Traditional Coagulants

  • | user2 |
  • Viewer: 1189

Traditional Coagulants ,Coagulation of milk is the main step in the manufacture of cheese and can be achieved

by a number of proteolytic enzymes from various sources, such as different animal species, microbial proteinases and proteinases extracted from fruits and plants. Calf rennet is still the most commonly used enzyme in cheese producing. However, the increasing consumption of cheese and coupled with a world shortage of calf rennet have encouraged a search for alternative milk coagulants.

Extraction of traditional coagulant

Traditional coagulant is extracted from the stomach of a mammal or more usually from the fourth stomach of a calf. In the lack of commercial preparations of rennet smallholders may get the coagulant (rennin, pepsin or chymosin) from calves, goat kids or from older fodder-eating bovines.

A crude rennet extract may be obtained from the fourth stomach (abomasum) of goat kids or calves when they are about four weeks old. Male goat kids or calves that have been fed on milk and that are not needed for breeding are usually used. To obtain the rennet, the washed fourth stomach of the kid or calf is sliced into strips which are extracted in a sodium chloride (12–20% salt) solution. This salt solution of rennet enzymes and abomasum strips is mixed well and allowed to settle for two to three days at room temperature. The mixture is then filtered through a coarse sieve and a fine mesh (muslin) cloth. Filtering through muslin cloth should be repeated a few times to obtain a clear filtrate. A pinch of boric acid is usually added to the filtrate as a preservative. This crude rennet extract may be used for producing cheese at rates that will coagulate milk in about 35 minutes.

Young calves may not always be available so an alternative source of a milk coagulating enzyme, pepsin, is the abomasum of adult cattle, sheep or goats. commonly the abomasa can be obtained in plentiful supply from abattoirs. To obtain a crude extract of bovine pepsin the abomasum is washed and then cut open. The folding of the abomasum mucosa or lining tissue contain the bovine pepsin. An adult cow or ox will yield about 500 g of mucosa. A liter of a solution containing sodium chloride (150 g), calcium chloride (40 g) and acetic acid (10 ml) is added to the finely chopped mucosa in a glass jar or beaker and mixed well. The mixture is allowed to remain for about 24 hours and then is filtered through a muslin cloth until a clear filtrate is obtained. This extract can be stored at about 25 °C for 5–6 weeks without any significant loss in milk coagulating strength. About 100 ml of the extract are required to coagulate 20 liters of milk in 30–40 minutes. The rennet take from a young milk-fed calf contains 88–94% rennin and about 6–12% pepsin, while the extracts from the adult bovine contain 90–94% pepsin and 6–10% rennin. There may be a different amount of pepsin in rennets depending on the age and feeding of the calf from which the extract is obtained. Over the past twenty years milk and cheese production in many developed countries has increased. For financial reasons calf rennets became scarce and this led to the investigation of others sources of a milk coagulating enzyme. Today, in addition to calf rennet, bovine rennet, bovine pepsin, porcine pepsin, calf rennet/bovine pepsin and calf rennet/porcine pepsin mixtures are used. A lot of work was dedicated to improve coagulum formation process using various proteolytic enzymes obtained from animal, plant, and microbial sources. In general, bovine chymosin is the most used enzyme in a cheese-making procedure. However, the availability of calf rennet has become limited due to the worldwide increase in cheese manufacture, coupled with the reduction in the murder of calves due to their low meat production, and has led to search for alternative milk-clotting enzymes, as suitable rennet substitutes.

Among different alternative coagulants applied in cheese production, aspartic proteases (APs) from flowers of thistle plants, particularly the Cynara L. genus, have gained special attention.

Vegetable curd

Thistle flowers are traditional coagulants that have been used for many years in southern Europe and northern Africa for cheese making. The flowers contain aspartic proteases (APs) with high milk-clotting and cheeses produced with the vegetable coagulants tend to have a creamier and softer texture and more intense odor and flavor compared with those made with commercial chymosin or calf rennet. 

Traditionally, to make cheese, the thistle flowers are harvested from ripe plants during June and July and dried under the shade before using. Preparation conditions have a significant effect on the proteolytic and milk-clotting activities of the coagulants.

Generally, it is necessary to store rennet at low temperatures to maintain its efficacy. Exposure to light also reduces rennet strength so it should be stored in light-proof or brown glass containers.

Some studies showed that cold storage (4 °C) of aqueous extracts obtained from thistle flowers are not a suitable method for their long-term storage because the milk-clotting activity and microbial quality of the extracts substantially reduced with the storage time. Thus, to improve shelf life and microbial quality of the thistle flowers extracts, lyophilisation has been suggested as a viable solution for long-term storage of the coagulants. Studies have confirmed that the lyophilisation step has no negative effect on functional properties of the thistle coagulants and cheese produced by the lyophilised coagulants have very similar organoleptic and textural characteristics to those produced by fresh coagulant extraction. 

The amount of rennet added to cheese milk is governed by the recipe which requires a suitable coagulum in a specified period of time. The recipe also specifies the acidity and temperature of the milk when the rennet is added.

 By,

ATAMAD technical support sector

 

Reference: 

1) Say, D. and GuzElEr, N., 2016. Production of Traditional Cheese Coagulant in Farmhouse and Coagulating Effect. Current Research in Nutrition and Food Science, 4(Special Issue), p.133.

2) O'Connor, C., 1993. Traditional cheesemaking manual. ILRI (aka ILCA and ILRAD).

3) Fguiri, I., Atigui, M., Sboui, A., Samira, A., Marzougui, C., Dbara, M., Hammadi, M. and Khorchani, T., 2021. Camel Milk-Clotting Using Plant Extracts as a Substitute to Commercial Rennet. Journal of Chemistry, 2021.

4) Alavi, F. and Momen, S., 2020. Aspartic proteases from thistle flowers: Traditional coagulants used in the modern cheese industry. International Dairy Journal, 107, p.104709.

 

FIND US ON SOCIAL MEDIA

GET IN TOUCH

03137765880
This email address is being protected from spambots. You need JavaScript enabled to view it.
03137765880
This email address is being protected from spambots. You need JavaScript enabled to view it.


Copyright © 2023 Atamad.com All right reserved


Website design and SEO services by Seohama team – Web hosting by Sarverhama


Copyright © 2023 Atamad.com All right reserved

Website design and SEO services by Seohama team – Web hosting by Sarverhama