EXPLORING THE MILK-CLOTTING PROPERTIES OF EXTRACTS FROM Bromelia pinguin FRUIT

Abstract

Plants represent an attractive source of milk-clotting proteases with potential use for chymosin substitution in cheesemaking process. A crude enzymatic extract from B. pinguin fruit showed capacity to clot milk efficiently in a short time. It showed a maximum milk-clotting activity around 4 U/mL in the range of 70-80 ºC. This value indicated that one mL of the extract was capable to clot around 400 mL of milk in 40 min at the specified condition. B. pinguin extract presented only 25% of its maximum activity under standard temperature (30-35 ºC) for cheese-making. Proteases inhibitors indicated that cysteine and serine proteases were present in the extract and could be responsible for the milk-clotting activity found. SDS-PAGE analysis of casein hydrolysis indicated that proteases in B. pinguin extract were more proteolytic than chymosin. The high presence of milk-clotting proteases in B. pinguin fruit offers an alternative new source of proteases for biotechnological processes.

Improvement of camel milk-clotting: Usefulness of crude extract from green pods of carob (Ceratonia siliqua. L) as a substitute for commercial rennet

“…Similar results were obtained by Moreno-Hernández et al (44) who found that crude extract from Bromelia pinguin L. fruit showed an efficient capacity to clot milk in a short time with a maximum MCA of around 3.99 U/ml.…”

“…In the cheese industry, the coagulation enzymes used are always sought to have a high coagulant activity and a low proteolytic activity (48), so CCE seemed to be the best because excessive proteolysis can lead to a decrease in cheese yield due to loss of peptides in the whey and defects in taste such as bitterness and texture of the ripened cheese (49). The PA values in this study were lower than those of other studies such as that of Withania coagulans fruit extract (30) and Bromelia pinguin fruit extract (44) with 1.06 U/mg-and 2.0 U/mg respectively. The MCA/PA ratio is one of the most important properties of the enzymes used in cheese making, which is the index of coagulation efficiency and suitability of the extract to be used as a substitute for rennet (50).…”

“…During different incubation times of camel caseins with CCE, there is a reduction in the intensity of major protein bands, indicating the hydrolysis of casein proteins. The milk clotting properties of proteases are dependent on their activity and hydrolysis preference for κ-casein compared to other milk proteins during the early stages of milk coa-gulation (44). Moreover, the primary phase of rennet action implicates the enzymatic hydrolysis of κ-casein, while the secondary phase involves the aggregation of rennet-altered micelles into the gel, its proteolytic specificity of milk coagulation (38).…”