Protection of microbial cells from acidic degradation

Abstract

A simple cellulose sulphate based microencapsulation technology has been applied to encapsulate bacterial or other microbial cells, which produce and release digestive enzymes and thereby provides an acid resistant shelter for these microbial cells. Surprisingly, the resulting spheres were found to provide sufficient protection for encapsulated cells from treatment with aqueous acidic solutions. Thereby the cellulose sulphate microencapsulated cells, such as probiotics are now enabled to survive passage, for example, through the stomach after consumption by a human or animal with a higher survival rate than those not within a microcapsule. After passing the stomach these cells are delivering products produced by them, e.g. enzymes or other nutrition factors. This technology therefore proves to be very useful in providing digestive or otherwise beneficial enzymes and / or of living microbial cells, into the lower gastrointestinal tract, where they could confer their health benefit to the host.

Description

FIELD OF THE INVENTION[0001]The invention refers to a (simple) cellulose sulphate based microencapsulation technology which has been applied to encapsulate bacterial or other microbial cells which produce and release digestive enzymes and thereby provides an acid resistant shelter for these microbial cells. Surprisingly, the resulting spheres were found to provide sufficient protection for encapsulated cells from treatment with aqueous acidic solutions. Thereby the cellulose sulphate microencapsulated cells, such as probiotics are now enabled to survive passage, for example, through the stomach after consumption by a human or animal with a higher survival rate than those not within a microcapsule. After passing the stomach, these cells are delivering products produced by them, e.g. enzymes or other nutrition factors. This technology therefore proves to be very useful in providing digestive or otherwise beneficial enzymes and / or of living microbial cells, into the lower gastrointesti...

AI Technical Summary

Benefits of technology

This patent describes a way to protect living microbial cells, like probiotics, from damage in acidic environments and allow them to pass through the digestive tract. The method involves using a specific microencapsulating material to create macroporous capsules that can withstand treatment with acidic solutions and intestinal fluids. The encapsulated cells remain viable and metabolically active, and can be used in the food industry to improve weight gain and food utilization in animals. The technology solves the problem of poor cell survival in dietary products and food additives.

Problems solved by technology

A lack of proteases can cause incomplete digestion that can lead to allergies and the formation of toxins.

Simply swallowing additional amounts of digestive enzymes might not be the ideal solution, because the exposure to stomach acid when passing through the stomach might have a detrimental effect to the enzymes.

Additional problems in providing enzymes as a food supplement are the taste of such enzymes, some of them cause a “burning sensation” in the mouth, and their sensitivity towards moisture.

Non-encapsulated enzymes have been reported to lose their potency when they are exposed to normal air humidity, they therefore also cannot be taken as a drink or be taken as ingredient of a moist meal, unless added just before consumption.

This can lead to irritation.

Sometimes if enzymes are taken in a drink, which gets to the upper lip, proteases can linger and can cause a rash there.

Pancreatic enzymes are not stable at wide ranges in pH or temperature and are destroyed by stomach acid.

All these stresses result in death of a significant percentage of these cells.

This technique however may not be suitable for all food product applications because, firstly, the residual oil in the encapsulated material may be detrimental to texture and organoleptic characteristics, and may not be suitable for the development of low-fat dairy products.

Secondly, the residual oil, emulsifier and surfactant in the encapsulated material can be toxic to live microbial cells and may interact with sensitive food components.

However, the encapsulated microbial cells did not show a significantly increased survival rate when subjected to low pH and high bile salt conditions during in vitro tests.

It turned out that Lactobacillus acidophilus is more sensitive than Bifidobacterium, but that the encapsulation did not protect the microbial cells from being degraded by aqueous acidic solutions (Sultana et al.

The overall survival rates, however, were higher at pH 3.0 also for the encapsulated cells indicating that the effects of acidic stress cannot completely be prevented.

The big problem with this process is that it yields products with poor shelf-life (even when refrigerated) and poor survival in the stomach—all the CFU, literally 99.99%, get killed by stomach acid.”

While this system provides one solution to provide viable probiotics to customers, it is however not suitable for all uses as a food ingredient, as it is generating rather large capsules, which need to be swallowed intact, and may not be bitten open.

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