the influence of probiotic microorganisms and pregastric lipase on organoleptic and biochemical characteristics of soft cheese made from a mixture of milk and buttermilk. The study was designed to determine how the temperature and exposure at this temperature affect the growth and development of lactose and bifidobacteria, as well as their quantity in the finished product. In order to increase the biological and nutritional value of the developed soft cheese, protein-carbohydrate raw materials rich in vitamins A, B12, D, E, phosphate and minerals were introduced into the production mixture. The addition of buttermilk increased the biological value of the product and improved its consistency. The taste and consistency of cheese was improved by a pregastric lipase preparation, widely used in the cheesemaking industry for production of various cheeses with high and low temperatures of the second heating. As a result of directed lipolysis, the finished product accumulates free fatty acids and diacylglycerols, acting as plasticizers and affecting the texture and organoleptic characteristics of the cheese. The results show that combining buttermilk and milk in an optimal ratio and addition of lipase produce a product with the best physicochemical parameters and a maximum evaluation of organoleptic characteristics. In the presence of a probiotic starter culture (provided there is a ready-made substrate), an active synthesis of enzymes necessary for the complete hydrolysis of milk fat begins. This all creates a functional product.

Synergistic action of Penicillium camemberti and Yarrowia lipolytica lipases in milk fat hydrolysis

Synergistic action of Penicillium camemberti and Yarrowia lipolytica lipases in milk fat hydrolysis

Investigating Enzyme Activity of Immobilized Candida rugosa Lipase

Candida rugosa lipase is a food-grade enzyme that is extensively utilized in the dairy processing industry for milk fat hydrolysis. The enzyme is mainly employed to modify the fatty acid chain length that results in the enhancement of flavors. The hydrolytic activities of C. rugosa lipase (fungal source) in its free and immobilized forms were investigated at different pH and temperature settings. The main objective of this study was to understand how different support materials (Celite-545, Sephadex G-25, and chitosan) and immobilization techniques alter lipase activity and stability. Our results indicated that hydrolytic activity increased significantly with immobilization on Celite-545. In general, immobilization resulted in considerable improvements in the stability of the enzyme with variations in pH and temperature. Immobilization on Celite-545 led to the highest catalytic efficiency. Remarkable improvements in the recovery and reusability of the immobilized lipases were noted. Comparatively, the acetone immobilization procedure resulted in higher activities than alcohol immobilization. In conclusion, the activity of C. rugosa lipase was enhanced most significantly when immobilized on Celite-545 using acetone as an adsorption solvent.

Metabolic engineering ofLactococcus lactisinfluence of the overproduction of lipase enzyme

The dairy industry uses lipase extensively for hydrolysis of milk fat. Lipase is used in the modification of the fatty acid chain length, to enhance the flavours of various chesses. Therefore finding the unlimited source of lipase is a concern of dairy industry. Due to the importance of lipase, this study was an attempt to express the lipase from Burkholderia cepacia in Lactococcus lactis. To achieve this, a gene associated with lipase transport was amplified and subcloned in inducible pNZ8148 vector, and subsequently transformed into Lc. lactis NZ9000. The enzyme assay as well as SDS-PAGE and western blotting were carried out to analysis the recombinant lipase expression. Nucleotide sequencing of the DNA insert from the clone revealed that the lipase activity corresponded to an open reading frame consisting of 1092 bp coding for a 37·5-kDa size protein. Blue colour colonies on nile blue sulphate agar and sharp band on 37·5-kD size on SDS-PAGE and western blotting results confirm the successful expression of lipase by Lc. lactis. The protein assay also showed high expression, approximately 152·2 μg/ml.h, of lipase by recombinant Lc. lactis. The results indicate that Lc. lactis has high potential to overproduce the recombinant lipase which can be used commercially for industrially purposes.

Enzymatic hydrolysis of conjugated linoleic acid-enriched anhydrous milk fat in supercritical carbon dioxide

Consumption of conjugated linoleic acid (CLA) has been associated with numerous health benefits. CLA in its free form can be obtained by enzymatic hydrolysis of milk fat. In this study, enzymatic hydrolysis of CLA-enriched anhydrous milk fat (AMF) using supercritical CO2 and Lipozyme TL IM were carried out to maximize the production of free fatty acids (FFAs). The effects of pressure (20–30MPa), fat:water ratio (1:5–1:30mol/mol) and their interaction in the FFA production were studied using response surface methodology. After performing the optimization, reactions at two different temperatures (45 and 65°C) and then with three different enzymes (Lipozyme RM IM, Novozyme 435, and immobilized enzyme from Candida rugosa) were carried out to assess the optimum FFA production. CLA content in its free form and major lipid classes (FFA, monoglycerides (MG), diglycerides (DG), and triglycerides (TG)) in the reaction products were quantified by gas chromatography. An increase in FFA and intermediate reaction products (MG and DG), together with a decrease in TG compared to the starting material was observed at all experimental conditions studied. The maximum level of FFA (86.79%, w/w) was achieved using Lipozyme TL IM at 23MPa, 1:5 fat:water ratio (mol/mol) and 55°C. The maximum CLA content in FFA form (6.81mg/gfat) was obtained using Lipozyme TL IM at 30MPa, 1:30 fat:water ratio (mol/mol) and 55°C that corresponds to 98% conversion of CLA in TG form to FFA form.

The effects of incorporating wild-type strains of Lactococcus lactis into Turkish white-brined cheese (Beyaz peynir) on the fatty acid and volatile content

The development of free fatty acids (FFA) and volatile flavour compounds in the Turkish white-brined cheese Beyaz peynir made by using three wild strains of Lactococcus lactis subsp. lactis was investigated over 90 days. Results showed that production of both FFA and flavour compounds in the control (PK1) and experimental cheeses (MBLL9, MBLL23 and MBL27) was strain dependent. The hydrolysis of milk fat was more evident in the cheese made using Lc. lactis subsp. lactis MBL27. Considering the production of fat breakdown compounds and acidification activities of the strains MBLL23 and MBL27, the combination of these strains could be proposed for the production of white-brined cheese.

Insuffisance pancréatique exocrine de l’enfant : diagnostic positif et étiologique

Lipid digestion is critical for infant development, and yet, the interconnection between lipid digestion and the microbiota is largely understudied. This review focuses on digestion of the human milk fat globule and summarizes the current understanding of the mechanisms underlying this process in infants. We first discuss the partial hydrolysis of milk fat in the stomach, which leads to rearrangement of lipid droplets, creating a lipid-water interface necessary for duodenal lipolysis. In the first few months of life, secretion of pancreatic triglyceride lipase, phospholipase A2, and bile salts is immature. The dominant lipases aiding fat digestion in the newborn small intestine are therefore pancreatic lipase-related protein 2 and bile salt–stimulated lipase from both the exocrine pancreas and milk. We summarize the interaction between ionic fatty acids and cations to form insoluble fatty acid soaps and how it is influenced by various factors, including cation availability, pH, and bile salt concentration, as well as saturation and chain length of fatty acids. We further argue that the formation of the soap complex does not contribute to lipid bioavailability. Next, the possible roles that the gut microbiota plays in lipid digestion and absorption are discussed. Finally, we provide a perspective on how the manufacturing process of infant formula and dairy products may alter the physical properties and structure of lipid droplets, thereby altering the rate of lipolysis.

Detection of lipase in skim and whole milk powders using triheptanoin as a substrate

As lipase catalysed hydrolysis of milk fat decreases the sensory quality of most dairy products, we developed an assay to measure lipase activity in skim and whole milk powders. Milk powder was incubated with triheptanoin at pH 6.0 for 7 days at 37 °C and the release of heptanoic acid was measured using headspace solid phase microextraction and gas chromatography mass spectrometry. The assay was applied to model samples containing milk powders spiked with commercial lipase preparations, and variables such as substrate amount and pH were optimised. Triheptanoin as a substrate was compared with both tributyrin and trioctanoin. Triheptanoin behaved in a manner similar to that of trioctanoin, but gave the analytical advantage of minimal interference from background levels of free fatty acids (FFAs). The response of the assay was linear over time and with enzyme concentration. The detection limit of the assay was calculated to be 0.05 nmol FFAs released min −1 g −1 powder.

Contribution of the products of fat hydrolysis to the frothing capacity of milk

The objective of this study was to determine the contribution of the products of lipolysis to milk foaming. Lauric acid and glycerol were added to skim and whole milk at 0.005, 0.010 and 0.015 M lauric acid and 0.011, 0.021 and 0.032 M glycerol. Monoglycerides were added to the milk at the rate of 0.1, 0.2 and 0.3% (m/v) instead of glycerol. Steam frothing value (SFV) of the milk was determined. Other milk samples were also stored for 15 days at 3 0.5 oC and SFV determined after 0, 5, 10 and 15 days. The mean SFV of whole and skim milk decreased on addition of 0.005 M lauric acid. Further increase in FFA did not significantly affect the SFV. The SFV of whole and skim milk decreased on addition of 0.1% monoglycerides. Further increase in monoglycride concentration did not significantly affect the SFV. Glycerol had no effect on the SFV. Storing milk for 15 days at 3oC slightly decrease the SFV of whole milk but increased the SFV of skim milk. This study indicates that monoglycerides and FFA affect milk frothing. Control of milk fat hydrolysis can be used to influence the foaming properties of milk products. Keywords : steam frothing value, fatty acids, monoglycerides, glycerol, foaming, skim milk, whole milk International Journal of Agricultural and Rural Development Vol. 5 2004: 114-120

Esterases of lactic acid bacteria and cheese flavour: Milk fat hydrolysis, alcoholysis and esterification

Free fatty acids (FFAs) and esters derived from FFAs are important flavour compounds in cheese. Evidence is provided that esterases of lactic acid bacteria (LAB) catalyse not only hydrolysis of milk fat glycerides to release FFAs, but also synthesis of esters from glycerides and alcohols via a transferase reaction. The esterases of LAB prefer di- and monoglycerides for both hydrolysis and ester synthesis and are, in fact, alcohol acyltransferases that use both water (hydrolysis) and alcohol (alcoholysis) as acyl acceptors. Therefore, esterases of LAB can impact on both the lipolytic and ester flavours of cheese. The impact of esterases of LAB on cheese flavour can be controlled by manipulating the amount of the esterase, by regulating alcohol availability and/or by increasing the mono- and diglyceride composition of milk fat. In addition, esterification may play a role in ester synthesis in hard cheeses (e.g. Italian type) where water activity is low.

The antimicrobial properties of milkfat after partial hydrolysis by calf pregastric lipase

Studies on the kinetic characteristics of calf pregastric lipase (EC 3.1.1.3) have shown that it preferentially releases short chain fatty acids (SCFAs) from bovine milkfat. The released fatty acids form mixed micelle structures. The aim of this investigation has been to test whether hydrolysed milkfat is antimicrobial, and how the state of the emulsion alters the bactericidal or bacteriostatic effects. Partial hydrolysis of milkfat by pregastric lipase was carried out in two types of emulsion systems, containing either Triton X-100 or casein/lecithin, plus milkfat in citrate/phosphate buffer (pH 5.0–6.0). The concentrations and compositions of fatty acids were determined by gas chromatography. The minimum percentages of hydrolysed milkfat which affected growth and survival of selected Gram-positive and Gram-negative bacteria were measured. The bacterial experiments were repeated using pure fatty acids at similar concentrations. Lauric acid (C12:0) was found to be the most potent bactericidal fatty acid against Enterococcae (Gram-positive), and caprylic acid (C8:0) was the most potent against coliforms (Gram-negative). Use of Triton X-100 for milkfat emulsification provided a more compatible medium for studying bacterial growth in the hydrolysed milkfat than did use of casein/lecithin. The results also show that the antimicrobial effects of individual fatty acids released from hydrolysed milkfat were at least additive and suggest that hydrolysis of milkfat may be a significant factor in controlling growth of organisms imbibed with food in pre-weaned animals. The amount of pregastric catalyzed triglyceride hydrolysis in the digestive tract is sufficient to produce an antibacterial concentration of fatty acids and monoglycerides.

Hydrolysis of Milk Fat By Lipase in Solvent‐free Phospholipid Reverse Micellar Media

ABSTRACTButterfat was hydrolyzed with lipases contained in lecithin reverse micelles. The influence of pH, temperature, molar ratio of surfactant to water (R) and surfactant concentration on the hydrolytic reaction indicated linear, quadratic, and interactive effects for reaction systems mediated by R. javanicus and C. rugosa lipases. The initial reaction rate was dependent on reaction parameters; however, the degree of hydrolysis was independent of pH. Both enzymes exhibited high thermal stability. The content and composition of milk fat hydrolysates prepared by R. javanicus lipase were most influenced by reaction temperature and R. The optimum conditions for production of free fatty acids, monoacyl‐glycerols, diacylglycerols and specific regio‐isomers were defined.

Some biochemical aspects of the anaerobic degradation of dairy wastewater

Low rate of anaerobic degradation together with inhibition problems caused by components such as milk fat and proteins were found to be reasons for restricted activity of high-rate anaerobic reactors operated with dairy effluent. The present research was aimed to investigate the influence of some relevant compounds, such as casein and milk fat and their degradation compounds, on process efficiency. Methanogenic activity and ATP content of the sludge were used as major follow up criteria for evaluating the influence of the tested compounds on process efficiency. It was found that casein was not degraded by anaerobic cultures which were not pre-acclimated for this compound. On the other hand, cultures acclimated to casein, utilized it very efficiently. Amino acids typical for casein degradation were also used efficiently with no inhibitory effects under the test conditions and with no need for culture pre-acclimatization. Milk fat was found to be a major cause for inhibition of methanogenic activity. It was found to have an immediate influence on reducing gas production rate in reactors to which it was added. Milk fat was also found to have long term effects: sludge pre-exposed to milk fat exhibited reduced methanogenic activity when tested in medium free of milk fat. Milk fat also reduced the ATP concentration in the sludge, indicating reduction of its total physiological activity. Oleic acid, which is a major derivative of milk fat hydrolysis was found to have inhibitory effects on methane production and on ATP concentration. According to the results of the present research, it would be advisable to treat dairy effluents by anaerobic digestion only after reduction of the milk fat concentration below 100 mg/L, and after careful acclimatization of the digester culture to casein.

Hydrolysis of fats and oils with moist oat caryopses

AbstractTo improve the economic feasibility of hydrolyzing fats and oils with moist oat caryopses, various factors affecting the efficiency of the process were studied. Caryopses produced with an impact‐type dehuller exhibited greater lipase activity than those produced by a wringer‐type dehuller. Abrasion of oat caryopses against each other in a fluidized bed released particles rich in lipase. Such lipase concentrates could be added to moist caryopsis reactors to speed fat hydrolysis. Beef tallow, lard, soybean oil and crambe oil were hydrolyzed more efficiently than corn oil, castor oil and milk fat. The poor hydrolysis of castor oil was attributed to the formation of esters with the hydroxy group of ricinoleic acid, and the hydrolysis of castor oil was increased by dilution of the substrate with hexane. Diglycerides inhibited the hydrolysis and accounted for the slower hydrolysis of corn oil. Hydrolysis of milk fat by moist oat caryopses resulted in preferential hydrolysis of C6 to C10 acids. Erucic acid was released from crambe oil at significantly slower rates than the other acyl groups. High conversions of fats and oils to free fatty acids could be attained by (i) exposing the fats and oils to two to three lots of moist caryopses, (ii) the use of special oat varieties with elevated lipase content, (iii) the addition of oat lipase concentrates to moist caryopsis reactors, and (iv) dilution of the substrate with hexane. Estimates of the cost of producing free fatty acids with these processes indicated that the first three should be profitable. Growth ofClostridium sporogenes spores could not be demonstrated in caryopsis reactors. During the incubation of moist oat caryopses immersed in oil, the free fatty acid content of the internal caryopsis lipid increased only slightly, but there were changes in its fatty acid composition.

Lipase-catalyzed hydrolysis of milk fat in lecithin reverse micelles

Reverse micelles formed by soybean lecithin in isooctane were used as a reaction medium for the lipase-catalyzed hydrolysis of milk fat. The pH value for the maximum enzyme reaction rate was 6.5, which is similar to that in aqueous solutions and AOT reverse micelles. The optimum temperature for enzyme activity was 55°C with an activation energy of 7.5 kcal/mol. The optimum temperature was 20°C higher than that in aqueous solutions and AOT reverse micelles. The hydrolysis reaction does not appear to follow Michaelis-Menten kinetics and it is suggested that the reaction rates are diffusion controlled. The dependence of the reaction rate on the molar ratio of water to surfactant concentration ( R value) showed a bell-shaped curve, with the maximum rate found at R=11. Enzyme activity varied little with surfactant concentration at a constant R value for up to 50 mmol dm −3 lecithin. Higher surfactant concentrations led to a decrease of enzyme activity, suggesting possible inhibition effects from lecithin. The composition of free fatty acids released during the reaction, which is responsible for the flavour of lipolyzed milk fat, can be manipulated by controlling the reaction conditions in the reverse micellar system. To promote the release of short-chain fatty acids, a higher concentration of enzyme, a higher R value, or a modest reaction temperature (45°C) should be used.

Use of Candida rugosa lipase immobilized in a spiral wound membrane reactor for the hydrolysis of milkfat

Lipase from C. rugosa was immobilized by adsorption on flat sheets made of microporous polypropylene and placed into a reactor in a spiral wound (axial-annular flow) configuration. Equations based on a Ping Pong Bi Bi kinetic mechanism are used to model the effect of the water content of the feed emulsion on the rate of hydrolysis of milkfat triglycerides. The kinetic data are consistent with a mechanism which assumes that deacylation of the enzyme is the rate-limiting step of the hydrolysis reaction. The optimum pH for hydrolysis is ca. 7.0. Operation of the reactor yielded relatively high conversions at short space times, thus indicating that this type of reactor is an interesting option for use on an industrial scale for the production of lipolysed butteroil.

Enhancement of Release of Short‐Chain Fatty Acids from Milk Fat with Immobilized Microbial Lipase

ABSTRACT Candida cylindracea or Rhizopus arrhizus lipase was entrapped in polymer gels prepared from photo‐cross‐linkable resin prepolymers. The immobilized enzyme was used in milk fat hydrolysis and effective in enhancing the release of short‐chain fatty acids compared with free enzyme. The molar percentage of short‐chain fatty acids (butyric acid to capric acid) released in the reaction increased significantly after enzyme immobilization. The gel composed of hydrophobic long‐chain prepolymer gave the highest increase, with 5.9‐fold and 4.5‐fold increases for C. cylindracea and R. arrhizus lipase, respectively. Difference in substrate diffusion rate between milk fat triglycerides may be responsible for this behavior.

Hydrolysis of Milk Fat with Lipase in Reversed Micelles

ABSTRACTEnzymatic hydrolysis of milk fat was studied in a reversed‐micelle system consisting of lecithin, water (1% total volume) and butteroil. Candida cylindracea lipase entrapped in the water pools of reversed micelles hydrolyzed surrounding triglycerides. The optimum temperature for enzyme activity was 55°C with an activation energy of 15.4 kcal/mole, while maximum enzyme activity was observed between pH 4 to 6. The molar ratio of water to surfactant (R value) in the system influenced enzyme activity with maximum activity at R = 10. Enzyme activity also increased with increasing surfactant or enzyme concentration.

Effect of Time of Onset of Rapid Cooling on Bovine Milk Fat Hydrolysis

Milk samples (n = 1818), collected from 261 cows, were used to evaluate effect of time of onset of rapid cooling on milk fat hydrolysis. Aliquots, either cooled immediately or after 1h at ambient temperarure, were analyzed for FFA content after storage at 4°C for 48h. Acid degree values for immediately cooled aliquots were higher than delayed cooled aliquots following adjustment for days in milk, days pregnant, milk yield, and SCC (.76 vs. .71). Correlation of .89 existed between aliquots; however, within a sample, aliquot response on cooling was variable in direction and magnitude. Immediate cooling enhanced lipolysis associated with increased days pregnant, decreased milk yield, and increased SCC. Consequently, effect of immediate cooling on milk fat hydrolysis was greater in milk collected from late lactation cows.