Filipino cheese makers have to thank Dr. Susana Mercado of the National Institute for Molecular Biology and Biotechnology (UPLB-Biotech) for developing microbial rennet fermented in coconut paring cake.
Rennet is the enzyme that transforms milk into a solid sourced only from the stomachs of ruminants like cattle, goat, and water buffaloes.
With rennet, cheese does not deteriorate and can be kept in shelves for longer periods.
Mercado says that previously, cheese makers, particularly those who make cottage cheese from carabao milk, had to scramble for the stomachs of slaughtered cows and carabaos for their supply of rennet.
She, however, said that the “rennet extracted from older ruminants also makes the cheese taste bitter.”
The rennet derived from plants is no better since it is unstable and sometimes makes the milk, and the cheese, also bitter.
Liquid rennet lasts only three months.
Mercado said experience has taught cheese makers that the best rennet should come from nursing ruminants that have not digested a large amount of grass. “Their digestive enzymes are not as complex as the older ruminants,” she added.
The coconut paring cake used in fermenting microbial rennet comes from the clean coconut, stripped of the copra meal and oil, and it allows triple microbial activity conducive to producing rennet, she added.
Work on improved rennet production started in 1994 when Mercado was doing her thesis and was wracking her brain on determining the microbial agent needed to produce the prophyletic enzyme.
However, only good animal rennet could be used but even with the substance derived from the stomach of ruminants, microbial activity slows down substantially, making it impractical to use.
Mercado tried to use wheat bran as agent for fermentation but the economics of it was disadvantageous to research and so she had to look for a substitute, which she found in coconuts in spite of her earlier fears about the risks posed by aflatoxin.
“Our first alternative was copra meal. The result was good since there was higher microbial activity but we eventually settled for coconut paring meal,” she said.
“With it, we were able to produce good rennet but the limitations posed by our old instruments forced us to go for the solid substrain since it was difficult to transport the liquid rennet to those requesting for it in Iloilo. We had queries from Cagayan province, Cagayan de Oro and Zamboanga. I told them we could not send you the liquid rennet since LBC does not accept such shipments,” Mercado admitted.
Mercado’s pioneering work in mass producing granulated rennet is a significant development for a dairy industry burdened by competition from foreign countries.
She added that those who have used biotech rennet said that their yield increased and the texture of the cheese is better. Five grams of the granulated rennet is used to make cheese out of a liter of milk while 10 ml of liquid rennet is used for a liter of milk.
The National Dairy Authority (NDA) is in fact working on a plan to substantially reduce the importations of liquid milk and milk byproducts like cheese.
Up to 81 percent of the liquid milk requirements of the country come from overseas while local cheese producers hold an insignificant share in the cheese market.
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