Proteolysis is an important biochemical process during cheese ripening that impacts flavor and texture. It occurs in three stages: premanufacture, coagulation, and ripening. During coagulation, rennet cleaves K-casein, reducing micelle stability. In ripening, indigenous and starter bacterial enzymes further degrade proteins into peptides, amino acids, and other flavor compounds. Proteolysis contributes to flavor, sapid compound release, pH changes, and texture modification. Researchers assess proteolysis using methods like solubility, extraction, fractionation, and analysis of compounds like amino acids and reactive groups.
This presentation gives you the overall information of how enzymes are used in dairy industry and detailed explanation on production of cheese. Refer to the references for more detailed information.
This presentation gives you the overall information of how enzymes are used in dairy industry and detailed explanation on production of cheese. Refer to the references for more detailed information.
Enzymes are a biological substance that accelerates the rate of various biochemical reactions in a living organism without being used up in the reaction. Their role in food processing has also been recognized for many centuries. Even before this knowledge about enzymes, they have been used in a number of processes such as the tenderization of meat using papaya leaves, soy sauce preparation, curd or cheese making, baking, brewing, etc. From animals to plants to microbial sources, enzymes may be extracted from any living organisms. Of the hundred or so enzymes being used in industries, more than half are of microbial origin. In the food industry, microbial enzymes have been extensively used to increase the diversity, variety, and quality of food. Microorganisms as an enzyme source are always preferred over other sources as large amounts of enzymes can be produced from them in a controlled manner that is also faster and cheaper. Moreover, the minimum of potentially harmful content is present in microbial enzymes in comparison to those of plants and animals. This chapter includes microbial enzymes used in food processing and the food industry, their physicochemical and biological properties, recent developments, and future prospects.
Casein Hydrolysates and Coprecipitates.pptxAakash Gill
This presentation deals with the technology of casein hydrolysates and coprecipitates. For more useful presentations, visit my blog at aakashgill1.wordpress.com
Enzymes are a biological substance that accelerates the rate of various biochemical reactions in a living organism without being used up in the reaction. Their role in food processing has also been recognized for many centuries. Even before this knowledge about enzymes, they have been used in a number of processes such as the tenderization of meat using papaya leaves, soy sauce preparation, curd or cheese making, baking, brewing, etc. From animals to plants to microbial sources, enzymes may be extracted from any living organisms. Of the hundred or so enzymes being used in industries, more than half are of microbial origin. In the food industry, microbial enzymes have been extensively used to increase the diversity, variety, and quality of food. Microorganisms as an enzyme source are always preferred over other sources as large amounts of enzymes can be produced from them in a controlled manner that is also faster and cheaper. Moreover, the minimum of potentially harmful content is present in microbial enzymes in comparison to those of plants and animals. This chapter includes microbial enzymes used in food processing and the food industry, their physicochemical and biological properties, recent developments, and future prospects.
Casein Hydrolysates and Coprecipitates.pptxAakash Gill
This presentation deals with the technology of casein hydrolysates and coprecipitates. For more useful presentations, visit my blog at aakashgill1.wordpress.com
Several species of amebae are capable of colonizing the human gastrointestinal tract but, in contrast to Entamoeba histolytica, are not considered pathogenic. The nonpathogenic intestinal amebae include several Entamoeba species (E. coli, E. hartmanni,
Cottage cheese is a curdled milk product with a mild flavor and a creamy, heterogenous, soupy texture. It is made from skimmed milk by draining curds, but retaining some of the whey and keeping the curds loose
Lecture for the general student (third year) at faculty of veterinary medicine, Benha university. the lecture was taken on 20.2.2020. it presented a summary in cheese technology including some faults occur during storage and manufacture. in addition the nutritive value of cheese.
Cheese is a very popular food produced worldwide from the milk of ruminants using a combination of physical treatments. Key milk components for the transformation of milk into curd are casein and calcium. The majority of cheese varieties are based on the curd of modified casein micelles that result from the enzymatic rennet clotting of milk in the presence of calcium ions. The remarkable ability of the spontaneous syneresis of rennet-induced curds can be adjusted to the desired level by biological acidification, cutting, stirring, heating, pressing and salting in order to achieve the desired level of water removal in the form of whey. The mode of curdling (acid or rennet coagulation), the conditions, and the combinations of curd treatments result in numerous cheese varieties with different appearances, textures, flavors and shelf lives. Moreover, most of them are kept under specific temperature and humidity conditions to ripen for a short or a considerable amount of time. The classification of cheese varieties is not unambiguous and can be based on various criteria. For example, cheeses can be classified according to their moisture content related to yield and shelf life or according to specific features related to the treatments applied during cheesemaking and ripening. During ripening, the main solid constituents of young cheese—fat and caseins—undergo changes that increase the concentration of small size compounds in cheese—such as peptides, amino acids, small volatile molecules—control moisture loss and configure textural properties. In particular, the compounds of mature cheese flavor result from complicated biochemical pathways that take place during cheese ripening or even storage.
Industrial production of lactic acid & monosodium glutamateWishal Butt
Widely occurring organic acid
Applications in industry, food , textile, pharmaceutical
White in solid
Extremely soluble
DISCOVERY:-
In 1780 discovered by a Swedish chemist SCHEELE by sour milk.
1839, FERMY from sugar , milk , starch , dextrin.
1857 , PASTEUR, discovered that it is not a component of milk , but a metabolite that certain microorganisms produced by fermentation.Monosodium glutamate (MSG, also known as sodium glutamate) is the sodium salt of glutamic acid,
one of the most abundant naturally occurring non-essential amino acids.
It is commonly known as Ajinomoto.
It is found naturally in tomatoes, cheese and other foods.
It is used in the food industry as a flavor enhancer.
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One of the top cities of India, Hyderabad is the capital of Telangana and home to some of the biggest companies. But the other aspect of the city is a huge chunk of population that is even deprived of the food and shelter. There are many people in Hyderabad that are not having access to
Ang Chong Yi Navigating Singaporean Flavors: A Journey from Cultural Heritage...Ang Chong Yi
In the heart of Singapore, where tradition meets modernity, He embarks on a culinary adventure that transcends borders. His mission? Ang Chong Yi Exploring the Cultural Heritage and Identity in Singaporean Cuisine. To explore the rich tapestry of flavours that define Singaporean cuisine while embracing innovative plant-based approaches. Join us as we follow his footsteps through bustling markets, hidden hawker stalls, and vibrant street corners.
At Taste Of Middle East, we believe that food is not just about satisfying hunger, it's about experiencing different cultures and traditions. Our restaurant concept is based on selecting famous dishes from Iran, Turkey, Afghanistan, and other Arabic countries to give our customers an authentic taste of the Middle East
2. Introduction
Proteolysis is probably the most important biochemical event during the ripening of most
cheese varieties, with a major impact on flavor and texture.
Division of proteolysis
in Cheese
Premanufacture Coagulation Ripening
3. Division of Proteolysis in Cheese
Premanufacture:
There are two main causes of proteolysis in cheese milk premanufacture:
a. Microbial
b. Indigenous milk proteinases.
Milk comes from the cow, contains many proteinases, the principal one being plasmin, which
hydrolysis
a. β-casein to γ-caseins and proteose peptones.
b. αs2-casein rapidly hydrolyzed, but the products have not been identified.
c. αs1-Casein is hydrolyzed slowly; g-casein may be one of the products.
d. Plasmin has little effect on k-casein,
Coagulation:
Rennet coagulation of milk involves proteolysis with formation of Para casein and NPN.
Rennet coagulation is a two-stage process
1. The first involving the enzymatic formation of para-casein and peptides
2. The second stage involving the precipitation of para-casein by Ca2+ at temperatures >20°C
4. Primary Phase of Rennet Action
Proteolysis occurs during the primary phase of rennet action, that this proteolysis was complete
before the onset of coagulation.
Only K-casein is hydrolyzed during the primary phase of rennet action, the cleavage site being
Phel05-Metl06
Hydrolysis of K-casein by chymosin during the primary phase of rennet action releases:
Highly charged,
Hydrophilic-terminal segment of K-casein
Zeta potential(ZP) of the casein micelles is reduced: ZP is potential difference b/w the dispersion
medium and stationary layer of fluid attached to the dispersed particle
Protruding peptides (hairs) are removed from their surfaces,
Destruction of the principal micelle-stabilizing factors (electro-satic and steric) and their colloidal
stability
5. Factors affecting hydrolysis of K-Casein
Factors
Organic
acids
• Polyprotic acids, especially EDTA, citrate, and phytate, prevent or inhibit the
rennet coagulation of milk, undoubtedly due to the chelation of Ca 2+.
• Several fatty acids also retard or prevent rennet coagulation.
Degree of
Glycosylatio
n
• Efficiency of casein as a substrate for chymosin decreases with the degree of
glycosylation.
Heat
Treatment of
milk
• It has long been recognized that heat treatment >65"C adversely affects the rennet
coagulation of milk if the exposure is of sufficient duration.
• If heat treatment is very severe (>90°C for 10 min), the milk fails to coagulate on
renneting.
pH • Isolated K-casein is optimally hydrolyzed at pH 5.2 to 5.5
• The pH optimum for the first stage of rennet action in milk to be -6.0 at both 4 and
30°C.
Temperature • The optimum temperature for the coagulation of milk by calf rennet at pH 6.6 is
near 45°C.
Ionic
Strength
• Increasing ionic strength reduces the rate of hydrolysis.
• Reported by Kato that
6. Secondary (Non-enzymatic) Phase of Coagulation:
Proteolysis of K-casein reduces the zeta potential and steric stabilization of the casein micelles.
When approximately 85% of the K-casein has been hydrolyzed, the casein micelles begin to aggregate.
Ripening:
• During ripening, a multitude of chemical and biochemical changes occur in which the
principal constituents of the cheese-proteins, lipids, and residual lactose-are degraded to
primary products and later to secondary products.
Among the principal compounds that have been isolated from several cheese varieties
are:
• Peptides.
• Amino acids.
• Amines.
• Acids.
7. • Thiols.
• Thioesters (from proteins).
• Fatty acids.
• Methyl ketones.
• Lactones.
• Esters (from lipids).
• Organic acids, especially lactic acid but also acetic and propionic acids.
• Carbon dioxide, esters, and alcohols (from lactose).
These compounds are responsible for the characteristic flavor of various
cheeses.
8. Significance of Proteolysis
Proteolysis contributes to cheese ripening in at least four ways.
1. A direct contribution to Flavor via, e.g., amino acids and
peptides, ( Hemme et al. 1982)
2. Greater release of sapid compounds during mastication.
( McGugan et al. 1979)
3. changes in pH via the formation of NH3.
4. changes in texture from breakdown of the protein network,
increase in pH and greater water binding by the newly formed
amino and carboxyl groups.
9. Proteolytic Agents in Cheese
Agents
Rennet/Rennet substitute e.g. Chymosin, Pepsin, Microbial
Proteinases
Indigenous milk enzymes Especially important for cheeses subject to
high cook temp. like raw milk cheeses and
pasteurized milk cheeses
Starter bacteria and their enzymes Released after cells lyse and include
bacteria
Enzymes from secondary starters Include bacteria(propionic acid bacteria),
yeasts, molds
e.g. Penicillium roqueforti, Penicillium cand
idum
Nonstarter bacteria Organisms that survive pasteurization of
cheese milk or gain access to paateurized
milk or curd during manufacture; cells lyse
and release enzymes
10. Assessment of proteolysis in cheese
Approaches Method
Solubility • Water, buffers near pH 4.5; 5% NaCI; 2, 5, 10, or 12% TCA; 5% phosphotungstic acid; 2.5%
sulphosalicilic acid; picric acid; ethanol; ethanol-acetone; chloroform- methanol.
Extraction
method
• 14.4 g acetic acid, 34 g sodium acetate, 3 H20, 11.75 g NaC1, and 2.23 g CaCI2 (anhydrous)/L.
The pH of this solution is 5.5 (Dahl-berg and Kosikowski)
• 137 mol CaCI2 and .684 mol NaCI/L and adjusted to pH 5.1 (Noomen and Visser)
• To separate the fat and aqueous phases, centrifuged cheese (presumably grated) at 30,000 ×
g for 25 min (temperature not stated).(McGugan et al.)
• Chloroform extraction of an aqueous extract of cheese had been used earlier by Raadsveld to
concentrate bitter peptides from Gouda cheese,
• Chloroform-methanol (2:1) was used by Visser et al. to isolate bitter peptides from casein
hydrolysates.
• Rank et al. (182) report that more N is consistently extracted by chloroform-methanol than by
direct water extraction.
Fractionation
of Extracts
• Several protein precipitants, especially TCA (2 to 12%), have been used to precipitate medium
and small peptides in the water- or pH 4.5- soluble extract of cheese.
• Use 70% ethanol instead of 12% TCA; gives very clean fractionation of peptides than TCA
Several approaches have been adopted to monitor quantitatively proteolysis in cheese
during ripening:
11. • Formation of amino acid N is commonly used as an index of ripening and precipitation of
water extracts with a mixture of phosphotungstic acid (PTA)-H2SO4 has been widely used too
prepare an amino N fraction (71, 106, 160, 186, 208, 225).
• Hickey et al. extracted the free amino acids from cheese by macerating the sample (10 g) with
33 ml .15 M Ba(OH) 2 and 33 ml .14 M ZnSO,
Formation of
reactive groups
• Trinitrobenzene sulphonic acid, fluorescamine, or ninhydrin, these reagents can be applied to
cheese or fractions thereof; when applied to cheese, they have the obvious advantage of
measuring a direct consequence of proteolysis (e.g., formation of amino groups).
• Absorbance of UV light has been widely used to monitor proteolysis in cheese;
Chromatograph
y
Paper chromatography
• Used for free fatty acid
Thin layer chromatography
• Used for free fatty acid but more commonly for resolution of small peptides
Gel permeation chromatography
• Application of gel filtration to cheese ripening
12. • Too slow to be suitable for samples.
• Effective for resolving water soluble fraction
• Homogenous fractions are not obtained due to aggregation of peptides
Hydrophobic chromatography
• It was used to fractionate water-soluble N into two well
resolved fractions on phenyl or octyl sepharose
• Isolated bitter peptides
High performance liquid chromatography
• Gives promising results on fractionation of cheese peptides
• Suitable method for large water insoluble peptides in cheese
Ion exchange chromatography
• Suitable for analysis of free fatty acids found in cheese
Silica gel chromatography
• Used to fractionate bitter peptides from rennet treated casein
Electrophoresis
• Used for monitoring primary proteolysis in cheese
• First experiment was done by using paper electrophoresis on several cheese
varietes